HomeMy WebLinkAboutAppendix A - 2020 Newport Bay Watershed Biota MonitoringNewport Bay Watershed Biota Monitoring
Selenium and Organochlorine Compounds in Newport Bay Watershed Fish
and Bird Eggs, 2010 - 2020
October 29, 2020
County of Orange, California
Newport Bay Watershed Biota Monitoring
Document No. 4 i
Newport Bay Watershed Biota Monitoring
Project No: D32388
Project Manager: Gary Santolo
Author: Gary Santolo and Earl Byron
Jacobs Engineering Group Inc.
2485 Natomas Park Drive, Suite 600
Sacramento, California 95833-2937
United States
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provisions of the contract between Jacobs and the client. Jacobs accepts no liability or responsibility whatsoever for, or in respect of, any use of, or reliance
upon, this document by any third party.
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Contents
Acronyms and Abbreviations ............................................................................................................................. iii
Executive Summary ............................................................................................................................................. vi
1. Introduction ............................................................................................................................................... 1
2. Methods ..................................................................................................................................................... 1
2.1 Fish ............................................................................................................................................................. 2
2.2 Bird Eggs..................................................................................................................................................... 3
2.3 Laboratory Analyses ................................................................................................................................... 4
2.4 Statistical Analyses ..................................................................................................................................... 5
2.5 Screening-Level Analysis of Risk ............................................................................................................... 5
3. Fish Results ............................................................................................................................................... 6
3.1 Selenium ..................................................................................................................................................... 6
3.2 Organochlorine Compounds ..................................................................................................................... 12
3.1.4.2 Organochlorines ........................................................................................................................................ 22
4. Bird Egg Results ..................................................................................................................................... 27
4.1 Selenium ................................................................................................................................................... 27
4.2 Organochlorine Compounds ..................................................................................................................... 31
4.2.1 p,p’-DDE.................................................................................................................................................... 31
4.2.2 PCBs and Other Organochlorines ............................................................................................................ 35
4.2.3 Eggshell Thinning ..................................................................................................................................... 39
4.3 Summary of 2010 to 2020 Bird Egg Sampling and Data Analysis ........................................................... 39
5. Discussion ............................................................................................................................................... 44
5.1 Selenium in Fish ....................................................................................................................................... 44
5.2 Organochlorines in Fish ............................................................................................................................ 45
5.3 Selenium in Bird Eggs ............................................................................................................................... 45
5.4 Organochlorines in Bird Eggs ................................................................................................................... 46
6. Conclusions ............................................................................................................................................ 47
7. References ............................................................................................................................................... 48
Tables:
Table 3.1: Selenium Concentrations and Percent Moisture in Fish from the Newport Bay Watershed, 2020 ........ 7
Table 3.2: Organochlorine Compounds and Percent Lipids in Fish ...................................................................... 12
Table 3.3: Frequency of Fish Samples over the Selenium Target Concentration, 2010 to 2020 .......................... 21
Table 4.1: Selenium Concentrations in Bird Eggs Collected in May and June 2020 from the Newport Bay
Watershed. ............................................................................................................................................................. 27
Table 4.2: p,p’-DDE, Percent Lipid, and Shell Thickness in Bird Eggs from the Newport Bay Watershed, 2020 . 31
Table 4.3: Number of PCB Congeners Detected and Concentrations of Total PCBs (tPCBs), Total Aroclors
(tAroclor), Trans-nonachlor (the most commonly detected chlordane), and Toxaphene (μg/g ww) found in Bird
Eggs from Sample Locations in the Newport Bay Watershed, 2020. .................................................................... 35
Table 4.5: Number of Eggs Collected from the Newport Bay Watershed by Species and Year (2010 – 2020) ... 39
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Table 4.5: Frequency (percent of eggs) Equal to or over the Target Selenium Concentration of 8.0 μg/g (USEPA
2019) for Shorebirds, Piscivores, all Eggs in the Watershed, and all Eggs Excluding Eggs from BCGC from 2010
to 2020. .................................................................................................................................................................. 42
Figures
Figure 2.1: Newport Bay Watershed Sampling Locations, 2020 ............................................................................. 2
Figure 3.1: Selenium Concentrations in Fish Species by Location, 2020 ............................................................. 10
Figure 3.2: tDDTs in Fish by Location and Species ............................................................................................... 17
Figure 3.3: tPCBs Concentrations in Fish by Location and Species ..................................................................... 19
Figure 3.4: Selenium Concentrations in Fish by Location and Year, 2010 to 2020............................................... 20
Figure 3.5: Selenium Concentrations in Fish in the Newport Bay Watershed from 2010 to 2020 ........................ 21
Figure 3.6: Total DDT Concentrations in Fish by Location and Year, 2010 to 2020 ............................................. 23
Figure 3.7: Total PCB Concentrations in Fish by Location and Year, 2010 to 2020 ............................................. 24
Figure 3.8: Total DDT Concentrations in Fish (ng/g ww) and Year from 2010 - 2020 in the Newport Bay
Watershed. ............................................................................................................................................................. 25
Figure 3.9: Total PCB Concentrations in Fish (ng/g ww) and Year from 2010 - 2020 in the Newport Bay
Watershed. ............................................................................................................................................................. 26
Figure 4.1: Geometric Means and Ranges of Selenium Concentrations (μg/g dw) in Eggs Collected in 2020 by
Species ................................................................................................................................................................... 30
Figure 4.2: Geometric Means and Ranges of Selenium Concentrations (μg/g dw) in Eggs Collected in 2020 by
Sample Location .................................................................................................................................................... 30
Figure 4.3: Geometric Means and Ranges of p,p’-DDE Concentrations in Eggs by Species in the Newport Bay
Watershed, 2020 .................................................................................................................................................... 34
Figure 4.4: Geometric Means and Ranges of p,p’-DDE Concentrations in Eggs by Location in the Newport Bay
Watershed, 2020 .................................................................................................................................................... 35
Figure 4.5: Geometric Means and Ranges of tPCBs Concentrations in Eggs by Species in the Newport Bay
Watershed, 2020 .................................................................................................................................................... 38
Figure 4.6: Geometric Means and Ranges of tPCBs Concentrations in Eggs by Location in the Newport Bay
Watershed, 2020. ................................................................................................................................................... 38
Figure 4.7: Geometric Means and Ranges of Selenium Concentrations (μg/g dw) in Eggs Collected from 2010 -
2020 by Sample Location....................................................................................................................................... 41
Figure 4.8: Geometric Means and Ranges of p,p’-DDE Concentrations (μg/g ww) in Eggs Collected from 2010 -
2020 by Sample Location....................................................................................................................................... 43
Figure 4.9: Forster’s Tern p,p’-DDE Concentrations (μg/g ww) and Eggshell Thickness in Eggs Collected from
2010 - 2020 in the Newport Bay Watershed. ......................................................................................................... 44
Acronyms and Abbreviations
μg/L microgram(s) per liter
μg/g microgram(s) per gram
AMAV American avocet
AMCO American coot
ANOVA analysis of variance
BBS Back Bay Shellmaker Island
BCGC Big Canyon Golf Course
BCP Big Canyon Wash lower pond
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BCW Big Canyon Wash
BG bluegill
BLSK black skimmer
BNST black-necked stilt
CDFW California Department of Fish and Wildlife
CRP common carp
CRY crayfish
DDD dichlorodiphenyldichloroethane
DDE dichlorodiphenyldichloroethylene
DDT dichlorodiphenyltrichloroethane
dw dry weight
FHM fathead minnow
FOTE Forster’s tern
GLD goldfish
GM geometric mean
GSF green sunfish
IRWD Irvine Ranch Water District ponds
LMB largemouth bass
Jacobs Jacobs Engineering Group Inc.
KFH killifish
KILL killdeer
lw lipid weight
MDL method detection limit
mg/L milligram(s) per liter
MOU memorandum of understanding
μg Se/g microgram selenium per gram
MSF mosquitofish
MSS inland (or Mississippi) silverside
MWFB Museum of Wildlife and Fish Biology
ng/g nanogram(s) per gram
OCs organochlorines
PBGR pied-billed grebe
PCB Polychlorinated biphenyls
PCW Peters Canyon Wash
Physis Physis Environmental Laboratory
RSH red shiner
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SADC Santa Ana Delhi Channel
SADCL Santa Ana Delhi Channel (Lower)
SARWQCB Santa Ana Regional Water Quality Control Board
SDC San Diego Creek
Se selenium
SHPE shiner perch
tDDTs total of the o,p’- and p,p’-isomers of DDT and its breakdown products, DDE and DDD
TFS threadfin shad
TMDL total maximum daily loads
TOSM topsmelt
tPCBs total PCB congeners
UCI University of California Irvine
UNB Upper Newport Bay
USEPA U.S. Environmental Protection Agency
USFWS U.S. Fish and Wildlife Service
WEGR western grebe
WFVZ Western Foundation of Vertebrate Zoology
ww wet weight
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Executive Summary
The Santa Ana Regional Water Quality Control Board adopted an Organochlorine Compounds TMDL in 2011
and a Selenium TMDL in 2017 to address potential impairments related to these toxic contaminants in the
Newport Bay Watershed. Due to the potential for bioaccumulation of these contaminants, tissue-related targets
were incorporated into the TMDLs, including fish tissue and bird egg targets for selenium and fish tissue targets
for organochlorines. As a result, tissue monitoring was initiated in the Watershed beginning in 2010 for selenium
and in 2013 for organochlorines to better understand exposure and bioaccumulation of these contaminants in
the Watershed, and to assess compliance with TMDL targets.
Fish and bird egg samples were collected from various sites throughout the Watershed in May and June 2020. A
total of 76 fish tissue samples, including crayfish as fish surrogates when fish were not present, and 50 bird
eggs were analyzed for selenium and organochlorine compounds.
Fish Tissue
Consistent with previous years, most watershed fish tissue selenium concentrations exceeded the Newport Bay
Watershed Selenium TMDL (Se TMDL) fish tissue selenium target of 8.1 μg/g dw. Fish tissues collected from
Newport Bay had the lowest selenium concentrations. Highest fish tissue concentrations were observed in
samples from the Big Canyon Golf Course ponds, followed by San Diego Creek Basin 2 and lower Big Canyon
Wash, which is consistent with previous years.
Although selenium concentrations in fish tissues remain elevated, they declined for the period 2010 through
2019 when averaging all species at all sites over time, but trends varied by site and then concentrations
generally increased again in 2020. As a result, the period 2010 through 2020 does not show a significant decline
in fish tissue selenium concentrations in the combined San Diego Creek sites, although individual sites showed
improvement. In a separate Newport Bay drainage, the Big Canyon Wash sites showed the largest decrease in
fish tissue selenium concentration over the period of monitoring record.
None of the 76 fish tissue samples exceeded any organochlorine fish tissue targets except three shiner samples
from upper Newport Bay that exceeded the Bay wildlife target for DDTs.
Examining all years of record, DDTs in fish have shown a significant decline over time in the San Diego Creek
drainage as well as Big Canyon Wash sites, while PCBs in fish have declined in San Diego Creek sites but
significantly increased in Big Canyon Wash.
Bird Eggs
Five of the 50 bird eggs exceeded the Se TMDL target of 8 μg/g dw. The overall geometric mean of watershed
bird egg selenium concentrations (excluding eggs collected from Upper Newport Bay) was 5.5 μg/g. The
geometric mean of all eggs was 4.7 μg/g.
Selenium concentrations varied within and among species, and among sites. UCI was the only site where there
has been a significant decreasing trend in bird egg selenium concentrations. No significant decrease has been
observed on a watershed-wide scale. Eggs collected from all sampling locations had geometric mean
concentrations below 8 μg/g and eggs from UCI and Upper Newport Bay were the lowest in the Watershed.
Generally, eggs collected from freshwater areas had higher selenium concentrations than those collected from
Newport Bay. Overall, selenium concentrations in eggs collected from the Watershed were not at concentrations
that would be expected to affect reproduction or embryo effects.
p,p’-DDE was detected in all eggs, and concentrations varied within and among sites. Concentrations in eggs
from IRWD ranged from 0.2 to 4.7 μg/g ww. Concentrations in the higher end of the range were due to western
grebe eggs, which had the highest p,p’-DDE concentrations of all eggs collected. Nineteen eggs had a
concentration above 1.6 μg/g, the lowest literature-derived threshold associated with eggshell thinning in brown
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pelicans. However, there was no significant relationship between eggshell thinning and p,p’-DDE except in
Forster’s terns where there was a significant negative relation between eggshell thickness and p,p’-DDE
concentrations.
Similarly, PCBs were detected in all eggs, but all were at concentrations that were below literature-derived
thresholds for passerines, a group of birds with intermediate sensitivity to PCBs. Organochlorine concentrations
in egg collected from the Watershed were not at concentrations that would be expected to cause egg breakage
due to eggshell thinning or reproductive failure.
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1. Introduction
The 152-square-mile (97,280-acre) Newport Bay Watershed (Watershed) encompasses most of the urbanized
area in central Orange County, California. Fish and bird egg tissue monitoring was conducted from 2010 through
2020 with a goal of providing baseline data for use in the Total Maximum Daily Loads (TMDLs) for selenium and
organochlorines in the Watershed. Samples of target fish and bird eggs were collected from the freshwater
drainage sites and off-channel wetlands, as well as from the Upper Newport Bay (UNB), which is a California
State Ecological Reserve and serves as refuge, foraging area, and nesting area for two threatened and
endangered bird species. All fish species commonly sampled in the Watershed are non-native, invasive species
and samples usually were analyzed as composites of several individuals. Bird eggs were collected, and the
contents of eggs were analyzed individually. Biota sampling in the Watershed was coordinated with routine
County of Orange (County) water and sediment quality sampling.
San Diego Creek is the largest of the numerous creeks and channels that drain into Newport Bay, contributing
about 85 percent of the freshwater flow to the Bay. The largest tributary of San Diego Creek is Peters Canyon
Wash, draining the northern portion of the Watershed (Figure 2.1). The balance of freshwater input into Newport
Bay is primarily from Santa Ana-Delhi Channel, Big Canyon Wash, and other smaller drainages.
The Watershed has undergone profound changes in hydrology and land use during the past 150 years. Past
legal agricultural pesticide uses and industrial/commercial activities have left soils in parts of the Watershed with
elevated levels of organochlorine compounds (OCs) (CDFA 1985) including dichlorodiphenyltrichloroethane and
its analogs and isomers (collectively termed DDTs), chlordanes, toxaphene, and polychlorinated biphenyls
(PCBs) (SARWQCB 2011). Additionally, changes in hydrology and drainage patterns may be influencing
shallow groundwater enrichment with naturally-occurring selenium. These pollutants (in certain years including
trace metals) are collectively targeted by this monitoring effort.
Elevated levels of selenium have been measured in water, sediment, and biota in the lower parts of the
Watershed (Figure 2.1), especially near the historical Swamp of the Frogs area. Selenium can bioaccumulate in
aquatic food chains, thereby contaminating the diets of and potentially inducing reproductive effects in fish and
birds. Concentrations of 8 μg Se/g dry weight (dw) for bird eggs and 8.1 μg Se/g dw for whole-body fish tissue
for protection of fish and 5.0 μg Se/g dw for whole-body fish tissue for protection of piscivorous birds have been
adopted as protective targets in the Watershed (SARWQCB 2017, USEPA 2019). Numeric targets provided for
the TMDLs are divided into two categories with different fish tissue targets: one applies where the bird egg
target has been met, and the other applies where the bird egg target has not been met. If the bird egg target of 8
μg/g dw has been attained, a higher (less stringent) fish tissue target of 8.1 μg/g dw applies. This fish tissue
target serves as a protective target for fish (i.e., aquatic life), as a separate endpoint. The bird egg target serves
to protect shorebirds (i.e., aquatic-dependent wildlife). Where the bird egg target has not been attained, a lower
(more stringent) fish tissue target of 5 μg/g dw applies. This Technical Memorandum describes sampling
methods and provides the results of the Watershed sampling and analyses for tissue chemistry conducted in
2020 and compares results to those from previous years (2010 through 2019). Bird eggs and fish also were
sampled in 2005 (Santolo et al. 2016); however, the results of those analyses are not included here to minimize
the variability of analytical results among laboratories.
2. Methods
Sample locations for the fish, crayfish (Procambarus clarkii) and bird egg collections are indicated in Figure 2.1,
and collection methods are described below. Water and sediment samples were collected from the same or
nearby locations and similar dates by Orange County staff. The collection and analysis methods and results for
those media are available from the County.
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Figure 2.1: Newport Bay Watershed Sampling Locations, 2020
Newport Bay Watershed showing locations where fish and bird eggs were sampled, as follows: Peters Canyon Wash
(PCW; fish only), Santa Ana-Delhi Channel Lower (SADCL; fish only), Irvine Ranch Water District ponds (IRWD), University
of California San Joaquin Marsh Reserve ponds (UCI; bird eggs and crayfish), San Diego Creek (SDC fish; SDC bird eggs),
Upper Newport Bay (UNB; bird eggs only), Big Canyon Golf Course ponds (BCGC; fish only), Big Canyon Pond (BCW; fish
only), and Back Bay Shellmaker Island (BBS, fish only).
2.1 Fish
For small fish collected in June 2020, most samples were composites of five or more whole-body fish of the
same species and similar size. No larger-bodied fish, suitable for potential human consumption, were collected.
Members of the sunfish family (Centrarchidae) were targeted as selenium exposure indicators because of their
widespread occurrence and the extensive body of selenium toxicity research for some of those species.
Fish were collected using a 50-foot by 4-foot, 0.25-inch-mesh beach seine and minnow and bait-fish traps. Data
for fish sample locations in PCW are for all sites pooled (PCW) or for specific locations near road crossings (e.g.,
PCW@Barranca). Minnow trapping proved to be a somewhat successful fishing technique at a new location in the
lower Santa Ana-Delhi Channel, immediately upstream of the Bay (SADCL); however, tidal influence at the
location may confound the usefulness of this site as a measure of contaminants coming down from the watershed.
As in 2018 and 2019, no fish were seen at the original, upstream SADC sampling location or in the UCI ponds.
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Crayfish were collected from minnow traps at the University of California San Joaquin Marsh Reserve ponds
(UCI) ponds in 2020. All freshwater collections were conducted following California Department of Fish and
Wildlife (CDFW) notification under California Scientific Collecting Permit SC-9225 (to Ava Edens).
Saltwater and estuarine fish from Newport Bay were collected near Shellmaker Island (BBS) by Suzanne Welsh
(CDFW).
Fish samples were prepared for analysis as whole-body composites of small fish (or non-fish substitutes). The
goal of composite samples of small fish was to pool five or more small, whole-body fish of similar size to submit
for analysis. However, in some cases, fewer than five fish were available for whole-body composite samples after
samples were sorted and separated by similar size; the numbers of fish per composite samples are shown in
Table 3.1 (see Results Section).
All fish tissue samples were analyzed for selenium (Se) as well as organochlorine pesticides and PCBs, % lipids,
and % solids. Results are reported on a dry-weight (dw) basis for selenium and a wet-weight (ww) basis for
organic compounds to facilitate comparison to applicable guidelines.
Hitt and Smith (2014) modeled the effects of number of replicates on precision of estimating mean fish tissue
selenium concentrations using whole-body fish (three common fish species were used: creek chub [Semotilus
atromaculatus], green sunfish [Lepomis cyanellus], and central stoneroller [Campostoma anomalum]), similar or
identical to the species in lower San Diego Creek (SDC) and Irvine Ranch Water District ponds (IRWD). The
study indicated that from one to four fish composites were equivalent in precision. However, for accurate
comparisons to tissue targets as high as 8 μg/g dw, at least eight replicate samples would be required to detect
a 2 μg/g dw difference from the target. Lower concentration targets required fewer samples to achieve sufficient
confidence on attainment of the target. As shown in Table 3.1 (see Results Section), these sample size targets
were met for PCW, SDC, and IRWD when assessed across species.
2.2 Bird Eggs
Due to the timing of egg-laying by different bird species and nest availability in the Watershed, egg collection
occurred during multiple sampling events that differed among years. Eggs were collected only from nests that
contained two or more eggs, and they were considered “random” eggs as opposed to a biased sample (such as
“failed-to-hatch” or salvaged eggs). All egg collections were under California Scientific Collecting Permit SC-
2407 and MOU and under federal migratory bird permit MB829185-1 (to Gary Santolo). Eggs were not collected
from some nests for various reasons (e.g., chicks were pipping the shell or there was only a single egg in a
nest). To keep track of each egg and nest site, each egg was marked at collection with its unique nest code, and
the number of eggs in the clutch and the date it was removed from the nest were recorded. Those data were
recorded along with a location point using a hand-held global positioning system (GPS) unit. In addition, each
nest was photographed with the date, time, latitude and longitude stamped on the image. Eggs were placed in a
container to avoid damage and placed on wet ice and then refrigerated until they were examined and processed
for chemical analyses.
Eggs were cleaned of dirt, feces, and surface debris and, if necessary, deionized water was used to wash the
egg surface before processing for examination and analyses. Basic egg measurements were recorded (e.g.,
total weight, length, breadth). Volume was calculated from length and breadth measurements (Hoyt 1979). Eggs
were opened by cutting around the air cell with scissors. In this way, the position of the embryo, if present, could
be observed and evaluated for pre-hatch malpositions (Romanoff and Romanoff 1972). Eggs with embryos
greater than Day 13 of development were considered to be assessable for abnormalities because by this stage
of development, abnormalities can be seen by gross examination. Eggs were examined to determine their
fertility, stage of embryo development (Pisenti et al. 2001), the position of the embryo, embryo viability and
normality in assessable eggs, and whether pipping had occurred (i.e., whether the embryo had pipped into the
air cell or begun to break out of the egg). Fertility was determined as described in Pisenti et al. (2001). Embryos
were considered viable if the egg was fertile or the embryo was apparently alive at the time of collection and
could be observed during processing. Each embryo was examined for evidence of external deformities. The
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entire contents were then saved in chemically-cleaned glass containers and stored at -20 degrees Celsius (°C)
until they were shipped on wet ice to the laboratory for chemical analyses.
Eggshell thickness was measured and related to egg residue levels to help evaluate the effect of
organochlorines on the reproductive status of birds. These shell measurements were compared to either
literature-reported pre-DDT-era eggshells or, whenever possible, museum eggshells of pre-DDT-era eggs were
measured for comparison using a recently developed technique (Santolo 2018) to determine eggshell percent
thinning (% thinning). Museum eggshell measurements are appropriate for shell thickness comparisons to other
field-collected eggs because they represent unbiased samples (Blus et al. 1972a). Eggshells were allowed to air
dry at room temperature for at least 1 month before shell thickness was measured to the nearest 0.001 mm
using a Magna-Mike 8600 Hall-effect thickness gauge (Olympus Scientific Solutions Americas Inc., Waltham,
MA; Santolo 2018). Measurements of each eggshell were taken as near to the equator as possible to produce a
single value for each egg. The eggshell measurement included the shell and shell membrane.
Pre-DDT-era Forster’s tern (Sterna forsteri) eggshell thickness reported by King et al. (1978) was 0.219 mm;
however, to reduce uncertainty from differences in location and provide a more accurate comparison, 60
Forster’s tern eggs from 20 clutches collected from 1932 to 1939 (i.e., pre-DDT) from Monterey County, CA
were measured at the Western Foundation of Vertebrate Zoology (WFVZ; Camarillo, CA) for comparison (x̄ =
0.192 mm, SE = 0.0019, Range = 0.166 – 0.215 mm) and they were about 12 percent thinner (Santolo 2018)
than the average thickness reported by King et al. (1978). In addition, pre-DDT-use American avocet
(Recurvirostra americana) eggs from Los Angeles County, CA (1895 to 1936; n = 15, x̄ = 0.248 mm, SE =
0.0016, Range = 0.236 – 0.258 mm), black-necked stilt (Himantopus mexicanus) eggs from Orange County, CA
(1893 to 1928; n = 17, x̄ = 0.216 mm, SE = 0.0018, Range = 0.181 – 0.232 mm), and killdeer (Charadrius
vociferous) eggs (post-DDT 1948; n = 4, x̄ = 0.180 mm, SE = 0.0051, Range = 0.168 – 0.192 mm) from the
Museum of Wildlife and Fish Biology (MWFB); University of California at Davis and WFVZ were measured using
a Magna-Mike 8600 for comparison to eggs collected in the Newport Bay Watershed. We used the mean (0.24
mm) of 28 black skimmer (Rynchops niger) eggs (pre-DDT; 1882-1930) measured at WFVZ by White et al.
(1984), which was similar to measurements of skimmer eggs from the Texas coast taken by Custer and Mitchell
(1987; 0.24 mm) for comparison to skimmer eggs we collected. We also compared our measurements to
published eggshell measurements from the San Francisco Bay (Peterson et al. 2020).
2.3 Laboratory Analyses
All bird egg samples collected from 2010 to 2014 were analyzed for 22 metals/trace elements: aluminum (Al),
antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), cadmium (Cd), chromium (Cr), cobalt (Co), copper
(Cu), iron (Fe), lead (Pb), manganese (Mn), molybdenum (Mo), nickel (Ni), Se, silver (Ag), strontium (Sr),
thallium (Tl), tin (Sn), titanium (Ti), vanadium (V), zinc (Zn). Unlike selenium, the concentrations of metals in
eggs were below critical levels so analyses for those metals were discontinued in 2015 and samples were
analyzed only for selenium and organochlorines from 2015 on.
Fish and egg samples were analyzed for selenium, PCBs, and chlorinated pesticides by Physis Environmental
Laboratory. Selenium was analyzed by ICP-HG, which improves selenium detection (Campbell 1992);
chlorinated pesticides and PCBs were analyzed by GCMS using EPA 8270C; percent solids were determined by
EPA 160.3 and then converted to percent moisture; percent lipids were measured by gravimetric method.
Total PCBs (tPCBs) were determined by totaling the 53 most common PCB congeners. The Aroclors were not
added to tPCBs because they represent mixtures of certain congeners and including the Aroclors in the tPCBs
calculation would count some congeners twice. Thus, the Aroclors were evaluated separately. One reason this
is suitable is that many of the toxicology data are based on exposure to certain Aroclor mixtures (usually 1254,
but sometimes 1260 or others) and typically the toxicology value is used as a surrogate for tPCBs. Thus, it is
more accurate and provides more information to compare the Aroclor data to the toxicology value for the same
Aroclor mixture.
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2.4 Statistical Analyses
Descriptive statistics are provided for summary purposes. Generally, tissue concentration results data did not
meet the assumption of normality (D'Agostino & Pearson normality test; GraphPad Software 2020). Thus,
nonparametric tests were used for statistical comparisons and geometric mean and ranges of concentration
results are presented (GraphPad Software 2020). Dunn’s multiple comparison test and Tukey-Kramer means
comparison were used to test for mean separation when ANOVA showed significant differences. For identifying
outliers, the Grubbs test (Extreme Studentized Deviate [ESD], Alpha = 0.01] was used. Statistical summaries
and tests were performed using the program GraphPad Prism (GraphPad Software 2020) at a statistical
significance level of 0.05; specific tests are addressed in the results section.
2.5 Screening-Level Analysis of Risk
The results of the chemical analyses for the various constituents were compared to the most recent, applicable
criteria, guidelines, or TMDL numeric targets, which included the selenium and organochlorine TMDLs
(SARWQCB 2011, USEPA 2019) targets for fish tissue and bird eggs. In addition, other screening levels were
used when they were available (e.g., effect levels documented in original sources identified through reviews
such as those by Eisler 1990, USEPA 2018). However, comparison to literature-derived screening levels is
provided for informational purposes only as they do not represent regulatory targets. Exceedance of TMDL
screening levels was considered as indication for ecological risk to wildlife receptors.
To compare to literature values, concentrations are presented as μg/g (parts-per-million) for selenium in fish and
bird eggs. Concentrations of organochlorines are presented as μg/g for bird eggs and ng/g for fish. Results for
selenium are presented on a dry-weight basis and wet weight was used for organochlorines.
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3. Fish Results
Ten non-native, invasive fish species (I) were sampled in 2020 from the freshwater portions of the Watershed
and three native species (N) were collected from Newport Bay (including the estuarine killifish from SADCL):
x Bluegill (BG; Lepomis macrochirus) – Found in SDC (I), IRWD pond 2 (but much reduced in numbers over
previous years), BCW (I), and Big Canyon Wash Golf Course Pond 4 (BCGC) (I)
x Green sunfish (GSF; Lepomis cyanellus) – Found in SDC (I)
x Common carp (CRP; Cyprinus carpio) – Found throughout PCW and SDC (I)
x Fathead minnow (FHM; Pimephales promelas) – Found in PCW, SDC, IRWD, BCW, and BCGC (I)
x Goldfish (GLD; Carassius auratus) – SDC (I)
x Killifish (KFH; Fundulus parvipinnis) – SADCL (N)
x Largemouth bass (LMB; Micropterus salmoides) – Common in SDC and IRWD Pond 2 (I)
x Mosquitofish (MSF; Gambusia affinis) – Found in PCW, SDC, BCW, and BCGC (I). In contrast to most prior
years of sampling, they were not found in UCI in 2018 through 2020 or in SADC (nor were any other fish
species at those locations). In general, their abundance was noticeably lower since 2018.
x Inland (or Mississippi) silverside (MSS; Menidia beryllina) - Found in IRWD Pond 2 (I)
x Red shiner (RSH; Notropis lutrensis) – Abundant in PCW (I)
x Threadfin shad (TFS; Dorosoma petenense) – Found in SDC and IRWD Pond 2 (I)
x Shiner perch (SHPE; Cymatogaster aggregata) – Common in the Bay (BBS) (N)
x Topsmelt (TOSM; Atherinops affinis) – Common in the Bay (BBS; N)
Additional species and collections found in low numbers in previous years included brown bullhead (Ameiurus
nebulosus) in IRWD, SDC, and UCI and striped mullet (Mugil cephalus) found in lower BCW in 2015. Note that
striped mullet are the only native fish observed and sampled in the freshwater portions of the Watershed during
the years of study. Additional species found in the Bay (BBS) and collected in 2018 but not since then included
arrow goby (Clevelandia ios), and wooly sculpin (Clinocottus analis).
Crayfish (CRY; Procambarus clarkii) were collected for whole-body composite analysis at the UCI ponds
because no fish were found there but crayfish could be used as a surrogate estimate of fish tissue chemistry. In
addition, various sites in the Watershed were sampled for crayfish as well as fish in 2019 (Jacobs 2019) to
establish a ratio between co-located fish and crayfish tissue selenium (i.e., fish concentration = 2.1 x crayfish
concentration) that could be used to estimate fish selenium where only crayfish were available. Crayfish size
was limited to less than 9 cm rostrum to telson length in the composite samples to ensure adequate grinding,
digestion, and extraction of the hard chitinous carapace. In 2020, only crayfish were sampled in the UCI ponds.
3.1 Selenium
Whole-body composite fish sample results for selenium and percent moisture (% M) results are presented in
Table 3.1. All freshwater fish samples analyzed for selenium exceeded the TMDL site-specific objective for
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 7
selenium in whole-body fish of 8.1 μg/g dw (USEPA 2019). The crayfish sample as well as the estuarine and
marine fish from SADCL and BBS were notably lower in selenium concentrations while the Big Canyon sites
(BCW and BCGC) remain the areas with highest fish tissue selenium concentrations (Table 3.1).
Table 3.1: Selenium Concentrations and Percent Moisture in Fish from the Newport Bay Watershed, 2020
Selenium concentrations (μg/g dw) and percent moisture (% M) in composite whole-fish samples (generally, upstream to
downstream), Orange County TMDL tissue sampling 2020. Composite Number is the number of individuals in the composite
sample. Only the non-fish (crayfish) sample, SADCL, and BBS fish did not exceed the TMDL target value of 8.1 μg/g dw. Species
codes are given above in Section 3.1.
Sample Site Species Composite Number Result Se dw % M
PCWBARFHM1 PCW FHM 25 8.9 76.4
PCWBARFHM2 PCW FHM 21 10.5 78.7
PCWBARFHM3 PCW FHM 31 11.9 81.6
PCWBARRSH1 PCW RSH 7 10.1 76.6
PCWBARRSH2 PCW RSH 7 10.2 78.2
PCWBARRSH3 PCW RSH 8 9.2 74.5
PCWWARCRP PCW CRP 2 11.7 82.1
PCWWARFHM1 PCW FHM 78 11.5 79.4
PCWWARFHM2 PCW FHM 77 12.9 81.6
PCWWARFHM3 PCW FHM 78 12.1 81.0
PCWWARMSF PCW MSF 7 15.6 78.1
PCWWARRSH1 PCW RSH 78 12.1 77.5
PCWWARRSH2 PCW RSH 77 12.2 77.7
PCWWARRSH3 PCW RSH 77 11.8 78.0
SDCBG1 SDC BG 5 19.0 71.2
SDCBG2 SDC BG 5 19.1 74.5
SDCBG3 SDC BG 5 23.7 72.6
SDCBG4 SDC BG 5 19.1 73.0
SDCCRP SDC CRP 1 33.8 79.5
SDCFHM1 SDC FHM 40 23.0 77.7
SDCFHM2 SDC FHM 40 25.0 78.1
SDCFHM3 SDC FHM 40 22.6 77.2
SDCFHM4 SDC FHM 40 20.9 77.6
SDCFHM5 SDC FHM 40 20.8 76.3
SDCGLD SDC GLD 1 18.0 74.1
SDCGRN1 SDC GSF 8 32.1 77.4
SDCGRN2 SDC GSF 8 34.1 79.7
SDCGRN3 SDC GSF 9 36.4 78.6
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 8
SDCLMB1 SDC LMB 14 24.6 78.8
SDCLMB2 SDC LMB 14 24.0 79.2
SDCLMB3 SDC LMB 14 25.4 78.5
SDCMSF SDC MSF 9 25.2 75.9
SDCTFS SDC TFS 2 22.8 79.8
IRWDP1BG IRWD BG 4 22.2 80.0
IRWDP2BG1 IRWD BG 6 13.3 77.9
IRWDP2BG2 IRWD BG 6 14.8 78.7
IRWDP2BG3 IRWD BG 6 13.3 77.4
IRWDP2FHM IRWD FHM 2 22.9 76.7
IRWDP2LMB1 IRWD LMB 3 11.5 80.3
IRWDP2LMB2 IRWD LMB 3 11.3 80.1
IRWDP2LMB3 IRWD LMB 3 14.3 82.4
IRWDP2MSS IRWD MSS 1 9.4 78.0
IRWDP2TFS1 IRWD TFS 30 8.8 80.0
IRWDP2TFS2 IRWD TFS 30 9.6 79.9
IRWDP2TFS3 IRWD TFS 30 9.6 81.6
IRWDP2TFS4 IRWD TFS 30 9.5 80.4
IRWDP2TFS5 IRWD TFS 30 10.1 81.0
UCIP5CRY UCI CRY 1 1.0 69.2
SADCLKFH1 SADCL KFH 76 7.8 77.2
SADCLKFH2 SADCL KFH 66 8.0 80.7
SADCLKFH3 SADCL KFH 54 7.3 77.9
BCWBG BCW BG 1 28.0 77.3
BCWFHM1 BCW FHM 4 20.5 78.5
BCWFHM2 BCW FHM 4 21.1 78.4
BCWFHM3 BCW FHM 4 22.1 77.7
BCWMSF BCW MSF 1 32.1
BCGCP4FHM1 BCGC FHM 20 39.2 76.8
BCGCP4FHM2 BCGC FHM 21 36.8 74.7
BCGCP4FHM3 BCGC FHM 21 35.7 75.3
BCGCP4MSF1 BCGC MSF 32 40.1 78.1
BCGCP4MSF2 BCGC MSF 33 23.0 76.7
BCGCP4MSF3 BCGC MSF 33 40.5 76.3
BCGCP5BG BCGC BG 3 15.1 75.2
BCGCP5FHM BCGC FHM 3 18.9 76.4
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 9
The wide range of selenium concentrations in whole-body fish is shown in Figure 3.1 as the geometric mean
and range of individual sample concentrations by species and location. The non-parametric analysis of variance
(Kruskal-Wallis test; GraphPad Software 2020) comparisons indicated Big Canyon Golf Course (BCGC) site fish
had higher selenium concentrations than fish from any other location (P < 0.05). SDC fish had higher selenium
concentrations than fish from all other locations (P < 0.05) except BCW and BCGC, and BCW fish
concentrations were higher than fish from all other locations (P < 0.05) except for SDC, IRWD, and BCGC fish.
The crayfish sample from UCI with 1.0 μg Se/g dw had the lowest selenium tissue concentrations as compared
to fish at any given site (Figure 3.1). As an estimated fish concentration, the value would be 2.1 μg/g dw (based
on ratio derived in 2019; Jacobs 2019), comparable to the lowest values found in bay fish (BBS, Table 3.1).
The percent moisture for fish samples did not vary significantly among species or sites. Whole-body composites
ranged from 69.2 to 82.4 percent moisture and the mean percent moisture was 77.7 (Table 3.1). Sample-
specific values may be used to convert tissue selenium concentrations between dry- and wet-weight results if
desired.
BCGCP5MSF1 BCGC MSF 10 22.4 76.1
BCGCP5MSF2 BCGC MSF 10 23.2 76.6
BCGCP5MSF3 BCGC MSF 9 24.1 77.1
BCGCP6MSF1 BCGC MSF 17 28.0 76.9
BCGCP6MSF2 BCGC MSF 21 18.9 76.8
BCGCP6MSF3 BCGC MSF 21 23.7 75.8
NBSI-SHPE-1 BBS SHPE 3 2.2 78.7
NBSI-SHPE-2 BBS SHPE 3 2.5 79.5
NBSI-SHPE-3 BBS SHPE 3 2.0 78.6
NBSI-TOSM-1 BBS TOSM 3 2.9 76.0
NBSI-TOSM-2 BBS TOSM 3 2.5 74.6
NBSI-TOSM-3 BBS TOSM 3 2.4 74.7
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 10
CRP
FHM
RSH
MSF
AllFish
0
5
10
15
20
25
PPgSe/gdw
PCW
BG
LMB
CRP
FHM
GRN
GLD
TFS
MSF
All Fish
0
10
20
30
40
PPgSe/gdw
SDC
BG
FHM
LMB
MSS
TFS
AllFish
0
5
10
15
20
25
PPgSe/gdw
IRWD
CRY
0
5
10
15
20
25
PPgSe/gdw
UCI
KFH
0
5
10
15
20
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 11
x PCW > SADCL (3, 7.7 μg Se/g, NS
x SADCL > BBS (6, 2.4 μg Se/g, NS)
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 12
3.2 Organochlorine Compounds
Results for samples with at least one detectable organochlorine compound are shown in Table 3.2 and Figure 3.2 for whole-body small fish composites, non-fish
from UCI. The complete list of detected and nondetected organochlorines and their laboratory detection limits are provided in Appendix A. Almost all fish had
detectable DDT compounds (mostly as p,p’-DDE concentrations). No organochlorine exceedances of TMDL targets were found (Table 3.2) except for the three
shiner perch samples from Newport Bay for tDDT.
Table 3.2: Organochlorine Compounds and Percent Lipids in Fish
Concentrations of detected organochlorine compounds (ng/g ww) and percent lipids (%lipids) in whole-body composite fish samples, Orange County TMDL tissue
sampling, 2020. Full results are in Appendix A. Location and species codes are given in Section 3.1, above.
Sample ID Location
Species
Tissue
%Lipids
Aroclor 1260
tDDTs
Chlordane-alpha
Chlordane-gamma
cis-Nonachlor
Hexachlorobenzene
Toxaphene
trans-Nonachlor
tPCBs
MDL
0.01 10
1 1 1 1 10 1
RL
0.05 20
5 5 5 5 50 5
Method
Gravimetric
EPA
8270D
EPA
8270D
EPA
8270D
EPA
8270D
EPA
8270D
EPA
8270D
EPA 8270D-
NCI
EPA
8270D
EPA
8270D
Geometric Mean 3.0 18.5 42.8 1.5 0.9 1.3 0.5 14.7 3.1 9
Min 0.7 10.4 1.0 0.3 0.2 0.3 0.3 11.7 0.3 0.91
Max 6.8 50.7 247.5 18.9 9.9 14.5 1.2 31.9 25.7 40.8
Total Hits 72 45 73 67 52 67 26 14 72 73
TMDL Tissue Targets
(HH/FW/NB)1
100/1000
/50
NA/NA/
50
NA/NA/
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 13
Sample ID Location
Species
Tissue
%Lipids
Aroclor 1260
tDDTs
Chlordane-alpha
Chlordane-gamma
cis-Nonachlor
Hexachlorobenzene
Toxaphene
trans-Nonachlor
tPCBs
PCWWARFHM1 PCW FHM C 3.5
45.1 1.5 0.6 0.8
12.3 2.4 3.0
PCWWARFHM2 PCW FHM C 2.8
37.1 1.3 0.8 0.5
12.1 2.0 2.6
PCWWARFHM3 PCW FHM C 2.9
41.9 1.7 0.7 0.7
2.1 2.7
PCWWARCRP PCW CRP C 2.0 11.4 73.2 0.6 4.1 3.5
4.5 9.2
PCWWARCRP PCW CRP C
PCWWARMSF PCW MSF C
PCWBARRSH1 PCW RSH C 3.2 14.2 143.4 3.5 1.8 1.0 0.6
3.5 11.5
PCWBARRSH2 PCW RSH C 3.7 11.6 145.6 3.7 2.2 1.5 0.5
4.1 9.0
PCWBARRSH3 PCW RSH C 5.2 15.8 184.3 4.3 2.3 1.2 0.7 12.2 4.0 12.7
PCWWARRSH1 PCW RSH C 5.3 16.3 72.2 2.3 1.4 1.3 0.5 12.0 3.6 12.9
PCWWARRSH2 PCW RSH C 5.2
61.7 2.1 1.4 0.9 0.5 26.0 3.8 3.0
PCWWARRSH3 PCW RSH C 5.1
57.8 2.1 1.4 0.8 0.4
3.1 3.4
SDCBG1 SDC BG C 6.8 28.6 196.5 5.1 4.6 4.1 0.7
8.0 23.0
SDCBG2 SDC BG C 4.7 25.5 193.3 1.5
1.3
3.6 20.5
SDCBG3 SDC BG C 6.3 13.4 155.0 1.3
1.3 0.3
3.7 10.6
SDCBG4 SDC BG C 6.0 20.2 161.9 2.1 0.3 1.9 0.4
4.0 16.3
SDCCRP SDC CRP C 1.6
46.9 0.3
0.8 4.4
SDCGLD SDC GLD C 5.3 15.0 172.4 1.8 1.3 1.1 0.4
3.5 12.1
SDCMSF SDC MSF C 2.8 24.6 71.9 0.3
1.0
3.5 19.5
SDCTFS SDC TFS C 4.0
91.1 1.3 0.7
1.5 6.4
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 14
Sample ID Location
Species
Tissue
%Lipids
Aroclor 1260
tDDTs
Chlordane-alpha
Chlordane-gamma
cis-Nonachlor
Hexachlorobenzene
Toxaphene
trans-Nonachlor
tPCBs
SDCFHM1 SDC FHM C 4.0
84.9 0.8 0.4 0.5
1.5 5.1
SDCFHM2 SDC FHM C 3.8 12.7 160.3 1.6 0.9 1.0 0.3
2.9 11.4
SDCFHM3 SDC FHM C 4.5 15.2 216.8 2.7 0.9 1.4
4.5 13.7
SDCFHM4 SDC FHM C 4.3 16.3 191.8 1.7 0.8 1.2 0.3
3.3 14.5
SDCFHM5 SDC FHM C 4.6 11.3 247.5 2.8 1.2 1.6 0.7
4.9 10.2
SDCGRN1 SDC GSF C 3.8 19.1 75.1 2.1 0.8 1.6
3.8 15.2
SDCGRN2 SDC GSF C 3.2
50.2 1.0
0.7
2.9 7.1
SDCGRN3 SDC GSF C 3.5
49.1 1.1 0.2 0.7 0.3
2.4 7.9
SDCLMB1 SDC LMB C 1.2 14.3 97.7 0.7 0.2 0.9
1.7 11.4
SDCLMB2 SDC LMB C 1.1 19.0 117.4 0.7 0.3 0.7
1.8 15.3
SDCLMB3 SDC LMB C 1.5 17.9 115.3 0.7 0.2 0.9
1.7 14.4
IRWDP2BG1 IRWD BG C 1.9
164.8 0.3
0.6
1.5 6.0
IRWDP2BG2 IRWD BG C 2.3
187.0 0.4
0.9
1.7 5.7
IRWDP2BG3 IRWD BG C 2.1
195.2 0.5
0.8
1.5 6.2
IRWDP1BG IRWD BG C
49.1
0.3 4.4
IRWDP2FHM IRWD FHM C
IRWDP2LMB1 IRWD LMB C 0.7
101.8
0.3
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 15
Sample ID Location
Species
Tissue
%Lipids
Aroclor 1260
tDDTs
Chlordane-alpha
Chlordane-gamma
cis-Nonachlor
Hexachlorobenzene
Toxaphene
trans-Nonachlor
tPCBs
IRWDP2TFS1 IRWD TFS C 3.8
134.4 1.6 0.5 0.3
31.9 1.0 4.1
IRWDP2TFS2 IRWD TFS C 3.8
123.0 1.2 0.4
11.7 0.9 2.5
IRWDP2TFS3 IRWD TFS C 3.2
99.3 0.9 0.4 0.3
1.2 2.3
IRWDP2TFS4 IRWD TFS C 3.5
127.6 1.2 0.5 0.5
1.4 3.3
IRWDP2TFS5 IRWD TFS C 3.9
115.3 1.3 0.5 0.6
1.0 2.7
UCIP5CRY UCI CRY C 1.4
1.0
0.9
SADCLKFH1 SADC KFH C 2.0 34.3 15.9 1.1 0.2 0.8
11.7 1.9 27.6
SADCLKFH2 SADC KFH C 1.7 29.6 10.8 0.9
0.6
1.6 23.8
SADCLKFH3 SADC KFH C 1.9 38.6 14.5 1.0 0.2 1.1
2.0 31.1
BCWBG BCW BG C 3.1 22.5 10.8 5.9 1.3 14.5 0.3
25.1 17.8
BCWFHM1 BCW FHM C 4.2 27.4 22.4 18.9 9.9 10.2 0.4 16.0 25.7 21.8
BCWFHM2 BCW FHM C 2.4 22.3 12.7 9.4 3.9 7.0
15.9 17.5
BCWFHM3 BCW FHM C 4.2 30.0 23.4 15.3 6.8 9.8 0.5
24.0 23.9
BCWMSF BCW MSF C
BCGCP5BG BCGC BG C 2.9 23.6 6.4 3.1 0.8 4.9 0.9 12.6 11.5 18.9
BCGCP4FHM1 BCGC FHM C 5.1 11.3 6.0 6.5 3.8 3.6 1.2
8.9 9.1
BCGCP4FHM2 BCGC FHM C 6.5 13.3 7.8 10.1 5.2 4.4 1.1
12.7 10.6
BCGCP4FHM3 BCGC FHM C 5.9 13.7 7.6 7.8 3.4 3.9 1.0 13.6 11.4 11.0
BCGCP5FHM BCGC FHM C 5.1 25.7 6.4 7.7 4.3 4.9 1.1 14.1 12.4 20.7
BCGCP4MSF1 BCGC MSF C 2.8
2.9 0.4
2.2
4.7 7.5
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 16
Sample ID Location
Species
Tissue
%Lipids
Aroclor 1260
tDDTs
Chlordane-alpha
Chlordane-gamma
cis-Nonachlor
Hexachlorobenzene
Toxaphene
trans-Nonachlor
tPCBs
BCGCP4MSF2 BCGC MSF C 3.1
3.9 0.6 0.5 1.9
7.9 7.1
BCGCP4MSF3 BCGC MSF C 3.2 10.4 4.5 0.9 0.5 2.5
6.2 8.2
BCGCP6MSF1 BCGC MSF C 3.4
6.7
1.8
5.5 5.7
BCGCP6MSF2 BCGC MSF C 4.6 12.5 6.2 0.7
2.3
6.2 9.9
BCGCP6MSF3 BCGC MSF C 3.7 10.5 7.2
1.9
5.5 8.3
BCGCP5MSF1 BCGC MSF C 3.2 14.9 4.1 0.4
2.2
6.4 12.0
BCGCP5MSF2 BCGC MSF C 2.8
3.1 0.7 0.4 1.6
5.1 7.7
BCGCP5MSF3 BCGC MSF C 2.6 12.4 2.7 0.5
2.0
5.4 9.9
NBSI-SHPE-1 BBS SHPE C 1.9 41.7 118.1 1.4 0.6 1.6
2.5 33.3
NBSI-SHPE-2 BBS SHPE C 1.5 50.7 126.5 1.0 0.5 1.4
2.3 40.8
NBSI-SHPE-3 BBS SHPE C 1.8 45.8 131.9 2.0 0.8 2.0
2.8 36.5
NBSI-TOSM-1 BBS TOSM C 1.0 16.3 34.7 0.3
0.5
0.6 13.0
NBSI-TOSM-2 BBS TOSM C 1.1 19.6 41.5 0.4 0.2 0.6
1.0 15.8
NBSI-TOSM-3 BBS TOSM C 1.1 14.6 32.5 0.3 0.3 0.7 11.6
Blank cells are nondetect values.
1 (HH/F/NB) = (Human Health/Freshwater/Newport Bay; SARWQCB 2007)
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 17
The percent lipid for fish samples varied by about 9.7 percent (0.7% to 6.8%) among species or sites with a
geometric mean of 3.0 percent (Table 3.2). Sample-specific values can be used to convert fish organochlorine
concentrations between wet- and lipid-weight (lw) results if desired.
Figure 3.2 shows geometric mean fish total DDT (tDDT) tissue concentration comparisons among locations and
species for 2020. Fish tissue tDDTs concentrations tended to increase with age/size within any one species.
Length-concentration relationships for such compounds may confound the ability to compare results among
sites if fish are not normalized to a standard length. However, too few samples and too few larger fish at any
given location were collected as part of this sampling to allow such use of normalization as an aid to comparison
among sites. An example DDE concentration-length relationship for carp from all TMDL sampling locations
combined was provided in a previous report when a full range of size classes was available (CH2M HILL 2012).
CRP
FHM
RSH
All Fish
0
50
100
150
200
ng tDDT/g ww
PCW
BG
CRP
FHM
GLD
GSF
LMB
MSF
TSF
All Fish
0
50
100
150
200
250
300
ng tDDT/g ww
SDC
BG
LMB
TFS
All Fish
0
50
100
150
200
ng tDDT/g ww
IRWD
CRY
0
2
4
6
8
10
ng tDDT/g ww
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 18
x IRWD > PCW (13, 82.9 ng tDDTs/g ww, NS)
x PCW > BBS (6, 67.2 ng tDDTs/g ww, NS)
x BBS > BCW (4, 16.4 ng tDDTs/g ww, NS)
x BCW > SADCL (3, 13.6 ng tDDTs/g ww, NS)
x SADCL > BCGC (15, 5.2 ng tDDTs/g ww, NS)
x BCGC > UCI (non-fish 1, 1.0 ng tDDTs/g ww)
Figure 3.3 shows geometric mean fish tPCBs tissue concentration comparisons among locations and species
for 2020. Comparing across species, shiner perch from the Bay and killifish from SADCL in general had higher
tPCBs tissue concentrations with geometric means for all species ranging from 27.3 (SADCL) down to 3.7
(IRWD; the single crayfish sample from UCI was 0.9 ng/g ww) ng tPCBs/g ww in 2020. The rankings of
geometric mean fish tPCBs concentrations by location, for combined species (high to low, followed by statistical
significance, NS = not significant), for composites for pairwise comparisons were as follows:
x SADCL (3, 27.3 ng tPCBs/g ww) > BBS (6, 22.2 ng tPCBs/g ww, NS)
x BBS > BCW (4, 20.1 ng tPCBs/g ww, NS)
x BCW > SDC (20, 11.7 ng tPCBs/g ww, NS)
x SDC > BCGC (15, 9.9 ng tPCBs/g ww, NS)
x BCGC > PCW (13, 5.8 ng tPCBs/g ww, NS)
x PCW > IRWD (11, 3.7 ng tPCBs/g ww, NS)
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 19
CRP
FHM
RSH
AllFish
0
5
10
15
ng tPCB/g ww
PCW
BG
CRP
FHM
GLD
GSF
LMB
MSF
TSF
All Fish
0
5
10
15
20
25
ng tPCB/g ww
SDC
BG
LMB
TFS
All Fish
0
5
10
15
ng tPCB/g ww
IRWD
CRY
0
1
2
3
4
5
6
7
8
9
10
ng tPCB/g ww
UCI
BG
FHM
MSF
All Fish
0
5
10
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 20
The pattern at each sample location over all the years can be seen in Figure 3.4 and the pattern for the San
Diego Creek drainage (without BCGC, BCW, and BBS) is shown in Figure 3.5.
Figure 3.4: Selenium Concentrations in Fish by Location and Year, 2010 to 2020
Geometric mean (horizontal lines) and ranges of selenium concentrations (μg/g dw) in whole-body composite fish
samples by location, and all locations combined (Newport Bay Watershed), 2010 – 2020.
Location codes in text above. The dashed line indicates the TMDL target threshold concentration for whole-body fish
selenium of 8.1 μg/g.
1 ACF and ACFL
aSADCL only
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
5
10
15
20
25
30
35
PPgSe/gdw
PCW
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
10
20
30
40
PPgSe/gdw
SDC
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 21
Figure 3.5: Selenium Concentrations in Fish in the Newport Bay Watershed from 2010 to 2020
Pattern of selenium concentrations in fish (2018 and 2019 include tadpoles/frogs from UCI) over all the years monitored
for the San Diego Creek drainage and ranges of all stations and species pooled, excluding BCGC, BCW, and BBS, 2010 –
2020 (regression line is 2010 – 2019). The dashed line indicates the target threshold concentration for whole-body fish
selenium of 8.1 μg/g.
The Newport Bay Watershed Selenium TMDL established a composite, whole-body fish tissue target value of
8.1 μg Se/g dw and SARWQCB and USEPA (2017, 2019) provides numeric targets for the TMDLs divided into
two categories with different fish tissue targets: one applies where the bird egg target has been met, and the
other applies where the bird egg target has not been met. If the bird egg target of 8 μg/g dw has been attained, a
higher (less stringent) fish tissue target of 8.1 μg/g dw applies. This fish tissue target serves as a protective
target for fish (i.e., aquatic life), as a separate endpoint. The bird egg target serves to protect shorebirds (i.e.,
aquatic-dependent wildlife). Where the bird egg target has not been attained, a lower (more stringent) fish tissue
target of 5 μg/g dw applies. Based on this target, the 2010 through 2020 sample set indicates general
exceedances for SDC (Table 3.3) and BCW watersheds. The geometric mean for all fish sampled from the SDC
Watershed was 14.5 μg Se/g dw. BCW results had 100 percent exceedances for all years (but with a marked,
lowering trend in concentrations through 2019, Figure 3.4). Centrarchids (sunfish, bass), identified as the prime
indicators for selenium toxicity, tended to show higher overall frequency of TMDL tissue target exceedance than
fish from other families (Table 3.3) except for 2019.
Table 3.3: Frequency of Fish Samples over the Selenium Target Concentration, 2010 to 2020
Frequency (percent of samples) over the target selenium concentration of 8.1 μg Se/g dw for whole-body fish
for centrarchids or all fish species in the SDC Watershed and BCW Watershed from 2010 to 2020.
Year n SDC Centrarchid SDC All BCW
2010 17 90.1 82.4 100
2011 33 100 96.9 100
2012 35 100 86.8 100
2013 44 100 93.2 100
2014 32 100 93.8 100
2008 2010 2012 2014 2016 2018 2020 2022
0
10
20
30
40
Newport Bay Watershed
μg Se/g dw
2010 - 2020 r2
=0.006,P = 0.107
2010 - 2019 r2
= 0.087, P <0.001
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 22
Table 3.3: Frequency of Fish Samples over the Selenium Target Concentration, 2010 to 2020
Frequency (percent of samples) over the target selenium concentration of 8.1 μg Se/g dw for whole-body fish
for centrarchids or all fish species in the SDC Watershed and BCW Watershed from 2010 to 2020.
Year n SDC Centrarchid SDC All BCW
2015 32 100 90.6 100
2016 54 100 96.2 100
2017 35 100 96.9 100
2018 61 100 98.4 1001
2019 53 58 62.3 100
2020 50 100 94 100
1 African clawed frogs only
3.1.4.2 Organochlorines
The Newport Bay watershed record of organochlorines in fish tissue shows mixed results. In contrast to
selenium, there have been very few exceedances of TMDL tissue targets since 2010. The recent addition of
Bay fish to the monitoring suggests that DDT compounds may be mobilized into the food web in the Bay more
than what has been observed in the freshwater portions of the Watershed (Table 3.2, Figures 3.6 and 3.7). In
fact, DDT compounds in whole-body fish tissues have shown apparent decreases over time in BCW (Figure 3.6)
while PCBs have decreased in fish tissue concentrations in both IRWD and SDC over time (Figure 3.7).
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 23
Figure 3.6: Total DDT Concentrations in Fish by Location and Year, 2010 to 2020
Geometric mean (horizontal lines) and ranges of total DDT (tDDTs) concentrations (ng/g ww) in whole-body composite
fish samples by location, and all locations combined (Newport Bay Watershed), 2010 – 2020.
Location codes in text above.
1 ACF and ACFL
aSADCL only
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
200
400
600
ng tDDT/g ww
PCW
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
200
400
600
800
ng tDDT/g ww
SDC
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
1
0
1000
2000
3000
ng tDDT/g ww
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 24
Figure 3.7: Total PCB Concentrations in Fish by Location and Year, 2010 to 2020
Geometric mean (horizontal lines) and ranges of total PCBs (tPCBs) concentrations (ng/g ww) in whole-body composite
fish samples by location, and all locations combined (Newport Bay Watershed), 2010 – 2020.
Location codes in text above.
1 ACF and ACFL
aSADCL only
When results are grouped by drainage and examined over all the years of record, several patterns emerge. DDT
compounds in fish have decreased over time in the combined San Diego Creek drainage sites as well as the Big
Canyon wash sites (Figure 3.8). In contrast, PCB compounds have also decreased over time in fish from the
combined San Diego Creek sites but increased at Big Canyon Wash sites (Figure 3.9). This general trend for
San Diego Creek may be associated with sediment-bound organochlorine compounds being washed out over
time and/or stabilized prior to reaching the upper drainage but continuing to accumulate in the Bay, where some
fish tissue tDDT results exceed tissue guidance levels for the TMDL (Table 3.2). Future monitoring results
should help describe the significance of Watershed trends and any consistent differences in concentration
between fish in the freshwater drainages versus those in the Bay and between Big Canyon Wash and San
Diego Creek.
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
100
200
300
400
ng tPCB/g ww
PCW
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
10
20
30
ng tPCB/g ww
SDC
2010
2011
2012
2013
2014
2015
2016
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Newport Bay Watershed Biota Monitoring 25
Figure 3.8: Total DDT Concentrations in Fish (ng/g ww) and Year from 2010 - 2020 in the Newport Bay Watershed.
Total DDTs (tDDTs) concentrations (ng/g ww) in whole-body composite fish samples year (Newport Bay Watershed), 2010
– 2020.
Location codes in text above.
2010 2015 2020
0
200
400
600
800
PCW-SDC-IRWD-UCI-SADC tDDT x Year
Year
ng DDT/g ww
r2
=0.012
P = 0.085
2010 2015 2020
0
10
20
30
40
50 BCW-BCGC tDDT x Year
Year
ng DDT/g ww
r2
=0.20
P = 0.008
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Newport Bay Watershed Biota Monitoring 26
Figure 3.9: Total PCB Concentrations in Fish (ng/g ww) and Year from 2010 - 2020 in the Newport Bay Watershed.
Total PCBs (tPCBs) concentrations (ng/g ww) in whole-body composite fish samples year (Newport Bay Watershed),
2010 – 2020.
Location codes in text above.
2010 2015 2020
0
20
40
60
80 PCW-SDC-IRWD-UCI-SADC tPCB x Year
Year
ng tPCB/g ww
r2
=0.029
P = 0.006
2010 2015 2020
0
10
20
30 BCW-BCGC tPCB x Year
Year
ng tPCB/g ww
r2
=0.12
P = 0.027
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 27
4. Bird Egg Results
In 2020, nests were found in all locations except BCGC, where bird nesting habitat was mostly removed.
Nesting was highest at IRWD and there continued to be increased nesting at UCI and SDC over what was
observed in recent years. At UCI, American coot (Fulica americana) nests were found in 2019 but not 2020 and
pied-billed grebe (Podilymbus podiceps) nests were found in 2020 but not in 2019. The higher number of nests
found at UCI is likely because water was kept in the ponds through the nesting season in 2019 and 2020. Other
factors also affected nesting at the various sites. No Forster’s tern nests were found on Hot Dog Island in UNB,
which they shared with least terns (Sternula antillarum) and black skimmers in most other years, nesting in
vegetation on the north and west edges of the island; however, as in 2019, terns nested at IRWD. The least tern
colony on Hot Dog Island is monitored by CDFW.
During the 2020 nesting season, 50 eggs were collected from active nests of western grebe (7; WEGR;
Aechmophorus occidentalis), pied-billed grebe (5; PBGR), black-necked stilt (13; BNST), American avocet (4;
AMAV), killdeer (6; KILL), Forster’s tern (7; FOTE), and black skimmer (8; BLSK) in the Newport Bay Watershed
and upper Newport Bay. These eggs were collected from SDC (6), IRWD (25), UCI (8), UNB (11) (Figure 2.1);
no nests were found in PCW or BCGC during this sampling year. Twelve percent of the eggs were stilts and
avocets from SDC; 50 percent of the eggs were collected at IRWD from western grebe, black-necked stilt,
American avocet, killdeer, and Forster’s tern nests in Ponds 1 and 2; 16 percent of the eggs were collected at
UCI from pied-billed grebe, stilt, and killdeer nests; and 22 percent of the eggs collected in 2020 came from
UNB, where all nests were black skimmer and killdeer nests located on Hot Dog Island in the Upper Bay.
4.1 Selenium
Five eggs (10%) collected in 2020 exceeded the 8 μg Se/g tissue concentration compliance level. Those eggs
were collected from the creek and off-channel wetlands (i.e., SDC, IRWD, and UCI); one was from SDC and the
four others were from IRWD (Table 4.1). The highest egg selenium was found in a black-necked stilt egg from
SDC (18.5 μg Se/g).
One of the 6 eggs from SDC (17%), 4 of the eggs from IRWD (16%), and none of the eggs from UCI (0%) or
UNB (0%) were above the selenium TMDL target level (Table 4.1). Overall geometric mean selenium
concentration of the 50 bird eggs was 4.7 μg/g (95% CI = 4.1 – 5.4 μg Se/g dw [all eggs]) and the geometric
mean for the 39 eggs from the Watershed above Upper Newport Bay was 5.5 μg/g (95% CI = 4.8 – 6.4 μg Se/g
dw). The geometric mean of shorebird egg selenium from the Watershed above the Bay was 4.9 μg/g (95% CI =
4.1 – 6.6 μg Se/g dw). Thus the 8 μg Se/g dw approved TMDL was met and 8.1 μg Se/g dw fish tissue applies
(USEPA 2019).
Table 4.1: Selenium Concentrations in Bird Eggs Collected in May and June 2020 from the Newport Bay Watershed.
Shaded rows indicate egg selenium concentrations above the 8 μg Se/g dw target for bird eggs (USEPA 2019). Location and
species codes provided above in Section 4.
Species AOU Code Location μg Se/g dw % Moisture
Black-necked stilt BNST SDC 5.9 74.9
Black-necked stilt BNST SDC 6.6 76.7
Black-necked stilt BNST SDC 5.8 74.8
Black-necked stilt BNST SDC 18.5 76.6
American avocet AMAV SDC 4.1 74.0
American avocet AMAV SDC 5.2 73.3
Western grebe WEGR IRWD 11.0 76.9
Western grebe WEGR IRWD 8.5 77.6
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Newport Bay Watershed Biota Monitoring 28
Table 4.1: Selenium Concentrations in Bird Eggs Collected in May and June 2020 from the Newport Bay Watershed.
Shaded rows indicate egg selenium concentrations above the 8 μg Se/g dw target for bird eggs (USEPA 2019). Location and
species codes provided above in Section 4.
Species AOU Code Location μg Se/g dw % Moisture
Western grebe WEGR IRWD 7.6 78.9
Western grebe WEGR IRWD 7.9 78.0
Western grebe WEGR IRWD 8.6 81.6
Western grebe WEGR IRWD 7.1 79.8
Western grebe WEGR IRWD 7.7 80.7
Black-necked stilt BNST IRWD 3.4 75.8
Black-necked stilt BNST IRWD 5.9 76.2
Black-necked stilt BNST IRWD 5.2 76.4
Black-necked stilt BNST IRWD 5.3 73.5
Black-necked stilt BNST IRWD 5.9 73.0
Black-necked stilt BNST IRWD 5.3 74.7
Black-necked stilt BNST IRWD 4.7 74.2
Black-necked stilt BNST IRWD 6.8 74.2
American avocet AMAV IRWD 4.1 74.3
American avocet AMAV IRWD 4.7 73.9
Killdeer KILL IRWD 6.8 74.9
Forster's tern FOTE IRWD 8.1 76.8
Forster's tern FOTE IRWD 7.2 76.1
Forster's tern FOTE IRWD 6.1 78.9
Forster's tern FOTE IRWD 3.5 78.3
Forster's tern FOTE IRWD 7.3 78.1
Forster's tern FOTE IRWD 7.7 78.3
Forster's tern FOTE IRWD 3.8 78.3
Pied-billed grebe PBGR UCI 3.8 80.2
Pied-billed grebe PBGR UCI 2.9 78.8
Pied-billed grebe PBGR UCI 4.2 81.8
Pied-billed grebe PBGR UCI 4.9 77.6
Pied-billed grebe PBGR UCI 4.0 80.8
Black-necked stilt BNST UCI 3.6 76.1
Killdeer KILL UCI 1.4 75.0
Killdeer KILL UCI 4.6 70.7
Killdeer KILL UNB 2.6 72.6
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Table 4.1: Selenium Concentrations in Bird Eggs Collected in May and June 2020 from the Newport Bay Watershed.
Shaded rows indicate egg selenium concentrations above the 8 μg Se/g dw target for bird eggs (USEPA 2019). Location and
species codes provided above in Section 4.
Species AOU Code Location μg Se/g dw % Moisture
Killdeer KILL UNB 3.9 74.4
Killdeer KILL UNB 5.1 76.6
Black skimmer BLSK UNB 2.3 75.6
Black skimmer BLSK UNB 2.5 78.8
Black skimmer BLSK UNB 2.3 79.1
Black skimmer BLSK UNB 2.5 78.1
Black skimmer BLSK UNB 2.4 78.3
Selenium concentrations varied within and among species (Table 4.1, Figure 4.1) and among locations (Figure
4.2). Egg selenium concentrations from highest to lowest were western grebe (GM = 8.3 μg Se/g) > tern (GM =
5.9 μg Se/g) ~ stilt (GM = 5.8 μg Se/g) ~ avocet (GM = 4.5 μg Se/g) ~ pied-billed grebe (GM = 3.9 μg Se/g) ~
killdeer (GM = 3.6 μg Se/g) ~ skimmer (GM = 2.4 μg Se/g). By location, geometric mean egg concentrations
were (from highest to lowest) SDC (GM = 6.7 μg Se/g) ~ IRWD (GM = 6.2 μg Se/g) > UCI (GM = 3.5 μg Se/g) ~
UNB (GM = 2.7 μg Se/g).
In 2020, the geometric means of eggs from all sample locations and for all aquatic-dependent shorebirds were
below 8.0 μg/g and the TMDL target was attained (USEPA 2019). At IRWD, individual eggs from two species,
both piscivores (3 western grebes [11, 8.6, and 8.5 μg/g] and 1 Forster’s tern [8.1 μg/g]) and at SDC 1 egg from
a stilt (18.5 μg/g) were above 8.0 μg/g.
There was a significant trend (r2 = 0.93, P = 0.038) of decreasing selenium concentration from upstream to
downstream with UCI and UNB having the lowest egg selenium concentrations. However, when all years were
combined (2010 – 2020) the relationship was weak (r2= 0.27), although the decreasing trend from higher
upstream to lower downstream egg selenium was significant (P < 0.001).
The percent moisture for bird egg samples varied by about 12 percent (70.7% to 81.8%) among species or sites
with a mean of 76.7 percent (Table 4.1). Sample-specific values can be used to convert egg selenium
concentrations between dry- and wet-weight results if desired.
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Newport Bay Watershed Biota Monitoring 30
Figure 4.1: Geometric Means and Ranges of Selenium Concentrations (μg/g dw) in Eggs Collected in 2020 by Species
The dashed line indicates the target threshold concentration for egg selenium of 8 μg/g. WEGR = western grebe;
PBGR = pied-billed grebe; BNST = black-necked stilt; AMAV = American avocet; KILL = killdeer; FOTE = Forster’s tern;
BLSK = black skimmer.
Figure 4.2: Geometric Means and Ranges of Selenium Concentrations (μg/g dw) in Eggs Collected in 2020 by
Sample Location
The dashed line indicates the target threshold concentration for egg selenium of 8 μg/g.
WEGR
PBGR
BNST
AMAV
KILL
FOTE
BLSK
0
5
10
15
20
PgSe/gdw
SDC
IRWD
UCI
UNB
0
5
10
15
20
PgSe/gdw
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 31
4.2 Organochlorine Compounds
There are no TMDL targets for organochlorines in bird eggs, but fish tissue targets for San Diego Creek and
tributaries, which are expected to be protective for both aquatic life and wildlife, have been identified (SWRCB
2013) for some organochlorines in the Watershed. Egg samples were analyzed for 97 separate organochlorine
compounds (including 53 PCB congeners), and 70 of those compounds were found in at least one egg. tDDTs,
tPCBs, tAroclor, and eight other organochlorine compounds were found in eggs in 2020 (Table 4.2). DDT
breakdown products and the number of eggs they occurred in follows: o,p’-DDD was found in 7 eggs, o,p’-DDE
was found in 5 eggs, o,p’-DDT was found in 4 eggs, p,p’-DDD was found in 25 eggs p,p’-DDT was found in 25
eggs, and p,p’-DDE (Table 4.3) was found in all the eggs collected. Although some organochlorines were found
in eggs from all species and all sample locations, concentrations for all but p,p’-DDE were below levels that
would be expected to affect reproduction (Table 4.2). For example, of the PCB congeners tested, 45 congeners
were found in the eggs, and at least 6 congeners were found in each of the eggs sampled (Table 4.4). tPCBs
ranged from 0.019 to 1.3 μg/g ww. Seven Aroclors were tested and either Aroclor 1254 or 1260 was found in all
of the eggs at concentrations that ranged from 0.024 to 1.6 μg/g. Trans-nonachlor was detected in all except two
pied-billed grebe eggs from UCI in 2020 and ranged from 0.0003 – 0.139, Analytical results for all
organochlorines tested are provided in Appendix A.
The percent lipid for bird egg samples varied by about 36 percent (1.7% to 62%) among species or sites with a
geometric mean of 12.8 percent (Table 4.3). Sample-specific values can be used to convert egg organochlorine
concentrations between wet- and lipid-weight results if desired. However, the relationship between contaminant
and lipid concentrations should be examined prior to lipid-normalizing (Hebert and Keenleyside 1995). There
was no difference in percent egg lipid among piscivore eggs (P = 0.06) or among percent lipids in shorebird
eggs (P = 0.485); however, the percent egg lipid was significantly higher in shorebirds (GM = 11.0%) than
piscivores (GM = 7.6%, P < 0.001). Thus, piscivore egg and shorebird species egg lipid-normalized
organochlorine concentrations could be compared within each group but not between the groups.
4.2.1 p,p’-DDE
Bird species are not equally affected by p,p’-DDE and, in many species, associations between DDE residues
and eggshell thinning have not been found; however, threshold values for effects used for evaluation of results
were based on literature effects in species known to be sensitive. Blus et al. (1972b) developed an association
of DDE residues in brown pelican (Pelecanus occidentalis) eggs with the percent of eggshell thinning relative to
pre-1947 (i.e., pre-DDT) eggshell thickness (Y = 95.787-15.686 × [log10 DDE]). Based on this equation, about
2.4 μg DDE/g ww would cause about 10 percent thinning in pelicans, which is suggested as the impairment
threshold for white-faced ibis (Plegadis chihi) by Henny and Herron (1989); and none of the eggs were above
the 15 percent thinning threshold for pelicans (Table 4.2). Three of the eggs with elevated DDE concentrations
were from shorebirds (stilt from SDC and a stilt and killdeer from IRWD) and the other 16 were from piscivorous
birds (i.e., 8 western grebes, 2 pied-billed grebes, 3 Forster’s terns, and 3 black skimmers). The western grebe
and tern eggs were from IRWD, the pied-billed grebe eggs were from UCI, and all the skimmer eggs were from
UNB. DDE varied widely throughout the Watershed; p,p’-DDE concentrations ranged from 0.17 to 4.7 μg/g ww
(GM = 1.1 μg/g ww).
Table 4.2: p,p’-DDE, Percent Lipid, and Shell Thickness in Bird Eggs from the Newport Bay Watershed, 2020
p,p’-DDE concentrations (μg DDE/g ww), percent lipid, μg DDE/g lw, shell thickness (mm), and eggshell thickness compared to pre-DDT
eggshells1 (%) in bird eggs collected in May and June 2020 from the Newport Bay Watershed.
Species AOU Code Location
p,p’-DDE
(μg/g ww) % Lipids
p,p’-DDE
(μg/g lw)
Shell
(mm)
Eggshell
Difference
(% Pre-DDT)1
Black-necked stilt BNST SDC 0.84 12.1 6.9 0.196 -9.26
Black-necked stilt BNST SDC 0.19 11.1 1.7 0.219 1.39
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 32
Table 4.2: p,p’-DDE, Percent Lipid, and Shell Thickness in Bird Eggs from the Newport Bay Watershed, 2020
p,p’-DDE concentrations (μg DDE/g ww), percent lipid, μg DDE/g lw, shell thickness (mm), and eggshell thickness compared to pre-DDT
eggshells1 (%) in bird eggs collected in May and June 2020 from the Newport Bay Watershed.
Species AOU Code Location
p,p’-DDE
(μg/g ww) % Lipids
p,p’-DDE
(μg/g lw)
Shell
(mm)
Eggshell
Difference
(% Pre-DDT)1
Black-necked stilt BNST SDC 1.38 9.1 15.2 0.226 4.63
Black-necked stilt BNST SDC 1.62 9.79 16.5 0.223 3.24
American avocet AMAV SDC 1.48 11 13.5 0.249 0.40
American avocet AMAV SDC 0.3 11.5 2.6 0.254 2.42
Western grebe WEGR IRWD 1.95 9.33 20.9 0.372 -3.38
Western grebe WEGR IRWD 3.53 8.88 39.8 0.342 -11.17
Western grebe WEGR IRWD 4.71 9.88 47.7 0.257 -33.25
Western grebe WEGR IRWD 3.05 8.08 37.7 0.256 -33.51
Western grebe WEGR IRWD 3.10 5.24 59.2 0.341 -11.43
Western grebe WEGR IRWD 4.67 7.53 62.0 0.332 -13.77
Western grebe WEGR IRWD 3.28 7.26 45.2 0.340 -11.69
Black-necked stilt BNST IRWD 1.92 12.90 14.9 0.200 -7.41
Black-necked stilt BNST IRWD 0.20 10.70 1.9 0.194 -10.19
Black-necked stilt BNST IRWD 0.64 9.81 6.5 0.223 3.24
Black-necked stilt BNST IRWD 0.58 13.1 4.4 0.192 -11.11
Black-necked stilt BNST IRWD 0.78 10.8 7.2 0.196 -9.26
Black-necked stilt BNST IRWD 0.39 8.5 4.6 0.202 -6.48
Black-necked stilt BNST IRWD 0.53 11.9 4.5 0.207 -4.17
Black-necked stilt BNST IRWD 0.39 10.9 3.6 0.204 -5.56
American avocet AMAV IRWD 0.60 11.2 5.4 0.253 2.02
American avocet AMAV IRWD 1.09 12.8 8.5 0.256 3.23
Killdeer KILL IRWD 2.1 9.49 22.1 0.161 -10.56
Forster's tern FOTE IRWD 1.61 7.71 20.9 0.194 1.04
Forster's tern FOTE IRWD 1.71 7.10 24.1 0.196 2.08
Forster's tern FOTE IRWD 2.13 7.57 28.1 0.189 2.08
Forster's tern FOTE IRWD 1.4 6.82 20.5 0.190 0.52
Forster's tern FOTE IRWD 1.43 8.06 17.7 0.178 -3.65
Forster's tern FOTE IRWD 0.95 9.12 10.4 0.194 2.60
Forster's tern FOTE IRWD 0.60 7.79 7.7 0.183 -2.60
Pied-billed grebe PBGR UCI 2.58 7.02 36.8 0.275 5.36
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Newport Bay Watershed Biota Monitoring 33
Table 4.2: p,p’-DDE, Percent Lipid, and Shell Thickness in Bird Eggs from the Newport Bay Watershed, 2020
p,p’-DDE concentrations (μg DDE/g ww), percent lipid, μg DDE/g lw, shell thickness (mm), and eggshell thickness compared to pre-DDT
eggshells1 (%) in bird eggs collected in May and June 2020 from the Newport Bay Watershed.
Species AOU Code Location
p,p’-DDE
(μg/g ww) % Lipids
p,p’-DDE
(μg/g lw)
Shell
(mm)
Eggshell
Difference
(% Pre-DDT)1
Pied-billed grebe PBGR UCI 0.17 8.69 2.0 0.255 -2.30
Pied-billed grebe PBGR UCI 2.37 4.18 56.7 0.264 1.15
Pied-billed grebe PBGR UCI 0.27 6.21 4.3 0.256 -1.92
Pied-billed grebe PBGR UCI 1.24 5.42 22.9 0.255 -2.30
Black-necked stilt BNST UCI 0.95 10.7 8.9 0.217 0.46
Killdeer KILL UCI 0.74 10 7.4 0.162 -10.00
Killdeer KILL UCI 2.16 12.6 17.1 0.162 -10.00
Killdeer KILL UNB 0.48 12.6 3.8 0.158 -12.22
Killdeer KILL UNB 1.18 12.5 9.4 0.172 -4.44
Killdeer KILL UNB 0.65 10.3 6.3 0.147 -18.33
Black skimmer BLSK UNB 1.23 9.5 12.9 0.223 -10.44
Black skimmer BLSK UNB 4.5 8.22 54.7 0.243 -2.41
Black skimmer BLSK UNB 1.93 7.66 25.2 0.242 -2.81
Black skimmer BLSK UNB 1.03 8.58 12.0 0.224 -10.04
Black skimmer BLSK UNB 3.55 7.83 45.3 0.246 -1.20
Black skimmer BLSK UNB 1.47 9.24 15.9 0.231 -7.23
Black skimmer BLSK UNB 1.32 8.69 15.2 0.226 -9.24
Black skimmer BLSK UNB 1.34 8.24 16.3 0.227 -8.84
1 Positive values indicate that the shell is thicker than reference eggshells. Only a single literature value for black skimmer eggshell
thickness (0.249) was found.
Individually, a western grebe egg from IRWD (4.7 μg/g ww) had the highest DDE concentration. A pied-billed
grebe egg from UCI had the lowest measured egg concentration of 0.17 μg DDE/g ww. An adequate number of
eggs (≥ 3 eggs) was collected from all species for statistical comparisons of DDE concentrations. DDE among
species ranked from highest to lowest (in μg/g ww) as follows: western grebes (GM = 3.2) ~ skimmers (GM =
1.8) ~ terns (GM = 1.3) ~ killdeer (GM = 1.0) ~ pied-billed grebes (GM = 0.81) ~ avocets (GM = 0.73) ~ stilts
(GM = 0.64; Figure 4.3). Western grebe eggs had significantly higher p,p’-DDE than stilt (P < 0.001), avocet (P =
0.014), and killdeer (P = 0.04) eggs. However, none of the eggs sampled had concentrations high enough that
eggshell breakage or reproductive failure would be expected.
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 34
Figure 4.3: Geometric Means and Ranges of p,p’-DDE Concentrations in Eggs by Species in the Newport Bay
Watershed, 2020
The dashed line indicates the lowest known threshold concentration for egg p,p’-DDE of 1.6 μg/g ww. WEGR
= western grebe; PBGR = pied-billed grebe; BNST = black-necked stilt; AMAV = American avocet; KILL =
killdeer; FOTE = Forster’s tern; BLSK = black skimmer. Piscivores include WEGR, PBGR, FOTE, and BLSK,
Shorebirds include BNST, AMAV, and KILL.
DDE concentrations in eggs did not significantly vary among sites (P = 0.625); eggs from SDC ranged from 0.19
to 1.6 μg/g (n = 6, GM = 0.74 μg/g), IRWD ranged from 0.20 to 4.7 μg/g (n = 25, GM = 1.3 μg/g), UCI ranged
from 0.17 to 2.6 μg/g (n = 8, GM = 0.92 μg/g), and UNB eggs ranged from 0.48 to 4.5 μg/g (n = 11, GM = 1.4
μg/g). DDE among sites ranked from highest to lowest (in μg/g ww) as IRWD ~ UNB ~ UCI ~ SDC (Figure 4.4).
Piscivore egg (grebes, terns, and skimmers) DDE concentration (n = 27, GM = 1.7 μg DDE/g ww) was
significantly higher (P < 0.001) than shorebird (stilts, avocets, and killdeer) egg concentration (n = 23, GM = 0.74
μg DDE/g ww).
The four species of piscivorous birds sampled from three locations in the Watershed showed different DDE
concentrations. Western grebe eggs collected from IRWD had significantly higher geometric mean DDE
concentrations than tern eggs from IRWD (P = 0.033) and pied-billed grebe eggs from UCI (P = 0.048) but they
were similar to concentrations in skimmer eggs from UNB (P = 0.172).
WEGR
PBGR
BNST
AMAV
KILL
FOTE
BLSK
Piscivores
Shorebirds
0
1
2
3
4
5
PgDDE/gww
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 35
Figure 4.4: Geometric Means and Ranges of p,p’-DDE Concentrations in Eggs by Location in the Newport Bay
Watershed, 2020
The dashed line indicates the lowest known threshold concentration for egg p,p’-DDE of 1.6 μg/g ww.
4.2.2 PCBs and Other Organochlorines
Of the 53 PCB congeners analyzed, 45 were found in bird eggs collected during 2020. All eggs contained one or
more PCB congeners (Table 4.3). All of the PCBs by bird species (Figure 4.5) and by location (Figure 4.6) were
below the literature threshold for passerines (6 – 9 μg/g ww in eggs), which are species with intermediate
sensitivity (Harris and Elliott 2011). Western grebes (n = 7, GM = 0.867 μg/g ww), black skimmers (n = 8, GM =
0.577 μg/g ww), and Forster’s terns (n = 7, GM = 0.303 μg/g ww) had significantly higher egg tPCBs
concentrations than were found in black-necked stilts (n = 13, GM = 0.049 μg/g ww; P < 0.001, P < 0.001, P =
0.029, respectively), and western grebes also had significantly higher tPCBs than avocets (n = 4, GM = 0.071
μg/g ww; P = 0.020). Eggs from UNB (n = 11, GM = 0.322 μg/g ww) had significantly higher tPCBs than eggs
from SDC (n = 6, GM = 0.056 μg/g ww; P = 0.043), and all other locations had similar concentrations. Piscivore
egg tPCB concentration (n = 27, GM = 0.42 μg tPCB/g ww) was significantly higher (P < 0.001) than the
concentration in shorebird eggs (n = 23, GM = 0.068 μg tPCB /g ww).
Table 4.3: Number of PCB Congeners Detected and Concentrations of Total PCBs (tPCBs), Total Aroclors (tAroclor),
Trans-nonachlor (the most commonly detected chlordane), and Toxaphene (μg/g ww) found in Bird Eggs from
Sample Locations in the Newport Bay Watershed, 2020.
Species Site
No. of PCB
Congeners
Detected
tPCBs1 tAroclor
(1254/1260)
Trans-nonachlor
(μg/g ww)
Toxaphene2
(μg/g ww) (μg/g ww) (μg/g ww)
Black-necked stilt SDC 18 0.063 0.078 0.0046 0.109
Black-necked stilt SDC 16 0.019 0.024 0.0034
Black-necked stilt SDC 19 0.074 0.094 0.0084 0.287
Black-necked stilt SDC 11 0.060 0.074 0.0043 0.086
SDC
IRWD
UCI
UNB
0
1
2
3
4
5
Pg DDE/g ww
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 36
Table 4.3: Number of PCB Congeners Detected and Concentrations of Total PCBs (tPCBs), Total Aroclors (tAroclor),
Trans-nonachlor (the most commonly detected chlordane), and Toxaphene (μg/g ww) found in Bird Eggs from
Sample Locations in the Newport Bay Watershed, 2020.
Species Site
No. of PCB
Congeners
Detected
tPCBs1 tAroclor
(1254/1260)
Trans-nonachlor
(μg/g ww)
Toxaphene2
(μg/g ww) (μg/g ww) (μg/g ww)
American avocet SDC 30 0.148 0.184 0.0025 0.039
American avocet SDC 22 0.040 0.051 0.0017
Western grebe IRWD 42 0.547 0.689 0.0615 0.317
Western grebe IRWD 40 0.901 1.120 0.1180 0.678
Western grebe IRWD 44 1.276 1.590 0.1340 0.906
Western grebe IRWD 44 1.246 1.550 0.1380 0.821
Western grebe IRWD 42 0.629 0.791 0.0689 0.477
Western grebe IRWD 42 1.227 1.520 0.1390 0.849
Western grebe IRWD 40 0.611 0.759 0.0722 0.390
Black-necked stilt IRWD 9 0.046 0.058 0.0010 0.070
Black-necked stilt IRWD 6 0.020 0.025 0.0064
Black-necked stilt IRWD 15 0.102 0.126 0.0028 0.131
Black-necked stilt IRWD 12 0.044 0.055 0.0014 0.014
Black-necked stilt IRWD 12 0.056 0.070 0.0016 0.070
Black-necked stilt IRWD 11 0.038 0.048 0.0006 0.082
Black-necked stilt IRWD 11 0.060 0.075 0.0041 0.035
Black-necked stilt IRWD 9 0.040 0.051 0.0039 0.029
American avocet IRWD 18 0.050 0.063 0.0015
American avocet IRWD 21 0.086 0.109 0.0051 0.038
Killdeer IRWD 30 0.393 0.487 0.0475 0.173
Forster's tern IRWD 31 0.415 0.515 0.0114 0.032
Forster's tern IRWD 30 0.235 0.292 0.0178 0.058
Forster's tern IRWD 36 0.833 1.030 0.0376 0.044
Forster's tern IRWD 37 0.763 0.947 0.0163 0.053
Forster's tern IRWD 32 0.149 0.187 0.0154 0.014
Forster's tern IRWD 32 0.161 0.203 0.0112 0.011
Forster's tern IRWD 32 0.157 0.195 0.0487 0.019
Pied-billed grebe UCI 16 0.050 0.063 0.0003 0.178
Pied-billed grebe UCI 26 0.347 0.437 0.0009
Pied-billed grebe UCI 17 0.050 0.062 0.0004 0.171
Pied-billed grebe UCI 20 0.142 0.179
0.010
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Newport Bay Watershed Biota Monitoring 37
Table 4.3: Number of PCB Congeners Detected and Concentrations of Total PCBs (tPCBs), Total Aroclors (tAroclor),
Trans-nonachlor (the most commonly detected chlordane), and Toxaphene (μg/g ww) found in Bird Eggs from
Sample Locations in the Newport Bay Watershed, 2020.
Species Site
No. of PCB
Congeners
Detected
tPCBs1 tAroclor
(1254/1260)
Trans-nonachlor
(μg/g ww)
Toxaphene2
(μg/g ww) (μg/g ww) (μg/g ww)
Pied-billed grebe UCI 24 0.517 0.642 0.031
Black-necked stilt UCI 15 0.092 0.115 0.0066 0.172
Killdeer UCI 20 0.102 0.129 0.0102
Killdeer UCI 32 0.387 0.488 0.0092
Killdeer UNB 16 0.074 0.092 0.0135 0.028
Killdeer UNB 18 0.076 0.095 0.0195
Killdeer UNB 18 0.057 0.071 0.0066
Black skimmer UNB 37 1.026 1.270 0.0728 0.036
Black skimmer UNB 34 1.080 1.340 0.0161 0.021
Black skimmer UNB 33 0.519 0.653 0.0163
Black skimmer UNB 27 0.279 0.351 0.0063
Black skimmer UNB 28 0.882 1.090 0.0155 0.060
Black skimmer UNB 30 0.613 0.762 0.0064
Black skimmer UNB 28 0.544 0.685 0.0066 0.024
Black skimmer UNB 28 0.259 0.321 0.0068 0.013
1 Shaded numbers are above the fish tissue informational TMDL of 0.50 protective of aquatic life and wildlife in San Diego Creek and
tributaries (SWRCB 2013).
2 Shaded numbers are above the fish tissue TMDL target of 0.10 protective of aquatic life and wildlife in San Diego Creek and tributaries
(SWRCB 2013).
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Newport Bay Watershed Biota Monitoring 38
Figure 4.5: Geometric Means and Ranges of tPCBs Concentrations in Eggs by Species in the Newport Bay Watershed,
2020
WEGR = western grebe; PBGR = pied-billed grebe; AMAV = American avocet; BNST = black-necked stilt; KILL =
killdeer; FOTE = Forster’s tern; BLSK = black skimmer.
Figure 4.6: Geometric Means and Ranges of tPCBs Concentrations in Eggs by Location in the Newport Bay Watershed,
2020.
WEGR
PBGR
AMAV
BNST
KILL
FOTE
BLSK
0.0
0.5
1.0
1.5
Pg tPCB/g ww
SDC
IRWD
UCI
UNB
0.0
0.5
1.0
1.5
Pg tPCB/g ww
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 39
4.2.3 Eggshell Thinning
Only three tern eggs were slightly above the lowest literature threshold for effects for Forster’s tern eggs (i.e.,
7% eggshell thinning) found by King et al. (1991). Even though eggshell thinning was observed in some species
(especially western grebes) when compared to pre-DDT eggshells (Table 4.3), the levels of DDE found in most
bird eggs in the Newport Bay Watershed would be unlikely to cause a level of eggshell thinning that could affect
reproduction.
4.3 Summary of 2010 to 2020 Bird Egg Sampling and Data Analysis
Selenium and organochlorine monitoring of bird eggs has been conducted since 2010. Nests were found in all
months from March through July, but most nests of the targeted species (i.e., western grebes, pied-billed
grebes, American coots, black-necked stilts, American avocets, killdeer, black skimmers, and Forster’s terns)
were found in May and June of each year and current surveys focus on these months. Because of the extensive
coverage of suitable nesting habitat during nest searches, it is likely that most target species’ nests were found
(i.e., those that nested in May and June) during the years of sampling and that the fluctuations in the number of
eggs collected (Table 4.5) were indicative of the number of birds nesting. However, the number of eggs
collected does not represent the total number of nests that were found in that, when the target number of nests
were found, egg collection for that species was discontinued (i.e., five eggs per species per site were collected
in 2010 through 2013 and this was increased to eight eggs per species per site thereafter). In addition, eggs
sometimes were not collected for various reasons (e.g., less than 2 eggs in the nest, chick pipping the eggshell).
Table 4.4: Number of Eggs Collected from the Newport Bay Watershed by Species and Year (2010 – 2020)
Species
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 Total
Eggs
Pied-billed
grebe
5 7 1 6 5 2 1 2
5 34
Western grebe
1
8 7 16
Green heron
2
1
3
American coot 5 1 1 3
2 1 8
21
American
avocet
6 5 5 3 7 12 3 15 10 5 4 75
Black-necked
stilt
2 5 2 1 8 6 5 9 9 4 13 64
Killdeer
2 1 4 1 5 1 6 20
Black
skimmer
7 5
1
5 8 8 9 8 8 59
Forster’s tern 5 5
5 6 2 5 5
11 7 51
Total Eggs
30 28 9 19 29 30 26 42 35 45 50 343
Selenium concentrations in eggs have varied from year-to-year by sample site, but egg selenium concentrations
from within the Watershed above Newport Bay (i.e., excluding UNB and BCGC) generally have been relatively
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 40
similar from 2010 to 2020 (r2 = 0.006, P = 0.265) with a few exceptions. In 2016, the Watershed geometric mean
egg selenium concentration was at a ten-year low. After increasing again in 2017, geometric mean egg selenium
has remained relatively stable through 2020 (Figure 4.7). At individual sample locations, only SDC and IRWD
have had geometric mean egg selenium concentrations above 8.0 μg Se/g. At SDC, although there were no
significant differences in geometric mean egg selenium among years, in 3 of the 5 years that eggs were found,
the geometric mean was over 8.0 μg Se/g (2010 [n = 4, GM = 13 μg Se/g]; 2017 [n = 6, GM = 13 μg Se/g]; and
2019 [n = 3, GM = 10 μg Se/g]. At IRWD, 3 out of 10 years had geometric mean egg selenium concentrations at
or above 8.0 μg Se/g (2010 [n = 6, GM = 8.0 μg Se/g]; 2015 [n = 18, GM = 8.6 μg Se/]; and 2019 [n = 22, GM =
8.5 μg Se/]). Although individual eggs from UCI and UNB have been above 8.0 μg Se/g over the ten years, there
were no years for which geometric mean egg selenium was at or above 8.0 μg Se/g and, at UCI, only one
individual egg since 2011 has been above this threshold. Conversely, at BCGC, all but one (considered an
outlier; Grubbs test [ESD]; GraphPad Software 2020) of the 15 eggs collected from 2010 through 2018 were
above 8.0 μg Se/g, although there was a significant trend of decreasing egg selenium concentration from 2010
(37 μg Se/g) to 2018 (11 μg Se/g; r2= 0.92, P < 0.001). No nests were found in 2019 or 2020, likely due to
management activities that removed most of the nesting habitat (Figure 4.7).
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 41
Figure 4.7: Geometric Means and Ranges of Selenium Concentrations (μg/g dw) in Eggs Collected from 2010 - 2020 by
Sample Location
Watershed-wide results do not include eggs from BCGC and UNB. The dashed line indicates the target threshold
concentration for egg selenium of 8 μg/g.
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
5
10
15
20 SDC Eggs
GM and Range PPgSe/gdw
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
10
20
40
50 IRWD Eggs
GM and Range PPgSe/gdw
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
5
10
15
20
25 UCI Eggs
GM and Range PPgSe/gdw
2010
2011
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 42
The frequency of eggs with geometric mean selenium concentrations ≥ 8.0 μg/g varied among years and
species (Figure 4.5). Birds feeding in the freshwater and marine areas had different egg selenium
concentrations with 21.1 percent of freshwater piscivore eggs from IRWD and UCI and none of marine piscivore
eggs from UNB over 8.0 μg/g. No eggs were collected from BCGC in 2016, 2019, or 2020.
Table 4.5: Frequency (percent of eggs) Equal to or over the Target Selenium Concentration of 8.0 μg/g (USEPA 2019)
for Shorebirds, Piscivores, all Eggs in the Watershed, and all Eggs Excluding Eggs from BCGC from 2010 to 2020.
Percent of Eggs with 8.0 μg Se/g or greater
Year N (all eggs) Shorebirds Piscivoresa All Eggs No BCGC Eggs
2010 30 62.5 0.0 33.3 28.6
2011 23 0.0 20.0 (M) 13.0 5.0
2012 14 14.3 0.0 14.3 7.7
2013 19 0.0 16.7 (M) 15.8 5.9
2014 29 33.3 16.7 (M) 34.5 29.6
2015 30 61.1 14.3 (M) 50.0 44.4
2016 26 0.0 21.4 (M) 11.5 11.5
2017 42 40.0 6.6 (M) 28.5 25.0
2018 35 37.5 10.0 (M) 28.6 26.5
2019 45 60.0 44.4 (68.8 [FW]; 9.1[M] 40.0 40.0
2020 50 4.0 14.8 (21.1 [FW]; 0.0 [M] 10.0 10.0
a FW = freshwater; M = Marine
Unlike for selenium, there are no TMDL thresholds for organochlorines in bird eggs. Concentrations of p,p’-DDE
in eggs have varied from year-to-year but, except for 2013 and excluding UNB and BCGC eggs, geometric
mean egg p,p’-DDE remained similar overall from 2010 until 2020, when there was a slight increase. Geometric
mean p,p’-DDE concentration in eggs from the in eggs was second highest among all years, although it was not
statistically different than most years. Concentrations increased from 2018 (GM = 0.31 μg/g), doubling in 2019
(GM = 0.62 μg/g), and almost doubling again in 2020 (1.1 μg/g; Figure 4.8). At individual sample locations, only
IRWD in 2010, 2013, and 2019, UCI in 2018, and UNB in 2015 and 2018 had geometric mean egg p,p’-DDE
concentrations above the lowest available literature threshold for effects (1.6 μg/g ww). There was a general
upward trend of egg p,p’-DDE concentration from 2010 (GM = 0.195 μg/g) to 2020 (GM = 1.1 μg/g) but the trend
was not significant (r2= 0.12, P = 0.371; Figure 4.8).
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 43
Figure 4.8: Geometric Means and Ranges of p,p’-DDE Concentrations (μg/g ww) in Eggs Collected from 2010 - 2020
by Sample Location
Watershed-wide results do not include eggs from BCGC and UNB. The dashed line indicates the literature-based
threshold concentration for egg selenium of 1.6 μg/g.
Eggshell thinning for all species, except possibly Forster’s terns, does not seem to be sensitive to DDE and no
significant correlations were found between individual organochlorine compounds and eggshell thinning.
Although King et al. (1991) did not find a relation between DDE and eggshell thickness in Forster’s tern eggs
from Lavaca and San Antonio Bay, Texas, eggshells from Forster’s tern eggs collected from the Newport Bay
Watershed from 2010-2020 were combined and did show a significant negative relation between p,p’-DDE and
eggshell thickness (r2 = 0.44, F1,44 = 35.1, P < 0.001; Figure 4.9). There was no trend observed of DDE
concentration in Forster’s tern eggs over time (2010 – 2020 DDE in tern eggs (r2 = 0.0058, P = 0.614). Although
these results suggests that p,p’-DDE may affect tern eggshell thickness, the thickness of the eggs sampled
would not be expected to affect egg breakage or reproductive effects. This is still a relatively small dataset that
2010
2017
2019
2020
0.0
0.5
1.0
1.5
2.0
2.5
PPg DDE/g ww
SDC Eggs
2010
2013
2014
2015
2016
2017
2018
2019
2020
0
2
4
6
8
10
12
14
16
PPg DDE/g ww
IRWD Eggs
2010
2013
2014
2015
2016
2017
2018
2019
2020
0
5
10
15
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 44
contains mostly eggs with p,p’-DDE concentrations below 1.6 μg/g ww and the concentrations are generally
below what are likely to affect reproduction in the Watershed.
Figure 4.9: Forster’s Tern p,p’-DDE Concentrations (μg/g ww) and Eggshell Thickness in Eggs Collected from 2010 - 2020 in
the Newport Bay Watershed.
The dashed line indicates the mean (ݔҧ= 0.192, SE = 0.0019) pre-DDT eggshell thickness of Forster’s tern eggshells from
CA (Santolo 2018).
5. Discussion
5.1 Selenium in Fish
The diversity and abundance of fish in the Watershed continues to vary from year to year, necessitating the use
of new collecting techniques and moving of sampling sites (for example, SADCL). No larger fish, appropriate for
evaluating human health exposure, were caught in 2020. Winter flooding of the channel and channel
maintenance and flow management operations may have significant effects on the resident fish populations in
both the main channel and offsite wetlands ponds.
Selenium concentrations in fish tissue and in surrogate species in the freshwater drainage and Bay continue to
indicate the importance of location in determining overall levels of bioaccumulation across species as opposed
to variation among species (Figure 3.1). The main San Diego Creek channel at Basin 2 (SDC) had the highest
fish tissue selenium concentrations except for the separate drainage of BCGC/BCW, as has been apparent in
previous years. UCI continues to be a site of very low tissue selenium concentrations (crayfish and frogs) but it
has been increasingly difficult to find fish for a direct TMDL target comparison. Marine and estuarine species
from the Bay were also notably low in selenium concentrations (Figure 3.1).
The overall fish tissue selenium concentrations across all species and locations showed an increase in the
percentage of fish samples with TMDL target exceedance in 2020 (Table 3.3). The combined data showed a
significant decline in tissue concentrations through 2019, followed by an increase in 2020 (Figure 3.5).
01234
0.140
0.150
0.160
0.170
0.180
0.190
0.200
0.210
0.220
p,p'-DDE (Pg/g ww)
Eggshell Thickness (mm)
CA pre-DDT
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 45
5.2 Organochlorines in Fish
Organochlorine pesticides and PCBs analysis of fish tissue in 2020 showed similar patterns as in previous
years. Like selenium, organochlorine tissue concentrations varied more by location than by species (Table 3.2,
Figures 3.2 and 3.3). Only Bay fish exceeded TMDL threshold values for tissue concentrations (tDDT, Table
3.2), but more fillets of larger fish will need to be sampled in the future to determine compliance with human
health TMDL tissue targets for organochlorines.
The highest concentrations of key organochlorines in fish were DDT compounds in SDC, IRWD, and BBS and
total PCBs in SADCL and BBS (Figures 3.2 and 3.3). These results indicate possible upstream sources and
accumulation and biological cycling in the Bay but with concentrations in fish tissue generally below those of
concern for fish and wildlife or human exposure.
An examination of fish tissue organochlorine contaminants over the period of record indicates generally
improving conditions, with significant declines over time in the San Diego Creek drainage for both fish tissue
DDT and PCB compounds. The Big Canyon Wash results are mixed, with improvements in DDT but increased
concentrations of fish tissue PCBs over time (Figures 3.8 and 3.9).
5.3 Selenium in Bird Eggs
The bird egg selenium results suggest that, similar to fish findings, there was variable exposure of birds, likely
reflecting the variable concentrations of selenium in the sediments, plants, invertebrates, and fish in the
Watershed. Only five of the 50 eggs (10%) collected in 2020 were above the 8.0 μg Se/g target and only one of
these was a shorebird egg (18.5 μg Se/g) from SDC. Geometric mean selenium concentrations from all
sampling locations in 2020 were below the target selenium concentration of 8.0 μg/g (GM of bird eggs = 4.7
μg/g); even excluding UNB, where egg selenium concentrations were lower, the overall geometric mean was 5.5
μg Se/g and including only shorebirds the geometric mean was 4.8 μg/g.
In 2020, eggs of western grebes and Forster’s terns, two piscivorous species, were collected from IRWD; grebe
egg selenium concentrations were significantly higher than in tern eggs (P = 0.041). The difference in selenium
concentrations may be partly explained by differences in their prey species and foraging behavior. To try to
determine if there was a difference in prey species between these two bird species, the presence or absence of
organochlorine compounds matching or missing from fish and the eggs was investigated. Based on
organochlorines in the four fish species sampled from IRWD, only threadfin shad had concentrations of
chlordane-gamma, which was found in grebe eggs but not found in tern eggs, suggesting that the grebes were
feeding on the shad and the terns were not. Western grebe egg selenium (10 μg/g) was nearly equal to shad
selenium concentration (9.5 μg/g). However, this does not explain why grebe egg selenium concentrations were
higher than terns because the other fish species from IRWD had higher selenium concentrations. An alternate
hypothesis is that western grebes usually forage in the water body where they are nesting (LaPorte et al. 2020)
and are unlikely to forage far from their nests at IRWD. However, possibly like nesting Forster’s terns in San
Francisco Bay that foraged 6.2 km linear distance from their nests on average (Bluso-Demers et al. 2008), terns
nesting at IRWD could be foraging outside of IRWD and even in the Bay, which is less than 3 km from IRWD,
thereby reducing or diluting the effect of higher selenium in prey at IRWD. The Forster’s tern egg selenium was
significantly higher than black skimmer egg selenium (P < 0.001), and skimmers forage in the Bay, and perhaps
farther out to sea where selenium in fish tissue is lower (for example see Table 3.1). Furfey (2014) reported that
female skimmers nesting on barrier islands in Louisiana foraged 0.86 km and males 0.65 km from their nests.
However, in subsequent studies by Rolland et al. (2019), skimmers were found to forage over much longer
distances (i.e., up to 16 km from the nest) and almost exclusively at night. This suggests that the low egg
selenium in skimmers, even those few that nested at IRWD in earlier years (CH2M HILL 2010), may not reflect
concentrations in food items from IRWD or upstream from the Bay for this species, even though they are
frequently observed along SDC.
There was no significant trend of increasing or decreasing selenium concentrations over time Watershed-wide,
and UCI was the only site with decreasing egg selenium observed over the 2010 to 2020 time period (r2 = 0.21,
P < 0.001).
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 46
5.4 Organochlorines in Bird Eggs
Legacy organochlorines continue to be found in bird eggs collected in the Newport Bay Watershed. The primary
metabolite of DDT, p,p’-DDE, causes eggshell thinning in some species and it was found in all bird eggs. DDE
relations to eggshell thickness in wild birds show extreme species differences in sensitivity and there is a higher
rate of thinning per microgram per gram of DDE at lower residues (Blus 2011). The sensitivity of different bird
species to DDE-induced eggshell thinning varies. More than 20 percent of species are considered quite
sensitive, fewer than 20 percent of species are moderately sensitive, and the remaining species are considered
insensitive (Lundholm 1987). Eggshell thickness of the eggs collected from the Watershed was compared to
published or measured pre-DDT eggshell thicknesses; 72 percent of the eggs showed some thinning compared
to pre-DDT eggshells (Table 4.3) but, when only eggs collected in 2020 were considered, there was no apparent
DDE-related thinning. Also, in some species, literature-based pre-DDT eggshell measurements were used and
these eggshells could reflect geographic or subspecies differences due to where the birds were from or
measurement or instrument differences (Santolo 2018). Generally, DDE concentrations were relatively low in the
Watershed with 62 percent of the eggs sampled below 1.6 μg/g ww, the lowest literature-based affect
concentration. At least one egg with 1.6 μg/g p,p’-DDE was found at each location and the highest
concentrations of p,p’-DDE were found in the 7 western grebe eggs collected from IRWD.
It is interesting to note that the two piscivorous species from IRWD had significantly different egg DDE
concentrations (P = 0.001) even though they were nesting in the same ponds. As explained above, they were
possibly not foraging on the same fish species or from the same populations, based on their differences in
foraging areas (i.e., grebes foraging exclusively within the IRWD ponds and terns possibly foraging in the ponds
as well as down into the Bay). In addition, western grebes from IRWD had significantly higher egg DDE
concentrations than skimmer eggs from UNB (P = 0.040) but terns did not (P = 0.694). Based on results of other
studies (e.g., King et al. 1991), the DDE concentrations were not at a level associated with egg breakage or
reproductive failure (Table 4.2). In 2020 eggs, western grebes from the freshwater upstream wetlands at IRWD
had higher DDE levels than the black skimmers presumably foraging in the marine waters of Newport Bay.
Forster’s tern eggs from IRWD had slightly lower, but similar DDE concentrations to skimmers reflecting the
marine diet from downstream parts of the Watershed as would be suggested by various studies (e.g., Hobson
1995, Hobson et al. 1997, Hobson et al. 2000, Elliott et al. 2007, Clatterbuck et al. 2016). However, western
grebes, piscivores nesting in the same IRWD pond as the terns, had a geometric mean DDE concentration in
eggs about 28 times the DDT concentration found in fish from IRWD and 2.4 times higher than that in the tern
eggs. Some possible explanations as mentioned above are that the terns may be feeding outside of the pond
more (i.e., average of 6.2 linear distance from the nest in San Francisco Bay; Bluso-Demers et al. 2008) while
the grebes’ home range on their breeding grounds is largely determined by the size of the body of water
(LaPorte et al. 2020). It is also possible that the grebes may be feeding on a fish species with higher DDE
concentrations than terns in the pond (e.g., larger individuals or those with higher lipid content), or they may be
mobilizing more DDE from fat stores.
Grebe eggs from IRWD in 2020 had a geometric mean of 3.2 μg DDE/g ww, lower than in 2019 (7.9 μg DDE/g
ww). Compared to other western grebes in California, the 2019 IRWD grebe egg concentration was more than 5
times and 2020 egg concentration was 2.3 times the DDE concentration found in 12 western grebe eggs
collected from Tule Lake National Wildlife Refuge (NWR) in 1981 (1.4 μg/g ww; Boellstorff et al. 1985).
However, mean IRWD grebe eggshell thickness (2019 = 0.345 mm; 2020 = 0.320 mm) was similar to the mean
for 11 eggshells from 1952 – 1960 (0.355 mm: Boellstorff et al. 1985) and somewhat thinner than pre-DDT
eggshells (0.385 mm) or eggshells collected in 1972 and 1981 from Tulare Lake NWR (Range of means 0.383 -
0.390; P = 0.250; Wilcoxon Signed Rank Test; GraphPad Software 2020) but did not show a concentration-
dependent regression (r2 = 0.005; P = 0.851; GraphPad Software 2020). Thus, western grebe eggshell
thickness does not appear to be affected by DDE.
Of the organochlorines tested, DDE is the only one that was found consistently and at elevated concentrations
in fish and in bird eggs. Fish acquire DDE from the Watershed, in contrast to birds, which may be exposed both
from inside and outside of the Watershed. Since DDE is lipid soluble and retained in adipose tissues of a bird
after exposure (Bernard 1966), the DDT stored passively in fat deposits of migratory species can be released to
other tissues during periods of stress (e.g., starvation; Findlay and Defreitas 1971, Ohlendorf et al. 1980). Thus,
egg concentrations could be from exposure of the female in the wintering grounds outside of the Watershed that
may have occurred months, or possibly even years, earlier. However, the egg concentrations observed in eggs
Newport Bay Watershed Biota Monitoring
Newport Bay Watershed Biota Monitoring 47
from the upper Newport Bay Watershed are likely from legacy DDT in the Watershed where DDTs from
historical agricultural practices persist in the soils (CDFA 1985) and continue to cycle through the foodweb,
albeit in a decreasing scale over the years. This is supported by studies by Ohlendorf et al. (1978) that
concluded that organochlorine residues in black-crowned night-heron eggs likely reflected contamination in their
nesting grounds and by Hobson (1995), and Hobson et al. (1997, 2000), which showed that concentrations in
bird eggs of some species (i.e., mallards [Anas platyrhynchos], quail [Coturnix japonica], prairie falcons [Falco
mexicanus], peregrine falcons [F. peregrinus], and gyrfalcons [F. rusticolus]) reflected a female’s exposure over
about eight days prior to laying. In addition, Elliott et al. (2007) found that organochlorines on the wintering site
had no significant effect on contaminant concentrations in sample eggs from ospreys (Pandion haliaetus);
rather, concentrations of p,p’-DDE were predicted by breeding site. Clatterbuck et al. (2016) concluded that
there was a correlation between local aquatic food and seabird egg DDE concentrations indicating that birds
were exposed to organochlorines on their breeding grounds in the Southern California Bight. This suggests that
DDE concentrations in the bird eggs sampled reflect exposure in the Newport Bay Watershed; however, the
concentrations found in bird eggs in the Watershed are generally below toxicity thresholds and are likely
decreasing over time.
6. Conclusions
Selenium in fish varies by species, location, and year and concentrations are generally above TMDL threshold
concentrations, but bird eggs also vary and remain near or below TMDL threshold concentrations with few
exceptions. Organochlorines tested are widespread but generally below effect levels for fish and birds.
Newport Bay Watershed Biota Monitoring
Document No. 4
7. References
Bernard, R. F. 1966. DDT residues in avian tissues. Journal of Applied Ecology 3:193-198.
Blus, L. J. 2011. DDT, DDD, and DDE in Birds. in W. N. Beyer, and J. P. Meador, editors. Environmental
Contaminants in Biota: Interpreting Tissue Concentrations, Second Edition. CRC Press, Boca Raton,
FL.
Blus, L. J., C. D. Gish, A. A. Belisle, and R. M. Prouty. 1972a. Further analysis of the logarithmic relationship of
DDE residues to eggshell thinning. Nature 240:164-166.
Blus, L. J., C. D. Gish, A. A. Belisle, and R. M. Prouty. 1972b. Logarithmic relationship of DDE residues to
eggshell thinning. Nature 235:376-377.
Bluso-Demers, J., M. A. Colwell, J. Y. Takekawa, and J. T. Ackerman. 2008. Space use by Forster’s Terns
breeding in South San Francisco Bay. Waterbirds 31:357-369.
Boellstorff, D., H. Ohlendorf, D. Anderson, E. O'Neill, J. Keith, and R. Prouty. 1985. Organochlorine chemical
residues in white pelicans and western grebes from the Klamath Basin, California. Archives of
Environmental Contamination and Toxicology 14:485-493.
California Department of Food and Agriculture (CDFA). 1985. Agricultural Sources of DDT Residues in
California's Environment. Sacramento, CA.
Campbell, A. D. 1992. A critical survey of hydride generation techniques in atomic spectroscopy (Technical
Report). Pure and Applied Chemistry 64:227-244.
CH2M HILL. 2010. 2010 Selenium Monitoring Results: Fish and Bird Egg Tissue Chemistry, Newport Bay
Watershed.
_____. 2012. Selenium and Organochlorine Compounds in Newport Bay Watershed Fish and Bird Eggs, 2012.
Clatterbuck, C. A., R. A. Lewison, N. Dodder, C. Zeeman, and K. Schiff. 2016. Southern California Bight 2013
Regional Monitoring Program: Volume V. Contaminant Bioaccumulation in Seabird Eggs of the
Southern California Bight. Technical Report 944. Southern California Coastal Water Research Project
Authority.
Custer, T. W. and C. A. Mitchell. 1987. Organochlorine contaminants and reproductive success of black
skimmers in South Texas, 1984. Journal of Field Ornithology 58:480-489.
Eisler, R. 1990. Chlordane hazards to fish, wildlife, and invertebrates: a synoptic review. U.S. Fish and Wildlife
Service,.
Elliott, J. E., C. A. Morrissey, C. J. Henny, E. R. Inzunza, and P. Shaw. 2007. Satellite telemetry and prey
sampling reveal contaminant sources to Pacific Northwest ospreys. Ecological Applications 17:1223-
1233.
Findlay, G. M. and A. S. W. Defreitas. 1971. DDT movement from adipocyte to muscle cell during lipid utilization.
Nature 229:63-65.
Furfey, B. C. 2014. The Reproductive And Foraging Ecology of Black Skimmers (Rynchops Niger) on a Barrier
Island Refuge in Coastal Louisiana. MS, Arkansas State University, Jonesboro, AR.
GraphPad Software. 2020. GraphPad Prism 8 Version 9.0.0 for Windows. San Diego, CA.
Harris, M. L. and J. E. Elliott. 2011. Effects of Polychlorinated Biphenyls, Dibenzo-p-Dioxins and Dibenzofurans,
and Polybrominated Diphenyl Ethers in Wild Birds. in W. N. Beyer, and J. P. Meador, editors.
Environmental Contaminants in Biota: Interpreting Tissue Concentrations, Second Edition. CRC Press,
Boca Raton, FL.
Hebert, C. E. and K. A. Keenleyside. 1995. To normalize or not to normalize? Fat is the question. Environmental
Toxicology and Chemistry 14:801-807.
Henny, C. J. and G. B. Herron. 1989. DDE, selenium, mercury, and white-faced ibis reproduction at Carson
Lake, Nevada. Journal of Wildlife Management 53:1032-1045.
Hitt, N. P. and D. R. Smith. 2014. Threshold-dependent sample sizes for selenium assessment with stream fish
tissue. Integrated Environmental Assessment and Management 11:143-149.
Hobson, K. A. 1995. Reconstructing avian diets using stable-carbon and nitrogen isotope analysis of egg
components: patterns of isotopic fractionation and turnover. Condor 97:752-762.
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Hobson, K. A., K. D. Hughes, and P. J. Ewins. 1997. Using stable-isotope analysis to identify endogenous and
exogenous sources of nutrients in eggs of migratory birds: Applications to GreatLlakes contaminants
research. Auk 114:467-478.
Hobson, K. A., J. Sirois, and M. L. Gloutney. 2000. Tracing nutrient allocation to reproduction with stable
isotopes: A preliminary investigation using colonial waterbirds of Great Slave Lake. Auk 117:760-774.
Hoyt, D. F. 1979. Practical methods of estimating volume and fresh weight of bird eggs. Auk 96: 73-77.
Jacobs. 2019. Newport Bay Watershed Biota Monitoring Selenium and Organochlorine Compounds in Newport
Bay Watershed Fish and Bird Eggs, 2010 - 2019. Prepared for: County of Orange.
King, K. A., T. W. Custer, and J. S. Quinn. 1991. Effects of mercury, selenium, and organochlorine contaminants
on reproduction of Forster's terns and black skimmers nesting in a contaminated Texas Bay. Archives of
Environmental Contamination and Toxicology 20:32-40.
King, K. A., E. L. Flickinger, and H. H. Hildebrand. 1978. Shell thinning and pesticide residues in Texas aquatic
bird eggs, 1970. Pesticides Monitoring Journal 13:16-21.
LaPorte, N., R. W. Storer, and G. L. Nuechterlein. 2020. Western Grebe (Aechmophorus occidentalis), version
1.0. in P. G. Rodewald, editor. Birds of the World. Cornell Lab of Ornithology, Ithaca, NY, USA.
Lundholm, E. 1987. Thinning of eggshells in birds by DDE: Mode of action on the eggshell gland. Comparative
Biochemistry and Physiology Part C: Comparative Pharmacology 88:1-22.
Ohlendorf, H. M., E. E. Klaas, and T. E. Kaiser. 1978. Environmental pollutants and eggshell thinning in the
black-crowned night heron. Pages 63-82 in Wading Birds, Research Report #7. National Audubon
Society, New York, NY.
Ohlendorf, H. M., D. M. Swineford, and L. N. Locke. 1980. Organochlorine Poisoning of Herons. Proceedings of
the Colonial Waterbird Group 3:176-185.
Peterson, S. H., J. T. Ackerman, M. P. Herzog, M. S. Toney, B. Cooney, and C. A. Hartman. 2020. Avian
eggshell thickness in relation to egg morphometrics, embryonic development, and mercury
contamination. Ecology and Evolution n/a.
Pisenti, J. M., G. M. Santolo, J. T. Yamamoto, and A. A. Morzenti. 2001. Embryonic development of the
American Kestrel (Falco sparverius): external criteria for staging. Journal of Raptor Research 35:194-
206.
Rolland, V., B. C. Furfey, and A. Pierce. 2019. Foraging movements of Black Skimmers (Rynchops niger)
Nesting on the Isles Dernieres Barrier Island Refuge, Louisiana, USA. Waterbirds 42:95-99, 95.
Romanoff, A. L. and A. J. Romanoff. 1972. Pathogenesis of the Avian Embryo: an Analysis of Causes of
Malformations and Prenatal Death. John Wiley and Sons, New York.
Santa Ana Regional Water Quality Control Board (SARWQCB). 2007. Total Maximum Daily Loads for
organochlorine compounds: Technical staff report, November 2007. in Kathy Rose Ph.D., SARWQCB.
_____. 2011. Attachment 2 To Resolution No. R8-2011-0037: Revised Organochlorine Compounds TMDLs for
San Diego Creek, Upper and Lower Newport Bay. in Attachment 2 to Resolution No. R8-2007-0024.
_____. 2017. Draft Basin Plan Amendment – Total Maximum Daily Loads for Selenium in Freshwater in the
Newport Bay Watershed. REVISED 03-01-2017.
Santolo, G. M. 2018. A new nondestructive method for measuring eggshell thickness using a non-ferrous
material thickness gauge. The Wilson Journal of Ornithology 130:502-509.
Santolo, G. M., E. R. Byron, and H. M. Ohlendorf. 2016. Contaminants in sediment, food-chain biota, and bird
eggs from the Newport Bay watershed, Orange County, California. Environmental Monitoring and
Assessment 188:113-131.
State Water Resorces Control Board (SWRCB). 2013. Attachment 2 to Resolution No. R8-2011-0037: Revised
Organochlorine Compounds TMDLs for San Diego Creek, Upper and Lower Newport Bay (Attachment 2
to Resolution No. R8-2007-0024). .
U.S. Environmental Protection Agency (USEPA). 2018. Water Quality Standards; Establishment of a Numeric
Criterion for Selenium for the State of California: Proposed Rule. 40 CFR Part 131 12/13/2018.
_____. 2019. Total Maximum Daily Loads for Toxic Pollutants: Newport Bay Watershed Freshwater Selenium
Total Maximum Daily Loads (TMDLs). U. S. Environmental Protection Agency, Region 9.
White, D. H., C. A. Mitchell, and D. M. Swineford. 1984. Reproductive Success of Black Skimmers in Texas
Relative to Environmental Pollutants. Journal of Field Ornithology 55:18-30.
Newport Bay Watershed Biota Monitoring
Document No. 4
PPg DDE/g ww
UCI Eggs
2010
2013
2014
2015
2016
2017
2018
2019
2020
0
2
4
6
8
12
PPg DDE/g ww
UNB Eggs
2010
2013
2014
2015
2017
0.0
0.5
1.0
1.5
2.0
PPg DDE/g ww
BCGC Eggs
2010
2013
2014
2015
2016
2017
2018
2019
2020
0
2
4
10
15
PPg DDE/g ww
Watershed Eggs
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
5
10
15
40
45
50 UNB Eggs
GM and Range PPgSe/gdw
2010
2011
2012
2013
2014
2015
2016
2017
2018
0
10
20
30
40
50 BCGC Eggs
GM and Range PPgSe/gdw
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
5
10
15
20
25 Watershed Eggs
GM and Conc. PPgSe/gdw
2017
2018
2019
2020
0
10
20
30
40
ng tPCB/g ww
IRWD
2010
2011
2012
2013
2014
2015
2016
2017
2018
1
2019
1
2020
1
0
2
4
6
8
ng tPCB/g ww
UCI
2010
2011
2012
2013
2014
2015
2016
2017
2018
1
2019
2020
0
10
20
30
ng tPCB/g ww
BCW
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
1
2020
1
0
100
200
300
400
ng tPCB/g ww
2010
2011
2012
2013
2014
2015
2016
2017
2018
1
2019
2020
0
5
10
15
20
25
ng tPCB/g ww
BCGC
2010
2011
2012
2013
2014
2015
2016
2017
2018
1
2019
2020
0
20
40
60
80
ng tPCB/g ww
BBS
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
20
40
60
80
ng tPCB/g ww
SADC
IRWD
2010
2011
2012
2013
2014
2015
2016
2017
2018
1
2019
1
2020
1
0
2
4
6
8
10
ng tDDT/g ww
UCI
2010
2011
2012
2013
2014
2015
2016
2017
2018
1
2019
2020
1
0
10
20
30
40
50
ng tDDT/g ww
BCW
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
5
10
15
20
25
ng tDDT/g ww
SADC(L)
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
5
10
15
ng tDDT/g ww
BCGC
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
100
200
300
400
500
ng tDDT/g ww
BBS
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
1
0
200
400
10000
ng tDDT/g dw
2020
0
5
10
15
20
25
PPgSe/gdw
IRWD
2010
2011
2012
2013
2014
2015
2016
2017
2018
1
2019
1
2020
1
0
5
10
15
20
PPgSe/gdw
UCI
2010
2011
2012
2013
2014
2015
2016
2017
2018
1
2019
2020
0
10
20
30
40
50
60
70
80
PPgSe/gdw
BCW/BCP
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
a
2020
a
0
5
10
15
20
25
PPgSe/gdw
SADC & SADCL
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
2
4
6
8
10
PPgSe/gdw
BBS
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
0
10
20
30
40
PPgSe/gdw
BCGC
2010
2011
2012
2013
2014
2015
2016
2017
2018
1
2019
1
2020
0
10
20
30
40
50
PPgSe/gdw
Newport Bay Watershed
15
20
25
ng tPCB/g ww
BCW
SHPE
TOSM
All Fish
0
10
20
30
40
50
ng tPCB/g ww
BBS
KFH
0
5
10
15
20
25
ng tPCB/g ww
SADCL
BG
FHM
MSF
All Fish
0
5
10
15
20
25
ng tPCB/g ww
BCGC
PCW
SDC
IRWD
UCI
1
SADCL
BCW
BCGC
BBS
0
10
20
30
40
50
ng tPCB/g ww
A
C
BC A BD BD ACD BD
Figure 3.3: tPCBs Concentrations in Fish by Location and Species
Geometric mean (horizontal lines) and ranges of whole-body tissue tPCBs concentrations (ng/g ww) by location and fish
and non-fish species, and locations for all species combined (locations sharing the same letters are not significantly
different), Newport Bay Watershed, 2020. Location and species codes in text above.
3.1.4 Summary of 2010 to 2020 Fish Sampling and Data Analysis
3.1.4.1 Selenium
Across locations, the 2020 fish tissue selenium concentration was statistically different from 2019, 2018, and
2015 (Kruskal-Wallis, P < 0.05; GraphPad Software 2020). Since 2010, the lowest geometric mean fish
selenium concentrations were found in 2014, 2015, or 2019, depending on location (Figure 3.4). Over time,
when combined for all fish samples and sites (i.e., PCW, SDC, IRWD, UCI, SADC[L]), selenium in fish
decreased in the Watershed through 2019 (2010 -2019 r2= 0.09, P < 0.001) but significantly increased for the
entire dataset when 2020 was added (2010 -2020 r2= 0.006, P = 0.107) mostly driven by PCW, SDC, and
IRWD. Individual locations showed varying results. All locations except SDC [r2= 0.035, P < 0.001] show a
decrease of selenium concentration in fish over time (i.e., SADC [not significant [r2= 0.10, P = 0.209] and UCI
[r2= 0.27, P = 0.086]; IRWD [r2= 0.15, P < 0.001]; PCW ( [r2= 0.05, P = 0.001]); BCW (r2= 0.70, P < 0.001]), with
BCW showing the most dramatic reductions (Linear regression by year; GraphPad Software 2020) since 2010.
UCI
BG
FHM
All Fish
0
5
10
15
ng tDDT/g ww
BCW
SHPE
TOSM
All Fish
0
50
100
150
200
ng tDDT/g ww
BBS
KFH
AllFish
0
50
100
150
200
ng tDDT/g ww
SADCL
BG
FHM
MSF
AllFish
0
2
4
6
8
10
ng tDDT/g ww
BCGC
PCW
SDC
IRWD
UCI
1
SADCL
BCW
BCGC
BBS
0
50
100
150
200
250
ng tDDT/g ww
AAA AABA
Figure 3.2: tDDTs in Fish by Location and Species
Geometric mean (horizontal lines) and ranges of whole-body tissue tDDTs concentrations (ng/g ww) by location and fish and non-
fish species, and locations for all species combined (locations sharing the same letters are not significantly different), Newport Bay
Watershed, 2020. Location and species codes in text above.
Comparing across species, geometric means for all species ranged from 119 (SDC) down to 5.2 (BCGC; the
single crayfish sample from UCI was 1 ng/g ww) ng tDDTs/g ww in 2020. No fish samples exceeded the tDDTs
fish tissue target for protection of aquatic life and wildlife of 1000 ng/g ww (SARWQCB 2007). The rankings of
geometric mean fish tDDTs concentrations by location, for combined species (high to low, followed by statistical
significance, NS = not significant), for composites pairwise comparisons were as follows:
x SDC (20, 119 ng tDDTs/g ww) > IRWD (11, 114 ng tDDTs/g ww, NS)
0.4 2.7
IRWDP2LMB2 IRWD LMB C
IRWDP2LMB3 IRWD LMB C 1.4
60.3
0.4 3.2
IRWDP2MSS IRWD MSS C
50 NA NA 30/100 NA
NA/NA/
500
PCWBARFHM1 PCW FHM C 4.6 12.0 166.7 4.0 2.3 1.4 0.4 15.9 3.8 9.5
PCWBARFHM2 PCW FHM C 3.2
120.5 2.4 1.1 1.1 0.3
3.0 5.8
PCWBARFHM3 PCW FHM C 2.5
85.1 2.6 0.9 0.6
2.1 4.5
25
PPgSe/gdw
SADCL
SHPE
TOSM
All Fish
0
5
10
15
20
25
PPgSe/gdw
BBS
BG
FHM
MSF
AllFish
0
10
20
30
40
PPgSe/gdw
BCW
BG
FHM
MSF
AllFish
0
10
20
30
40
50
PPgSe/gdw
BCGC
PCW
SDC
IRWD
UCI
1
SADCL
BCW
BCGC
BBS
0
10
20
30
40
50
PPgSe/gdw
AC B AC AC AC B A
Figure 3.1: Selenium Concentrations in Fish Species by Location, 2020
Geometric mean (horizontal lines) and ranges of tissue selenium concentrations (μg/g dw) by location and fish and non-
fish species, and locations for all species combined (locations sharing the same letters are not significantly different),
Newport Bay Watershed, 2020. The dashed line is the TMDL site-specific objective for selenium in whole-body fish of 8.1
μg/g dw (USEPA 2017). Location and species codes in text above.
Figure 3.1 depicts the geometric means of selenium concentrations across all fish species by location for whole-
body samples in 2020. The rankings of geometric mean whole-body fish selenium concentrations, high to low,
by location across species, followed by the number of samples (n) and indication of statistical differences (NS =
not significant) to the next-lower rank, were as follows:
x BCGC ponds (14, 26.5 μg Se/g) > SDC (19, 24.2 μg Se/g, NS)
x SDC > BCW (6, 23.6 μg Se/g, NS)
x BCW > IRWD (14, 12.3 μg Se/g, NS)
x IRWD > PCW (15, 11.4 μg Se/g, NS)