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HomeMy WebLinkAboutSS2 - 2004 Drinking Water Quality Report on Public Health Goals• CITY OF NEWPORT BEACH CITY COUNCIL STAFF REPORT Study Session Item No. SS? November 23, 2004 TO: HONORABLE MAYOR AND MEMBERS OF THE CITY COUNCIL FROM: Utilities Department Eldon Davidson, Utilities Director 949 - 718 -3400 edavidson@city.newport-beach.ca.us SUBJECT: 2004 Drinking Water Quality Report on Public Health Goals RECOMMENDATION: Receive and file report. DISCUSSION: • Background: Provisions of the California Health and Safety Code Section 116470 (b) specify that public water systems serving more than 10,000 service connections must prepare a special report by July 1, 2004 if their water quality measurements have exceeded any Public Health Goal (PHG). We met this reporting goal. PHGs are non - enforceable goals established by the California Office of Environmental Health Hazard Assessment ( OEHHA). The law also requires that where OEHHA has not adopted a PHG for a constituent, the water suppliers are to use the Maximum Contaminant Level Goal (MCLG) adopted by U.S. EPA. Only constituents which have a California primary drinking water standard and for which either a PHG or MCLG has been set need to be in the Report. The Report is required to state if a constituent was detected in the City's water supply between 2001 and 2003 at a level exceeding an applicable PHG or MCLG. Along with the numerical public health risk associated with the Maximum Contaminant Level (MCL) and the PHG or MCLG, the Report includes: 1. A category or type of risk to health that could be associated with each - constituent; 2. The best treatment technology available that could be used to reduce the constituent level; and 3. An estimate of the cost to install that treatment if it is appropriate and feasible. • 2004 Drinking WQ Report — Public Health Goals November 23, 2004 Page 2 What are PHGs? PHGs are set by the California OEHHA, which is part of Cal -EPA, and are based solely on public health risk considerations. The PHGs are not enforceable and are not required to be met by any public water system. MCLGs are the federal equivalent to PHGs. Guidelines Followed: The Association of California Water Agencies (ACWA) formed a workgroup that prepared guidelines for water utilities to use in preparing these newly required reports. The ACWA guidelines were used in the preparation for our Report. No guidance was available from state regulatory agencies. Best Available Treatment Technology and Cost Estimates: Both the U.S. EPA and CDHS adopt what are known as Best Available Technologies (BAT), which are the best known methods of reducing contaminant levels to the MCL. Costs can be estimated for such technologies. However, since many PHGs and all MCLGs are set much lower than the MCL, it is not always possible or feasible to determine what treatment might reduce a constituent downward to or near the PHG or MCLG, many of which are set at zero. Estimating the costs to reduce a constituent to zero is difficult, if not impossible, because it is not possible to verify, by analytical means, that the level has been lowered to zero. In some cases, installing treatment to try and further reduce very low levels of one constituent may have adverse effects on other aspects of water quality. Constituents Detected That Exceed a PHG or a MCLG: The following is a discussion of constituents that were detected in one or more of our drinking water sources at levels above the PHG, or if no PHG, above the MCLG. Definition of Units mg/I - milligrams per liter (one part per million) ug/I - micrograms per liter (one part per billion) pCi /I - picoCuries per liter Copper & Lead Copper and lead generally do not occur in significant amounts in source waters, but occur as the result of corrosion of copper and lead plumbing materials in contact with the water. Since most copper /lead- bearing material is located in household plumbing, State and Federal regulations require public water systems to periodically collect a representative number of water samples at taps inside homes of residential customers. • r 1 U 2004 Drinking WQ Report — Public Health Goals November 23, 2004 Page 3 • There is currently no MCL for copper or lead. Instead, the State has set a health -based advisory level called an Action Level. Action Levels are established for chemicals in drinking water where no MCLs have been set. Action Levels are set at a level which will pose no significant health risk. The 90`h percentile value of all samples from household taps in the distribution system cannot exceed an Action Level of 1.3 mg /I for copper and 15ug/l for lead. If 10% of the tap water samples collected are over the Action Level, then treatment may be required to inhibit corrosion or to adjust the mineral content of the water. The PHG for copper is 0.17 mg /I and lead is 2 ug/I. The category of health risk for copper and lead is gastrointestinal irritation. Numerical health risk data on copper and lead have not yet been provided by OEHHA, the State agency responsible for providing that information. All of our source water samples taken from wells in 2001, 2002 and 2003 were less than the PHG for copper and lead. Based on extensive sampling of our distribution system via household testing, in 2003, our 90`h percentile value for copper was 0.30 mg /I and lead was 9 ug /I, which is well below the Action Level. Therefore, our water system is in full compliance with lead and copper standards. Further, we are deemed by CDHS to have 'optimized corrosion control' for our system. • In general, optimizing corrosion control is considered to be BAT to deal with corrosion and any lead or copper findings. We continue to monitor our water quality parameters that relate to corrosivity, such as the pH, hardness, alkalinity, total dissolved solids, and will take action if necessary to maintain our system. Uranium: The PHG set by OEHHA for uranium is 0.5 pCi /I and the MCL is 20 pCi/l. Uranium naturally occurs in groundwater. We have detected uranium in all of our wells at levels between 2.6 to 13 pCi /I. The levels detected were below the MCLs at all times. The category of health risk associated with uranium, and the reason that a drinking water standard was adopted for it, is that people who drink water containing uranium above the MCL throughout their lifetime could experience an increased risk of cancer. CDHS says that "drinking water which meets this standard (the MCL) is associated with little to none of this risk and should be considered safe with respect to uranium." The BAT treatment for uranium to lower the level below the MCL is Ion ExchangeNVater Softening treatment. Since the level of uranium in each of the City wells is already below the MCL, the Ion ExchangedNVater Softening treatment method would likely be used to attempt to lower the uranium level below the 0.5 pCi /I PHG. The U.S. EPA has estimated that a centralized treatment plant of this type would cost approximately $5 million per year, including initial construction costs and additional operations and maintenance costs. This would result in an assumed increased cost for each water • customer of about $268.00 per year on their annual water usage costs. 2004 Drinking WQ Report — Public Health Goals November 23, 2004 Page 4 Coliform Bacteria: During 2001, 2002, and 2003, we collected over 4,524 samples for coliform analysis. In September of 2003, one sample was found to be positive for coliform bacteria but negative for fecal. Three re -check samples were negative. The MCL for coliform is 5% positive samples of all samples per month and the MCLG is zero. The reason for the coliform drinking water standard is to minimize the possibility of the water containing pathogens, which are organisms that cause waterbome disease. Because coliform is only a surrogate indicator of the potential presence of pathogens, it is not possible to state a speck numerical health risk. While U.S. EPA normally sets MCI-Gs "at a level where no known or anticipated adverse effects on persons would occur," they indicate that they cannot do so with coliform. Coliform bacteria are indicator organisms that are ubiquitous in nature and are not generally considered harmful. They are used because of the ease in monitoring and analysis. If a positive sample is found, it indicates a potential problem that needs to be investigated and follow -up sampling done. It is not at all unusual for a system to have an occasional positive sample. It is difficult, if not impossible, to assure that a system will never get a positive sample. Our follow -up samples were negative, which indicate no potential problem and no need for further investigation. is We add chlorine at our sources to kill bacteria and to assure that the water served is • microbiologically safe. The chlorine residual levels are carefully controlled to provide the best health protection without causing the water to have undesirable taste and odor or increasing the disinfection byproduct level. This careful balance of treatment processes is essential to continue supplying our customers with safe drinking water. Other equally important measures that we have implemented include: ♦ An effective cross - connection control program, ♦ Maintenance of a disinfectant residual throughout our system, ♦ An effective monitoring and surveillance program, and ♦ Maintaining positive pressures in our distribution system. Our system has already taken all of the steps described as BATs for coliform bacteria. Summary Constituent PHG /MCLG Goal Our Level Action Level Copper 0.17 mg /I 0.3 mg /I 1.3 mg /I Uranium 0.5 pCi/l 2.6 to 1Ci/I 20 pCi /I Lead 2 ug /I 9 ug /I 15 ug /I Coliform 0 1 positive test 0 L • C� • 2004 Drinking WQ Report — Public Health Goals November 23, 2004 Page 5 RECOMMENDATIONS FOR FURTHER ACTION: The drinking water quality of the City of Newport Beach meets all State of California, Department of Health Services and U.S. EPA drinking water standards set to protect public health; therefore, no action is proposed. Prepared by: Pe a Antista, Operations Manager Submitted by: 4041� Eldon Davidson, Utilities Director