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HomeMy WebLinkAboutS28 - 2007 Water Quality Report on Public HealthCITY OF NEWPORT BEACH CITY COUNCIL STAFF REPORT Agenda Item No. S28 June 26, 2007 TO: HONORABLE MAYOR AND MEMBERS OF THE CITY COUNCIL FROM: Utilities Department George Murdoch, Acting Utilities Director 949 - 718 -3400 or gmurdoch @city.newport - beach.ca.us SUBJECT: 2007 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, 2007 if their water quality measurements have exceeded any Public Health Goal (PHG). PHGs are non - enforceable goals established by the Cal - EPA's 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 addressed. If a constituent was detected in the City's water supply between 2004 and 2006 at a level exceeding an applicable PHG or MCLG, this report provides the information required by the law. Included is 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. 2007 Drinking Water Quality Report— Public Health Goals June 26, 2007 Page 2 of 6 What are PHGs? PHGs are set by the California Office of Environmental Health Hazard Assessment (OEHHA), which is part of Cal -EPA, and are based solely on public health risk considerations. None of the practical risk - management factors that are considered by the U.S. EPA or the California Department of Health Services (CDHS) in setting drinking water standards (MCLs) are considered in setting the PHGs. These factors include analytical detection capability, treatment technology available, benefits and costs. The PHGs are not enforceable and are not required to be met by any public water system. MCLGs are the federal equivalent to PHGs. Water Quality Data Considered: All of the water quality data collected by our water system between 2004 and 2006 for purposes of determining compliance with drinking water standards was considered. This data was all summarized in our 2004, 2005, and 2006 Annual Consumer Confidence Reports, which are mailed to all of our customers annually by July 1. 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 Technoloav 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. 2007 Drinking Water Quality Report — Public Health Goals June 26, 2007 Page 3 of 6 Coliform Bacteria: During 2004, 2005, and 2006, we collected over 4680 samples for coliform analysis. In November of 2006, one sample was found to be positive for coliform bacteria but absence for fecal. Three re -check samples were negative and follow up actions were taken. 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 waterborne disease. Because coliform is only a surrogate indicator of the potential presence of pathogens, it is not possible to state a specific numerical health risk. While U.S. EPA normally sets MCLGs "at a level where no known or anticipated adverse effects on persons would occur", they indicate that they cannot do so with coliforms. 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. We add chlorine at our sources 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 by CDHS as "best available technology' for coliform bacteria in Section 64447, Title 22, CCR. Arsenic: Arsenic is an element that occurs in the earth's crust. Accordingly, there are natural sources of exposure. Exposure to arsenic at high levels can pose serious health effects, as it is known to cause skin cancer and other cancers of the internal organs. In addition, it has been reported to affect the vascular system and has been associated with the development of diabetes. The U.S. Environmental Protection Agency (U.S. EPA) established a maximum contaminant level (MCL) for arsenic of 50 parts per billion in 1975. In January 2002, U.S. EPA adopted a new standard for arsenic in drinking water that requires water suppliers to reduce arsenic to 10 parts per billion by January 2007 Drinking Water Quality Report — Public Health Goals June 26, 2007 Page 4 of 6 2006. Groundwater and imported water in Orange County generally range between non - detectable levels and 5 parts per billion. The Best Available Technologies treatment for Arsenic to lower the level below the MCL is adsorptive media systems. Since the level of Arsenic in each of the City wells is already below the MCL, the adsorptive media systems treatment method would likely be used to attempt to lower the Arsenic level below the 0.004 ppb PHG. The U.S. EPA has estimated that a centralized treatment plant of this type would cost approximately $8 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 $327 per customer annually. Uranium: The PHG set by OEHHA for Uranium is 0.5 picocuries per liter (pCi /L), and the CDHS has set the MCL for Uranium at 20 pCi /L. Uranium is naturally occurring in groundwater. We have detected Uranium in all of our wells at levels between 2.1 to 15 pCi /L. 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 Best Available Technologies treatment for Uranium to lower the level below the MCL is Ion Exchange/Water Softening treatment. Since the level of Uranium in each of the City wells is already below the MCL, the Ion Exchanged/Water Softening treatment method would likely be used to attempt to lower the Uranium level below the 0.5 pCi /L PHG. The U.S. EPA has estimated that a centralized treatment plant of this type would cost approximately $10 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 $506 per customer annually. Gross Alpha: Gross Alpha is the measurement of radioactive particle activity for a group of radionuclide's which include: Uranium, Combined Radium, and Radon. The CDHS has established the MCL for Gross Alpha as 15 pCi /L (excluding Uranium and Radon), which is used as a screening standard to determine if further radionuclide monitoring is necessary. There is no PHG set by OEHHA, but the U.S. EPA has an MCLG for Gross Alpha of zero. We have detected Gross Alpha in some of our wells at levels up to 11 pCi /L. However, the level of Gross Alpha detected is mainly contributed to the Uranium content. After the Uranium content is deducted, the net Alpha is less than the minimum 2007 Drinking Water Quality Report — Public Health Goals June 26, 2007 Page 5 of 5 detectible level for regulatory reporting. Therefore, no health risks or estimates of treatment are included in this report. Summary Constituent PHG /MCLG Actual MCL/Action Level Coliform 0 1/4680 0 Arsenic .004 ppb ND -2.3 p b 10 ppb Uranium 0.43 Ci /I 2.1 to 15 pCi /I 20 pCi /I Gross Alpha 0 ND to 11 pCi /I 15 Ci /I RECOMMENDATIONS FOR FURTHER ACTION: The drinking water quality of the City Utilities Division meets all State of California, Department of Health Services and U.S. EPA drinking water standards set to protect public health. To further reduce the levels of the constituents identified in this report that are already significantly below the health -based Maximum Contaminant Levels established to provide "safe drinking water ", additional costly treatment processes would be required. The effectiveness of the treatment processes to provide any significant reductions in constituent levels at these already low values is uncertain. The health protection benefits of these further hypothetical reductions are not at all clear and may not be quantifiable. Therefore, no action is proposed. Environmental Review: This action requires no environmental review. Funding Availability: No funding is required for this report. Prepared by: Submitted by: je ure och Acting Utilities Director