City of San Juan Capistrano Agen~~~ port

Transcription

1 8/19/2014 TO: FROM: DATE: SUBJECT: City of San Juan Capistrano Agen~~~ port E3 Karen P. Brust, City Manage~ ~)~~ Keith VanDer Maaten, P.E., Public Works and Utilities Director--1}~.. Prepared by: Eric Bauman, P.E., Utilities Engineer tm"-'..kf.z~ August19, 2014 Consideration of Domestic Water Public Health Goals RECOMMENDATION: Open a public hearing, accept public testimony, close the public hearing; and by motion, receive and file. EXECUTIVE SUMMARY: The drinking water quality of the City of San Juan Capistrano meets all State of California, Department of Health Services and the United States Environmental Protection Agency drinking water standards set to protect public health. Even so, the California Department of Public Health requires that all water service providers evaluate and hold a public hearing every three years describing what it would take to treat water that is delivered to customers to an even higher level to meet Public Health Goals that are more stringent than current water standards. As part of the public hearing, the California Department of Public Health requires that a plain language report be presented that identifies and describes any constituents in the City's water system that are candidates to consider for additional treatment to meet Public Health Goals, the category of risk to public health for each particular constituent, the best available technology for treatment, the estimated cost to lower the constituent level to the Public Health Goal level, and any recommended actions. DISCUSSION/ANALYSIS: The Maximum Contaminant Level is defined as the highest "safe" concentration level of a constituent that is allowed in public drinking water systems and is set at a level that provides protection to consumers against health risks. Public Health Goals are constituent levels in drinking water that are more stringent than the Maximum Contaminant Level and are defined as the level of constituent below which there is no known or expected risk to health. A Public Health Goal is not a regulatory standard as drinking water that comp lies with all the Maximum Contaminant Levels is considered safe to drink. The following constituents in the City's water system are candidates to consider for additional treatment to meet Public Health Goals as they are well within the safe limits for drinking water but are above the Public Health Goals: Arsenic, Lead, Combined Radium, Gross Alpha Radiation, Gross Beta Radiation, Uranium, and Coliform Bacteria.

2 August19,2014 Page 2 of 5 Arsenic: Arsenic is an element that is found in water at low concentrations and can come from either natural occurrences (such as volcanic rock, erosion of rock, or a result of forest fires) or human activities (such as mining, agriculture, or manufacturing). Arsenic is most commonly found in water sources as a result of natural leaching from soils (naturally occurring). Arsenic consumed over a long period of time above the Maximum Contaminant Level may cause cancer and other noncancerous effects on humans including cardiovascular, immunological, and neurological effects. The Public Health Goal for arsenic is set at milligrams per liter and the Maximum Contaminant Level for arsenic is milligrams per liter. Arsenic was detected above the Public Health Goal in the imported water from the Metropolitan Water District of Southern California and from City produced groundwater between 2010 and The levels detected were well below the Maximum Contaminant Level at all times and ranged from non-detect readings to milligrams per liter. The best available technologies for treating arsenic are activated alumina, coagulation/filtration, ion exchange, lime softening, reverse osmosis, electro dialysis, and/or oxidation/filtration. Currently, the Metropolitan Water Dit?trict of Southern California uses coagulation/filtration and the City uses oxidation/filtration and reverse osmosis which are best available technologies for reducing arsenic levels. Because arsenic is currently being treated with recommended best available technologies for the Ground Water Recovery Plant wells and the imported water, no additional actions are recommended for these sources. The water from the North Open Space well does not have a best available technology treatment system in place to meet Public Health Goals. To treat the well water with ion exchange (the lowest cost option) it is estimated to cost a minimum of $2.17 per hundred cubic feet of water, or $611,000 per year. The effectiveness of the treatment processes to provide any significant reductions at these already low values is uncertain as the best available technologies and costs are based on treatment to the Maximum Contaminant Levels and there is no supporting analytical information that additional treatment will be successful in meeting Public Health Goals, no matter how much money is spent. No further action is recommended at this time. Lead: Lead is found in the air and in our food. This metal comes from galvanized pipes, solder used with copper pipes, auto exhausts, and other sourcesr Lead enters drinking water systems mainly from corrosion of lead plumbing materials. Excessive amounts of lead, well above any current levels found in the City's water, may cause nervous system disorders or brain or kidney damage and can retard the physical and mental development of children. The Public Health Goal for lead is milligrams per liter. There is no Maximum Contaminant Level for lead; instead, the 90th percentile value of all samples from household taps in the distribution system cannot exceed an Action Level of milligrams per liter. Exceedance of the Action Level is not a violation of the rules to protect public health, but can trigger other requirements that include monitoring, corrosion control treatment, or service line replacements. Every three years, selected residents are tested for copper and lead at the tap as part of the City's lead and copper testing program. The most recent set of thirty samples was collected in At that time, the City

3 August 19, 2014 Page 3 of 5 detected lead above the Public Health Goal but well below the Action Level at all times. The goth percentile value was reported at milligrams per liter. The best available technology for treating lead is the removal of any plumbing materials in the water system that contain lead. To further reduce levels of lead to the Public Health Goal would require extensive studies of the water quality at each customer's tap and potentially the replacement of the customer's service line or internal house plumbing or fixtures. Estimated costs for the study to meet the Public Health Goals, including sufficient collection and testing of water samples at customer's taps, would be approximately $500,000 and the cost for each customer to replace their service line or internal house plumbing and fixtures could range from a few hundred dollars to tens of thousands of dollars. As the City has a tri-annual copper and lead testing program, has testing results that show lead well below the Action Level, and due to the high costs on the City and its customers to do extensive testing and retrofitting, no further action is recommended at this time. Radionuclides: Radium and uranium occur naturally in the ground and dissolve into groundwater supplies. The natural radioactivity results from well water passing through deposits of naturally occurring radioactive materials. Radium and uranium consumed over a long period of time above the Maximum Contaminant Level may cause cancer. The specific constituents that are regulated include Combined Radium (Radium 226 and Radium 228), Gross Alpha Radiation, Gross Beta Radiation, and Uranium. Combined Radium: The Public Health Goal for radium-226 is 0.05 picocuries per liter and picocuries per liter for radium-228. The Maximum Contaminant Level for combined radium is 5.0 picocuries per liter. The City reported a detection of combined radium that ranged from non-detect to 0.66 picocuries per liter from the City's groundwater supplying the Ground Water Recovery Plant and the City's North Open Space well in The levels detected were well below the Maximum Contaminant Level at all times but above the Public Health Goal. Gross Alpha and Gross Beta Radiation: Alpha and beta radiation is used as an indicator of the presence of radium-226, radium-228, radon, uranium and other radionuclides. The Public Health Goal for gross alpha and gross beta radiation is 0.0 picocuries per liter. The Maximum Contaminant Level for gross alpha is 15.0 picocuries per liter and for gross beta it is set at 50 picocuries per liter by California law and 4 millirem per year by federal law. The City detected gross alpha above the Public Health Goal in the imported water from the Metropolitan Water District of Southern California and in the City's groundwater wells between 2010 and The levels detected were below the Maximum Contaminant Level at all times, averaging 3.65 picocuries per liter and ranging between non-detect and 9.3 picocuries per liter for the imported water and averaging 7.41 picocuries per liter in the North Open Space well and 6.15 picocuries per liter in the Ground Water Recovery Plant wells. The two groundwater sources ranged from non-detect to 13.7 picocuries per liter. The City detected gross beta above the Public Health Goal in the imported water from the Metropolitan Water District of Southern California between 2010 and 2013.

4 August 19, 2014 Page4 of5 The levels detected were below the Maximum Contaminant Level at all times, averaging approximately 1.07 picocuries per liter and ranging from non-detect to 6.4 picocuries per liter. Uranium: The Public Health Goal for uranium is 0.43 picocuries per liter. The Maximum Contaminant Level for uranium is 20.0 picocuries per liter. The City detected uranium above the Public Health Goal in the imported water from the Metropolitan Water District of Southern California and in the City's groundwater wells between 2010 and The levels detected were well below the Maximum Contaminant Level at all times, and averaged picocuries per liter in the imported water, 5.8 picocuries per liter in the Ground Water Recovery Plant wells, and 5.0 picocuries per liter in the City's North Open Space well. Values from the various sources ranged from 2.0 to 7.5 picocuries per liter. The best available technologies to treat combined radium, gross alpha, gross beta, and uranium are ion exchange, reverse osmosis, and/or lime softening treatment. These contaminants are currently being treated with a recommended best available technology at the Ground Water Recovery Plant through reverse osmosis and at the Metropolitan Water District of Southern California treatment plant with ion exchange. No further actions are recommended for the Ground Water Recovery Plant and the imported water. The Northwest Open Space well currently does not use any of the best available technology treatments. If the use of the best available treatment (ion exchange) were to be installed at the North Open Site Well it would cost a minimum of $2.17 per hundred cubic feet of water, or $611,000 per year to operate. The effectiveness of the treatment processes to provide any significant reductions at these already low values is uncertain as the best available technologies and costs are based on treatment to the Maximum Contaminant Levels and there is no supporting analytical information that additional treatment will be successful in meeting Public Health Goals, no matter how much money is spent. No further action is recommended at this time Coliform Bacteria: Coliform bacteria are ubiquitous in nature and are not generally considered harmful. Coliform bacteria are an indicator organism for potential pathogens or organisms that can cause waterborne disease and are used in testing because of the ease in the monitoring and analysis of this type of bacteria. 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. The Public Health Goal for coliform bacteria is zero (0) positive samples per month and the Maximum Contaminant Level is 5% positive samples of all samples per month. Between 2010 and 2013, of the 55 to 60 samples collected monthly, the highest fraction of positive samples testing positive for coliform bacteria was 1.97% which is above the Public Health Goal but well below the Maximum Contaminant Level. The City adds chlorine at key points in the distribution system that test low for chlorine residual 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

5 August19,2014 Page 5 of 5 water to have undesirable taste and odor or increasing the disinfection byproduct level. This process is essential in supplying our customers with safe drinking water. Additionally, the City implements an effective cross connection control program, an effective monitoring and surveillance program, and maintains positive pressures in our distribution system. The City has taken all of the steps described by the California Department of Public Health as the best available technology for coliform bacteria in and therefore no further action is recommended. Summary of Recommendations for Further Action: The drinking water quality of the City of San Juan Capistrano meets all State of California, Department of Health Services and United States Environmental Protection Agency drinking water standards set to protect public health. To further reduce the levels of the constituents 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 as the best available technologies and costs are based on treatment to the Maximum Contaminant Levels and there is no supporting analytical information that additional treatment will be successful in meeting Public Health Goals no matter how much money is spent. Additionally, in some cases, installing treatment to further reduce very low levels of one constituent may have adverse effects on other aspects of water quality. Therefore, no further action is recommended at this time. ENVIRONMENTAL IMPACT: FISCAL IMPACT: PRIOR CITY COUNCIL REVIEW: At its scheduled meeting of April 21 5 ', 2009, the City Council held a public hearing, accepted public testimony, and closed the public hearing in consideration of Public Health Goals NOTIFICATION: California Department of Public Health A TT ACHMENT(S):