Public Notice: Maximum Contaminant Level Violation MCL, Lraa

Public Notice: Maximum Contaminant Level Violation MCL, LRAA / TOTAL HALOACETIC ACIDS (HAA5) On December 18, 2018, the City of Atlanta, Department of Watershed Management (DWM) received a notice of violation from the Georgia Environmental Protection Division. DWM was notified that the water system recently violated a drinking water standard. Although this is not an emergency, you, as our customers, have a right to know what happened, what you should do, and what we are doing to correct this situation. We are required to monitor your drinking water for the presence of disinfection byproducts (DBPs) on a quarterly basis. The EPD has determined that the water system exceeded maximum contaminant level (MCL) for Total Haloacetic Acids (HAA5) at sampling point 509 (located at 850 Mount Vernon Highway). The HAA5 MCL at sampling point 509 was exceeded during the third quarter of 2018 (07/01/2018 09/30/2018), with a locational running annual average (LRAA) of 0.062 mg/L. This constitutes a violation of the Georgia Rules for Safe Drinking Water and Title 40 CFR § 141.64(b), which set the LRAA MCL for HAA5 at 0.060 mg/L. There is nothing you need to do at this time. This violation does not pose a threat to the quality of the water supplied. You do not need to boil your water or take other corrective actions. Residents should not be alarmed and do not need to seek alternative water supplies. The supplier is taking corrective actions to ensure that adequate monitoring and reporting will be maintained. Some people who drink water-containing HAA5 in excess of the maximum contaminant level (MCL) over many years, experience problems with their liver, kidneys, or central nervous system, and may have an increased risk of getting cancer. If you have a severely compromised immune system, have an infant, are pregnant, or are elderly, you may be at increased risk and should seek advice from your health care providers about drinking this water. When disinfectants are used in the treatment of drinking water, disinfectants react with naturally occurring organic and inorganic matter present in water to form disinfection byproducts (DBPs). We have taken the following corrective actions: When informed of the increased levels from the July 2018 sampling event, DWM quickly began an enhanced flushing program to decrease the age of the water in the system, especially in low use areas. Just as quickly as DWM became aware of the increased levels, DWM resampled for HAA5 at each of the twelve monitoring locations where some elevated levels were detected. The amounts detected were well below the MCL of 0.06 mg/L at all twelve sampling site locations. The result at location 509 was 0.043 mg/L. However, Total Haloacetic Acid (HAA5) levels are determined by averaging the levels measured each quarter. Even though the levels during the October 2018 sampling event are less than the MCL of 0.06 mg/L, the locational running average is above the MCL due to the third quarter of this monitoring period. DWM has procured an engineering firm to assess sustainable measures to mitigate this issue. Additionally, DWM has deployed monitoring instrumentation to provide additional means for the laboratory to monitor for disinfection by-products, and we have increased the frequency that we test the water, as well as the frequency of flushing to circulate water in this area of the system. This means the frequency of checking DBP levels will increase and will validate that DWM's corrective actions are effective. If you have any questions, please contact Paul Moisan at 404-546-1232, or at 72 Marietta Street NW, Atlanta, GA 30303. 1-12/2019