2015.04.14 Work Session Minutes - Laserfiche WebLink

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He explained that EPA has identified DX as a possible human carcinogen based on animal studies. The MDH advisory health risk limit was set based on a 1 in 100,000 greater chance of getting cancer after consuming two liters of contaminated water or more each day for a lifetime (identified as being 70 years or more). He pointed out that the MDH limit is more conservative than the EPA risk assessment procedure that would result in a limit of 3.5 — 4 parts per billion of DX. He pointed out that, while the City is taking this issue seriously, it is not the same situation that New Brighton had in 1981. Keil described the various testing processes required to find emerging contaminants and outlined how the Federal Safe Drinking Water Act, the EPA's Unregulated Contaminated Monitoring Rule 3 (UCMR 3) and the Minnesota Department of Health's Health Risk Limits (HRL) affect the City of New Brighton. He informed the City Council that there is a long cycle of activity that takes place between when a contaminant is first identified and when that contaminant is regulated. He pointed out that as technology changes, we are able to search for and detect a growing number of potential contaminants. He explained that as the risks and sources of contamination are studied and are better understood, regulation can be put into place. Keil reiterated that MDH conducted testing as part of a voluntary water testing program and discovered DX in January 2014 and in July 2014. The MDH sent the City a letter stating that this testing showed no health risk to persons served by the public water supply. The MDH admitted this letter was an error when they notified the City of the presence of DX in a meeting on February 3, 2015. Although compliance is voluntary, MDH demanded immediate publication of these DX testing results through the Consumer Confidence Report and delivery of a notification letter to all New Brighton residents. Keil provided an overview of other key dates regarding DX since NBCGRS was constructed. Lotter informed the Council that the City met with the MN Department of Health regarding DX on February 17, 2015 wherein they expressed their preference that the City take the lead in and control the messaging related to this issue. The City met with the Army on March 5, 2015. On March 19, 2015, the City conducted split sampling with the MDH and used an independent testing facility to verify the water testing results. He stated that another meeting was held with the MPCA, EPA, MDH and the City on April 7, 2015 and representatives of all groups supported the City's interim response to the issue. He indicated that a meeting was held with the Army on April 14, 2015 which was extremely productive as the Army was candid and supportive of the City. Keil stated that he has reviewed the results from the independent testing of water samples and indicated that they range from 2.9 parts per billion to 5.9 parts per billion in the effluent of the treated water from the water treatment plant. Accordingly, we know the GAC does not have an impact on DX. He stated that, depending on where they are located in the plume, the concentration of DX in untreated wells range from 2 parts per billion to 7 parts per billion and reminded the Council that this issue affects Fridley as well as New Brighton. He confirmed that the Mount Simon Hinckley (MSH) wells were tested and found to be uncontaminated. He recommended that, as a first response, the City switch to these uncontaminated MSH aquifer wells as the City's primary water supply and to use the NBCGRS only as minimally necessary to meet peaking demands during the summer months. He suggested that policy conversations may be necessary to determine whether the Council would be interested in reducing the demand for water in the peak period by controlling irrigation. Keil stated that the City has talked with the Army about the potential of continuing remediation through temporary surface water discharge and is looking at implementing a supplemental treatment method to address the DX as quickly as possible. Snyder clarified that during their April 14, 2015 meeting the Army confirmed that they want to continue pumping and treating the water for TCE, that they want to continue to meet their obligation to clean TCE from