McKinley Lake IA 05-PLA-1470

Fish consumption uses remain assessed (monitored) as “partially supported” based on results of U.S.EPA/DNR fish contaminant (RAFT) monitoring at McKinley Lake in 2009, 2010, and 2015. The existence of, or potential for, a fish consumption advisory is the basis for Section 305(b) assessments of support of fish consumption uses in Iowa’s rivers and lakes. The fish contaminant data generated from the 2009 RAFT sampling conducted at McKinley Lake showed that levels of PCBs were sufficiently high for concern and thus justified follow-up monitoring. Results from this sampling showed that the level of PCBs in the sample of channel catfish fillets (0.212 ppm) exceeded the 1 meal/week trigger level (0.2 ppm) as defined in Iowa’s fish consumption advisory protocol. According to DNR’s assessment methodology, the single occurrence of contaminant above an advisory trigger level neither warrants issuance of an advisory nor indicates impairment of the fish consumption uses: two consecutive samplings that show contaminant levels are above the trigger level in fillet samples are needed to justify issuance of an advisory. Follow-up sampling conducted in 2010 showed that levels of PCBs in common carp (0.263 ppm) again exceeded the 1 meal/week trigger level (0.2 ppm).Follow-up sampling conducted in 2015 showed that levels of PCBs in common carp (0.490 ppm) again exceeded the 1 meal/week trigger level (0.2 ppm).Thus a one meal per week fish consumption advisory was issued for McKinley Lake, and the fish consumption uses are thus assessed as “partially supported.”

Note: In the late summer and fall of 2016, McKinley Lake level will be lowered for bridge replacement. Due to the lowering of the lakelevel fish kills may occur. A temporary relaxation of the fishing regulations will be in place to deal with the increasedconcentration of fish due to the decreased volume of water.