Fort Des Moines Park Pond IA 04-LDM-1099

Assessment Comments

Assessment is based on results of Iowa DNR fish contaminant monitoring in August 2007.

Basis for Assessment

SUMMARY: The Class B(LW) (aquatic life) uses are "not assessed" due to a lack of water quality monitoring at this lake.   The fish consumption uses are assessed (monitored) as "fully supporting" based on results of IDNR fish contaminant monitoring in August 2007.  

EXPLANATION:  The Class B(LW) (aquatic life) uses are "not assessed" due to a lack of water quality monitoring at this lake.   Fort Des Moines Park Pond is not monitored through the Iowa State University Lake monitoring program or the ambient lake monitoring program done by the University of Iowa Hygienic Laboratory.

Fish consumption uses are assessed (monitored) as “fully supported” based on results fish contaminant monitoring conducted by Iowa DNR at this lake in August 2007 in response to a contaminant concern.   Fish contaminant monitoring conducted by Iowa DNR in 1995 had shown a level of the pesticide methoxychlor that, although not exceeding any consumption advisory trigger levels, did suggest the need for follow-up monitoring.   The result of monitoring in 2007 showed low levels of the primary contaminants in the composite samples of fillets from largemouth bass and channel catfish.   Levels in the sample of largemouth bass fillets were as follows:  mercury: 0.27 ppm; DDD: 0.024 ppm; and DDE: 0.038 ppm.   Levels in the sample of channel catfish fillets were as follows:  mercury: 0.027 ppm; DDD: 0.025 ppm; and DDE: 0.030 ppm.   Methoxychlor was not detected in either sample.   Levels of the DDT metabolites DDD and DDE in the Fort Des Moines Pond tissue samples were typical of levels seen in other samples of Iowa fish and do not suggest a risk to human health.  

The existence of, or potential for, a fish consumption advisory is the basis for Section 305(b) assessments of the degree to which Iowa’s lakes and rivers support their fish consumption uses.   Prior to 2006, IDNR used action levels published by the U.S Food and Drug Administration to determine whether consumption advisories should be issued for fish caught as part of recreational fishing in Iowa.   In an effort to make Iowa’s consumption more compatible with the various protocols used by adjacent states, the Iowa Department of Public Health, in cooperation with Iowa DNR, developed a risk-based advisory protocol.   This protocol went into effect in January 2006 (see http://www.iowadnr.gov/fish/news/consump.html for more information on Iowa’s revised fish consumption advisory protocol).   The levels of contaminants in the samples collected in 2007 do not exceed any of the new (2006) advisory trigger levels, thus suggesting no justification for issuance of a consumption advisory for this waterbody.   The level of mercury in the sample of largemouth bass (0.27 ppm) does, however, approach Iowa's trigger level for a one meal per week advisory (0.3 ppm).   Thus, Iowa DNR plans to conduct follow-up monitoring at this lake on an every-other-year basis to monitor levels of mercury in largemouth bass.