Assessment Comments
Assessment is based on results of (1) IDNR/UHL ambient monitoring conducted from 2002-04 in support of TMDL development and (2) biological monitoring conducted by IDNR and UHL in 1995 and (3) EPA/IDNR fish contaminant (RAFT) monitoring in 2003.
Basis for Assessment
SUMMARY: The Class B(WW) aquatic life uses are assessed (monitored) as "fully supported" based on results TMDL-related water quality monitoring from 2002 through 2004. Fish consumption uses are assessed (monitored) as “fully supported” based on results of fish contaminant monitoring in 2003. The sources of data for this assessment are the results of (1) monthly monitoring conducted by IDNR and UHL at one location near Ionia (STORET station 11190001 (station 69)) from January 2002 through December 2004 as part of monitoring in support of TMDL development and (2) U.S. EPA/IDNR fish contaminant (RAFT) monitoring in 2003.
EXPLANATION: The assessment of the Class B(WW) uses for the current (2002-2004) assessment period ("fully supported") is based on results of TMDL-related monitoring near Ionia from 2002 through 2004 that showed no violations of Class B(WW) criteria for dissolved oxygen or pH in the 41 samples collected, or for ammonia-nitrogen in the 32 samples collected and analyzed. The parameter coverage at this station is somewhat limited (i.e., no analysis for toxic metals or pesticides). This assessment is consistent with previous assessments of aquatic life uses (“fully supported”) based on results of IDNR/UHL biocriteria sampling in 1995 and on results of IDNR stream use assessments in 1995 (see assessment developed for the 2000 report).
Fish consumption uses were assessed (monitored) as “fully supported” based on results of U.S.EPA/IDNR fish contaminant (RAFT) monitoring at Chickasaw Park in 2003. 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. 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). Because the revised (2006) protocol is more restrictive than the previous protocol based on FDA action levels; fish contaminant data that previously suggested “full support” may now suggest impairment of the fish consumption uses.
Although this scenario does not apply to the fish contaminant data generated from the 2003 RAFT sampling conducted in this assessment segment, levels of contaminant are sufficiently high for concern and justify follow-up monitoring. The levels of at least one contaminant from past monitoring now exceeds one or more advisory trigger levels, thus suggesting the need for additional (follow-up) monitoring to determine whether a consumption advisory should be issued.
The composite samples of fillets from common carp and smallmouth bass had generally low levels of contaminants. Levels of primary contaminants in the composite sample of carp fillets were as follows: mercury: 0.097 ppm; total PCBs: 0.09 ppm; and technical chlordane: < 0.03 ppm. Levels of primary contaminants in the composite sample of smallmouth bass fillets were as follows: mercury: 0.225 ppm; total PCBs: 0.09 ppm; and technical chlordane: < 0.03 ppm. Although assessed as “fully supported” for this reporting cycle, the level of at least one contaminant does, however, now exceed one or more advisory trigger levels: the level of mercury in the sample of smallmouth bass fillets (0.225 ppm) slightly exceeds the one meal per week trigger level of 0.20 ppm. According to the IDNR/IDPH advisory protocol, this single result 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. But, this elevated level does indicate a concern and the need to conduct additional monitoring to better define contaminant levels in fish from this river segment. Thus, follow-up monitoring will be conducted in 2006 to better determine (1) levels of mercury in the edible portions (fillets) of fish in this river segment and (2) whether a one-meal-per-week consumption advisory needs to be issued.
