Assessment Comments
Assessment based on results of (1) biological monitoring by IDNR Fisheries Bureau in 2000, (2) EPA/IDNR fish contaminant (RAFT) monitoring near Algona in 2002, and (3) an IDNR investigation of a fish kill in February 2004.
Basis for Assessment
[Prior to the 2004 assessment, this segment was referred to as IA 04-EDM-0010_3. Segment IA 04-EDM-0010_3 was broken into two smaller segments, now listed as IA 04-EDM-0010_2 and IA 04-EDM-0010_3 to reflect the location descriptions and classifications (HQR) as described in the Surface Water Classification. All previous assessments referring to this segment (previously known as IA 04-EDM-0010_3) can now be found listed in the documentation for segment IA 04-EDM-0010_4.]
SUMMARY: The Class B(WW) aquatic life uses are assessed (evaluated) as "partially supported" based on occurrence of a fish kill in February 2004. Results of biological monitoring in 2000, however, suggest "full support" of these aquatic life uses. Fish consumption uses are assessed (monitored) as "fully supported" based on results of fish contaminant monitoring in 2002. The sources of data for this assessment are (1) the results of stream (fisheries) sampling by the IDNR Fisheries Bureau in 2000 and (2) results of U.S. EPA/IDNR fish contaminant (RAFT) monitoring near Algona in July 2002.
EXPLANATION: The occurrence of a fish kill in February 2004 suggest that the Class B(WW) uses should be assessed (evaluated) as "partially supported". This kill occurred on or before February 10, 2004; the kill was attributed to natural causes (winterkill). An estimated 100 fish were killed. No information on the species killed was provided; no estimate of the value of the fish killed was provided. The kill affected approximately 10 miles of river. According to the IDNR investigation, dead fish were observed at three riffle sites. Dissolved oxygen readings on February 10th were extremely low (less than 1ppm) at all the riffle sites (Patterson Recreation Area, Plum Creek Dam, and Veteran’s Park). According to IDNR’s assessment/listing methodology, the occurrence of a single pollutant-caused fish kill, or a fish kill of unknown origin, on a waterbody or waterbody reach during the most recent assessment period (2002-2005) indicates a severe stress to the aquatic community and suggests that the aquatic life uses should be assessed as “impaired”. If a cause of the kill was not identified during the IDNR investigation, or if the kill was attributed to non-pollutant causes (e.g., winterkill), the assessment type will be considered “evaluated.” Such assessments, although suitable for Section 305(b) reporting, lack the degree of confidence to support addition to the state Section 303(d) list of impaired waters (IR Category 5). Waterbodies affected by such fish kills will be placed in IR subcategories 2b or 3b and will be added to the state list of waters in need of further investigation.
In contrast to the assessment of the Class B(WW) uses based on the February 2004 fish kill, results of biological monitoring in 2000 suggest "full support" of these uses. This monitoring was conducted as part of a DNR Fisheries stream sampling project: Manchester research station. A series of biological metrics which reflect stream water quality and habitat integrity were calculated from the Fisheries sampling data. The biological metrics are based on the numbers and types of fish species that were collected in the stream sampling reach. The biological metrics were combined to make a fish community index of biotic integrity (F-IBI). The index ranks the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 2000 evaluated Fish IBI = 39 (fair). The aquatic life use support was assessed (evaluated) as Fully Supporting (=FS), based on a comparison of the F-IBI score with biological assessment criteria established for previous Section 305(b) reports. The biological assessment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2001.
Fish consumption uses were assessed (monitored) as “fully supported” based on results of U.S.EPA/IDNR fish contaminant (RAFT) monitoring near Algona in 2002. The composite samples of fillets from channel catfish and walleye had low levels of contaminants. Levels of primary contaminants in the composite sample of channel catfish fillets were as follows: mercury: 0.069 ppm; total PCBs: <0.09 ppm; and technical chlordane: <0.03 ppm. Levels of primary contaminants in the composite sample of walleye fillets were as follows: mercury: 0.154 ppm; total PCBs: <0.09 ppm; and technical chlordane: <0.03 ppm.
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). 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 either a threat to, or impairment of, fish consumption uses. This scenario, however, does not apply to the fish contaminant data generated from the 2002 RAFT sampling conducted in this assessment segment: the levels of contaminants do not exceed any of the new (2006) advisory trigger levels, thus indicating no justification for issuance of a consumption advisory for this waterbody.
