Assessment Comments
Assessment remains based on: (1) the results of the INDR investigation of the September 2002 fish kill and (2) the results of fish contaminant monitoring conducted near the Volga River Recreation Area in 2001 and 2005 as part of U.S. EPA/IDNR fish contaminant (RAFT) monitoring.
Basis for Assessment
[Note: Prior to the 2008 Section 305(b) cycle, this stream segment was designated only for Class B(WW) aquatic life uses. Due to changes in Iowa’s surface water classification that were approved by U.S. EPA in February 2008 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf), this segment is now presumptively designated for Class A1 (primary contact recreation) uses. This stream segment remains designated for aquatic life uses (now termed Class B(WW1) aquatic life uses). Thus, for the current (2010) assessment, the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW1) water quality criteria.]
SUMMARY: The presumptive Class A1 (primary contact recreation) uses remain “not assessed” due to the lack of information upon which to base an assessment. The Class B(WW1) uses of this stream are assessed (evaluated) as “partially supported” due to a fish kill in September 2002. Thus, this waterbody was moved to IR Category 4d for the 2006 and 2008 assessment/listing cycles. Fish consumption uses are assessed (monitored) as “partially supported” based on fish contaminant monitoring in 2001 and 2005. The sources of data for this assessment include (1) the results of the INDR investigation of the September 2002 fish kill and (2) the results of fish contaminant monitoring conducted near the Volga River Recreation Area in 2001 and 2005 as part of U.S. EPA/IDNR fish contaminant (RAFT) monitoring.
EXPLANATION: The presumptive Class A1 (primary contact recreation) uses remain “not assessed” due to the lack of information on levels of indicator bacteria upon which to base an assessment.
The Class B(WW1) aquatic life uses remain assessed (monitored) as “partially supported” based on a fish kill in 2002. The fish kill occurred on September 3, 2002, and resulted from the discharge liquid manure when a pipe failure occurred. The manure flowed to this tributary of the Little Volga River; the Little Volga River was not affected by this kill. Approximately 1.2 miles of this unnamed tributary was affected killing an estimated 12,700 fish. IDNR sought and received restitution related to this fish kill.
According to DNR's assessment methodology for Section 305(b) reporting, occurrence of a single pollution-caused fish kill during an assessment period indicates "partial support" of the aquatic life uses. If, however, a consent order has been issued to the party responsible for the kill and monetary restitution has been sought for the fish killed, the affected waterbody should be placed in IR Category 4d (impaired but TMDL not required). Thus, this segment was placed in Category 4d of Iowa’s 2008 Integrated Report. IDNR considers IR 4d fish kill waters with no subsequent kills reported in at least five year subsequent to the kill as appropriate for movement from IR Category 4d to either categories 2b or 3b (i.e., Iowa’s list of waters in need of further investigation). Thus, this impairment will be moved to Category 3b of Iowa’s 2010 Integrated Report.
Fish consumption uses are assessed (monitored) as “partially supported” based on results of U.S.EPA/IDNR fish contaminant (RAFT) monitoring near the Volga State Recreation Area in 2001 and in 2005. 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 (IDPH), 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 applies to the fish contaminant data generated from the RAFT sampling conducted in this segment of the Volga River: levels of mercury in samples of smallmouth bass from consecutive samplings exceeded advisory trigger levels, thus suggesting the need for a consumption advisory. According to IDNR’s assessment methodology, the existence of a one-meal-per-week consumption advisory indicates that fish consumption uses should be assessed as “partially supported”.
For the 2001 RAFT sampling, the composite samples of fillets of smallmouth bass contained 0.326 ppm of mercury. The level of mercury in the sample of 2005 composite sample smallmouth bass fillets was 0.545 ppm. According to the IDNR/IDPH advisory protocol, if two consecutive samplings show that contaminant levels are above the trigger level in fillet samples, issuance of a consumption advisory is justified. This advisory was issued by IDNR and IDPH in January 2006 and covers the segments of the Volga River upriver from the county road C2W bridge at Volga in western Clayton County.
