Assessment Comments
Assessment is based on results of chemical/physical and bacterial monitoring from May 2011 to November 2012 at station LVR-10 and remain based on the results of the INDR investigation of the September 2002 fish kill and the results of fish contaminant monitoring conducted near the Volga River Recreation Area in 2001 and 2005 with follow-up fish tissue monitoring conducted in 2007, 2008 and 2012.
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, 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 (2012) 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 are assessed (monitored) as “not supported” (IR 5p) due to violations of Iowa water quality criteria for indicator bacteria. This is a new impairment for this assessment segment. The Class B(WW1) uses of this stream are assessed (monitored) as “fully supported” (IR 2a) based on chemical/physical monitoring in 2011 and 2012. Fish consumption uses are assessed (monitored) as “partially supported” (IR 5a) based on fish contaminant monitoring in 2001 and 2005 that resulted in issuance of a one meal per week consumption advisory in 2006. The sources of data for this assessment include (1) results of monitoring from May 2011 to November 2012 at station LVR-10 (STORET station 15330008), (2) the results of the INDR investigation of the September 2002 fish kill, and (3) 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 are assessed (monitored) as "not supported" based on levels of indicator bacteria that exceeded state water quality criteria. The geometric means of indicator bacteria (E. coli) in the seven monthly samples collected during the recreational season of 2011 (753 orgs/100 ml), and the geometric mean of the eight samples collected during 2012 (2,069 orgs/100 ml) both exceeded the Class A1 criterion of 126 orgs/100 ml. Thirteen of the combined 15 samples (87%) exceeded Iowa’s single-sample maximum criterion of 235 orgs/100 ml. According to U.S. EPA guidelines for Section 305(b) reporting and IDNR’s assessment/listing methodology, if the geometric mean is greater than 126 orgs/100 ml., the primary contact recreation uses are "not supported" (see pgs 3-33 to 3-35 of U.S. EPA 1997b).
The Class B(WW1) aquatic life uses are assessed (monitored) as “fully supported” based on results of chemcial physical monitoring from May 2011 to November 2012. Results of chemical/physical monitoring from May 2011 to November 2012 at station LVR-10 show no violations of Class B(WW1) aquatic life criteria for DO, pH, or ammonia in the 15 samples collected, thus suggesting no impacts to support of these uses.
A 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 was moved to Category 3b of Iowa’s 2010 Integrated Report. IDNR considers IR Category 4d waterbodies where no additional kills have been reported for this stream for over 10 years, as appropriate for IR Category 3a (not assessed). Thus, this assessment is moved to IR Category 3a for the 2014 cycle.
Fish consumption uses remain 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. 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.
Follow-up monitoring was conducted as part of the Iowa DNR/U.S. EPA RAFT program in 2007 and 2008. The 2007 samples of smallmouth bass fillets contained 0.24 ppm of mercury; the 2008 sample of smallmouth bass fillets contained 0.33. Because the level of mercury in the 2008 sample exceeded the IDNR/IDPH advisory trigger level of 0.3 ppm, the advisory issued in 2006 continued. Results of from the 2012 RAFT showed that levels of mercury in the five smallmouth bass sampled ranged from 0.16 to 0.27 ppm with an average level of mercury of 0.214 (standard deviation of 0.051 ppm). This level of mercury is below Iowa’s threshold for a one meal/week advisory of 0.3 ppm of mercury. According to Iowa’s consumption advisory protocol, however, two consecutive samplings that show levels of fish contaminants are below the advisory threshold are needed to rescind an existing advisory. Thus, follow-up monitoring will be conducted in 2014 to better define levels of mercury in this segment of the Volga River and to determine whether the existing advisory should be rescinded.
