Mississippi River IA 01-NEM-62

The Class A (primary contact recreation) uses are assessed as “partially supported” based on the impairment of primary contact recreation uses identified for this segment of the Upper Mississippi River by the Illinois EPA for the 2016 Section 303(d) listing cycle. The Illinois EPA identified an impairment of primary contact recreation uses in this river segment due to high levels of indicator bacteria (fecal coliforms). This assessment was developed as result of interstate consultation on Section 303(d) listing conducted through the Upper Mississippi River Basin Association’s “Water Quality Task Force” in June 2016.   

Similar to the previous assessments, the Class B(WW1) aquatic life uses are assessed (monitored) for the current (2016) cycle as “not supported” (IR Category 5a) based on results of Illinois EPA monitoring at station M-02 near Rock Island, IL.  The data from this station from 2012 through 2014 show repeated violations of Iowa’s aquatic life criteria for aluminum.  Twenty-four of the 25 samples analyzed for total aluminum (96%) exceeded the chronic criterion for aluminum (87 ug/l).  [Iowa’s aquatic life criteria for metals are expressed as “total recoverable” in the Iowa Water Quality Standards].  In addition, nine of the 25 samples analyzed for total aluminum (36%) exceeded the acute aquatic life criterion (750 ug/l).  Based on Iowa DNR’s assessment/listing methodology, more than one violation of a chronic or acute water quality criterion for a toxic parameter over a three-year period suggests impairment of aquatic life uses.  Thus, the frequency of violations of the aquatic life criteria for aluminum suggests that the Class B(WW1) aquatic life uses of this assessment segment should be assessed as “not supported”, and thus this assessment segment is placed in IR Category 5a.  

For cadmium, chromium, copper, lead, nickel, and zinc, none of the 25 samples analyzed for these metals exceed the respective chronic aquatic life criteria during the 2012-2014 period.  Similarly, none of the 16 samples exceeded Iowa’s Class B(WW1) criteria for dissolved oxygen, pH, or ammonia/nitrogen.  Levels of pesticides monitored at this station during the assessment period (chlorpyrifos, dieldrin, and DDT and metabolites DDD and DDE) were all below their respective Class B(WW1) criteria.  The only other violation of a Class B(WW1) criterion during the 2012-2014 assessment period was for sulfate.  One of the 25 samples (4%) exceeded the Class B(WW1) criterion.  According to Iowa DNR assessment/listing methodology, a violation frequency of less than 10% for sulfate does not suggest impairment of aquatic life uses.

The Class C (drinking water) uses are assessed as “fully supporting”.  Levels of pesticides (e.g.,Monitoring results for other parameters do not show violations of Class C (drinking water) criteria.  Maximum and average levels of nitrate in the 25 samples collected (3.25 mg/l and 1.4 mg/l, respectively), atrazine (maximum value of 0.49 ug/l and average of 0.1 ug/l in 25 samples), and Class C toxic metals (beryllium, cadmium, chromium, lead, and silver) at station M-02 were well below their respective MCLs and Class C human health criteria during the 2012-2014 period.  

None of the 25 samples analyzed during the 2012-2014 assessment period contained detectable levels of dieldrin (method detection level of 0.0014 ug/l).  Based, however, on the assessment developed for the previous (2014) assessment cycle, the Human Health designated use (including the fish consumption use) will remain assessed (evaluated) as “partially supporting” (IR Category 3b-potentially impaired).  One of the 16 samples analyzed by ILEPA for dieldrin at station M-02 during the 2010-2012 period (the only detectable level reported) exceeded the Iowa human health-fish (HH-fish) criterion for dieldrin of 0.00054 ug/l; the detected level of dieldrin was 0.0021 ug/l.  According to IDNR’s assessment/listing methodology, if the mean level of a toxic metal or pesticide is greater than its respective human health criterion, impairment ("nonsupport") of the Human Health use is indicated.  However, the samples with detectable levels of dieldrin were too few (two) and the method detection level (0.0014 ug/l) was too high (2.5 times the HH criterion for dieldrin) to allow calculation of a meaningful summary statistic (i.e., mean) for dieldrin at station M-02.  Monitoring for dieldrin at station M-02 is expected to continue as part of Illinois EPA monitoring.  See the previous (2014) assessment developed for this assessment segment for more information on dieldrin in water samples and fish tissue. 

Fish contaminant monitoring was conducted in this segment of the Mississippi River in September 2012 as part of ongoing studies by ALCOA to update the levels of PCBs in UMR Pool 15 fish (channel catfish and common carp) and to identify any trends in PCB contamination based on periodic monitoring in this Pool over the last 25 years.  Sampling was conducted at three locations: Pool 15 near the ALCOA facility, Pool 14 near LeClaire, IA, and Pool 15 on the Illinois side of the river.  The LeClaire and Illinois sites were chosen as reference sites.  ALCOA used performance standards of 0.226 mg/kg for channel catfish and 0.231 mg/kg for common carp (these performance standards approximate Iowa’s threshold for issuing a one-meal/week consumption advisory).  Results showed that levels of PCBs in channel catfish were low at all sample sites and met the performance standard.  Levels of PCBs in common carp met performance standards at the LeClaire (Pool 14) and Illinois-side sites, but levels near the ALOCA facility were above the performance standard.  It was hypothesized that the larger size of fish collected in Pool 15 near ALCOA was, in part, responsible for the higher levels of PCBs seen.  An Iowa DNR review of the 2012 ALCOA data shows that levels of PCBs in the sizes of common carp collected for the Iowa DNR’s fish tissue monitoring program (12-21 inches, total length) were well below Iowa’s advisory threshold for PCBs of 0.2 mg/kg at all sites sampled in 2012.  For common carp between 12 and 21 inches in total length, none of the PCB levels in fish from any of the ALCOA sites sampled exceeded 0.1 mg/kg (i.e., half the Iowa consumption advisory trigger).  PCB levels tended to exceed the Iowa advisory trigger in fish greater than 24 inches in total length (the largest common carp analyzed was nearly 30 inches in total length).  None of the PCB levels seen in the larger common carp, however, exceeded Iowa’s “do not eat” advisory threshold of 2.0 mg/kg: the maximum PCB concentration was 0.715 mg/kg of total PCBs.  Based on the low levels of PCBs in samples of channel catfish from all study locations, (2) low levels of PCBs in common carp from all sites except near the ALCOA facility, and (3) low levels of PCBs in common carp of sizes that meet EPA/Iowa DNR fish tissue monitoring guidelines, the human health/fish consumption uses of this assessment segment are assessed as “fully supported”.  

Based on results of the 2012 ALCOA study, however, follow-up fish tissue monitoring was conducted in UMR Pool 15 in 2013 and 2014 as part of Iowa DNR’s fish tissue monitoring program.  In the 2013 sampling, the average levels of mercury in tissue plugs from three largemouth bass was 0.24 ppm; this level is below the Iowa threshold of 0.3 ppm for a one-meal/week consumption advisory.  The level of PCBs in the composite sample of fillets from five Common Carp was reported as < 0.6 ppm.  This unusually high non-detect level, which is three time higher than Iowa’s threshold for a one-meal/week consumption advisory, was due to laboratory method detection levels of 0.2 ppm for each of the three Aroclors (1248, 1254, and 1260) analyzed to determine “total PCBs”.  Thus, results of follow-up monitoring for PCBs in Common Carp in this river segment were inconclusive.

Due to problems with analysis of the 2013 fish tissue samples for PCBs, monitoring was again conducted in this river segment in 2014.  A status sampling to determine levels of mercury in predator fish species and bottom-feeder sampling was conducted.  The average level of mercury in the tissue plugs from five white bass was 0.186 ppm which is below the 0.3 ppm consumption advisory threshold.  The level of total PCBs in the composite sample of fillets from the Common Carp was <0.06 ppm (lower detection levels for Aroclors were used for the 2014 samples (0.02 ppm) compared to the detection levels used for the 2013 samples (0.2 ppm)).  This level of PCBs is well below the consumption advisory threshold of 0.2 ppm.  Due, however, to the high level of total PCBs seen in ALCOA’s 2012 sample of large Common Carp from 24 to 30 inches in total length, the 2014 Iowa DNR sampling included collection of an additional composite sample of fillets from three Common Carp that averaged 26.7 inches in total length.  By design, this fish in this composite sample were much larger (longer) than the upper length limit of 21 inches used for routine Iowa DNR fish contaminant monitoring.  The level of total PCBs in the 2014 composite sample of large Common Carp was 0.42 ppm which is approximately two-times higher than the one-meal/week consumption advisory threshold.  The only Aroclor detected was 1254 at 0.38 ppm; the other two Aroclors (1248 and 1260) were reported as less than the detection level of 0.02 ppm.  Based on this confirmation sampling, a one meal per week consumption advisory for large Common Carp (> 20 inches) was issued by Iowa DNR and Iowa DPH.