Pollmiller Park Lake IA 03-SKM-888

Results of IDNR beach monitoring from 2012 through 2014 suggest that the Class A1 uses are "Fully Supported." Levels of indicator bacteria at Pollmiller Park Beach were monitored once per week during the primary contact recreation seasons (May through September) of 2012 (13 samples), 2013 (13 samples) and 2014 (9 samples), as part of the IDNR beach monitoring program.   According to IDNR’s assessment methodology two conditions need to be met for results of beach monitoring to indicate “full support” of the Class A1 (primary contact recreation) uses: (1) the geometric mean of the samples from each recreation season of the three-year assessment period are less than the state's geometric mean criterion of 126 E.  coli orgs/100 ml and (2) not more than 10% of the samples during any one recreation season exceeds the state's single-sample maximum value of 235 E.  coli orgs/100 ml. If a sampling season geometric mean exceeds the state criterion of 1000 orgs/100 ml during the three-year assessment period, the Class A1 uses should be assessed as “not supported.” Also, if a sampling season geometric mean exceeds the state criterion of 126 orgs/100 ml during the three-year assessment period and/or if significantly more than 10% of the samples in any one of the three recreation seasons exceed Iowa's single-sample maximum value of 235 E.  coli orgs/100 ml, the Class A1 uses should be assessed as “partially supported.” This assessment approach is based on U.S.   EPA guidelines (see pgs 3-33 to 3-35 of U.S.   EPA 1997b).

At Pollmiller Park Beach, the geometric means from 2012, 2013 and 2014 were all below the Iowa water quality standard of 126 E.  coli orgs/100 ml.   The geometric mean was 9 E.  coli orgs/100 ml in 2012, 13 E.  coli orgs/100 ml in 2013 and 13 E.  coli orgs/100 ml in 2014.   The percentage of samples exceeding Iowa's single-sample maximum criterion (235 E.  coli orgs/100 ml) was 0% in 2012, 0% in 2013 and 0% in 2014.   None of these are significantly greater than 10% of the samples and therefore do not suggest impairment of the Class A1 uses.   According to IDNR's assessment methodology and U.S.  EPA guidelines, these results suggest "Fully Supported" of the Class A1 uses.

For the 2016 assessment/listing cycle, the Class A1 (primary contact recreation) uses of Pollmiller Pake Lake are assessed (monitored) as "fully supported" based on information from the ISU lake survey. Using the median values from these surveys from 2010-2014 (approximately 15 samples), Carlson 's (1977) trophic state indices for Secchi depth, chlorophyll a, and total phosphorus were 57, 54.5, and 55 respectively for Pollmiller Pake Lake. According to Carlson (1977) the Secchi depth, chlorophyll a, and total phosphorus values all place Pollmiller Pake Lake in the Eutrophic category. These values suggest relatively low levels of chlorophyll a and suspended algae in the water, relatively good water transparency, and relatively low levels of phosphorus in the water column. The data show one violation of the Class A1 criterion for pH in 15 samples.

The level of inorganic suspended solids was moderately high at Pollmiller Pake Lake, and does suggest that non-algal turbidity may contribute to the impairment at this lake. The median level of inorganic suspended solids in Pollmiller Pake Lake (2.8 mg/L) was ranked 69th among the 138 lakes by the ISU lake survey.

Data from the 2010-2014 ISU lake survey suggest a moderate population of cyanobacteria exists at Pollmiller Pake Lake. These data show that cyanobacteria comprised 93% of the phytoplankton wet mass at this lake. The median cyanobacteria wet mass (17.4 mg/L) was ranked 54th of the 138 lakes sampled.

The Class B(LW) (aquatic life) uses are assessed (monitored) as "fully supported." Results of the ISU lake survey from 2010-2014 show there were no violations of the criterion for ammonia in 15 samples(0%), no violations of the criterion for dissolved oxygen in 15 samples(0%), and one violation of the criterion for pH in 15 samples(7%). Based on IDNR's assessment methodology these violations are not significantly greater than 10% of the samples and therefore suggest (fully supported/monitored) of the Class B(LW) uses of Pollmiller Pake Lake.

Fish consumption uses are assessed (monitored) as “partially supported” based on results of U.S.  EPA/IDNR turtle contaminant (RAFT) monitoring at Pollmiller Park Lake in 2010 and 2012.   The 2010 composite samples of shoulder tissue from snapping turtle had generally low levels of contaminants.   Levels of primary contaminants in the shoulder sample of snapping turtle were as follows: mercury: 0.297 ppm; total PCBs: 0.09 ppm; and technical chlordane: <0.03 ppm.   The level of mercury (0.297 ppm), however, was essentially equal to Iowa's advisory threshold for a one-meal/week consumption advisory.   Iowa's consumption advisory protocol requires that, before a consumption advisory is issued, two consecutive samplings are needed that show elevated contaminant levels.  Thus, follow up mercury monitoring was conducted in 2012.   Results of the 2012 follow-up showed that the composite sample of shoulder muscle from snapping turtle contained mercury levels of 0.403 ppm which also exceeded the threshold for a one-meal/week consumption advisory of 0.3 ppm.   Thus, a one-meal/week consumption advisory was issued for snapping turtle from this lake.   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.    The existence of the consumption advisory suggest that the fish consumption uses should be assessed as "partially supporting".    

Fish consumption uses are assessed (monitored) as “partially supported” based on results of IDNR fish contaminant monitoring was conducted at Pollmiller Park Lake in 2013 and 2014.   The composite samples of fillets from common carp had low levels of contaminants.    Levels of primary contaminants in the composite sample of common carp fillets were as follows: mercury: 0.22 ppm; total PCBs: <0.6 ppm; and technical chlordane: <0.2 ppm.   All of these levels are below thresholds for a one-meal/week consumption advisory.   The average level of mercury in tissue samples from five largemouth bass, however, was 0.487 ppm (SD=0.08; maximum=0.58).   This level is above the 1 meal per week advisory level (0.3 ppm).   According to IDNR’s assessment methodology, the single occurrence of contaminant above an advisory trigger level 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.    Thus, follow-up monitoring will be conducted at Pollmiller Park Lake in 2014.   Results of the 2014 sampling showed the average level of mercury in tissue samples from four largemouth bass was 0.333 ppm (SD=0.07; maximum=0.42).   This level is above the 1 meal per week advisory level (0.3 ppm).  Thus, a one-meal/week consumption advisory was issued for largemouth bass from this lake. 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.    The existence of the consumption advisory suggest that the fish consumption uses should be assessed as "partially supporting".