Pollmiller Park Lake IA 03-SKM-888

Results of DNR beach monitoring from 2014 through 2016 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 2014 (9 samples), 2015 (12 samples) and 2016 (13 samples), as part of the DNR beach monitoring program. According to DNR’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 2014, 2015 and 2016 were all below the Iowa water quality standard of 126 E. coli orgs/100 ml. The geometric mean was 13 E. coli orgs/100 ml in 2014, 15 E. coli orgs/100 ml in 2015 and 8 E. coli orgs/100 ml in 2016. The percentage of samples exceeding Iowa's single-sample maximum criterion (235 E. coli orgs/100 ml) was 0% in 2014, 8% in 2015 and 0% in 2016. None of these are significantly greater than 10% of the samples and therefore do not suggest impairment of the Class A1 uses. According to DNR's assessment methodology and U.S. EPA guidelines, these results suggest "Fully Supported" of the Class A1 uses.

For the 2018 assessment/listing cycle, the Class A1 (primary contact recreation) uses of Poll Miller Pake Lake are assessed (monitored) as "fully supported" based on information from the ISU lake survey. Using the median values from these surveys from 2012-2016 (approximately 15 samples), Carlson 's (1977) trophic state indices for Secchi depth, chlorophyll a, and total phosphorus were 54, 50, and 53 respectively for Poll Miller Pake Lake. According to Carlson (1977) the Secchi depth, chlorophyll a, and total phosphorus values all place Poll Miller Pake Lake in the Eutrophic category. These values suggest low levels of chlorophyll a and suspended algae in the water, very good water transparency, and low levels of phosphorus in the water column. The data show no violations of the Class A1 criterion for pH in 15 samples.

Fish consumption uses are assessed (monitored) as “partially supported” based on results of U.S.EPA/DNR 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 suggests that fish consumption uses should be assessed as "partially supporting".

Fish consumption uses are assessed (monitored) as “partially supported” based on results of DNR 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 DNR’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 suggests that the fish consumption uses should be assessed as "partially supporting".