Minnesota Pollution Control Agency Research Articles

The recovery of a shallow lake within an agricultural landscape of Minnesota—an interdisciplinary approach to understanding change

Perleberg DJ, Anderson JP, Streitz AR. 2023. The recovery of a shallow lake within an agricultural landscape of Minnesota—an interdisciplinary approach to change. Lake Reserv Manage. 39:311–326.This case study of Lake Shaokatan, Minnesota, reveals how long-term climate, hydrology, water chemistry, and macrophyte data can explain and predict shallow lake phase shifts. After decades of agricultural landscape nutrient loadings, lake and watershed management efforts successfully reduced summer mean total phosphorus and chlorophyll a concentrations to levels that met standards set specifically for shallow lakes in the Northern Glaciated Plains ecoregion (0.09 mg/L and 0.03 mg/L, respectively). The lake “flipped” from a turbid, phytoplankton-dominated phase (<20% macrophyte occurrence) to a clear, macrophyte-dominated phase (annual average of 90% occurrence), and the Minnesota Pollution Control Agency removed it from the state’s impaired waters list. A paired groundwater and lake water quality investigation was critical in understanding how increased precipitation might affect lake water quality, the relationship between groundwater and surface water in this system, and how compounds such as chloride and phosphorus are transported through the watershed. Lakewide macrophyte occurrence has been sustained for at least 7 yr. While abundant macrophyte growth helps maintain a clear water state, it can also create recreational boating issues. Lake managers question how long the lake will remain in the present clear phase as lake users weigh the recreational and aesthetic differences between the 2 phases.

Estimation of Serum PFOA Concentrations from Drinking and Non-Drinking Water Exposures.

Estimation of Serum PFOA Concentrations from Drinking and Non-Drinking Water Exposures.

Measuring the effect of fireworks on air quality in Minneapolis, Minnesota

Air quality was measured before, during, and after a 4th of July fireworks display in downtown Minneapolis, Minnesota using a mix of low-cost sensors (CO, CO2, and NO) for gases and portable moderate cost instruments for particle measurements (PM2.5, lung deposited surface area, and number weighted particle size distributions). Meteorological conditions—temperature, humidity, and vertical temperature profile were also monitored. Concentrations of particles and most gaseous species peak between 10 pm and midnight on July 4th, decrease in the middle of the night but increase again and by between 6 and 7 am reach concentrations as high or higher than during fireworks. This overnight increase is likely due to a temperature inversion trapping emissions. Between 10 pm and midnight on July 4th the measures of particle concentration increase by 180–600% compared to the same period on July 3rd. Particle size distributions are strongly influenced by fireworks, shifting from traffic-like bimodal distributions before to a nearly unimodal distribution dominated by a large accumulation mode during and after. The shape of the size distribution measured during the early morning peak is nearly identical to that observed during fireworks, suggesting that the early morning peak is mainly due to trapped fireworks emissions not early morning traffic. Gaseous species are less strongly influenced by fireworks than particles. Comparing measurements made between 10 pm and midnight on July 4th and the same period on July 3rd, the concentration of CO increases 32% while the CO2 increases only 2% but increases by another 15% overnight. The NO concentration behaves oddly, decreasing during fireworks, but then recovering the next morning, more than doubling overnight. Our measurements of CO, NO, and PM2.5 are compared with those made at the nearest (~ 2 km away) Minnesota Pollution Control Agency Air Monitoring Station. Their NO results are quite different from ours with much lower concentrations before fireworks, a distinct peak during, followed by a strong overnight increase and an early morning peak somewhat similar in shape and concentration to ours. These differences are likely due mainly to malfunction of our low-cost NO sensor. Concentrations of CO and PM2.5 track ours within 25% but peak shapes are somewhat different, which is not unexpected given the spatial separation of the measurements.Article highlightsLow-cost and moderate-cost sensors are used to monitor the impact of a 4th of July fireworks display on local air quality.Particle concentrations and size are more strongly influenced by fireworks than are concentrations gaseous pollutants.Particle size distributions produced by fireworks are distinctly different from those associated with urban traffic sources.

A chemical prioritization process: Applications to contaminants of emerging concern in freshwater ecosystems (Phase I)

Contaminants of emerging concern (CECs), such as pharmaceuticals, personal care products, and hormones, are frequently found in aquatic ecosystems around the world. Information on sublethal effects from exposure to commonly detected concentrations of CECs is lacking and the limited availability of toxicity data makes it difficult to interpret the biological significance of occurrence data. However, the ability to evaluate the effects of CECs on aquatic ecosystems is growing in importance, as detection frequency increases. The goal of this study was to prioritize the chemical hazards of 117 CECs detected in subsistence species and freshwater ecosystems on the Grand Portage Indian Reservation and adjacent 1854 Ceded Territory in Minnesota, USA. To prioritize CECs for management actions, we adapted Minnesota Pollution Control Agency's Aquatic Toxicity Profiles framework, a tool for the rapid assessment of contaminants to cause adverse effects on aquatic life by incorporating chemical-specific information. This study aimed to 1) perform a rapid-screening assessment and prioritization of detected CECs based on their potential environmental hazard; 2) identify waterbodies in the study region that contain high priority CECs; and 3) inform future monitoring, assessment, and potential remediation in the study region. In water samples alone, 50 CECs were deemed high priority. Twenty-one CECs were high priority among sediment samples and seven CECs were high priority in fish samples. Azithromycin, DEET, diphenhydramine, fluoxetine, miconazole, and verapamil were high priority in all three media. Due to the presence of high priority CECs throughout the study region, we recommend future monitoring of particular CECs based on the prioritization method used here. We present an application of a chemical hazard prioritization process and identify areas where the framework may be adapted to meet the objectives of other management-related assessments.

Prey electivity of the slimy sculpin within the Lake Superior-North Watershed

ABSTRACTWe evaluated the prey electivity of lotic slimy sculpin (Cottus cognatus) within the Lake Superior-North Watershed, an area characterized by high gradient streams and lacking the preferred prey of Gammarus. Fish and macroinvertebrates were sampled at 67 sites within 52 rivers and streams during 2013 in the Lake Superior-North Watershed by the Minnesota Pollution Control Agency. Fish sampling was conducted with the use of backpack and stream tote barge electrofishers, and macroinvertebrates were collected using qualitative multi-habitat sampling within D-Frame kick nets. Feeding electivity was calculated using Strauss’ modified feeding electivity model for three rivers. In total we sampled 174 slimy sculpins within the Lake Superior-North Watershed and found sculpins positively selected for Hydropsychidae (47.3% of total taxa consumed) and Perlidae (11% of total taxa consumed) instead of abundant Chironomidae (20% of total taxa sampled).

Mapping and Analyzing Stream Network Changes in Watonwan River Watershed, Minnesota, USA

Much of the Watonwan River tributary system to the upper Mississippi River basin (UMR), and the fluvial systems to which it drains, are listed as impaired under the United States Environmental Protection Agency Clean Water Act303(d) and/or by the Minnesota Pollution Control Agency. In addition, eutrophic conditions and excessive sedimentation rates exist in Lake Pepin, a riverine lake to which the UMR drains. Thus, understanding the hydrogeomorphic change throughout the UMR is vital in order to establish appropriate efforts to mitigate environmental hazards downstream. This study attempts to evaluate hydrogeomorphic change at the watershed scale in the Watonwan River watershed between 1855 and the near present. Historical plat maps, digital elevation models (DEMs), aerial images, soil/topographic characteristics, land-use change, and field surveys are analyzed. Surficial hydrologic features digitized from historical plat maps are compared with contemporary stream networks extracted from high-resolution DEMs. Scale effects are investigated using multi-resolution (1 m, 3 m, 8.5 m, and 30 m) DEMs, with 8.5 m DEMs being ideal for watershed scale analysis, and 1–3 m DEMs being ideal for subwatershed analysis. There has been a substantial hydrogeomorphic change in the watershed since 1855, but most significantly, we interpret that the highest rates of erosion occur in the eastern watershed, where knickzone propagation has produced substantial relief.

Estimating the Public Health Impact of Air Pollution for Informing Policy in the Twin Cities: A Minnesota Tracking Collaboration.

The Minnesota Department of Health and the Minnesota Pollution Control Agency used local air pollution and public health data to estimate the impacts of particulate matter and ozone on population health, to identify disparities, and to inform decisions that will improve health. While air quality in Minnesota currently meets federal standards, urban communities are concerned about the impact of air pollution on their health. The Twin Cities (Minneapolis-St Paul) metropolitan area includes 7 counties where fine particulate levels and rates of asthma exacerbations are elevated in some communities. We used the Environmental Protection Agency's BenMAP (Environmental Benefits Mapping and Analysis Program) software, along with local PM2.5 (fine particulate) and ozone ambient concentrations, census and population health data, to calculate impacts for 2008 at the zip code level. The impacts were summed across all zip codes for area-wide estimates. American Community Survey data were used to stratify zip codes by poverty and race for assessment of disparities. Attributable fraction, attributable rate and counts for all-cause mortality, asthma and chronic obstructive pulmonary disease hospitalizations, asthma emergency department (ED) visits, and cardiovascular disease hospitalizations. In the Twin Cities (2008), air pollution was a contributing cause for an estimated 2% to 5% of respiratory and cardiovascular hospitalizations and ED visits and between 6% and 13% of premature deaths. The elderly (aged 65+ years) experienced the highest air pollution-attributable rates of death and respiratory hospitalizations; children experienced the highest asthma ED visit rates. Geographical and demographic differences in air pollution-attributable health impacts across the region reflected the differences in the underlying morbidity and mortality rates. Method was effective in demonstrating that changes in air quality can have quantifiable health impacts across the Twin Cities. Key messages and implications from this work were shared with the media, community groups, legislators and the public. The results are being used to inform initiatives aimed at reducing sources of air pollution and to address health disparities in urban communities.

Toxicity of sulfide to early life stages of wild rice (Zizania palustris).

The sensitivity of wild rice (Zizania palustris) to sulfide is not well understood. Because sulfate in surface waters is reduced to sulfide by anaerobic bacteria in sediments and historical information indicated that 10 mg/L sulfate in Minnesota (USA) surface water reduced Z. palustris abundance, the Minnesota Pollution Control Agency established 10 mg/L sulfate as a water quality criterion in 1973. A 21-d daily-renewal hydroponic study was conducted to evaluate sulfide toxicity to wild rice and the potential mitigation of sulfide toxicity by iron (Fe). The hydroponic design used hypoxic test media for seed and root exposure and aerobic headspace for the vegetative portion of the plant. Test concentrations were 0.3, 1.6, 3.1, 7.8, and 12.5 mg/L sulfide in test media with 0.8, 2.8, and 10.8 mg/L total Fe used to evaluate the impact of iron on sulfide toxicity. Visual assessments (i.e., no plants harvested) of seed activation, mesocotyl emergence, seedling survival, and phytoxicity were conducted 10 d after dark-phase exposure. Each treatment was also evaluated for time to 30% emergence (ET30), total plant biomass, root and shoot lengths, and signs of phytotoxicity at study conclusion (21 d). The results indicate that exposure of developing wild rice to sulfide at ≥3.1 mg sulfide/L in the presence of 0.8 mg/L Fe reduced mesocotyl emergence. Sulfide toxicity was mitigated by the addition of Fe at 2.8 mg/L and 10.8 mg/L relative to the control value of 0.8 mg Fe/L, demonstrating the importance of iron in mitigating sulfide toxicity to wild rice. Ultimately, determination of site-specific sulfate criteria taking into account factors that alter toxicity, including sediment Fe and organic carbon, are necessary. Environ Toxicol Chem 2017;36:2217-2226. © 2017 SETAC.

Capturing Excess Nutrients from Waterways

Capturing Excess Nutrients from Waterways

Landfill site suitability assessment by means of geographic information system analysis

Abstract. Open dumping is the common procedure for final disposal of municipal solid waste (MSW) in Iran. Several environmental pollution and soil degradation problems were found as a consequence of poor planning of landfills. So recognition of the MSW landfill state is required to prevent environmental problems. The objective of this research was to study the suitability of existing municipal landfill sites using geographic information system methods. Tonekabon city in the west area of Mazandaran province, northern Iran, along the southern coast of the Caspian Sea, was chosen as a case study. In order to carry out this evaluation, two guidelines were used: Minnesota Pollution Control Agency (MPCA) and regional screening guidelines. The results indicate that the landfills were not located in suitable sites and also that there are few suitable locations to install the landfills.

Does Supplementing Dipnet Samples with Activity Traps Improve the Ability to Assess the Biological Integrity of Macroinvertebrate Communities in Depressional Wetlands?

Dipnet (DN) sampling is routinely employed for macroinvertebrate bioassessments in wetlands, but it has been demonstrated that some taxa are more effectively collected with activity traps (AT). The Minnesota Pollution Control Agency (MPCA) used both DN and AT methods to evaluate the biological condition of depressional wetlands in the Mixed Wood Plains (MWP) and Temperate Prairies (TP) ecoregions. Two indices of biotic integrity (IBIs) were developed for each ecoregion using: 1) DN data alone and 2) composite samples consisting of both DN and AT data. ATs collected more active taxa such as diving beetles and swimming Hemiptera. DNs collected more taxa and collected more skating taxa and those associated with sediment or vegetation. A comparison of the effectiveness of the IBIs to evaluate biological condition indicated that the composite data had a slightly better relationship with anthropogenic disturbance and was marginally more precise. A comparison of sampling and processing costs revealed that sampling using composite samples was 130 % greater and processing was 50 % greater compared to DN-only samples. Based on the cost and limited benefit of adding AT samples, a DN-only sampling protocol is recommended to assess biological condition in depressional wetlands.

Summary of microcystin concentrations in Minnesota lakes

Minnesota has compiled a fairly extensive database on the cyanobacterial toxin microcystin (MC). These data have been acquired through targeted lake studies, incident-based investigations, and stratified random surveys as a part of the US EPA's 2007 and 2012 National Lakes Assessments. This paper updates previous efforts and provides a statistical summary of all Minnesota MC data collected by the Minnesota Pollution Control Agency from 2004 to 2012. These data provide a basis for (1) describing the influence sampling regimes have on reported MC values, (2) describing regional patterns in MC across 3 distinct Minnesota ecoregions, and (3) describing the relative risk of encountering elevated MC with respect to sampling regimes. This summary places MC concentrations in perspective for Minnesota and also provides a comparative database, which other entities that collect MC may use to place their results in perspective.

A Case Study in the Use of 3-Dimensional Ground Water Modeling and Solute Transport Engines as a Tool in Site Assessment

A case study was conducted on the application of modeling in site assessment. We determined the potential for migration of 3 heavy metals and several organic compounds from a site 300 yards north of a swimming area. The site has a history of environmental issues and incidents dating back to 1985. In 2010 the Minnesota Pollution Control Agency (MPCA) measure levels from 638 to 6847 mg kg-1 of ethyl benzene, toluene and xylenes (BTEX) compounds in manholes, tanks, and soil on the site. Previously, lead (Pb), cadmium (Cd) and chromium (Cr) concentrations in soil ranged from 210 to 18,000 ug kg-1. Using reactive transport models with MODFLOW, plumes were developed for metals and BTEX compounds based on data from sediment testing, geological features, and site data from MPCA. Our plume models predict that heavy metals would enter of the swimming lake through surface water runoff and a BTEX plume would enter the swimming lake and the Minnesota River through groundwater. Sediment samples from a drainage ditch adjacent to the site contained concentrations of Cd and Cr 10 times higher than a nearby reference site supporting our plume results. Sediment samples also indicated that Cd and Cr concentrations decreased down gradient, further supporting model predictions. BTEX compounds were not detected in sediment or water samples during the study. We find that incorporating three-dimensional groundwater modeling into a site assessment can provide a useful estimate of a plume’s direction and concentration and aid in determining future sampling locations.

A spreadsheet planning tool for assisting a state agency with cost-effective watershed scale surface water nitrogen planning

T he Minnesota Pollution Control Agency (MPCA) is developing a statewide nutrient reduction strategy and coordinating with other states to reduce nitrogen (N) and phosphorus (P) loads in the Mississippi River. Excess N in surface waters is of concern both because of toxicity to aquatic organisms locally and because many Minnesota watersheds feed into the Mississippi River and the Gulf of Mexico, where a 45% reduction in both N and P has been proposed (USEPA Science Advisory Board 2007). Minnesota's Nutrient Reduction Strategy identifies how the state intends to achieve its first 20% reduction in N leaving the state via the Mississippi River. To provide a scientific foundation for the N reduction efforts needed in Minnesota, the MPCA worked with the University of Minnesota and US Geological Survey to characterize N loading in watersheds throughout Minnesota. Other states in the Mississippi River Watershed are engaging in similar efforts, including Iowa (Iowa Department of Agriculture and Land Stewardship et al. 2013). The University of Minnesota's role in the project included estimating nonpoint source N loads from different sources (agriculture, forestry, and urban) and pathways (runoff, drainage, and groundwater discharge); a literature review on N reduction effectiveness of various best management practices (BMPs);…

Evaluation of the SO2 and NOX offset ratio method to account for secondary PM2.5 formation

The U.S. Environmental Protection Agency (EPA), state and local agencies have focused their efforts in assessing secondary fine particulate matter (aerodynamic diameter ≤2.5 µm; PM2.5) formation in prevention of significant deterioration (PSD) air dispersion modeling. The National Association of Clean Air Agencies (NACAA) developed a method to account for secondary PM2.5 formation by using sulfur dioxide (SO2) and nitrogen oxides (NOx) offset ratios. These ratios are used to estimate the secondary formation of sulfate and nitrate PM2.5. These ratios were first introduced by the EPA for nonattainment areas in the Implementation of the New Source Review (NSR) Program for Particulate Matter Less than 2.5 Micrometers (PM2.5), 73 FR 28321, to offset emission increases of direct PM2.5 emissions with reductions of PM2.5 precursors and vice versa. Some regulatory agencies such as the Minnesota Pollution Control Agency (MPCA) have developed area-specific offset ratios for SO2 and NOx based on Comprehensive Air Quality Model with Extensions (CAMx) evaluations for air dispersion modeling analyses. The current study evaluates the effect on American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) predicted concentrations from the use of EPA and MPCA developed ratios. The study assesses the effect of these ratios on an electric generating utility (EGU), taconite mine, food processing plant, and a pulp and paper mill. The inputs used for these four scenarios are based on common stack parameters and emissions based on available data. The effect of background concentrations also evaluates these scenarios by presenting results based on uniform annual PM2.5 background values. This evaluation study helps assess the viability of the offset ratio method developed by NACAA in estimating primary and secondary PM2.5 concentrations. An alternative Tier 2 approach to combine modeled and monitored concentrations is also presented. Implications: On January 4, 2012, the EPA committed to engage in rulemaking to evaluate updates to the Guideline on Air Quality Models (Appendix W of 40 CFR 51) and, as appropriate, incorporate new analytical techniques or models for secondary PM2.5. As a result, the National Association of Clean Air Agencies (NACAA) developed a screening method involving offset ratios to account for secondary PM2.5 formation. The use of this method is promising to evaluate total (direct and indirect) PM2.5 impacts for permitting purposes. Therefore, the evaluation of this method is important to determine its viability for widespread use.

The Beat

The Beat

Landscape factors influencing lake phosphorus concentrations across Minnesota

Total phosphorus (TP) concentrations are known to be a significant factor influencing fish populations in Minnesota lakes. Consequently, a primary focus of the Minnesota Department of Natural Resources to address fish habitat in lakes across the state has been to determine relationships between TP concentrations and watershed conditions in Minnesota lakes. Because phosphorus concentrations in Minnesota lakes vary widely corresponding to differences in geomorphology, nutrient criteria were established by the Minnesota Pollution Control Agency for specific ecoregions. To refine these relationships in Minnesota lakes managed for fishing, we gathered mean summer epilimnetic TP concentrations on 1330 natural lakes to identify where agricultural and urban development have elevated phosphorus levels. Random forest, regression tree, and generalized additive models were used to model spatial variation in lake phosphorus concentrations across Minnesota. Key landscape variables known to influence TP concentrations in lakes, including lake depth and watershed size, were used as explanatory variables in these models, along with agricultural and urban development quantified for lake watersheds from the National Land Cover Dataset. These models explained up to 60% of the variation in TP in lakes across the state and showed a critical benchmark of anthropogenic land use disturbance at 40%, that once exceeded could significantly alter TP levels and consequently fish populations. This information should be useful for fish managers to prioritize conservation efforts and to set appropriate fish population goals.

Wash Water in the Mix: Effects on the Compressive Strength of Concrete

The disposal of concrete wash water has become a significant issue in recent years. The Minnesota Pollution Control Agency currently requires control of all water used to wash concrete ready mix trucks, delivery chutes and tools used to finish concrete. Best Management Practices allow for containment of wash water either on the job site or at the ready mix plant but do not allow for the reuse of the water. ASTM Standards allow for limited reuse of the wash water, but the Minnesota Department of Transportation requires potable water in all concrete mixes used on their jobs. This research was designed to compare the compressive strength of the concrete when made with tap water to the compressive strength of concrete made with wash water. The research was a two by two design with two concrete mixes each paired with tap water and wash water. Fifteen cylinders of each type were mixed and stored for 28 days. They were then tested for compressive strength. When analyzed using a one-way analysis of variance (ANOVA), the cylinders made with wash water tested at a higher mean compressive strength than the cylinders made with tap water. The results were consistent across concrete mix designs.

From the Editors

From the Editors

Cumulative Risk Assessment and Environmental Equity in Air Permitting: Interpretation, Methods, Community Participation and Implementation of a Unique Statute

In 2008, the statute authorizing the Minnesota Pollution Control Agency (MPCA) to issue air permits was amended to include a unique requirement to analyze and consider “cumulative levels and effects of past and current environmental pollution from all sources on the environment and residents of the geographic area within which the facility’s emissions are likely to be deposited.” Data describing the Statute Area suggest it is challenged by environmental and socioeconomic concerns, i.e., concerns which are often described by the phrase ‘environmental equity’. With input from diverse stakeholders, the MPCA developed a methodology for implementing a cumulative levels and effects analysis when issuing air permits in the designated geographic area. A Process Document was created defining explicit steps a project proposer must complete in the analysis. An accompanying Reference Document compiles all available environmental health data relevant to the Statute Area that could be identified. The final cumulative levels and effects methodology is organized by health endpoint and identifies hazard, exposure and health indices that require further evaluation. The resulting assessment is summarized and presented to decision makers for consideration in the regulatory permitting process. We present a description of the methodology followed by a case study summary of the first air permit processed through the “cumulative levels and effects analysis”.