Minnesota Pollution Control Agency

About: Minnesota Pollution Control Agency is a government organization based out in Saint Paul, Minnesota, United States. It is known for research contribution in the topics: Stormwater & Sulfate. The organization has 154 authors who have published 214 publications receiving 7820 citations.

Background and overview of current sediment toxicity identification evaluation procedures

Abstract: Laboratory bioassays can provide an integrated assessment of the potential toxicity of contaminated sediments to aquatic organisms; however, toxicity as a sole endpoint is not particularly useful in terms of identifying remedial options. To focus possible remediation (e.g., source control), it is essential to know which contaminants are responsible for toxicity. Unfortunately, contaminated sediments can contain literally thousands of potentially toxic compounds. Methods which rely solely on correlation to identify contaminants responsible for toxicity are limited in several aspects: (a) actual compounds causing toxicity might not be measured, (b) concentrations of potentially toxic compounds may covary, (c) it may be difficult to assess the bioavailability of contaminants measured in a sediment, and (d) interactions may not be accounted for among potential toxicants (e.g., additivity). Toxicity identification evaluation (TIE) procedures attempt to circumvent these problems by using toxicity-based fractionation procedures to implicate specific contaminants as causative toxicants. Phase I of TIE characterizes the general physio-chemical nature of sample toxicants. Phase II employs methods to measure toxicants via different analytical methods, and Phase III consists of techniques to confirm that the suspect toxicants identified in Phases I and II of the TIE actually are responsible for toxicity. These TIE procedures have been used to investigate the toxicity of a variety of samples, including sediments. Herein we present a brief conceptual overview of the TIE process, and discuss specific considerations associated with sediment TIE research. Points addressed include: (a) selection and preparation of appropriate test fractions, (b) use of benthic organisms for sediment TIE work, and (c) methods for the identification of common sediment contaminants.

Source Apportionment and Distribution of Polycyclic Aromatic Hydrocarbons, Risk Considerations, and Management Implications for Urban Stormwater Pond Sediments in Minnesota, USA

Abstract: High concentrations of polycyclic aromatic hydrocarbons (PAHs) are accumulating in many urban stormwater ponds in Minnesota, resulting in either expensive disposal of the excavated sediment or deferred maintenance by economically challenged municipalities. Fifteen stormwater ponds in the Minneapolis—St. Paul, MN, metropolitan area were studied to determine sources of PAHs to bed sediments through the application of several environmental forensic techniques, including a contaminant mass balance receptor model. The model results were quite robust and indicated that coal tar-based sealant (CT-sealant) particulate washoff and dust sources were the most important sources of PAHs (67.1 %), followed by vehicle-related sources (29.5 %), and pine wood combustion particles (3.4 %). The distribution of 34 parent and alkylated PAHs was also evaluated regarding ancillary measurements of black carbon, total organic carbon, and particle size classes. None of these parameters were significantly different based on major land-use classifications (i.e., residential, commercial, and industrial) for pond watersheds. PAH contamination in three stormwater ponds was high enough to present a risk to benthic invertebrates, whereas nine ponds exceeded human health risk-based benchmarks that would prompt more expensive disposal of dredged sediment. The State of Minnesota has been addressing the broader issue of PAH-contaminated stormwater ponds by encouraging local municipalities to ban CT-sealants (29 in all) and to promote pollution prevention alternatives to businesses and homeowners, such as switching to asphalt-based sealants. A statewide CT-sealant ban was recently enacted. Other local and regional jurisdictions may benefit from using Minnesota’s approach where CT-sealants are still used.

Effects of land use on ground water quality in the Anoka Sand Plain Aquifer of Minnesota.

Abstract: We began a study, in 1996, to compare ground water quality under irrigated and nonirrigated agriculture, sewered and nonsewered residential developments, industrial, and nondeveloped land uses. Twenty-three monitoring wells were completed in the upper meter of an unconfined sand aquifer. Between 1997 and 2000, sampling occurred quarterly for major ions, trace inorganic chemicals, volatile organic compounds (VOCs), herbicides, and herbicide degradates. On single occasions, we collected samples for polynuclear aromatic hydrocarbons (PAHs), perchlorate, and coliform bacteria. We observed significant differences in water chemistry beneath different land uses. Concentrations of several trace inorganic chemicals were greatest under sewered urban areas. VOC detection frequencies were 100% in commercial areas, 52% in sewered residential areas, and <10% for other land uses. Median nitrate concentrations were greatest under irrigated agriculture (15,350 microg/L) and nonsewered residential areas (6080 microg/L). Herbicides and degradates of acetanilide and triazine herbicides were detected in 86% of samples from irrigated agricultural areas, 68% of samples from nonirrigated areas, and <10% of samples from other land uses. Degradates accounted for 96% of the reported herbicide mass. We did not observe seasonal differences in water chemistry, but observed trends in water chemistry when land use changes occurred. Our results show land use is the dominant factor affecting shallow ground water quality. Trend monitoring programs should focus on areas where land use is changing, while resource managers and planners must consider potential impacts of land use changes on ground water quality.