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Saint Paul, MN, United States

Crane J.L.,Minnesota Pollution Control Agency
Integrated Environmental Assessment and Management

Key Points: O'Reilly et al. (2013) made several errors in their paper regarding environmental forensic techniques for pyrogenic polycyclic aromatic hydrocarbons (PAHs). Their use of alkylated PAHs in forensic evaluations to determine petrogenic (i.e., oil-based) sources of PAHs is limited for urban sediments that are frequently classified as pyrogenic (i.e., combustion sources). O'Reilly et al. (2013) used a small number of samples from multiple sources in their principal components analysis figures and they simply do not have enough data to use this statistical technique. The authors recommended using both the USEPA's chemical mass balance and Unmix models for evaluating the source apportionment of PAHs in sediment data sets; however, this will not be feasible for most studies because the Unmix model requires a large sample size. © 2014 SETAC. Source

Sihota N.J.,University of British Columbia | Mayer K.U.,University of British Columbia | Toso M.A.,Minnesota Pollution Control Agency | Atwater J.F.,Estus Research
Journal of Contaminant Hydrology

The recent increase in the use of denatured fuel-grade ethanol (DFE) has enhanced the probability of its environmental release. Due to the highly labile nature of ethanol (EtOH), it is expected to rapidly biodegrade, increasing the potential for inducing methanogenic conditions in the subsurface. As environmental releases of DFE can be expected to occur at the ground surface or in the vadose zone (e.g., due to surficial spills from rail lines or tanker trucks and leaking underground storage tanks), the potential for methane (CH4) generation at DFE spill sites requires evaluation. An assessment is needed because high CH4 generation rates may lead to CH4 fluxes towards the ground surface, which is of particular concern if spills are located close to human habitation - related to concerns of soil vapor intrusion (SVI). This work demonstrates, for the first time, the measurement of surficial gas release rates at large volume DFE spill sites. Two study sites, near Cambria and Balaton, in MN are investigated. Total carbon emissions at the ground surface (summing carbon dioxide (CO2) and CH4 emissions) are used to quantify depth-integrated DFE degradation rates. Results from both sites demonstrate that substantial CO2 and CH4 emissions do occur - even years after a spill. However, large total carbon fluxes, and CH4 emissions in particular, were restricted to a localized area within the DFE source zone. At the Balaton site, estimates of total DFE carbon losses in the source zone ranged between 5 and 174 μmol m- 2 s- 1, and CH4 effluxes ranged between non-detect and 9 μmol m- 2 s- 1. At the Cambria site estimates of total DFE carbon losses in the source zone ranged between 8 and 500 μmol m- 2 s- 1, and CH4 effluxes ranged between non-detect and 393 μmol m- 2 s- 1. Substantial CH4 accumulation, coupled with oxygen (O2) depletion, measured in samples collected from custom-designed gas collection chambers at the Cambria site suggests that the development of explosion or asphyxiation hazards is possible in confined spaces above a rapidly degrading DFE release. However, the results also indicate that the development of such hazards is locally constrained, will require a high degree of soil moisture, close proximity to the source zone, a good connection between the soil and the confined space, and poorly aerated conditions. © 2013 Elsevier B.V. Source

Antony Chen L.-W.,Desert Research Institute | Watson J.G.,Desert Research Institute | Chow J.C.,Desert Research Institute | DuBois D.W.,Desert Research Institute | Herschberger L.,Minnesota Pollution Control Agency
Atmospheric Environment

The Minnesota Particulate Matter 2.5 (PM2.5) Source Apportionment Study was undertaken to explore the utility of PM2.5 mass, element, ion, and carbon measurements from long-term speciation networks for pollution source attribution. Ambient monitoring data at eight sites across the state were retrieved from the archives of the Interagency Monitoring of Protected Visual Environments (IMPROVE) and the Speciation Trends Network (STN; part of the Chemical Speciation Network [CSN]) and analyzed by an Effective Variance - Chemical Mass Balance (EV-CMB) receptor model with region-specific geological source profiles developed in this study. PM2.5 was apportioned into contributions of fugitive soil dust, calcium-rich dust, taconite (low grade iron ore) dust, road salt, motor vehicle exhaust, biomass burning, coal-fired utility, and secondary aerosol. Secondary sulfate and nitrate contributed strongly (49-71% of PM2.5) across all sites and was dominant (≥60%) at IMPROVE sites. Vehicle exhausts accounted for 20-70% of the primary PM2.5 contribution, largely exceeding the proportion in the primary PM2.5 emission inventory. The diesel exhaust contribution was separable from the gasoline engine exhaust contribution at the STN sites. Higher detection limits for several marker elements in the STN resulted in non-detectable coal-fired boiler contributions which were detected in the IMPROVE data. Despite the different measured variables, analytical methods, and detection limits, EV-CMB results from a nearby IMPROVE-STN non-urban/urban sites showed similar contributions from regional sources - including fugitive dust and secondary aerosol. Seasonal variations of source contributions were examined and extreme PM2.5 episodes were explained by both local and regional pollution events. © 2010 Elsevier Ltd. Source

Crane J.L.,Minnesota Pollution Control Agency
Archives of Environmental Contamination and Toxicology

This letter to the editor rebuts flawed analyses made by O'Reilly (2014) and points out duplicative comments that have already been rebutted in the peer-reviewed literature. O'Reilly (2014) provides little new scientific information on the source apportionment of polycyclic aromatic hydrocarbons (PAHs) in sediments, and the author stands by the results of her research. © 2014 Springer Science+Business Media New York. Source

Cain A.,U.S. Environmental Protection Agency | Morgan J.T.,Toxics Unit | Brooks N.,Minnesota Pollution Control Agency

While mercury (Hg) releases to air and water within the Great Lakes states have declined significantly, concentrations of mercury in fish remain a cause for concern regarding human and ecosystem health in the Great Lakes Basin. This paper assesses the priority that Hg source reduction ought to have in relation to some other environmental concerns, and explores the relative costs of various Hg reduction policies. Long-range transport of atmospheric mercury creates a collective action problem for states, since most of the mercury emitted within any given state deposits outside that state's borders, and since most of the mercury deposited within a state originated outside that state. This paper discusses some of the mechanisms that policy makers in the Great Lakes states employed to get beyond the collective action problem, including: providing an example for others to follow; using cross-jurisdiction cooperation to leverage the benefits of leadership on Hg reduction and control; and, promoting voluntary actions. Recommendations for future opportunities include: focusing reduction efforts on sources with the highest total mass of emissions rather than solely focusing on reduction of local deposition and utilizing all tools available in the clean air and clean water acts. © 2011 Springer Science+Business Media, LLC (outside the USA). Source

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