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Since the late 1970s, a large body of scientific literature has developed focused on attributing sources of polycyclic aromatic hydrocarbons (PAHs) in sediments. Forensic evaluation of sources of PAHs in sediments has typically relied on the use of the 'expanded PAH' analysis in which 'parent' (non-alkylated) and alkylated members of each homologous series are quantified and reported. Use of this method for source attribution is widely documented in the peer-reviewed literature and has gained wide acceptance in the forensics community. Although the expanded PAH analysis is the preferred method of using PAH data for source attribution, these detailed forensic data are often not collected during routine environmental site investigations. Conversely, the 16 United States Environmental Protection Agency “priority pollutant” PAHs, which include the parent PAH of each homologous series, are routinely analyzed for and reported. Because of the large number and relatively high costs of sediment and soil remediation projects focused on PAHs, there is significant interest in the use of these parent PAH data for forensic source attribution. The peer-reviewed literature contains a few case studies where parent PAHs have been used to attribute sources, including distinguishing between petrogenic (petroleum) and pyrogenic (combustion and pyrolytic) sources, and among multiple pyrogenic sources. This article focuses on a case study that demonstrates the use of parent PAH ratios or proportions for source attribution for PAHs in sediments offshore of a former wood treating facility located in a highly industrialized port of the northwestern United States. The wood-treating facility was assumed as the source for all of the PAHs present in the sediments; this assumption was questioned in the litigation brought to allocate costs for the sediment remediation. Because the sediment remediation was complete, additional sampling for sophisticated forensic testing was not possible; therefore, the forensics evaluation had to rely on the pre-existing parent PAH data. Using the forensic parent PAH proportions and ratios developed by Yunker et al. (2002) and those of Costa and Sauer (2005), PAHs in the sediments were categorized into those attributed primarily to the wood treating facility creosote and those attributed primarily to a mixture of pyrogenic and petrogenic sources common in the “urban background” of industrialized waterways. This approach provided a basis to propose cost allocation for each of the sediment areas that required remediation. [ABSTRACT FROM AUTHOR]

The goal of this project was to examine soil-sample handling techniques used by state regulatory agencies that regulate pesticides and their impact on soil-residue levels of the insecticide fipronil and to offer a standardized soil-sampling protocol. In the United States, the pesticide user industry is large for both agricultural and non-agricultural applications. The United States Environmental Protection Agency regulates pesticide use on a federal level, whereas each state has established a "state lead agency" (SLA) that is responsible for state regulation of pesticides. In the absence of mandatory federal protocols for sample collection by SLAs, each state is free to take environmental samples pursuant to administrative or criminal investigations as deemed appropriate. A comparative study of common sampling practices was performed to evaluate the impact of handling methods on results. Soil was treated with fipronil insecticide and placed in two types of storage containers: in opaque bags that block ultraviolet light or in clear glass jars. Soil samples were placed in a commercial freezer, a cooler with commercial ice, and a growth chamber (incubator) that exposed soil samples to heat, humidity, and ultraviolet light. The results of the experiment revealed that within 72 hr, exposure of the soil samples to freezing, humidity, 37.8°C, or commercial ice in a cooler had no statistically significant effect on the level of fipronil residue in the soil samples used in the experiment. However, soil in glass jars placed in the growth chamber and exposed to 51.6 Kj/m2 of ultraviolet light contained significantly less fipronil residue than the standard soil samples. [ABSTRACT FROM AUTHOR]

The goal of this project was to examine soil sample handling procedures of each state regulatory agency that regulates pesticides, and to offer a standardized soil sampling protocol. In the United States, the pesticide user industry is large for both agricultural and non-agricultural uses. The United States Environmental Protection Agency (USEPA) regulates pesticide use on a federal level. Each state has established a “state lead agency” (SLA) that is responsible for state regulation of pesticides. In the absence of mandatory federal protocols for sample collection by SLAs, each state is free to take environmental samples pursuant to administrative or criminal investigations as they see fit. A comparative study of common sampling practices was performed to evaluate the impact of handling methods on results. Soil was treated with permethrin insecticide and placed in two types of storage containers: opaque bags that block ultraviolet light, and clear glass jars that do not. Soil samples were placed in a commercial freezer, a cooler with commercial ice, and a growth chamber (incubator) that exposed the soil samples to heat, humidity, and ultraviolet light. The results of the experiment revealed that within seventy-two (72) hours, exposure of the soil samples to freezing, 51.6 Kj/m 2 of ultraviolet light, 75% humidity, 37.8°C, or commercial ice in a cooler had no statistically significant effect on the level of permethrin residue in the soil samples with the soil properties used in the experiment and a soil pH of 6.2. However, when pH of the soil was raised to 8.96, permethrin concentration was best preserved when soil was immediately frozen. [ABSTRACT FROM AUTHOR]

The meaning of “representativeness” is often bound to the environmental context in which the samples are taken. Examples of qualitative interpretations of representativeness drawn from environmental regulations are shown. The concept of macro- and microscale understanding of representativeness is discussed and linked to the U.S. Environmental Protection Agency's Quality System and its associated guidance. [ABSTRACT FROM AUTHOR]

The problem of allocating liability cleanup costs is an arduous task when more than one potentially responsible party has contributed to the groundwater plume. This problem is most likely to be encountered when dealing with methyl- tert -butyl-ether (MTBE) contamination, as MTBE is seen to travel large distances in underlying aquifers. There has been a signi®cant effort in the recent past to develop liability allocation methodologies that incorporate fate and transport behavior and toxicological characteristics of the contaminants. The application of such methods often requires estimation of contaminant input from the vadose zone into the underlying aquifer. A screening level analysis is presented here to develop preliminary insights on relative mass contributions arising from different source types. The analysis illustrates how different vadose zone conceptualizations lead to vastly different contaminant loadings. Parametric studies indicate that the contaminant flux into the aquifer is very sensitive to changes in water infiltration rates. Hence, a reliable estimate of this parameter is critical for equitable allocation of remedial costs. Conceptual model formulation, should focus on identifying whether the fuel present in the aquifer can flow as a separate phase. It is also important to obtain reliable estimates for fluid saturations at the site. [ABSTRACT FROM AUTHOR]

Because there is no specific legislative or regulatory guidance, there is no "right" way to allocate liability at Superfund sites. Allocation based on the cost of a remedy, and allocation based on the need for a remedy, i.e. risk-based allocation, represent two possibilities. Other allocation schemes can be located between these two philosophical poles. When waste streams and environmental impacts are qualitatively similar, allocation based solely on costs may make the most sense. When one or more potentially responsible parties (PRPs) have qualitatively different wastes or impacts, an allocation scheme based on both contribution to cost and to risk may be able to incorporate all PRPs. In any case, dissident PRPs, whose contribution to remedy costs is large but whose contribution to risk is small, may find satisfaction in the courts where there is precedent for risk-based allocation. [ABSTRACT FROM AUTHOR]

Remedial efforts at Superfund sites across the country focus on groundwater contaminant plumes that have been produced by contributions from multiple parties. Allocating cleanup costs between the parties in a fair and equitable manner can be a problem of substantial complexity. Considerable time and money may be spent determining the amount of contamination attributable to each party in order to apportion liability. Contaminant plumes that have evolved over long periods of time may affect large volumes of groundwater and require extensive remediation. Pump and treat remedial costs are driven by both the volume of water extracted and the mass of contaminants removed. Allocation methods based solely on the mass of contaminants contributed by each party are inadequate in this setting since they do not account for both components of the remedial costs. This paper presents an approach for equitably allocating remedial costs when addressing overlapping or commingled groundwater plumes. The method accounts for the major elements driving the costs of remediating dispersed contaminant plumes. [ABSTRACT FROM AUTHOR]

The new millennium ushers in changes for refiners of automobile gasoline in the United States, as well as for the state and federal regulators who establish guidelines for gasoline formulation and environmental regulation governing the fate of gasoline-related chemicals in the nation's air, soil and groundwater. One current issue in the gasoline formulation debate centers on the comparison of the proven benefits of the addition of chemical oxygenates--especially methyl tert -butyl ether (MTBE)--to gasoline (to improve tailpipe emission quality) against the presumed environmental problems caused by the presence of oxygenates in ground- and surface waters due to fugitive releases of gasoline. Credible debate on this subject presumes that current and past environmental monitoring data for MTBE in environmental samples is accurate and precise. Experience suggests that this assumption is not correct, in part because certain analytical methodologies--particularly older methods supported by the U.S. Environmental Protection Agency--can fall short of reasonable data quality goals for measurement of MTBE. This Technical Note summarizes the standard EPA methods available to site investigators who need to measure MTBE in environmental media, the limitations and advantages of these measurement techniques, and recommendations for improving these standard EPA methods to yield the highest quality MTBE environmental residue data. [ABSTRACT FROM AUTHOR]

Points out that environmental forensics has evolved as a technical discipline which involves a systematic examination of environmental information to determine sources of chemical contamination, the timing of releases to the environment, the spatial distribution of contamination, and potentially responsible parties. Prediction that it will play an increasingly important role in regulatory enforcement actions and cost-recovery litigation in the U.S.