Toward Identifying the Next Generation of Superfund and Hazardous Waste Site Contaminants

Reproduced with permission from Environmental Health Perspectives."This commentary evolved from a workshop sponsored by the National Institute of Environmental Health Sciences titled "Superfund Contaminants: The Next Generation" held in Tucson, Arizona, in August 2009. All the authors were workshop participants." doi:10.1289/ehp.1002497Our aim was to initiate a dynamic, adaptable process for identifying contaminants of emerging concern (CECs) that are likely to be found in future hazardous waste sites, and to identify the gaps in primary research that cause uncertainty in determining future hazardous waste site contaminants. Superfund-relevant CECs can be characterized by specific attributes: they are persistent, bioaccumulative, toxic, occur in large quantities, and have localized accumulation with a likelihood of exposure. Although still under development and incompletely applied, methods to quantify these attributes can assist in winnowing down the list of candidates from the universe of potential CECs. Unfortunately, significant research gaps exist in detection and quantification, environmental fate and transport, health and risk assessment, and site exploration and remediation for CECs. Addressing these gaps is prerequisite to a preventive approach to generating and managing hazardous waste sites.Support for the workshop, from which this article evolved, was provided by the National Institute of Environmental Health Sciences Superfund Research Program (P42-ES04940)

Environmental occurrence, analysis, and toxicology of toxaphene compounds.

Toxaphene production, in quantities similar to those of polychlorinated biphenyls, has resulted in high toxaphene levels in fish from the Great Lakes and in Arctic marine mammals (up to 10 and 16 microg g-1 lipid). Because of the large variabiliity in total toxaphene data, few reliable conclusions can be drawn about trends or geographic differences in toxaphene concentrations. New developments in mass spectrometric detection using either negative chemical ionization or electron impact modes as well as in multidimensional gas chromatography recently have led researchers to suggest congener-specific approaches. Recently, several nomenclature systems have been developed for toxaphene compounds. Although all systems have specific advantages and limitations, it is suggested that an international body such as the International Union of Pure and Applied Chemistry make an attempt to obtain uniformity in the literature. Toxicologic information on individual chlorobornanes is scarce, but some reports have recently appeared. Neurotoxic effects of toxaphene exposure such as those on behavior and learning have been reported. Technical toxaphene and some individual congeners were found to be weakly estrogenic in in vitro test systems; no evidence for endocrine effects in vivo has been reported. In vitro studies show technical toxaphene and toxaphene congeners to be mutagenic. However, in vivo studies have not shown genotoxicity; therefore, a nongenotoxic mechanism is proposed. Nevertheless, toxaphene is believed to present a potential carcinogenic risk to humans. Until now, only Germany has established a legal tolerance level for toxaphene--0.1 mg kg-1 wet weight for fish

Toward Identifying the Next Generation of Superfund and Hazardous Waste Site Contaminants

Reproduced with permission from Environmental Health Perspectives."This commentary evolved from a workshop sponsored by the National Institute of Environmental Health Sciences titled "Superfund Contaminants: The Next Generation" held in Tucson, Arizona, in August 2009. All the authors were workshop participants." doi:10.1289/ehp.1002497Our aim was to initiate a dynamic, adaptable process for identifying contaminants of emerging concern (CECs) that are likely to be found in future hazardous waste sites, and to identify the gaps in primary research that cause uncertainty in determining future hazardous waste site contaminants. Superfund-relevant CECs can be characterized by specific attributes: they are persistent, bioaccumulative, toxic, occur in large quantities, and have localized accumulation with a likelihood of exposure. Although still under development and incompletely applied, methods to quantify these attributes can assist in winnowing down the list of candidates from the universe of potential CECs. Unfortunately, significant research gaps exist in detection and quantification, environmental fate and transport, health and risk assessment, and site exploration and remediation for CECs. Addressing these gaps is prerequisite to a preventive approach to generating and managing hazardous waste sites.Support for the workshop, from which this article evolved, was provided by the National Institute of Environmental Health Sciences Superfund Research Program (P42-ES04940)

Synthetic organic toxicants in Lake Superior

Numerous synthetic organic toxicants have been reported in Lake Superior in the past quarter century although relatively few industrial centers are located on its shores. The chemicals enter the lake primarily through atmospheric deposition via transport from regional and distant sources. This contribution discusses research issues regarding the processes by which the chemicals enter and exit the lake, their in-lake cycling and bioaccumulation, and recently reported potential toxicological effects. Research issues that remain for historically important synthetic organic toxicants are discussed as well as those of emerging chemicals of concern. Although concentrations of some historically important toxicants are decreasing in Lake Superior\u27s waters through volatilization and sedimentation and burial, abiotic and biotic in-lake cycling opens routes of entry into the lake\u27s lower food web, contributing to concentrations in fish that warrant consumption advisories in certain cases. Concentrations of some non-polar emerging chemicals of concern that are increasing in production (such as polybrominated diphenyl ethers) can be expected to increase in the lake and be subject to similar processes occurring to historically important persistent organic pollutants unless regulatory intervention leads to decreasing atmospheric emissions. Other emerging chemicals of concern await measurement in Lake Superior. Our ability to understand the fate and effects of synthetic organic toxicants on the Lake Superior ecosystem, whether they are \u27legacy\u27 chemicals or emerging chemicals of concern, is limited by the availability of techniques to determine physical-chemical properties, concentrations, fluxes, bioaccumulation pathways and rates, and mechanisms of toxicity. Future research on synthetic organic toxicants in Lake Superior relies on advances in development of these techniques. Policy decisions must take into account the variety factors that lead to the presence of the chemicals in the lake and their toxic effects

Polychlorinated Biphenyls in the Great Lakes

This chapter reviews the scientific understanding of the concentrations, trends, and cycling of polychlorinated biphenyls (PCBs) in the Great Lakes. PCBs were widely used in the Great Lakes region primarily as addivites to oils and industrial fluids, such as dieletric fluids in transformers. PCBs are persistent, bioaccumulative, and toxic to animals and humans. The compaunds were first reported in the Great Lakes natural environment in the late 1960s. At that time, PCB production and use was near the maximum level in North America. Since then, inputs of PCBs to the Great Lakes have peaked and declined: sediment profiles and analyses of archived fish indicate that PCB concentrations have decreased markedly in the decades following the phase-out in the 1970s. Unfortunately, concentrations in some fish species remain too high for unrestricted safe consumption. PCB concentrations remain high in fish because of their persistence, tendency to bioaccumulate, and the continuing input of the compaunds from uncontrolled sources. PCBs are highly bioaccumulative and many studies have shown that the complex food webs of the Great Lakes contribute to the focusing of PCBs in fish and fish-eating animals. PCB concentrations in the open waters are in the range of 100-300 pg L-1, and are near equilibrium with the regional atmosphere. PCBs are hydrophobic yet are found in the dissolved phase of the water column and in the gas phase in the atmosphere, and they continue to enter the Great Lakes environment. The atmosphere, especially near urban-industrial areas, is the major source to the open waters of the lakes. Other sources include contaminated tributaries and in-lake recycling of contaminated sediments. Until these remaining sources are controlled or contained, unsafe levels of PCBs will be found in the Great Lakes environment for decades to come.JRC.I.3-Toxicology and chemical substance