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Military conflict has led to large-scale environmental changes throughout recorded human history. Pollution from war contaminates surface water and soil, releases large volumes of greenhouse gases into the air, and directly harms wildlife and biodiversity. While much is understood about the human toll of war, numerous examples of post-war reconstruction suggest that underestimating the severity of wartime damages to ecosystems and natural resources results in prolonged or incomplete recovery of the environment. A data-driven scientific approach closely aligned to the evidentiary rules standard in western legal systems is needed to quantify the injury, destruction, or loss of natural resources and to inform the estimation of the reparations necessary to restore the environment fully. The U.S. natural resource damage assessment (NRDA) process and the European Union environmental liability directive (ELD) are well-suited for a systematic and science-based analysis of the ecological injuries incurred during armed conflicts. Both approaches include a preliminary damage assessment process, which could be initiated during wartime to document and predict the likely severity of the injuries and prioritize, in advance, rehabilitation activities after the cessation of hostilities. In this paper, we refer to news reporting of Russia's February 2022 invasion of Ukraine as an example of how a preliminary damage assessment could be conducted remotely and later modified by in-country inspections and analysis to verify and refine the scale of injuries and to develop reparation proposals. This article is protected by copyright. All rights reserved. Integr Environ Assess Manag 2022;00:0-0. © 2022 SETAC.

As global salmon production accelerates in response to higher consumer demand for seafood, so does the need for sophisticated monitoring strategies to enable and maintain ethically sound, productive, and environmentally friendly production of fish. Innovative technologies are needed to ensure proper water quality, react to unfavorable hydrodynamic conditions, monitor for changes in fish health, and minimize ecological interactions with indigenous aquatic life, including fish escapes. Automated sensors connected wirelessly to data stations, visualization aids, and acoustic and physical tagging technologies are emerging tools capable of detecting environmental stress and its associated behavioral changes in farmed fish. Computer modeling of the monitoring data collected from a single salmon farm or collection of farms sharing a data network can be used to spot environmental trends vital for anticipating some of the consequences of climate change. Environmental regulations governing salmon farming in coastal areas are becoming more stringent in response to public pressures to protect coastal and ocean resources and to provide for multipurpose use of marine resources. As net-pen salmon aquaculture expands globally, new technologies will be essential to collect and interpret the anticipated larger volumes of data needed to meet these stringent regulatory requirements and to safeguard the high investment costs inherent in salmon farming. Integr Environ Assess Manag 2022;18:950-963. © SETAC.

The priorities for oil spill response (OSR) are to protect people, prevent or mitigate environmental damages, and minimize the long-term impacts. Several analytic approaches have emerged in the field of spill impact mitigation assessment (SIMA), a science-based framework evolved from net environmental benefits analysis (NEBA), to broaden the focus from consideration of mitigation of ecological impact to also include socioeconomic and cultural impact considerations. In the northern Gulf of Mexico (GOM), a comparative risk assessment (CRA) decision-support tool was developed for identifying and comparing the ecological consequences of different oil spill response technologies in temperate/sub-tropical deep water, including the use of subsea dispersants. Another analytic assessment tool, Environment & Oil Spill Response (EOS), was developed based on offshore western Greenland and the Baltic Sea to assist in selection of oil spill response options that best mitigate the consequences of spilled oil in polar / sub-polar aquatic ecosystems in the Nordic region. In this work, we briefly review the CRA and EOS tools and highlight the shared and unique attributes of both assessment frameworks and how ecological, environmental and oil chemistry characteristics are handled in contrasting climatic and ecosystem conditions.

Oil spill response (OSR) in the Arctic marine environment conducted as part of operational planning and preparedness supporting exploration and development is most successful when knowledge of the ecosystem is readily available and applicable in an oil spill risk assessment framework. OSR strategies supporting decision-making during the critical period after a spill event should be explicit about the environmental resources potentially at risk and the efficacy of OSR countermeasures that best protect sensitive and valued resources. At present, there are 6 prominent methods for spill impact mitigation assessment (SIMA) in the Arctic aimed at supporting OSR and operational planning and preparedness; each method examines spill scenarios and identifies response strategies best suited to overcome the unique challenges posed by polar ecosystems and to minimize potential long-term environmental consequences. The different methods are grounded in classical environmental risk assessment and the net environmental benefit analysis (NEBA) approach that emerged in the 1990s after the Exxon Valdez oil spill. The different approaches share 5 primary assessment elements (oil physical and chemical properties, fate and transport, exposure, effects and consequence analysis). This paper highlights how the different Arctic methods reflect this common risk assessment framework and share a common need for oil spill science relevant to Arctic ecosystems. An online literature navigation portal, developed as part of the 5-year Arctic Oil Spill Response Technologies Joint Industry Programme, complements the different approaches currently used in the Arctic by capturing the rapidly expanding body of scientific knowledge useful to evaluating exposure, vulnerability and recovery of the Arctic ecosystem after an oil spill.

Elevated levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and other contaminants have been reported in lower Passaic River, New Jersey, USA, sediments since the 1980s. Nearly 8000 surficial and buried sediment samples have been collected along the 17 miles (27.4 km) of river and analyzed for various contaminants, including the seventeen 2,3,7,8-substituted PCDD/F congeners. Principal component analysis and hierarchical cluster analysis reveal spatial heterogeneity in the distribution of dioxin congeners, with respect to both sediment depth and river mile. Polytopic vector analysis resolved 11 unique 2,3,7,8-substituted dioxin congener profiles in the river sediment. The profiles were consistent with multiple dioxin source types, including manufacture of certain dyes and pigments, chlorinated industrial chemicals, hexachlorophene, polychlorinated biphenyls, waste disposal and incineration, the production and use of 2,4,5-trichorophenol (2,4,5-TCP), and other industrial processes. The distribution of dioxin profiles in surface and buried river sediments is indicative of multiple inputs of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and other dioxins at different locations along the lower Passaic River. These findings are inconsistent with historical claims that a former herbicide manufacturing plant in the lower reach of the river is the only significant 2,3,7,8-TCDD source and consistent with evidence of several different inputs associated with the production, use, and/or disposal of 2,4,5-TCP at several locations along the lower Passaic River. Environ Toxicol Chem 2021;40:1499-1519. © 2020 SETAC.

2017-351 When there is risk for oil release into the marine environment, the priority for planners and responders is to protect human health and to minimize environmental impacts. The selection of appropriate response option(s) depends upon a wide range of information including data on the fate and behavior of oil and treated oil, the habitats and organisms that are potentially exposed, and the potential for effects and recovery following exposure. Spill Impact Management Assessment (SIMA; a refinement of Net Environmental Benefits Analysis, or NEBA, in the context of oil spill response) and similar comparative risk assessment (CRA) approaches provide responders a systematic method to compare and contrast the relative environmental benefits and consequences of different response alternatives. Government and industry stakeholders have used this approach increasingly in temperate and subtropical regions to establish environmental protection priorities and identify response strategies during planning that minimize impacts and maximize the potential for environmental recovery. Historically, the ability to conduct CRA-type assessments in the Arctic has been limited by insufficient information relevant to oil-spill response decision making. However, with an increased interest in shipping and oil and gas development in the Arctic, a sufficiently robust scientific and ecological information base is emerging in the Arctic that can support meaningful SIMA. Based on a summary of over 3,000 literature references on Arctic ecosystems and the fate and effects of oil and treated oil in the Arctic, we identify key input parameters supporting a SIMA evaluation of oil spill response in the Arctic and introduce a web portal developed to facilitate access to the literature and key considerations supporting SIMA.

During the International Conference on Deriving Environmental Quality Standards for the Protection of Aquatic Ecosystems held in Hong Kong in December 2011, an expert group, comprising scientists, government officials, and consultants from four continents, was formed to discuss the important scientific and regulatory challenges with developing sediment quality guidelines (SQGs). We identified the problems associated with SQG development and made a series of recommendations to ensure that the methods being applied were scientifically defensible and internationally applicable. This document summarizes the key findings from the expert group. To enable evaluation of current SQG derivation and application systems, a feedback mechanism is required to communicate confounding factors and effects in differing environments, while field validation is necessary to gauge the effectiveness of SQG values in sediment quality assessments. International collaboration is instrumental to knowledge exchange and method advancement, as well as promotion of 'best practices'. Since the paucity of sediment toxicity data poses the largest obstacle to improving current SQGs and deriving new SQGs, a standardized international database should be established as an information resource for sediment toxicity testing and monitoring data. We also identify several areas of scientific research that are needed to improve sediment quality assessment, including determining the importance of dietary exposure in sediment toxicity, mixture toxicity studies, toxicity screening of emerging chemicals, how climate change influence sediments and its biota, and possible use of new toxicity study approaches such as high throughput omic-based toxicity screenings.

Elevated levels of chromium, partly attributable to historical disposal of chromite ore processing residue, are present in sediment along the eastern shore of the lower Hackensack River near the confluence with Newark Bay. Due to anaerobic conditions in the sediment, the chromium is in the form of Cr(III), which poses no unacceptable risks to human health or to the river ecology. However, as water quality conditions have improved since the 1970s, aerobic conditions have become increasingly prevalent in the overlying water column. If these conditions result in oxidation of Cr(III) to Cr(VI), either under quiescent conditions or during severe weather or anthropogenic scouring events, the potential for adverse ecological effects due to biological exposures to Cr(VI) is possible, though the reaction kinetics associated with oxidation of Cr(III) to Cr(VI) are unfavorable. To investigate the stability of Cr(III) in Hackensack River sediments exposed to oxic conditions, sediment suspension and oxidation experiments and intertidal sediment exposure experiments that exposed the sediments to oxic conditions were conducted. Results revealed no detectable concentrations of Cr(VI), and thus no measurable potential for total chromium oxidation to Cr(VI). Furthermore, total chromium released from sediment to elutriate water in the oxidation and suspension experiments ranged from below detection (

Total and hexavalent chromium [Cr(VI)] were measured in sediment and sediment porewater in the lower Hackensack River (NJ) to assess the relationship between sediment geochemistry and chromium speciation, which in turn controls the mobility, bioavailability, and toxicity of chromium. Between 2003 and 2005, >100 surface (0 to 15 cm) sediment samples were tested for total chromium and Cr(VI), acid-volatile sulfides (AVS), ferrous iron (Fe(II)), divalent manganese (Mn(II)), ammonia, and organic carbon. Sediment porewater samples were collected by centrifugation or using in situ samplers colocated with the collection of sediments. In whole sediments, total chromium and Cr(VI) concentrations ranged from 5 to 9190 mg/kg dry weight (dw) and from

The long-term goal of monitored natural recovery (MNR) is to achieve ecological recovery of biological endpoints in order to protect human and ecological health. Insofar as ecological recovery is affected by surface-sediment-contaminant concentrations, the primary recovery processes for MNR are natural sediment burial and contaminant transformation and weathering to less toxic forms. This paper discusses the overall approach for effective implementation of MNR for contaminated sediment sites. Several lines of evidence that may be used to demonstrate natural recovery processes are summarized, including documentation of source control; evidence of contaminant burial; measurement of surface sediment mixing depths and the active sediment benthic layer; measurement of sediment stability; contaminant transformation and weathering; modeling sediment transport, contaminant transport, and ecological recovery; measuring ecological recovery and long-term risk reduction; knowledge of future plans for use and development of the site; and watershed and institutional controls. In general, some form of natural recovery is expected and should be included as part of a remedy at virtually all contaminated sediment sites. Further, MNR investigations and an understanding of natural recovery processes provide cost-effective information and support the evaluation of more aggressive remedies such as capping, dredging, and the use of novel amendments. The risk of dredging or capping may be greater than the risk of leaving sediments in place at sites where capping or dredging offer little long-term environmental gain but pose significant short-term risks for workers, local communities, and the environment.

Management strategies for addressing contaminated sediments can include a wide range of actions, ranging from no action, to the use of engineering controls, to the use of more aggressive, intrusive activities related to removing, containing, or treating sediments because of environmental or navigation considerations. Risk assessment provides a useful foundation for understanding the environmental benefits, residual hazards, and engineering limitations of different remedy alternatives and for identifying or ranking management options. This article, part of a series of panel discussion papers on sediment remediation presented at the Third International Conference on Remediation of Contaminated Sediments held 20–25 January 2005 in New Orleans, Louisiana, USA, reviews 2 types of risk that deserve careful consideration when evaluating remedy alternatives. The evaluation of remedy implementation risks addresses predominantly short-term engineering issues, such as worker and community health and safety, equipment failures, and accident rates. The evaluation of residual risks addresses predominantly longer-term biological and environmental issues, such as ecological recovery, bioaccumulation, and relative changes in exposure and effects to humans, aquatic biota, and wildlife. Understanding the important pathways for contaminant exposure, the human and wildlife populations potentially at risk, and the possible hazards associated with the implementation of different engineering options will contribute to informed decision making with regard to short- and long-term effectiveness, implementability, and potential environmental hazards.

Persistent organic pollutants (POPs) are environmental contaminants characterized by their persistence, long-range transport and biomagnification in food chains, and bioaccumulation in humans and wildlife. The presence of POPs in the aquatic environment is not a new phenomenon; it has only become more widely evident in the last decade because continually improving chemical analysis methods have lowered the limits of detection for a wide array of chemicals tested in surface waters, sediment, and biota. Advances in analytical techniques, statistical methods, and monitoring technologies for freshwater and marine environments are capable of tracing sources and fate of several newly emerging POPs. This chapter examines the challenges associated with five emerging POPs, including the perfluorinated chemicals, certain brominated flame retardants, active ingredients in pharmaceuticals and personal care products, engineered nanomaterials, and polyaromatic hydrocarbons from oil sands. Despite advances in forensic methods, the full magnitude and significance of POPs in the aquatic environment is largely unknown. Environmental risk assessment of POPs remains particularly challenging in freshwater and marine ecosystems; exposure and effects data relevant to the aquatic environment are critical limitations, and continual releases via land runoff, precipitation, plastic litter, industrial accidents, and treated or untreated wastewaters increasingly confound the understanding environmental impacts relative to so-called background, or uncontaminated, conditions.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in storm water collected from 15 outfalls in San Francisco Bay, California, considered representative of areas located adjacent to petroleum refineries and mixed urban/commercial/residential land uses. Storm water sampling was conducted hourly over a 12-h period at two outfalls located near the city of Oakland and the suburban community of Benicia, which represent urban and mixed urban/light industrial land uses, respectively. Sampling was conducted hourly to determine temporal changes in the concentrations and distributions of PCDD/Fs during the first major rainstorm event of the 1995/96 winter season. In addition, storm water sampling was conducted in December 1995 and February/April 1996 at six publicly owned treatment work (POTW) outfalls located adjacent to developed, undeveloped, mixed residential/commercial, and industrial lands. Storm water sampling also was conducted at five outfalls located adjacent to petroleum refineries. The sampling results were used to examine changes in PCDD/F loadings to San Francisco Bay at the onset and midway through the winter rainy season and to characterize differences in PCDD/F concentrations, if any, between refinery and nonrefinery areas. The concentrations of tetra- through octa-chlorinated homologues and 2,3,7,8-substituted congeners were assayed in filtered storm water samples according to US EPA Method 1613A. Principal components analysis (PCA) was used as an exploratory technique to examine the similarities and differences in the distributions of PCDD/Fs in storm water from different outfalls. The sampling results showed few significant differences between storm water discharged from outfalls located in mixed urban/commercial/residential areas and outfalls located adjacent to petroleum refineries. The concentrations of 2,3,7,8-TCDD were below the analytical limits of detection in all storm water samples, with the exception of samples collected after the sixth hour of sampling at the Oakland outfall. Fingerprint patterns were generally dominated by the higher chlorinated PCDD/F congeners including OCDD, OCDF, and 1,2,3,4,6,7,8-HpCDD. Total TEQs were generally below US EPA ambient water quality criteria and aquatic ecotoxicology guideline values. The results of this study strongly suggest that discrete sampling of storm water outfalls is insufficient to characterize the concentrations and distributions of persistent hydrophobic contaminants such as PCDD/Fs. In addition to surface water runoff from the city of Oakland, other nonindustrialized urban locations may represent important sources of PCDD/Fs to San Francisco Bay.http://link.springer-ny.com/link/service/journals/00244/bibs/37n3p290.html

Watershed-level thinking implies recognition of chemical and nonchemical stressors as well as other natural or anthropogenic stressors, in an entire drainage area. This editorial highlights the reemergence of watershed-level thinking by the regulatory community, identifies new and emerging watershed-level assessment methods and underscores the benefits to stakeholders by integrating a watershed-level assessment with economic, social, legal and political factors that affect management and engineering decisions in watersheds. Civil and environmental engineers can play a critical role in the further evolution of watershed-level thinking by developing tools to identify the likely contributors to key assessment benchmarks representing indications of an ecosystem's impairment, and assisting in the selection of appropriate remedial responses.

In recent decades, the paradigm of water quality management has shifted from complete prohibition of pollutant discharge (i.e. zero tolerance) to permitting limited discharge of pollutants to receiving water bodies based on the results of a risk-based assessment approach. This approach assumes that the aquatic ecosystem is able to cope with certain levels of pollutants without harming aquatic life and the health of local communities who rely on the water body for food, drinking water and enjoyment. A risk-based approach also assumes that safe levels can be defined for pollutants that do not cause unacceptable disruptions of the structure and function of the aquatic ecosystem. This approach acknowledges the presence of uncertainty associated with the current understanding of substance-specific ecotoxicity, the behaviour of chemical mixtures in the environment, ecology of the receiving waters and the ability to measure chemical contaminants in effluents and receiving waters accurately. Furthermore, a risk-based approach acknowledges that the most serious water pollutants in terms of human health worldwide may not be man-made chemicals, but rather the pathogenic organisms originating from untreated or improperly treated human wastes. In developed countries, pollutioncontrol technologies have reduced or eliminated most of sources of pathogens in inland surface waters, thereby affording attention on other contaminants in water such as industrial chemicals, metals, and agricultural chemicals. The situation, however, is quite different in less-developed countries. In 2012, it was estimated that 37 % of the world’s population still lack adequate sanitation while 11 % of the global population could not gain access to clean drinking water (WHO 2012). From this perspective, the use of a riskbased approach that is able to focus attention on the largest water quality challenges and can confidently direct scarce financial resources to actions that will affect the largest results for protection of clean drinking water is of paramount importance. Scientists and environmental authorities are confronted with the realities facing less-developed countries, the nature of current scientific uncertainties and recognition that zero tolerance of water pollutants will likely have unacceptable economic consequences for societies striving to improve quality of life. It is self-evident, therefore, that the derivation of risk-based environmental quality guidelines, threshold values, limits, objectives and benchmarks by national regulatory authorities is gaining widespread acceptance as an appropriate foundation for national and international water quality management.

The presence of numerous industrial and municipal sources such as former creosote wood preserving facilities, petroleum storage and refinery facilities, paint and chemical manufacturers, combined sewer overflows, and sewage treatment facilities along the shores of Newark Bay, New Jersey and its major tributaries suggests the potential for widespread contamination by polycyclic aromatic hydrocarbons (PAHs) and petroleum hydrocarbons. In this study, the concentrations and distributions of 19 PAHs and total extractable petroleum hydrocarbon (TEPH) were determined in 213 sediment samples obtained from 58 sediment cores collected between November 1991 and March 1993 from the Arthur Kill, Elizabeth River, Hackensack River, Kill Van Kull, Newark Bay, Upper New York Bay, and Rahway River. Chronological profiles of PAH and TEPH deposition from pre-1930 to the present were determined in each sediment core using 137Cs and 210Pb radioisotope measurements. The concentrations of total PAHs (tPAH) and individual PAHs were compared to National Oceanic and Atmospheric Administration (NOAA) benchmark sediment effects-range median (ER-M) values. The objectives of this study were to: (a) determine the spatial and temporal distributions of PAHs in sediments; (b) identify their possible sources; and (c) assess the potential for sediment toxicity within the estuary. The results indicate elevated concentrations of PAHs and TEPH in surface and buried sediments throughout the estuary, particularly in the Elizabeth River, the Arthur Kill, and in the Passaic River above the Dundee Dam and below the Jackson Street Bridge. Sediments collected from ship berths at Port Newark and Port Elizabeth in Newark Bay were also found to contain elevated levels of PAHs and TEPH. The concentrations of PAHs and TEPH in sediment generally increase with depth throughout the estuary. Comparisons to NOAA ER-M values indicate that the concentrations of many PAHs in surface and buried sediments at several locations in the estuary pose a significant hazard to aquatic organisms. Radiodating of sediment cores reveals that the highest concentrations of PAHs, and the greatest potential hazards to aquatic biota, occur in sediments deposited during the 1950s. Although the major inputs of PAHs are probably combustion sources and urban runoff entering the estuary through combined sewer overflows and storm drains, the unusually high concentrations of PAHs and TEPH found in some sediments may be best explained by point source inputs or catastrophic oil spills.

Two hundred and forty-six surface and buried sediment samples from Newark Bay, New Jersey, and its major tributaries (Passaic River, Hackensack River, Newark Bay, Arthur Kill, Elizabeth River, and Kill Van Kull) were assayed for p,p′-dichlorodiphenyltrichloroethane (p,p′-DDT), p,p′-dichlorodiphenyldichloroethane (p,p′-DDD), and p,p′-dichlorodiphenylchloroethylene (p,p′-DDE) between February 1990 and March 1993. Chronological profiles in sediments from pre-1940 to the present were determined by radioisotope activities of 210Pb and 137Cs. The concentrations of these chemicals were compared to National Oceanic and Atmospheric Administration (NOAA) benchmark sediment values (Long and Morgan 1991). The objectives were to (a) determine the spatial and temporal distributions of DDT compounds in sediments, (b) identify possible sources, and (c) assess the potential for sediment toxicity within the estuary. Mean concentrations in surface sediments in individual waterways ranged from 5 to 473 μg/kg for p,p′-DDT, 18 to 429 μg/kg for p,p′-DDD, and 5 to 111 μg/kg for p,p′-DDE. A regional background mean concentration of approximately 100–300 μg/kg Σp,p′-DDT (sum of p,p′-DDT, p,p′-DDD, and p,p′-DDE) was measured in surface sediments throughout the estuary, with the exception of the Arthur Kill, where mean concentrations exceeded 700 μg/kg. The elevated concentrations found in recently deposited surface sediments in the Arthur Kill may be due to the presence of ongoing sources. The highest concentrations in buried sediments occurred in the lower Passaic River at depths corresponding to historical deposits from 1940 to 1970, the peak time period for production and usage of DDT in the United States. Comparisons to NOAA benchmark sediment toxicity values indicate that p,p′-DDT, p,p′-DDD, and p,p′-DDE concentrations in surface sediments may pose a potential hazard to fish, shellfish, and other benthic and demersal organisms in some portions of the estuary, particularly in the upper and lower Arthur Kill.

An overview of the application of chemometric data analysis methods to complex chemical mixtures in various environmental media is presented. Reviews of selected research are given as examples of the application of principal components analysis and other statistical methods to identify contributions from multiple sources of contamination in air, water, sediments, and biota. Other examples are cited that illustrate how scientists have used classification and regression methods to model the distribution of anthropogenic contaminants and predict their environmental effects or fate.

Recent studies suggested that the presence of elevated levels of 2,4,6,8-tetrachlorodibenzothiophene (2,4,6,8-TCDT) in sediments collected from the lower Passaic River in Newark, New Jersey is due to operations at a former 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) manufacturing facility. This paper reviews the scientific literature to determine if 2,4,6,8-TCDT is commonly found in the aquatic environment and evaluates whether 2,4,6,8-TCDT is associated with the production of 2,4,5-T. Polychlorinated dibenzothiophenes (PCDTs) are generated by chemical processes that are similar to those that result in the formation of polychlorinated dibenzofurans (PCDFs). PCDTs have been found in pulp and paper mill effluents and waste incineration fly ash, and are associated with metal reclamation processes and incineration of PCBs (Peterman et al., 1986; Buser et al., 1991; Rappe, 1992; Sinkkonen et al., 1991, 1992a,b, 1993). Chemical processes similar to those that have resulted in the formation of PCDFs, such as dye, pigment, paint, pesticide, and raw chemical production, are likely significant sources of PCDTs if sulfur-containing organic chemicals are used in the manufacturing process. It has been estimated that there are over 300 PCDD and PCDF sources within the Newark Bay estuary, many of which are likely to have discharged PCDT-containing effluents to the Passaic River (Paustenbach, 1993). Chlorinated thiophenols and other sulfur-containing compounds such as sulfonated benzenes, chlorinated in the 2, 4, and 6 positions, and 2,3,5,2′,3′,5′-hexachlorobiphenyl, present in commercial PCB mixtures (Ballschmitter and Zell, 1980), have precisely the correct configuration of chlorine substitution for 2,4,6,8-TCDT formation. Elevated levels of both 2,4,6,8-TCDT (Pruell et al., 1993) and PCBs (Wenning et al., 1992c) in lower Passaic River sediments suggest that PCDT contamination of these sediments may be related to several sources, most notably, a known PCB contaminated site approximately one mile downstream of the former 2,4,5-T facility. The scientific literature provided no evidence to support the assertion that the presence of 2,4,6,8-TCDT in the environment was related to 2,4,5-T production. The reported presence of 2,4,6,8-TCDT in Passaic River sediments cannot be explained by production practices at the former 2,4,5-T facility.

Surficial sediments collected from 18 location in three major tributaries to Newark Bay, New Jersey were analyzed for seven toxic metals (As, Cd, Cu, Hg, Ni, Pb and Zn) and 16 other trace elements. In addition, the concentrations of Ca, Cu, K, Mg, Na and Pb were determined surficial sediments collected from 35 sites in two wetland areas along the Hackensack River. Possible sources of metals were identified based on tthe observed distributions. The potential for adverse effects to fish and shellfish was evaluated based on comparisons to available benchmark sediment quality criteria and toxicity guideline values. Trace metal concentrations varied greatly, but were highest in sediments collected in areas of high sediment deposition in the lower Passaic River and the Arthur Kill. The concentrations of As (17 ± 16 mg / kg ), Cd (10 ± 6 mg / kg ), Cu (237 ± 222 mg / kg ), Hg (2.1 ± 2.6. mg / kg ), Ni (39 ± 49 mg / kg ), Pb (421 ± 571 mg / kg ) and Zn (395 ± 403 mg / kg ) measured in the estuary exceeded several benchmark sediment quality values. Lead (275 ± 138 mg / kg ) and Cu 9116 ± 63 mg / kg ) concentrations in wetland sediments from Hackensack Area I were similar to those found in the Passaic River and the Arthur Kill. These results suggest that metal concentrations, particularly Cd, Hg and Pb, in surficial sediments in the Passaic River, Hackensack River, the Arthur Kill and portions of the Hackensack Meadowlands may pose a significant threat to aquatic biota.

This chapter summarizes knowledge on tissue residues and ecotoxicological effects typically observed in aquatic organisms exposed to dioxins, polychlorinated biphenyls (PCBs), and Polybrominated diphenyl ethers (PBDEs). It also summarizes the physical and chemical properties of compounds that are important to understanding environmental fate, bioaccumulation, distribution in the environment, and the significance of tissue residues in aquatic organisms. The chapter discusses what is understood about the environmental fate of these compounds, with an emphasis on factors that influence exposure and toxicity. It includes an overview of toxic equivalency factors (TEFs) assigned to different dioxins and certain dioxin-like PCBs used to evaluate the significance of environmental exposures, and a discussion of recent TEF schemes proposed to aid PBDE risk assessment. Although scientific interest regarding the ecological effects of dioxins, PCBs, and PBDEs stems from our knowledge of human health, much work remains regarding assessing risks to aquatic organisms.

The distributions of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) measured in surficial sediments from the lower Passaic River and Newark Bay, New Jersey, USA, were compared to those reported in various industrial process residues and effluents, contaminated soils, chemical formulations, and municipal waste disposal activities that are known or suspected to be sources of these compounds in the aquatic environment. Comparisons were conducted using data from published literature to determine whether the composition of tetra through octachlorinated congeners and 2,3,7,8-substituted residues reported in a broad range of potential environmental sources could explain the presence of these compounds in Newark Bay. Pattern similarities and differences between congener groups and isomers were obtained by principal components analysis. The congener and isomer fingerprint patterns found in surficial sediments appear to be the result of releases from several industrial and municipal sources commonly found in heavily industrialized and populated urban environments, including municipal sewage sludge, municipal solid waste incinerator fly ash, pentachlorophenol, sodium pentachlorophenate, newsprint, scrap metal reclamation incinerators, combustion engines, and pulp and paper mill black liquor recovery furnaces. The variations among the PCDD and PCDF residue and congener patterns were largely explained by the distributions of the hexa- and octachlorinated compounds and by 2,3,7,8,-TCDD, 2,3,7,8,-TCDF, and the penta-substituted isomers. Although it has been claimed that a single industrial source is responsible for the presence of these compounds in the sediments of Newark Bay, the available evidence indicates that the vast majority of the PCDDs and PCDFs are the result of contributions from several industries. There is no evidence from this analysis to indicate that a single source is responsible for the contamination.

Isomer-specific determinations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were performed in 19 surficial sediment samples collected from the lower Passaic River and Newark Bay, New Jersey. Total PCDD and PCDF concentrations ranged from 415 to 23,300 ng/kg (dry wt) and 37 to 8400 ng/kg, respectively. OCDD and OCDF were the predominant congeners in all samples, followed by the hepta-, hexa-, tetra-, and penta-chlorinated compounds. Forty-seven percent (9/19) of the sediment samples contained no detectable levels of 2, 3, 7, 8-TCDD. The concentrations of 2, 3, 7, 8-TCDD and 2, 3, 7, 8-TCDF ranged from nondetect to 510 ng/kg (geometric mean of 5 ng/kg) and from 2.8 to 480 ng/kg (geometric mean of 13 ng/kg), respectively. The composition of PCDD/Fs in sediments was evaluated using chemometric pattern recognition techniques. Principal components analysis and complete linkage:farthest neighbor cluster analysis revealed the presence of at least five distinctive fingerprint patterns in surficial sediments collected from different locations in the Newark Bay estuary. Differences among PCDD/F patterns were attributable to the relative presence or absence of 1, 2, 3, 4, 6, 7, 8-HpCDF and the hepta-, hexa-, and octa-chlorinated congeners. To determine whether the presence of PCDD/Fs in sediments could be associated with a single source, residues in sediments were compared to those found in three soil samples and one sump sediment sample from a former 2, 4, 5-T manufacturing plant. Significant compositional differences were observed between the two data sets. Fingerprint patterns in sediments were dominated by the higher PCDD/F chlorinated congeners and contained significantly lower levels of the tetra-chlorinated congeners, particularly 2, 3, 7, 8-TCDD, than soils from the former 2, 4, 5-T plant. These differences, as well as those observed among surficial sediments from different locations, indicate that there are clearly several different sources of 2, 3, 7, 8-TCDD and other PCDD/Fs to the estuary.

The distributions of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) measured in surficial sediments from the lower Passaic River and Newark Bay, New Jersey were compared to those observed in sediments from other waterways located within industrial or heavily populated areas using chemometric techniques. Comparisons were conducted using published data to determine whether the distributions of 2,3,7,8-substituted isomers in surficial sediments from industrialized waterways have similar or different fingerprint patterns. Chemometric evaluations consisted of principal components analysis and the complete linkage: farthest neighbor cluster method. The concentrations of individual isomers were normalized to the combined sum of the 2,3,7,8-substituted PCDD and PCDF isomer concentrations in order to evaluate relative distribution patterns. Several of the isomeric fingerprint patterns found in sediments from the lower Passaic River and Newark Bay were similar to those found in sediments from New Bedford Harbor, MA, USA, Black Rock Harbor, CT, USA, Providence River, RI, USA, Eagle Harbor, WA, USA, the Inner Stockholm archipelago, Sweden, Hamburg Harbor, Germany, and St. Laurensharbor, The Netherlands. Pattern differences were observed in sediments from Frierfjorden, Norway, Niagara River, NY, USA, and Chemieharbor, The Netherlands. The variations among the 2,3,7,8-substituted isomer patterns observed in different sediments were largely explained by the distributions of the higher chlorinated isomers. Other differences may be attributed to environmental conditions unique to each waterway such as tidal flux, shipping traffic, urbanization, sedimentation rates, and the presence of different industrial sources. Similarities in PCDD and PCDF patterns among the waterways were related to the presence of similar municipal and industrial sources, including effluents from pentachlorophenol and polychlorinated biphenyl manufacturing facilities, pulp and paper mills, automobile and shipping traffic, and municipal solid waste and industrial incinerators. The distributions of PCDDs and PCDFs in surficial sediments from some areas of the Newark Bay estuary were representative of those found in many industrialized regions. It wsa evident from this analysis that the application of chemometric analysis can be useful in characterizing the distribution of complex multi-constituent chemical residues and identifying sources of these compounds in freshwater, estuarine, and marine sediments.

A recent study reported elevated levels of 1,2,8,9-tetrachlorodibenzo-p-dioxin (1,2,8,9-TCDD) in crustaceans and finfish collected from Newark Bay, New Jersey (Rappe et al., 1989). The authors suggested that the presence of this compound in biota was due to operations at a former 2,4,5-trichlorophenoxy acetic acid (2,4,5-T) manufacturing facility located on the lower Passaic River. Since 1,2,8,9-TCDD had been identified in two soil samples claimed to be associated with the site, it was concluded that the former manufacturing plant was the source of this compound. A review of the scientific literature was conducted to evaluate whether this isomer is associated with the formulation of 2,4,5-T and to determine whether 1,2,8,9-TCDD is commonly found in the aquatic environment. Measurements and chromatographic data from known sources of polychlorinated dibenzo-p-dioxins indicate that incinerator fly ash, soot from wood-burning chimneys, and the combustion of polychlorinated biphenyls and some chlorophenoxy herbicides are sources of 1,2,8,9-TCDD. This isomer has never been found in samples of 2,4,5-T. We conclude, therefore, that the presence of 1,2,8,9-TCDD in Newark Bay biota is not associated with 2,4,5-T manufacturers but, rather, the result of various commercial, residential, municipal, and industrial combustion processes.

This paper briefly reviews the complex issues associated with remedy identification, screening, and selection at contaminated sediment sites in North America. We present two case studies illustrating approaches used by stakeholders to arrive at remedy decisions. These approaches include watershed-level thinking and net environmental benefit analysis (NEBA), both of which recognize the influences of chemical and non-chemical, natural and anthropogenic Stressors, and their respective influences on the integrity of the aquatic ecosystem.

The Moolgavkar-Venzon-Knudson (M-V-K) two-stage model for carcinogenesis was used to estimate the risk-specific dose (RsD) based on the incidence of tumors reported by Kociba et al. (1978) for Sprague-Dawley rats exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD; dioxin). The results from the recently completed (1990) reevaluation of the Kociba et al. study, which used the current National Toxicology Program (NTP) pathology criteria, were also evaluated. Time-to-tumor information for each rat was incorporated into the analysis. Model parameters for the approximate form of the hazard function of the two-stage M-V-K model were determined by maximum likelihood estimation. This simplification was significant but necessary, because laboratory data on the intermediate cell growth rate and the transition rates have not been determined. Estimates of the RsD (10(-6) risk) (based on the original 1978 histopathology results) were 10 fg/kg/d when carcinomas and hyperplastic nodules were combined and 150 fg/kg/d when only carcinomas were considered. In contrast, using the 1990 histopathology data, the RsD (10(-6) risk) was 80 fg/kg/d when adenomas and carcinomas were combined and 25,000 fg/kg/d when only hepatocellular carcinomas were considered. Since the two-stage M-V-K model is intended to predict the occurrence of malignant tumors, the mathematically appropriate RsD is 25,000 fg/kg/d (10(-6) risk). Because the model does not account for pharmacokinetics or the possibility of other toxic effects, the appropriate RsD (10(-6) risk) for humans should be much smaller. Using the carcinoma data only, a sensitivity analysis of key parameters in the model was conducted. Results indicated that the ranges of plausible values for the RsD (10(-6) risk) for the original 1978 and the 1990 reevaluation data were 70-2600 fg/kg/d and 120-50,000 fg/kg/d, respectively. The lowest plausible RsD is, therefore, approximately 10-fold greater than the current U.S. EPA RsD (10(-6) risk) of 6.4 fg/kg/d [which is based on the linearized multistage (LMS) model]. Even though these results must be considered preliminary until some of the values for the model parameters are experimentally determined and a complete physiologically based or receptor-based model is developed, this analysis shows that nearly any plausible laboratory data on tumor progression will yield a much higher RsD than currently embraced by the U.S. EPA.

As part of a comprehensive ecological risk assessment on a broad range of species, the potential for adverse effects in birds was evaluated at a chromate ore processing residue disposal site, Study Area 7, located at the confluence of the Lower Hackensack River, Passaic River, and Upper Newark Bay. Although detection of elevated concentrations of total chromium in sediment prompted the study, it was also necessary to consider potential risks related to other chemicals present in elevated concentrations due to widespread anthropogenic activities in Upper Newark Bay and its watershed. U.S. Army Corps of Engineers' TrophicTrace ® software was used to predict exposure to avian receptors using measured concentrations of chemicals in sediment, measured concentrations of chemicals in benthic invertebrates, and measured site physicochemical parameters. The TrophicTrace ® model was improved as part of the Study Area 7 ecological risk assessment to account for (1) incidental ingestion of sediment by dabbling and diving birds, (2) area use factors for spatial overlap of wide-ranging fish species and piscivorous birds, (3) spatially-explicit utilization of the site by birds with a variety of foraging strategies, and (4) temporal patterns of site utilization by migratory species. The ecological risk assessment demonstrated that chromium in sediment does not pose unacceptable hazards to avian receptors. Potentially unacceptable hazards were indicated for several organic chemicals (i.e., pesticides, polychlorinated biphenyls, and dioxins/furans), with hazard quotients highest for Upper Newark Bay reference conditions, reflecting potential widespread chemical impacts to the estuary. The modifications to TrophicTrace ® conducted for this assessment may be prudent and applicable for improving the accuracy and realism of other assessments involving avian receptors exposed to chemicals via contaminated sediment and transfer through the food web.