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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.

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.

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

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

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.

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.

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.

A Sediment Quality Triad (SQT) study consisting of chemical characterization in sediment, sediment toxicity and bioaccumulation testing, and benthic community assessments was performed in the Lower Hackensack River, New Jersey. Chemistry data in sediment and porewater were evaluated based on the equilibrium partitioning approach and other published information to investigate the potential for chemical effects on benthic organisms and communities. Relationships were supported by laboratory toxicity and bioaccumulation experiments to characterize chemical effects and bioavailability. Benthic community results were evaluated using a regional, multimetric benthic index of biotic integrity and four heterogeneity indices. Evidence of slight benthic community impairment was observed in five of nine sediment sample stations. Severe lethal toxicity to amphipods (Leptocheirus plumulosus) occurred in four of these five stations. Although elevated total chromium concentrations in sediment (as high as 1900 mg/kg) were the rationale for conducting the investigation, toxicity was strongly associated with concentrations of polycyclic aromatic hydrocarbons (PAHs) rather than total chromium. PAH toxic units (SigmaPAH TU) in sediment and SigmaPAH concentrations in laboratory organisms from the bioaccumulation experiment showed a clear dose-response relationship with toxicity, with 0% survival observed in sediments in which SigmaPAH TU1-2 and SigmaPAH concentrations in Macoma nasuta were2 micromol/g, lipid weight. Metals detected in sediment and porewater, with the possible exception of copper, did not correlate with either toxicity or levels in tissue, likely because acid-volatile sulfide levels exceeded concentrations of simultaneous extracted metals at all sample locations. The study reinforces the value of using multiple lines of evidence approaches such as the SQT and the importance of augmenting chemical and biological analyses with modeling and/or other approaches to evaluate chemical bioavailability and toxicity of sediments.

Some environmental monitoring programs have reported increasing levels of certain polybrominated diphenyl ether (PBDE) isomers in aquatic biota and in human breast milk. The commercial PBDE products are known as penta-, octa-, and deca-brominated diphenyl ethers (PeBDE, OBDE and DBDE, respectively). Aside from the current European Commission's risk assessment initiative and efforts underway in Sweden, Canada and elsewhere to evaluate environmental levels, little is understood about sources of exposure and risks to humans. In this study, a multi-pathway human health risk assessment was performed to predict theoretical chronic daily intakes (CDIs) of PeBDE, OBDE, and DBDE by five different age groups: 0-2, 2-6, 6-12, 12-18, and 18-70 years. Sources of exposure included air, drinking water, consumption of fish, vegetables, meat and dairy products, and ingestion of breast milk by infants. In addition to a deterministic analysis, the risk assessment included a probabilistic analysis to derive the probability density functions describing the range of plausible exposures associated with eight different pathways, as well as aggregate lifetime exposures for each age group. The results were compared to CDI point estimates calculated by the European Chemicals Bureau as part of the European Commission's Existing Substances Programme. The major sources of uncertainties are discussed, including environmental sources, levels in different environmental compartments, toxicity, and human exposure. This paper also discusses the limitations in the current state-of-the-science and provides recommendations for improving the scientific relevance and accuracy of future environmental risk assessments of PBDEs.

The identity and relative contributions of various sources of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) to recently deposited sediments collected in Newark Bay and its major tributaries were determined using polytopic vector analysis (PVA), a multivariate statistical technique relatively new in the chemometric literature. The concentrations of 2,3,7,8-substituted PCDD/Fs were assayed in eighty-one surface and near-surface sediment samples collected from the Passaic River, Hackensack River, Arthur Kill, Elizabeth River, Kill Van Kull, Port Elizabeth, and Port Newark navigation channels and Robins Reef, which is located in New York Harbor. PVA modeling revealed five predominant 2,3,7,8-substituted PCDD/F fingerprint patterns in geographically plausible distributions throughout the estuary. This was consistent with the current understanding of hydrodynamic and sedimentation conditions reported in the literature for Newark Bay. Three patterns contained 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), which is alleged to originate from a single industrial source on the lower Passaic River. One of the fingerprints containing 2,3,7,8-TCDD was present in moderate proportions (10–20%) in surface sediments near the site, but was generally observed in low abundance (

Thirteen sediment cores of 1.5–6 m depth were collected from the lower Passaic River in Newark, New Jersey and assayed for metals, total petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and Aroclor® and coplanar polychlorinated biphenyls (PCBs). Chronological profiles of chemical concentrations at specified depths and sediment accumulation rates in each core were determined by 137Cs and 210Pb radioisotope measurements. Temporal concentrations of these chemicals were compared to available benchmark sediment toxicity values to assess historic and current toxic hazards to aquatic organisms. Elevated concentrations of several metals, including copper, lead, mercury, nickel, and zinc, were found in surface and buried sediments at concentrations that greatly exceeded Long and Morgan (1991) Effects Range-Low (ER-L) and Effects Range-Median (ER-M) values. Aroclors® 1242, 1248, and 1254 and several PAHs were also found at concentrations exceeding Long and Morgan (1991) benchmark toxicity values. In general, the highest metal and PAH concentrations were found in sediment deposited prior to the 1960s. Elevated PCB concentrations were found in sediment deposited between 1950 and 1980. The results indicate that the lower Passaic River is heavily contaminated due to recent and historical municipal and industrial discharges from local and up-stream sources. The primary sources of PCBs, PAHs, and metals appear to be discharges of industrial effluents either directly into the waterway or through combined sewer overflows. Additional inputs are probably from urban runoff entering through combined sewer overflows and storm drains.

The role of reduction/oxidation cycling in the toxic effects of the bipyridyl herbicide paraquat was examined in the hepatopancreas of the ribbed mussel, Geukensia demissa. In vitro studies indicated a dose-dependent increase in the rate of superoxide anion (O2−) generation, as measured by the reduction of cytochrome c, in the microsomal fraction of the hepatopancreas. The highest concentration of paraquat employed (4 mM) elicited an 81% increase in O2− production above controls, which was inhibited by the addition of superoxide dismutase (SOD). For in vivo studies, a single application of paraquat (0.5, 1.0, or 2.0 mM) was added to aerated salt-water aquaria containing mussels. Biochemical analyses of antioxidant enzymes, reduced glutathione (GSH), and lipid peroxidation were performed in hepatopancreatic tissue of mussels after exposures of 6, 12, 24, and 36 h. Catalase activities were significantly elevated (p < 0.05) in all treatment groups above controls at 6 h, in the 0.5 and 1.0 mM treatment groups at 12 h, and in the 0.5 mM group at 36 h. Total SOD activities were nearly doubled from controls in each treatment group at 12 h. However, SOD activities in exposed mussels were generally similar to or below controls at other times. GSH concentrations were generally higher in exposed mussels than in controls at all exposure periods. Lipid peroxidation in most treatment groups was significantly higher than in controls at 6, 12, and 24 h. The results support the hypotheses that these bivalves can activate redox cycling compounds and demonstrate in vivo responses typical of oxidative stress as observed in other organisms.