Changing sources of polychlorinated dibenzo-p-dioxins and furans in sediments and ecological risk for nekton in the lower Passaic River and Newark Bay, New Jersey, USA

Spatial distributions, behaviors, and sources of PCDD/Fs in surface water and sediment from the Yangtze River Delta

The Yangtze River Delta (YRD), one of the most economically developed and industrialized regions in China, is confronted with challenges arising from rapid urbanization, particularly environmental pollution. The collection of surface water and sediment samples from forty-nine sites in the YRD was conducted to analyze 2378-substituted polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) congeners. The detected concentrations of PCDD/Fs were 0-5.3 pg TEQ/L in water and 0.12-1493 pg TEQ/g dw in sediment. The PCDD/Fs contamination in the sediment was widespread in the YRD. There were variations in the congener characteristics of PCDD/Fs in surface water and sediment. The proportion of OCDD was significantly lower in surface water samples compared to sediment, while the less chlorine-substituted homologs were found in larger proportions. To understand the partitioning and behavior of dioxins within the water-sediment system, we calculated the organic carbon normalized partition coefficients and fugacity fraction (ff) of PCDD/F congeners. The results revealed that the PCDD/Fs had not attained a state of distributional equilibrium, and the non-specific hydrophobic effect seemed minimally influential on their partitioning between sediment and water. The average ff values, which varied between 0.06 and 0.63, indicated differing migration directions for the PCDD/F congeners. Source identification analysis provided evidence that the dioxins in the river water were primarily attributed to industrial thermal processes. Iron and steel smelting, along with pesticide production and use, were likely responsible for the sediment contamination. This comprehensive analysis underscores the complex nature of PCDD/Fs pollution in the YRD and highlights the necessity for targeted environmental management strategies.

Sources of 2,3,7,8-Tetrachlorodibenzo-p-dioxin and Other Dioxins in Lower Passaic River, New Jersey, Sediments

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.

2,3,7,8-Tetrachlorodibenzo-p-dioxin Dechlorination is Differentially Enhanced by Dichlorobenzene Amendment in Passaic River, NJ Sediments

Polychlorinated dibenzo-p-dioxins (PCDDs) are a class of toxic organic compounds released by a number of industrial processes. Sediments of the Passaic River in New Jersey are contaminated by these compounds. To explore the ability of native organohalide respiring bacteria to dechlorinate PCDDs, we first enriched bacteria from sediments of the Passaic River on two organohalides, trichloroethene (TCE) and 1,2-dichlorobenzene (DCB). We then used these enriched sediment cultures and original, unamended sediment as the inocula in a secondary experiment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TeCDD), 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TeCDD), and 2,7-dichlorodibenzo-p-dioxin (2,7-DiCDD) as target organohalides. We observed dechlorination of 1,2,3,4-TeCDD by all inocula, although to different extents. We observed progressive dechlorination of 2,3,7,8-TeCDD only in bottles inoculated with the DCB enrichment culture, and dechlorination of 2,7-DiCDD almost exclusively in bottles inoculated with the original, unamended river sediment. Dechlorination of 1,2,3,4-TeCDD was more rapid than that of the other amended congeners. Phylotypes within the class Dehalococcoidia associated with organohalide dechlorination were differentially enriched in DCB versus TCE enrichment cultures, indicating that they may play a role in dechlorination of the PCDDs.

Assessing Benthic Bioaccumulation of Polychlorinated Dioxins/Furans and Polychlorinated Biphenyls in the Lower Passaic River (NJ, USA) Based on In Situ Passive Sampling

Passive sampling has emerged as a promising tool to assess the presence of hydrophobic organic contaminants (HOC) in water, sediment, and biota, such as polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) or polychlorinated biphenyls (PCBs). Previous work evaluated the ability of passive samplers to predict the bioavailability of sedimentary HOCs mostly in the laboratory, often for marine organisms. The present study assessed the use of low-density polyethylene (LDPE) to derive freely dissolved concentrations of PCDD/Fs and PCBs in porewater in situ versus ex situ and in river water. An LDPE-based multisampler system was deployed at 4 locations along the lower Passaic River (NJ, USA) in sediment and the water column, where sediment and benthic species samples were also collected. Good agreement was generally observed for PCDD/F and PCB concentrations comparing in situ and ex situ approaches (within 0.30-39%). Significant linear relationships were derived between log LDPE-based and log lipid-based concentrations of PCDD/Fs and PCBs. The in situ multisampler system showed promise to derive HOC concentrations in porewater and river water and to predict the bioaccumulation potential of HOCs in benthic biota. Environ Toxicol Chem 2020;39:1174-1185. © 2020 SETAC.

Uptake of hydrophobic organic compounds, including organochlorine pesticides, polybrominated diphenyl ethers, and perfluoroalkyl acids in fish and blue crabs of the lower Passaic River, New Jersey, USA

The bioavailability and bioaccumulation of sedimentary hydrophobic organic compounds (HOCs) is of concern at contaminated sites. Passive samplers have emerged as a promising tool to measure the bioavailability of sedimentary HOCs and possibly to estimate their bioaccumulation. We thus analyzed HOCs including organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in sediment, porewater, and river water using low-density polyethylene passive samplers and in 11 different finfish species and blue crab from the lower Passaic River. In addition, perfluorinated alkyl acids (PFAAs) were measured in grab water samples, sediment, and fish. Best predictors of bioaccumulation in biota were either porewater concentrations (for PCBs and OCPs) or sediment organic carbon (PBDEs and PFAAs), including black carbon (OCPs, PCBs, and some PCDD/F congeners)-normalized concentrations. Measured lipid-based concentrations of the majority of HOCs exceeded the chemicals' activities in porewater by at least 2-fold, suggesting dietary uptake. Trophic magnification factors were >1 for moderately hydrophobic analytes (log octanol-water partitioning coefficient [K_OW ] = 6.5-8.2) with low metabolic transformation rates (<0.01 d^-1 ), including longer alkyl chain PFAAs. For analytes with lower (4.5-6.5) and higher (>8.2) K_OW s, metabolic transformation was more important in reducing trophic magnification. Environ Toxicol Chem 2019;38:872-882. © 2019 SETAC.

Reconstruction of historical 2,3,7,8-tetrachlorodibenzo-p-dioxin discharges from a former pesticide manufacturing plant to the Lower Passaic River

Based on chemical fingerprinting and other lines of scientific evidence, a former pesticide manufacturing plant in Newark, New Jersey (U.S.A.) has been implicated in numerous journal articles as the major source of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the sediments of the Lower Passaic River (LPR). Although the site has been extensively studied for over three decades, no previous study has identified a pathway capable of discharging an amount of 2,3,7,8-TCDD comparable to the mass estimates made for 2,3,7,8-TCDD in the sediments of the LPR and Newark Bay, or examined the timing of specific manufacturing processes at the site in relation to 2,3,7,8-TCDD concentrations in dated sediment cores. A reconstruction of the historical operations at this site was performed, supporting it as the major source of 2,3,7,8-TCDD to the LPR. A 2,4,5-trichlorophenol purification process, utilized prior to September 1954, was specifically identified as a significant source of 2,3,7,8-TCDD to the LPR. This purification process generated a dioxin-rich sludge that was discharged to the river prior to September 1954. Annual 2,4,5-trichlorophenol production, coupled with modeling to predict concentrations of 2,3,7,8-TCDD, indicate that 2,3,7,8-TCDD discharges to the LPR from this one process (20-80 kg) are consistent with mass estimates of 2,3,7,8-TCDD in the river (30-50 kg). 2,3,7,8-TCDD and cesium-137 data from nearby sediment cores support this purification process as a major pathway by which 2,3,7,8-TCDD entered the river.

Forensic Analysis of Polychlorinated Dibenzo-p-Dioxin and Furan Fingerprints to Elucidate Dechlorination Pathways

Polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) are persistent organic pollutants whose main removal process in the environment is due to biodegradation, and particularly anaerobic reductive dechlorination. Since PCDD/F congeners that are substituted in the lateral 2, 3, 7, and 8 positions are the most toxic, removal of these chlorines is advantageous, but previous studies have only demonstrated their removal under laboratory conditions. We evaluated a concentration data set of PCDD/F congeners with four or more chlorines along with all 209 polychlorinated biphenyl (PCB) congeners in surface water, treated and untreated wastewater, landfill leachate, and biosolids (NY CARP data set) to determine whether peri and peri/lateral dechlorination of PCDD/Fs occurs in these environments. Positive Matrix Factorization (PMF) applied to the data set revealed a factor indicative of the microbial dechlorination of PCBs, and this factor also contained a variety of non-2,3,7,8 substituted PCDD/F congeners. These results suggest that dechlorination of PCDD/Fs at the lateral positions is facile if not preferred in these environments. The relative lack of tetra- and penta-chlorinated PCDD/Fs suggested that dechlorination proceeds to PCDD/F congeners with less than four chlorines. The PMF results were confirmed by examining three samples that contained >90% PCB dechlorination products from the Fresh Kills Landfill and the Hudson River. Even without factor analysis, these samples demonstrated almost identical PCDD/F congener patterns. This study suggests that PCDD/Fs are reductively dechlorinated to nontoxic non-2,3,7,8 PCDD/F congeners in sewers and landfills as well as in the sediment of the Upper Hudson River.

Using Polyethylene Passive Samplers To Study the Partitioning and Fluxes of Polybrominated Diphenyl Ethers in an Urban River

In the aquatic environment, the behavior of hydrophobic organic contaminants (HOCs), such as polybrominated diphenyl ethers (PBDEs), depends on the congeners' physicochemical properties, environmental conditions and the presence of competing natural sorbents, including particulate and dissolved organic carbon (DOC) and black carbon (BC). Although BC is known as an important sedimentary sorbent for HOCs, its affinity for PBDEs has been poorly constrained. To better understand the biogeochemical controls on PBDEs, 12 PBDE congeners were measured in air, water, sediment and porewater of the lower Passaic River. BDE-47 and BDE-99 dominated in all media. In sediments and water, the dual OC + BC approach better predicted PBDE partitioning compared to the simple OC isotherm. Field-derived K_BC values for PBDEs were inversely correlated with aqueous solubility [log K_{BC sediments(water)} = -log C_w^sat * 0.95 (1.2) + 0.36 (-0.69)]; they reflected near background to highly contaminated regions across the Passaic River. In the water column, PBDEs appeared at equilibrium partitioning between particles and colloids: OC + BC were responsible for the sorption of 65% of PBDEs, followed by colloids (30%); only 5% of PDBEs were truly dissolved. Calculated sediment-water diffusive fluxes greatly overwhelmed the atmospheric depositional flux to the river.