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Comment on “Levels of Polychlorodibenzo-p-dioxins and Dibenzofurans in Crab Tissues from the Newark/Raritan Bay System” SIR: In a recent publication of Environmental Science and Technology, Cai and co-workers (1) suggested that a former 2,4,5-T manufacturing facility in the lower Passaic River could be the sole source of 2,3,7,8-tetrachlorodibenzo-pdioxin (TCDD) and other polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in blue crab (Callinectes sapidus) samples from the Newark Bay Estuary. The authors’ conclusion was based on the reported presence of TCDD in crabs collected in 1991 and 1992 from a single location in Newark Bay, approximately 4 mi from the former 2,4,5-T site, and from three additional sites located in Raritan Bay, at distances of approximately 20-35 mi from the former 2,4,5-T site. In addition, the authors cite as a further basis for their conclusions the results of five dated sediment samples (2, 3) and two blue crab samples (4, 5) previously collected from Newark Bay and the lower Passaic River. These samples were also reported to contain TCDD and other PCDD/Fs. In a companion paper, Cai et al. (6) suggested that since crab tissue levels of 2,4,6,8-tetrachlorodibenzothiophene (2,4,6,8-TCDT) “correlated well” with TCDD levels measured in crabs collected from four locations in the estuary, a “common source” is likely responsible for the 2,4,6,8-TCDT and TCDD. Given the significant ramifications associated with such claims, we find it surprising that Cai et al. (1, 6) would draw such sweeping conclusions based on such limited data. We are more concerned with the fact that Cai et al. (1,6) did not cite the numerous papers in the peer-reviewed literature that directly conflict with their claims. First, the authors have ignored a number of comprehensive sediment and contaminant source investigations (7-12) that have revealed the presence of multiple sources of PCDD/Fs to the Newark Bay Estuary. Several of these sources have distinct PCDD/F fingerprints, particularly with respect to their relative concentrations of 2,3,7,8-substituted congeners, that are attributable to specific municipal and industrial sources (i.e., pulp and paper mills, municipal solid waste incinerators, combined sewer overflows, manufacturing of polychlorinated biphenyls, etc.) (8). Many of these source fingerprints are evident in sediments from several locations throughout the Estuary (7, 12). In addition, many of these fingerprints contain TCDD. The presence of multiple sources in the estuary was recently confirmed by Ehrlich et al. (13), who identified five source fingerprints. Second, Cai et al. (1) failed to cite the numerous EPA studies that report the presence of TCDD sources at sites very near those same sampling locations. For example, the U.S. Environmental Protection Agency’s (EPA) National Bioaccumulation Study found that elevated levels of PCDD/Fs in aquatic organisms collected from Raritan Bay are related to at least two sources in the Bay, including a pulp and paper mill and a petroleum refinery (14). In the same report, the EPA identified a chemical manufacturing facility along the Arthur Kill as a source of TCDD. Additionally, sediment data recently collected by the EPA, the National Oceanic
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and Atmospheric Administration (NOAA), and the U.S. Fish and Wildlife Service (FWS) strongly suggest the presence of a significant TCDD source near the Port Elizabeth Channel, just south of Cai et al.’s Newark Bay sample (15). Third, the Cai et al. (6) comments regarding a “common source” of TCDD and 2,4,6,8-TCDT are inconsistent with recent studies indicating that the manufacture of PCBs and not 2,4,5-T is likely responsible for elevated levels of polychlorinated dibenzothiophenes (PCDT) in the estuary (16). The source in question ceased operations in 1969. A review of historical bathymetry maps and the results of recent radioisotope dating analyses (17, 18) indicated that the mean sediment accumulation rates in the lower Passaic River adjacent to the site are the highest in the entire Newark Bay Estuary (3.8-15 cm yr-1). Sediments associated with the era that the facility ceased operations are buried under approximately 1-5 m of sediment and, therefore, are not believed to be mobile or bioavailable. In addition, on-site soils have been contained since operations ceased as part of ongoing remedial control activities for the former 2,4,5-T facility. Consequently, the former 2,4,5-T facility is not a plausible current source of PCDD/Fs or any other chemicals to sediments or biota in Newark Bay or the rest of the Estuary as Cai et al. (1, 6) have implied. Regardless, the data referred to by Cai et al. (1, 6) do not appear sufficiently robust to suggest evidence of a PCDD/F or PCDT source in the Passiac River. For example, as stated on page 1532 of Cai et al. (1), the authors have concluded that their results “show the distribution of PCDD/Fs levels [in blue crabs] as a function of distance from the putative source of PCDD/Fs”. This is a somewhat disingenuous statement given that blue crab samples were collected from only one location in the entire Newark Bay Estuary; this site being about 4 mi downstream from the alleged source. The remainder of the samples were collected in Raritan Bay, at locations over 20 mi from the former 2,4,5-T facility. At best, these samples can only be used to form hypotheses regarding the concentrations of PCDD/Fs in blue crabs from Raritan Bay; they cannot be used to investigate sources of PCDD/Fs in blue crabs, particularly from remote sites. In the Cai et al. (1) study, no samples were collected from any of the major tributaries to Newark Bay, most importantly the Arthur Kill, a 12-mi-long waterway linking the Newark and Raritan Bays. A spatial distribution of sample sites in this waterway as well as the other tributaries to Newark Bay would be required to evaluate any spatial pattern of PCDD/F contamination in blue crabs. These same concerns apply to the attempt by Cai et al. (6) to show a “pattern” of 2,4,6,8-TCDT levels in crabs collected from only four locations throughout a 35-mi stretch of the watershed. In summary, we believe it inappropriate to draw any conclusions regarding the spatial patterns of PCDD/Fs and PCDTs in blue crabs or sediments in the Newark Bay Estuary from such a limited dataset as that of Cai et al. (1, 6). Furthermore, any suggestion that a single source is responsible for all PCDD/F sediment contamination in the Newark Bay Estuary ignores a wide body of literature that indicates multiple sources are responsible for the PCDD/ Fs present in Newark Bay Estuary sediment and aquatic organisms. These include PCB users, pulp and paper
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manufacturers, sewage treatment plants, combined sewer overflows, paint manufacturers, and combustion sources. The widespread PCDD/F contamination of sediments throughout the industrialized waterways of the world (19) is clearly inconsistent with a single source theory and strongly argues that the ubiquitous nature of PCDD/Fs is the result of a multitude of sources.
Literature Cited (1) Cai, Z.; Ramanujam, V. M. S.; Gross, M. L.; Christini, A.; Tucker, R. K. Levels of polychlorodibenzo-p-dioxins and dibenzofurans in crab tissues from Newark/Raritan Bay system. Environ. Sci. Technol. 1994, 28, 1528-1534. (2) Tong, H. Y.; Monson, S. J.; Gross, M. L.; Bopp, R. F.; Simpson, H. J.; Deck, B. L.; Moser, F. C. Analysis of dated sediment samples from the Newark Bay area for selected PCDD/Fs. Chemosphere 1990, 20, 1497-1502. (3) Bopp, R. F.; Gross, M. L.; Tong, H.; Simpson, H. J.; Monson, S. J.; Deck, B. L.; Moser, F. C. A major incident of dioxin contamination: Sediments of New Jersey estuaries. Environ. Sci. Technol. 1991, 25, 951-956. (4) Belton, T. J.; Hazen, R.; Ruppel, B. E.; Lockwood, K.; Mueller, R.; Stevenson, E.; Post, J. J. A study of dioxin (2,3,7,8tetrachlorodibenzo-p-dioxin) contamination in select finfish, crustaceans and sediments of New Jersey waterways; New Jersey Department of Environmental Protection: Trenton, NJ, 1985. (5) Rappe, C.; Bergqvist, P. A.; Kjeller, L. O.; Swanson, S.; Belton, T.; Ruppel, B.; Lockwood, K.; Kahn, P. C. Levels and patterns of PCDD and PCDF contamination in fish, crabs, and lobsters from Newark Bay and the New York Bight. Chemosphere 1991, 22, 239-266. (6) Cai, Z.; Giblin, D. E.; Ramanujam, V. M. S.; Gross, M. L.; Christini, A. Mass-profile monitoring in trace analysis: Identification of polychlorinated dibenzothiophenes in crab tissues collected from the Newark/Raritan Bay system. Environ. Sci. Technol. 1994, 28, 1535-1538. (7) Finley, B.; Wenning, R. J.; Ungs, M. J.; Huntley, S.; Paustenbach, D. J. PCDDS and PCDFs in surficial sediments from the Lower Passaic River and Newark Bay; Dioxin ’90 Conference Proceedings; 1990. (8) Wenning, R.; Paustenbach, D.; Johnson, G.; Ehrlich, R.; Harris, M.; Bedbury, H. Chemometric analysis of potential sources of polychlorinated dibenzo-p-dioxins and dibenzofurans in surficial sediments from Newark Bay, New Jersey. Chemosphere 1993, 27, 55-64. (9) Wenning, R. J.; Harris, M. A.; Finley, B.; Paustenbach, D. J.; Bedbury, H. Application of pattern recognition techniques to evaluate polychlorinated dibenzo-p-dioxin and dibenzofuran distributions in surficial sediments from the lower Passaic River and Newark Bay. Ecotoxicol. Environ. Saf. 1993, 25, 103-125. (10) Wenning, R. J.; Paustenbach, D. J.; Harris, M. A.; Bedbury, H. Principal components analysis of potential sources of polychlorinated dibenzo-p-dioxin and dibenzofuran residues in surficial sediments from Newark Bay, New Jersey. Arch. Environ. Contam. Toxicol. 1993, 24, 271-289.
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(11) Wenning, R. J.; Harris, M. A.; Paustenbach, D. J.; Bedbury, H. Potential sources of 1,2,8,9-tetrachlorodibenzo-p-dioxin in the aquatic environment. Ecotoxicol. Environ. Saf. 1992, 23, 133146. (12) Wenning, R. J.; Harris, M. A.; Ungs, M. J.; Paustenbach, D. J.; Bedbury, H. Chemometric comparisons of polychlorinated dibenzo-p-dioxin and dibenzofuran residues in surficial sediments from Newark Bay, New Jersey and other industrialized waterways. Arch. Environ. Contam. Toxicol. 1992, 22, 397413. (13) Ehrlich, R.; Wenning, R. J.; Johnson, G. W.; Su, S. H.; Paustenbach, D. J. A mixing model for polychlorinated dibenzo-pdioxins and dibenzofurans in surface sediments from Newark Bay, New Jersey using polytopic vector analysis. Arch. Environ. Contam. Toxicol. 1994, 27, 486-500. (14) U.S. EPA. National Study of Chemical Residues in Fish; U.S. Environmental Protection Agency, Office of Science and Technology: Washington, DC, Sep 1992. (15) U.S. EPA. Memorandum Regarding EPA/NOAA Recent Data; U.S. Environmental Protection Agency, Emergency and Remedial Response Division, Region II: New York, Dec 22, 1993. (16) Huntley, S. L.; Wenning, R. J.; Paustenbach, D. J.; Wong, A. S.; Luksemburg, W. J. Potential sources of polychlorinated dibenzothiophenes in the Passaic River, New Jersey. Chemosphere 1994, 29, 257-272. (17) IT. Diamond Shamrock Sediment Study Computer Programs. International Technology Corporation: Jan 22, 1986; 84-6733. (18) Huntley, S. L.; Bonnevie, N. L.; Wenning, R. J. Polycyclic aromatic hydrocarbon and petroleum hydrocarbon contamination in sediment from the Newark Bay Estuary, New Jersey. Arch. Environ. Contam. Toxicol. 1995, 28, 93-107. (19) Clark, A. N.; Megehee, M. M.; Lowe, D. L.; Clarke, J. H. A review of polychlorinated dibenzofurans and polychlorinated dibenzodioxins in sediments in the United States and international waterways. Hazmat 1994, 11, 253-276.
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