Brian C. Butterworth

Geochemical Study of Sediment Contamination in New Bedford Harbor, Massachusetts

Chemical analyses of sediment samples collected along a transect in New Bedford Harbor revealed a gradient of increasing concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDS), polychlorinated dibenzofurans (PCDFs), polycyclic aromatic hydrocarbons (PAHs) and several trace metals from the southern to the northern areas of the estuary. Although the concentrations of contaminants generally increased with distance north in the estuary for all classes of compounds, differences were observed between the trends for many of the compounds. These differences are probably due to both the sources and differential environmental behaviors of the compounds in the estuary. The primary sources of PCBs, PCDFs and trace metals appear to be industrial discharges either directly into the estuary or through combined sewer overflows. Additional inputs of PCDFs may have also impacted the lower portions of the harbor. These inputs may be from the combustion of sewage sludge containing high concentrations of PCBs at the New Bedford Harbor Municipal Wastewater Treatment Plant. The major inputs of PAHs and PCDDs are probably from urban runoff entering the harbor through combined sewer overflows and storm drains.

Bioavailability of polychlorinated dibenzo-p-dioxins and dibenzofurans from contaminated Wisconsin River sediment to carp

Abstract The bioavailability of 2,3,7,8-TCDD from sediment to freshwater fish was studied in laboratory exposures. Carp (10g) exposed to Wisconsin River sediment (39 pg/g) for 55 days accumulated 7.5 pg/g. Maintaining exposured fish in clean water for an additional 205 days resulted in depuration of 32–34% TCDD. These values compare to field data where sediments ranged from 30–200 pg/g and 1.5 kg carp (70 pg/g) depurated 55% in 325 days. Analysis of sediment, laboratory exposed fish, and Wisconsin River fish for other PCDDs and PCDFs showed residues of 2,3,7 and 8 substituted congeners selectively enriched.

Branchial elimination of superhydrophobic organic compounds by rainbow trout (Oncorhynchus mykiss)

The branchial elimination of pentachloroethane and four congeneric polychlorinated biphenyls by rainbow trout was measured using a fish respirometer-metabolism chamber and an adsorption resin column. Branchial elimination was characterized by calculating a set of apparent in vivo blood:water partition coefficients (P(BW)). Linear regression was performed on the logarithms of P(BW) estimates and the log K(OW) value for each compound to give the fitted equation: log P(BW)=0.76 x log K(OW)-1.0 (r(2)=0.98). The linear nature of this relationship provides support for existing models of chemical flux at fish gills and suggests that a near equilibrium condition was established between chemical in venous blood entering the gills, including dissolved and bound forms, and dissolved chemical in expired branchial water. In vivo P(BW) estimates were combined with P(BW) values determined in vitro for a set of lower log K(OW) compounds (Bertelson et al., Environ. Toxicol. Chem. 17 (1998) 1447-1455) to give the fitted relationship: log P(BW)=0.73 x log K(OW)-0.88 (r(2)=0.98). The slope of this equation is consistent with the suggestion that chemical binding to non-lipid organic material contributes substantially to blood:water chemical partitioning. An equation based on the composition of trout blood (water content and the total amount of organic material) was then derived to predict blood:water partitioning for compounds with log K(OW) values ranging from 0 to 8: log P(BW)=log[(10(0.73 log K(ow)) x 0.16)+0.84].

A national study of chemical residues in fish: III: Study results

Abstract Bottom feeding and game fish, from each of nearly 400 sites throughout the United States were analyzed for 15 PCDD/PCDFs, PCBs, 21 pesticides and herbicides, and 13 other organic chemicals, and mercury. Seven of the PCDD/PCDFs and 15 of the chemicals were detected at over 50 percent of the sites. PCBs were detected at 91% of all sites at a mean concentration of 1.90 μg/g, and exceeded 10 μg/g at 10 sites. 2,3,7,8-TCDD was detected at 70 percent of the sites at a mean concentration of 6.9 ppt and a maximum concentration of 204 ppt. 2,3,7,8-TCDF was detected at 89 percent of the sites at a mean concentration of 13.6 ppt and a maximum concentration of 404 ppt. Fish from 75% of all sites had a total TCDD toxic equivalence concentrations (TEC) due to PCDD/PCDFs, below 10 pg/g. Those with the highest 2,3,7,8-TCDD concentrations also had the highest TEC. p,p 1 -DDE was the most frequently detected individual analyte (99% of samples), and was found at the highest maximum (14,000 ng/g) and mean (295 ng/g) concentrations. No correlation between specific sources and most of the analytes could be made. However, pulp and paper mills using chlorine appear to be a significant source of 2,3,7,8-TCDD and 2,3,7,8-TCDF in these samples which were collected between 1986 and 1989.

Potency of a Complex Mixture of Polychlorinated Dibenzo-p-dioxin, Dibenzofuran, and Biphenyl Congeners Compared to 2,3,7,8-Tetrachlorodibenzo-p-dioxin in Causing Fish Early Life Stage Mortality

Use of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity equivalents concentration (TEC) assumes that polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) act additively and via a common mechanism to cause toxicity. To test these assumptions, 11 TCDD-like congeners and three non-TCDD-like congeners were combined at ratios typically found in Lake Michigan lake trout. The potency of the mixture, expressed as TEC based on fish-specific toxic equivalency factors, was compared to TCDD for producing lake trout and rainbow trout early life stage mortality. Signs of toxicity following exposure of newly fertilized eggs to the mixture or to TCDD were indistinguishable; sac fry mortality associated with blue-sac disease, and slopes of the dose-response curves for percentage sac fry mortality versus egg TEC or versus egg TCDD were parallel. However, the mixture dose-response curves were significantly shifted to the right of the TCDD dose-response curves by 1.3- and 1.8-fold as illustrated by LD50 values. Following exposure to the mixture or TCDD, LD50S for lake trout early life stage mortality were 97 (89-110) pg TE/g egg and 74 (70-80) pg TCDD/g (LD50, 95% fiducial limits) and for rainbow trout were 362 (312-406) pg TE/g egg and 200 (148-237) pg TCDD/g egg. These data suggest that TCDD-like congeners act via a common mechanism to cause toxicity during trout early development, but may not act strictly additively when combined in a mixture of TCDD- and non-TCDD-like congeners at ratios found in Great Lakes fish. The deviation from additivity, however, is less than current safety factors of 10-fold commonly applied in ecological risk assessments, providing support for the continued use of a TE additivity model for assessing risk posed by complex mixtures of PCDDs, PCDFs, and PCBs to fish.

An isotope dilution high resolution gas chromatographic-high resolution mass spectrometric method for the determination of coplanar polychlorinated biphenyls: Application to fish and marine mammals

Abstract Analytical procedures and a quality assurance plan have been developed for the determination of coplanar PCBs in biological tissue at a target level of quantification of 5 pg/g. The methodology is based upon isotope dilution HRGC/HRMS and is analogous to rigorous protocols developed for PCDD/PCDFs. Results from the determination of coplanar PCBs in fish and marine mammals are presented.

A national study of mercury contamination of fish. IV: Analytical methods and results

Abstract The concentration of mercury has been determined in fish collected for a nation-wide survey of bioaccumulatable chemical contaminants. Samples were prepared using standard digestion procedures and analyzed by flameless atomic absorption. Over 660 samples were analyzed from 374 sites representing 10 site classifications. The national mean value for all samples (ND = 0) was 0.26 μg/g. The mean value for fish collected below Public Treatment Works was the highest at 0.59 μg/g. More than 90% of all sites contained fish with detectable mercury concentrations.

Partial life-cycle toxicity and bioconcentration modeling of perfluorooctanesulfonate in the northern leopard frog (Rana pipiens).

A number of recent monitoring studies have demonstrated elevated concentrations of perfluorooctanesulfonate (PFOS) in humans and wildlife throughout the world. Although no longer manufactured in the United States, the global distribution and relative persistence of PFOS indicates a need to understand its potential ecological effects. Presently, little is known concerning toxicity of PFOS in chronic exposures with aquatic species. Therefore, we evaluated the effects of PFOS on survival and development of the northern leopard frog (Rana pipiens) from early embryogenesis through complete metamorphosis. Exposures were conducted via water at measured PFOS concentrations ranging from 0.03 to 10 mg/L. Animals exposed to 10 mg/L began dying within approximately two weeks of test initiation. Survival was not affected by PFOS at lower concentrations; however, time to metamorphosis was delayed and growth reduced in the 3-mg/L treatment group. Tadpoles readily accumulated PFOS directly from water. Using a one-compartment bioaccumulation model, growth was shown to have a modest impact on steady-state PFOS concentrations. Variability in observed growth rates and the possible contribution of a size-dependent decrease in PFOS elimination rate contributed uncertainty to modeling efforts. Nevertheless, fitted uptake and elimination rate constants were comparable to those determined in earlier studies with juvenile rainbow trout. Overall, our studies suggest that R. pipiens is not exceptionally sensitive to PFOS in terms of either direct toxicity or bioconcentration potential of the chemical.

Isomer dependent bioavailability of polychlorinated dibenzo-p-dioxins and dibenzofurans from municipal incinerator fly ash to carp

The isomer-dependent bioavailability of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs and PCDFs) from municipal incinerator fly ash to freshwater fish was determined. It was observed that carp exposed to fly ash in a continuous-flow exposure readily accumulated select isomers of PCDDs and PCDFs. A preference for greater retention of isomers substituted in the 2, 3, 7 and 8 positions was observed. The Bioavailability Index (ratio of contaminant level in fish to level in fly ash) decreased with increasing degree of chlorination.

Contamination of fish by 2,3,7,8-tetrachlorodibenzo-P-dioxin: A survey of fish from major watersheds in the United States

Abstract A survey of contamination of fish from major watersheds in the United States by 2,3,7,8-TCDD has been conducted by the U.S. EPA. Bottom feeding and predator fish were collected at 90 statistically selected and 305 regionally selected sites and analyzed by GC/MS. It was found that 19% of the statistically sampled sites and 31% of the regionally selected sites were contaminated at or above a minimum level of detection varying from 0.5 to 2.0 pg/g. Ten percent of all samples were contaminated at levels greater than 5.0 pg/g. It was also observed that a subset of samples collected at sites near discharge from pulp/paper manufacture (N=28) had a higher frequency of TCDD contamination above 5.0 pg/g (38%). This subset of samples also contained the sample of the greatest level of TCDD contamination (85 pg/g).