Polychlorinated Biphenyls Concentrations In Fish Research Articles

Remedial effectiveness of a pond biomanipulation: Habitat value and concentrations of polychlorinated biphenyls in fish

The fish and plant communities in a pond contaminated with polychlorinated biphenyls (PCBs) in East Tennessee, USA, were manipulated to reduce ecological and human-health risk associated with exposure to the chemical contaminants. We evaluated the success of the remedial action using a habitat valuation approach, as well as measuring PCB concentrations in fish. Risk reduction objectives included: alter the fish community to favor fish that do not resuspend, bioaccumulate, or biomagnify PCBs; stabilize contaminated sediments to improve water quality; and stabilize shoreline soils and enhance riparian habitat. Fish targeted for removal included gizzard shad, largemouth bass, and nonnative carp. Reduced PCB concentrations in fish have characterized the new bluegill-dominated community, although a weir-overtopping event led to the need for additional removals of gizzard shad and largemouth bass. Sunfish abundance is high, as was intended. Moreover, amphibian and waterbird diversities have increased in the years following biomanipulation, possibly owing to improvements in the riparian zone and increased structural (vegetation) complexity in both the aquatic and terrestrial environment. Thus, the remedial action has improved aspects of habitat value, and PCB concentrations in sunfish have dropped below the remediation level (risk-based target value) for this pond (1 µg/g in fish fillets or 2.3 µg/g in whole body fish).

A novel analytical method for determining total polychlorinated biphenyl concentrations in fish and shellfish using a simple and rapid clean-up followed by GC–MS/MS

We developed an analytical method for determining total (sum of all 209 congeners) polychlorinated biphenyl (PCB) concentrations in fish and shellfish using a newly developed clean-up method and gas chromatography tandem mass spectrometry. The clean-up involved passing a sample extract through a column containing silica gel and sulfuric-acid-treated silica gel and then a column containing alumina and silver-modified alumina. This gave a short clean-up time and required less organic solvent. No marked losses of any of the 209 PCB congeners were found during clean-up. The trueness and repeatability of the analytical method for total PCBs and seven indicator PCBs in fish and shellfish spiked with a commercial PCB mixture were 92 %–94 % and 93 %–105 %, with relative standard deviations of <0.9 % and <3.1 %, respectively. A certified reference fish sample was analyzed, and the measured concentrations of the certified congeners were within the uncertainty limits of the certified concentrations. The concentration ratios for total PCB and the indicator PCBs in fish determined by the new method and the conventional method using high-resolution gas chromatography high-resolution mass spectrometry were 0.9–1.1 and 0.9–1.2, respectively. The results indicate that the developed method will be very useful for rapidly determining total PCB concentrations in fish and shellfish.

The relation between polychlorinated biphenyls and population metrics of 4 species of fish from the upper Hudson River, New York, USA.

In the upper Hudson River, New York, USA, fish were exposed to polychlorinated biphenyls (PCBs) from the 1940s to 1977, and PCBs still persist in this environment. Yellow perch (Perca flavescens), brown bullhead (Ameiurus nebulosus), smallmouth bass (Micropterus dolomieu), and largemouth bass (M. salmoides) were collected annually from 2003 to 2009 from 1 control site upstream of the PCB discharge locations and from 2 sites downstream from where PCBs were released. Fish PCB concentrations were estimated, and 3 population metrics were examined: 1) relative abundance, 2) weight-to-length ratio, and 3) growth. Normalized lipid-based PCB concentrations at the 2 PCB exposure pools averaged approximately 100 to 600 μg/g. Estimated relative abundances with electrofishing were higher for largemouth bass, smallmouth bass, and brown bullhead at PCB exposure sites compared to the control site; but yellow perch were more abundant at the control site. Weight to length ratios varied among sites and species, but no consistent pattern was evident in relation to PCBs at the population level or for individual fish. Growth rates for yellow perch and brown bullhead were similar among sites. Largemouth bass growth was slightly higher at the control site compared to the 2 PCB sites, but smallmouth bass growth was much higher at the PCB sites compared to the control site. We could not detect any relation or influence of PCBs on the 3 population metrics that we examined. the present results corroborated those of previous investigations concerning the effects of PCBs on fishes. We recommend stronger consideration of the biological impacts of PCBs at the population level when conducting risk assessments. Environ Toxicol Chem 2019;38:329-339. © 2018 SETAC.

A Bayesian assessment of polychlorinated biphenyl contamination of fish communities in the Laurentian Great Lakes

Polychlorinated biphenyl (PCB) contamination has historically posed constraints on the recreational and commercial fishing industry in the Great Lakes. Empirical evidence suggests that PCB contamination represents a greater health risk from fish consumption than other legacy contaminants. The present study attempts a rigorous assessment of the spatio-temporal PCB trends in multiple species across the Canadian waters of the Great Lakes. We applied a Bayesian modelling framework, whereby we initially used dynamic linear models to delineate PCB levels and rates of change, while accounting for the role of fish length and lipid content as covariates. We then implemented Bayesian hierarchical modelling to evaluate the temporal PCB trends during the dreissenid pre- and post-invasion periods, as well as the variability among and within the water bodies of the Great Lakes system. Our analysis indicates that Lake Ontario is characterized by the highest PCB levels among nearly all of the fish species examined. Historically contaminated local areas, designated as Areas of Concern, and embayments receiving riverine inputs displayed higher concentrations within each of the water bodies examined. The general temporal trend across the Great Lakes was that the high PCB concentrations during the early 1970s followed a declining trajectory throughout the late 1980s/early 1990s, likely as a result of the reductions in industrial emissions and other management actions. Nonetheless, after the late 1990s/early 2000s, our analysis provided evidence of a decline in the rate at which PCB concentrations in fish were dropping, accompanied by a gradual establishment of species-specific, steady-state concentrations, around which there is considerable year-to-year variability. The overall trends indicate that reduced contaminant emissions have brought about distinct beneficial changes in fish PCB concentrations, but past historical contamination along with other external or internal stressors (e.g., invasive species, climate change) continue to modulate the current levels, thereby posing potential risks to humans through fish consumption.

Bioconcentration may be favoured over biomagnification for fish PCB contamination in high altitude lakes

Cold aquatic ecosystems such as high altitude alpine lakes are expected to act as long-term sinks of polychlorinated biphenyls (PCBs), the burden of which might even be intensified by global warming. Because the physical, chemical, and biological structures of high altitude lakes are highly responsive to climate change, both PCB exposure and bioaccumulation are likely to be strongly altered in the near future. Yet, in the absence of mechanistic knowledge of the processes regulating fish contamination with PCB in such ecosystems, their fate cannot be predicted. The aim of this study was to investigate the relative roles of biomagnification and bioconcentration on the individual, seasonal, and between-site variability of fish PCB contamination in 2 alpine, high altitude lakes. The intra- and within-lake variability of fish PCBs was not related to differences in fish physiology (size, age, or lipid content) and only marginally tied to fish feeding habitats (assessed from fatty acid composition and δ13C) or trophic position (δ15N). These results suggested that the trophic pathway and biomagnification contributed little to the observed differences in fish PCB concentrations between lakes, seasons, and individuals. Moreover, the fish PCB levels did not depend on the total PCB concentration in the water, but the fish contamination dynamics during the spring thaw pointed to a significant role of dissolved PCBs during this season in both lakes. In high altitude lakes, low temperatures might contribute to kinetically limit equilibrium with dietary PCBs, thereafter favouring bioconcentration over biomagnification pathways by which fish become contaminated with PCBs.

Polychlorinated biphenyl exposure and fish recruitment from 1988 to 2002 in the upper Hudson River, New York, USA

Starting in the late 1940s, fish in the upper Hudson River, New York, USA, were exposed to polychlorinated biphenyls (PCBs) from discharges from two manufacturing plants. These discharges greatly decreased in 1976, and PCB concentrations in fish generally declined between 1980 and 1991, increased in 1992–1994 due to a failure in 1991 of a structure that contained PCBs, and then decreased after 1994. To assess the impact of PCBs on fish reproductive success and recruitment, we collected yellow perch (Perca flavescens), largemouth bass (Micropterus salmoides), and brown bullhead (Ameiurus nebulosus) from 2002 to 2006 at two sites just downstream of these PCB sources. A subsample of these fish were aged; ages of remaining fish were assigned using a length:age key, and linear catch curves [loge (Number-at-age)=age] were computed. Maximum ages ranged from 11 to 16 years across species, and residual values generated from these catch-curve regressions represented relative year-class abundances produced from the late 1980s to the early 2000s. Wet-weight muscle tissue PCB concentrations in adults varied from average highs of 18–30μg/g in the late 1980s-mid 1990s to lows of 3–9μg/g by 2002 at the site nearest to the PCB sources. PCB concentrations in adult fish were unrelated to the formation of weak or strong year-classes in all three fish species. Although PCB concentrations were 2 to 8 times higher at the site nearest the PCB sources compared to a downstream site, natural mortality rates (fish harvest prohibited) derived from catch-curves were similar between sites for all three species. Thus, longevity and production of older year classes were consistent between sites. For these three species, we did not detect any PCB-mediated effect on fish recruitment at the population level at adult PCB concentrations (18–30μg/g).

Toward ecosystem-based sediment quality guidelines for polychlorinated biphenyls (PCBs).

To investigate whether Sediment Quality Guidelines (SQGs) for polychlorinated biphenyls (PCBs) in Canada and British Columbia achieve their objective of protecting ecosystems, we measured and compiled concentrations of PCB congeners in sediments, bivalves, crustaceans, fish, and marine mammals from 3 areas off the Pacific coast of British Columbia, Canada. The concentration data showed that whereas PCB concentrations in sediments were predominantly below the SQG of 20 µg/kg dry weight, large fractions of the PCB concentrations in fish and shellfish species exceeded the tissue residue guideline for the consumption of fish and shellfish by wildlife (i.e., 50 µg/kg wet weight [ww]) but were below the tissue residue guideline for the consumption of fish and shellfish by human populations (i.e., 2000 µg/kg ww). Also, PCB concentrations in marine mammals exceeded toxicity reference concentrations. The concentration data were used to develop species- and location-specific Biota-Sediment Accumulation Factors (BSAF = Cbiota /Csediment ), that were used to estimate PCB concentrations in wildlife species that may exist if the PCB concentration in sediments are equal to the SQGs. The results show that if the PCB concentration is equal to the SQGs, then PCB concentrations in most wildlife species can be expected to exceed the tissue residue guideline for the consumption of fish and shellfish by wildlife species and by humans, as well as toxicity reference concentrations for marine mammals. A methodology for developing SQGs for PCBs that are protective of the health of different wildlife species and human consumers of fish and shellfish from general Canadian and coastal First Nations populations was developed and applied. The proposed guidelines may provide useful guidance to establish SQGs for PCBs that can account for the ecological diversity in coastal environments and that better achieve the intent of the guidelines to protect ecosystems. The proposed methodology for guideline development may also be useful in the development of SQGs for other bioaccumulative substances.

PCB contamination in fish community from the Gironde Estuary (France): Blast from the past

The contamination of the Gironde Estuary, southwest of France, by polychlorinated biphenyls (PCBs) was assessed using six fish of high ecological and economic importance as bioindicator species. The concentrations of 21 PCB congeners and total fat contents were determined in the muscle and liver of eels (Anguilla anguilla), seabass (Dicentrarchus labrax), flounders (Platichthys flesus), meagres (Argyrosomus regius), mullets (Liza ramada), and soles (Solea vulgaris). In addition, information regarding the trophic ecology of the studied fish was obtained through the analysis of carbon and nitrogen stable isotopes (i.e., δ13C and δ15N) in muscle. Results revealed high PCB concentrations in fish compared to monitored European estuaries. The muscle of eels was by far the most contaminated fish flesh (Σ7PCBs=1000±440ngg−1 on a dry weight basis), while the higher PCB concentrations in liver were measured in flounder (Σ7PCBs=2040±1160ngg−1d.w.). A quantile regression approach allowed to investigate the fate of PCBs in the Gironde estuarine fish assemblage, and revealed a general process of trophic magnification. Finally, most of the analysed fish presented PCB concentrations in muscle meat above the current European maximum limits for sea products, while the derived “Toxic Equivalent Quantity” (TEQ) revealed human health concerns only for high-fat fish consumption.

Monitoring Fish Contaminant Responses to Abatement Actions: Factors that Affect Recovery

Monitoring of contaminant accumulation in fish has been conducted in East Fork Poplar Creek (EFPC) in Oak Ridge, Tennessee since 1985. Bioaccumulation trends are examined over a twenty year period coinciding with major pollution abatement actions by a Department of Energy facility at the stream's headwaters. Although EFPC is enriched in many contaminants relative to other local streams, only polychlorinated biphenyls (PCBs) and mercury (Hg) were found to accumulate in the edible portions of fish to levels of human health concern. Mercury concentrations in redbreast sunfish were found to vary with season of collection, sex and size of individual fish. Over the course of the monitoring, waterborne Hg concentrations were reduced >80%; however, this did not translate into a comparable decrease in Hg bioaccumulation at most sites. Mercury bioaccumulation in fish did respond to decreased inputs in the industrialized headwater reach, but paradoxically increased in the lowermost reach of EFPC. As a result, the downstream pattern of Hg concentration in fish changed from one resembling dilution of a headwater point source in the 1980s to a uniform distribution in the 2000s. The reason for this remains unknown, but is hypothesized to involve changes in the chemical form and reactivity of waterborne Hg associated with the removal of residual chlorine and the addition of suspended particulates to the streamflow. PCB concentrations in fish varied greatly from year-to-year, but always exhibited a pronounced downstream decrease, and appeared to respond to management practices that limited episodic inputs from legacy sources within the facility.

Modelling growth and bioaccumulation of Polychlorinated biphenyls in common sole ( Solea solea)

Experiments were performed on juvenile sole in controlled conditions in the aim of understanding how the biology of common sole may affect the accumulation and dilution of Polychlorinated biphenyls (PCBs). The fish were raised in optimal conditions and divided into two tanks: one control tank and one PCB tank. 4 PCB congeners were added to food for 3 months in the PCB tank; the soles were subsequently fed unspiked food for 3 months. Growth (length and weight) and PCB concentrations were monitored in both tanks and juvenile sole growth was not significantly affected by PCBs in our experimental conditions. We used the Dynamic Energy Budget (DEB) theory to model sole biology and paid special attention to model calibration through the wide use of data from the literature. The model accurately reproduced fish growth in both tanks. We coupled a bioaccumulation model to reproduce the concentration dynamics of the 4 PCB congeners used. This model did not require additional calibration and was dependent solely on the growth model and PCB concentrations in food. The bioaccumulation model accurately simulated PCB accumulation in fish, but overestimated PCB concentrations in fish during the dilution phase. This may suggest that in addition to PCB dilution due to growth, PCB concentrations decreased due to other PCB elimination mechanisms. Finally, we discussed potential improvements to the model and its future applications.

Organochlorine pesticides and PCBs in fish from lakes of the Tibetan Plateau and the implications

High mountains may play significant roles in the global transport of persistent organic pollutants (POPs). This work aims to investigate the levels, patterns and distribution of semi-volatile organoclorine pollutants and to improve the understanding of the long-range atmospheric transport and fate of contaminants on the Tibetan Plateau. A total of 60 fish samples were collected from eight lakes located between 2813 and 4718 m above sea level across the Plateau. Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) including dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were measured in fish muscle. The results showed that concentrations of DDT, HCH and HCB were comparable to or lower than those found in remote mountains of Europe, Canada and US, while PCB concentrations in fish were, on average, about 4–150 times lower on Tibet than at other mountain areas. The transport and fate of contaminants in the Plateau are significantly influenced by the unique climatological and meteorological conditions, particularly by the summer Indian monsoon and winter westerly jet stream.

Use of a food web model to evaluate the factors responsible for high PCB fish concentrations in Lake Ellasjøen, a high Arctic Lake

Lake Ellasjøen, located in the Norwegian high arctic, contains the highest concentrations of polychlorinated biphenyls (PCBs) ever recorded in fish and sediment from high arctic lakes, and concentrations are more than 10 times greater than in nearby Lake Øyangen. These elevated concentrations in Ellasjøen have been previously attributed, in part, to contaminant loadings from seabirds that use Ellasjøen, but not Øyangen, as a resting area. However, other factors, such as food web structure, organism growth rate, weight, lipid content, lake morphology, and nutrient inputs from the seabird guano, also differ between the two systems. The aim of this study is to evaluate the relative influence of these factors as explanatory variables for the higher PCB fish concentrations in Ellasjøen compared with Øyangen, using both a food web model and empirical data. The model is based on previously developed models but parameterized for Lakes Ellasjøen and Øyangen using measured data wherever possible. The model was applied to five representative PCB congeners (PCB 105, 118, 138, 153, and 180) using measured sediment and water concentrations as input data and evaluated with previously collected food web data. Modeled concentrations are within a factor of two of measured concentrations in 60% and 40% of the cases in Lakes Ellasjøen and Øyangen, respectively, and within a factor of 10 in 100% of the cases in both lakes. In many cases, this is comparable to the variability associated with the data as well as the efficacy of the predictions of other food web model applications. We next used the model to quantify the relative importance of five major differences between Ellasjøen and Øyangen by replacing variables representing each of these factors in the Ellasjøen model with those from Øyangen, in separate simulations. The model predicts that the elevated PCB concentrations in Ellasjøen water and sediment account for 49%-58% of differences in modeled fish PCB concentrations between lakes. These elevated sediment and, to a lesser extent, water concentrations in Ellasjøen are due to PCB loadings from seabird guano. However, sediment-water fugacity ratios of PCBs are consistently greater in Ellasjøen compared with Øyangen, which suggests that internal lake processes also contribute to differences in sediment and water concentrations. We hypothesize that the nutrients associated with guano influence sediment-water fugacity ratios of PCBs by increasing the stock of pelagic algae. As both these algae and the guano settle, their organic carbon content is degraded faster than PCBs, which causes an extra magnification step in Ellasjøen before these detrital particles are consumed by benthic organisms, which are in turn consumed by fish. The model predicts that the remaining approximately 50% of the differences in PCB concentrations observed between the fish of these lakes are due to other subtle differences in their food web structures. In conclusion, based on the results of a food web model, we found that the most dominant factors influencing the higher PCB fish concentrations in Lake Ellasjøen compared with Øyangen are the higher sediment and water concentrations in Ellasjøen, caused by seabird guano. Together, sediment and water are predicted to account for 49%-58% of differences in fish concentrations between lakes. Although seabird guano provides a source of nutrients to the lake, in addition to contaminants, empirical data and indirect model results suggest that nutrients are not leading to decreased bioaccumulation, in contrast to what has been observed in temperate, pelagic food webs. The results of this study emphasize the importance of considering even small differences in food web structure when comparing bioaccumulation in two lakes; although the food web structures of Ellasjøen and Øyangen differ only slightly, the model predicts that these differences account for most of the remaining approximately 50% of the differences in PCB fish concentrations between the two lakes. This study further demonstrates the utility of food web models as we were able to predict and tease apart the influence of various factors responsible for the elevated concentrations in the fish from Lake Ellasjøen, which would have been difficult using the field data alone.

Foodweb modeling for polychlorinated biphenyls (PCBs) in the Twelvemile Creek Arm of Lake Hartwell, South Carolina, USA

PCBs from the Sangamo-Weston Superfund Site near Clemson, South Carolina, USA, were released into the Twelvemile Creek Arm of Lake Hartwell until the early 1990s. Monitoring data have shown that while PCB concentration in sediments declined since 1995, PCB concentrations in fish have remained elevated, e.g., largemouth bass ( Micropterus salmoides) concentrations have ranged from 5 to 10 ppm. The EPA aquatic ecosystem model AQUATOX was applied to this system to better characterize foodweb dynamics that lead to biomagnification of PCBs. The model was calibrated with observed fish biomass data. Simulated PCB loading over a 12-year period provided a reasonable fit to observed PCB data in fish. The model demonstrated that contaminated labile detritus loaded to the system was incorporated into the foodweb rather than deposited, thereby maintaining the PCB concentrations in fish while concentrations in the sediment declined. A dominant PCB pathway was from detritus to daphnia to shad to largemouth bass. Fish PCB concentrations showed moderate sensitivity to toxicant parameters; model runs incorporating uncertainty in these parameters predicted recovery (<2 ppm PCB) for all species in the range of years from 2008 to 2013. The high sensitivity of the model to parameters related to growth strongly affected PCB concentrations in fish and should be considered in future AQUATOX applications.

A food chain model to predict the levels of lipophilic organic contaminants in humans

A fugacity-based, nonsteady state, mechanistic model called ACC-HUMAN was developed to describe bioaccumulation of lipophilic organic pollutants from air, water, and soil to humans. The physical environment was linked via a marine and an agricultural food chain model to a human bioaccumulation model. Contaminant uptake via the primary dietary sources of persistent lipophilic contaminants in industrialized countries was addressed, namely fish, dairy products, and beef. In addition, uptake from air and water was considered, allowing the model also to treat less lipophilic compounds. To evaluate the model, the food chain characteristics were parameterized for southern Sweden and historical scenarios of polychlorinated biphenyl (PCB) concentrations in air, water, and soil in this region were constructed from published data. The resulting model predictions of PCB concentrations in fish, milk, beef, and human tissue agreed well with measured concentrations from Swedish monitoring programs. This suggests that ACC-HUMAN is a useful tool for predicting human exposure to bioaccumulative organic compounds. It can be linked easily to existing multimedia fate and transport models.

Dietary Uptake of Polychlorinated Biphenyls (PCBs) by Rainbow Trout

AbstractThe presence of detectable levels of polychlorinated biphenyls (PCBs) in commercially produced fish feed has raised a concern about the degree of biomagnification of these contaminants in hatchery‐reared trout. Our objectives were to (1) define the relationship between concentrations of PCBs in fish feed and in fish tissue and (2) estimate the relative contributions of feed and hatchery supply water to PCB concentrations in fish. We conducted a 6‐month feeding trial with fingerling rainbow trout Oncorhynchus mykiss fed commercial diets with four concentrations of PCBs: a low‐PCB diet (69 ng/g); a typical commercial diet (126 ng/g); and the typical diet spiked with PCBs at two levels (220 and 280 ng/g). The concentrations of PCBs in fillets after 1 month were commensurate with those in the feeds and remained relatively stable for the next 5 months; mean PCB concentrations in fillets ranged from 54 to 94 ng/g. Low levels of PCBs were detected in the hatchery supply water. We used the concentrations of PCBs in the feeds, absorption rates of PCBs, and two different rates of PCB depuration to estimate the potential uptake of PCBs from supply water. When we used a low depuration rate (half‐life = 219 d), the computed body burdens of PCBs could be entirely attributed to the feeds. When a high depuration rate (half‐life = 66 d) was used, some uptake of PCBs from the supply water was likely, but most of the total body burden originated from the feeds. We concluded that rainbow trout fed a diet with 126 ng/g PCBs would have a PCB concentration of about 60 ng/g in their fillets, which is high enough to warrant issuance of a consumption advisory (no more than one meal of fish per week) under a protocol adopted by some Great Lakes states.

Polychlorinated biphenyls (PCBs) and their congener-specific accumulation in edible fish from the Gulf of Gdańsk, Baltic Sea

Concentrations and composition profiles of polychlorinated biphenyls (PCBs) were investigated in composite samples of 10 species of edible fish from the Gulf of Gdańsk, in the southern part of the Baltic Sea, Poland, to understand the status of contamination and possible human exposure risk. Apart from the total PCBs, planar non-ortho (IUPAC nos 77, 126, 169) and mono-ortho (nos 105, 114, 118, 123, 156, 157, 167, 189) chlorobiphenyls were also quantified and their dioxin-like toxicity assessed. The absolute total PCB concentrations in fish ranged from 43 to 490 ng g-1 wet wt (910–11000 ng g-1 lipids), while of TCDD TEQs of planar members were from 0.15 to 3.1 pg g-1 wet wt (8.1–81 pg g-1 lipids). The penta- and hexa-CBs usually comprised 70–80% of the total PCBs and were followed by hepta-, tetra- and tri-CBs, and for a specific site tri- and tetra-CBs comprised as much as 22%. Among the individual CB congeners, nos 118, 153 (+132) and 138 (+160 +163 +164) were the most abundant, while no. 110 comprised between 6.8 and 9.3% of the total PCBs in some species. Principal component analysis (PCA) was applied to examine the interdependences among CB congeners in the factor space. The PCA model and cluster analyses were further used to examine site- and species-specific differences and similarities of PCB composition, and the results are discussed. An assessed daily intake rate of TCDD TEQ of planar PCBs with the fishmeal of the Gulf of Gdańsk in the 1990s was between 78 and 96 pg per capita or between 1.3 and 1.6 pg kg-1 body weight.

Importance of uncertainty and variability to predicted risks from trophic transfer of PCBs in dredged sediments.

Biomagnification of organochlorine and other persistent organic contaminants by higher trophic level organisms represents one of the most significant sources of uncertainty and variability in evaluating potential risks associated with disposal of dredged materials. While it is important to distinguish between population variability (e.g., true population heterogeneity in fish weight, and lipid content) and uncertainty (e.g., measurement error), they can be operationally difficult to define separately in probabilistic estimates of human health and ecological risk. We propose a disaggregation of uncertain and variable parameters based on: (1) availability of supporting data; (2) the specific management and regulatory context (in this case, of the U.S. Army Corps of Engineers/U.S. Environmental Protection Agency tiered approach to dredged material management); and (3) professional judgment and experience in conducting probabilistic risk assessments. We describe and quantitatively evaluate several sources of uncertainty and variability in estimating risk to human health from trophic transfer of polychlorinated biphenyls (PCBs) using a case study of sediments obtained from the New York-New Jersey Harbor and being evaluated for disposal at an open water off-shore disposal site within the northeast region. The estimates of PCB concentrations in fish and dietary doses of PCBs to humans ingesting fish are expressed as distributions of values, of which the arithmetic mean or mode represents a particular fractile. The distribution of risk values is obtained using a food chain biomagnification model developed by Gobas by specifying distributions for input parameters disaggregated to represent either uncertainty or variability. Only those sources of uncertainty that could be quantified were included in the analysis. Results for several different two-dimensional Latin Hypercube analyses are provided to evaluate the influence of the uncertain versus variable disaggregation of model parameters. The analysis suggests that variability in human exposure parameters is greater than the uncertainty bounds on any particular fractile, given the described assumptions.

Bioaccumulation of polychlorinated biphenyls (PCBs) in the marine pelagic food web, based on a seasonal study in the southern Gulf of St. Lawrence, 1976–1977

Polychlorinated biphenyls (PCBs) were quantified in bulk seawater (3.1 ± 1.0 ngl−1, N = 3) in 1976, in plankton (2.9 ± 3.3 ng g−1 wet weight, N = 176) in 1976 and 1977 and in fish (155 ± 194 ng g−1 wet weight, N = 135) in 1977 collected from St. Georges Bay in the southern Gulf of St. Lawrence. PCB concentrations in the plankton of the entire water column varied seasonally by ten times, with the highest values occurring in spring, lowest during summer and variable levels in late fall. The lower PCB levels in the total summer community coincide with a reduced biomass in certain size fractions in the Bay rather than a decrease in PCB concentration of the plankton. PCBs were concentrated in the middle-sized fractions of the planktonic community and this is attributed to the greater biomass present in these categories. PCB concentrations in plankton were most highly correlated with their lipid content at the time of sampling. Seasonal reductions of lipid in the plankton per m3 resulted in a higher concentration of PCB per unit lipid in the remaining community. Planktonic PCB concentrations, expressed on a lipid basis, are found to be correlated with cumulative rainfall 21 d before sampling for both years combined. Adult fish were more contaminated by PCBs than either their egg or juvenile stages. Mature gaspereau, herring and smelt had higher concentrations of PCB contamination than mackerel, capelin, white hake and silversides. No difference was found between PCB contamination of the sexes of fish species analyzed. PCBs were transferred from mother to offspring in fish, but at lower levels than the level present in the parent; and the maximum accumulation from the environment occurred between immature and adult fish. The best predictors of PCB contamination in fish in St. Georges Bay are lipid content followed by size and age. PCB concentrations in plankton, normalized to lipid content, did not increase with size or trophic level. PCB concentrations in fish increased with size and on average were ten times the levels found in plankton. Marine mammals collected by other researchers in the region during the 1970s had accumulated up to several orders-of-magnitude higher concentrations than those found in fish, with a more gradual increase with size of organism. Lipid content and age or exposure period appear to be the main factors which determine PCB concentrations in the marine food chain in the southern Gulf of St. Lawrence.

PCB concentrations in stream sunfish (Lepomis Auritus and L. Macrocmirus) in relation to proximity to chronic point sources

Sunfish (Lepomis auritus and L. macrochirus) were used to monitor polychlorinated biphenyl (PCB) contamination in a group of small streams flowing into a larger stream/reservoir system. Mean PCB concentrations in sunfish appeared to reflect exposure conditions at the site of capture. Fish from uncontaminated sites 1 to 2 km distant from PCB-contaminated sites did not exhibit PCB contamination, and PCB concentrations in fish downstream from a discrete source decreased at a rate greater than or equal to downstream dilution of the point source. Mean PCB concentrations in fish near the source exhibited relatively large (-40%) fluctuations between semi-annual sampling periods, suggesting that PCB concentrations in sunfish populations may respond rapidly to changes in exposure. Sunfish were not sensitive enough indicators of contamination to use in assessing whether or not problematic levels of contamination may occur in other species. Although the presence of PCB contamination in sunfish can be used to infer that PCBs are elevated in other species, the absence of PCB contamination in sunfish cannot be used to infer that older, fattier fish higher up the food chain are uncontaminated.