Concentrations Of Chlorinated Hydrocarbons Research Articles

Assessing aquitard integrity in a complex aquifer – aquitard system contaminated by chlorinated hydrocarbons

This study investigates for the first time the integrity of multiple stacked aquitards with different degrees of contaminant degradation. Aquitard integrity was assessed in a contaminated, multi-layered, alluvial aquifer-aquitard system (Ferrara, northern Italy). The system was contaminated by mixed organic contaminants of industrial origin (mostly chlorinated ethenes) that were illegally disposed in an urban dump four to five decades ago. High spatial resolution profiles of hydraulic head, geochemistry and chlorinated hydrocarbon concentrations were determined through the multi-layered system via discrete interval sampling of continuous cores and multilevel groundwater sampling, at three locations aligned along a transect adjacent to the buried waste to a maximum depth of 53 m below the water table.The profiles revealed that the two shallow aquitards had low integrity with respect to impeding downward migration of dense non-aqueous phase liquid (DNAPL), and provided little protection to the underlying aquifers against DNAPL contamination due to preferential pathways through imperceptible fractures and/or permeable micro-beds. However, both aquitards inhibited downward DNAPL migration to some extent due to DNAPL retention along its flow paths and accumulation at lower permeability interfaces, with decreasing peak concentrations at the top of successively deeper aquitard units. Moreover, both aquitards enhanced contaminant biodegradation due to the occurrence of organic rich sub-layers, influencing the contaminant plume composition, mobility and fate in the underlying and overlying aquifers.The deepest aquitard showed evidence of DNAPL accumulation at the top and slow diffusion-dominated transport consistent with 40 years of transport, suggesting higher integrity compared to the two shallower aquitards. However, the occurrence of micro-fractures and/or discontinuities in the aquitard upgradient under the dump (source) is the most likely explanation for contamination of the deepest aquifer. Analytical 1-D simulations of the diffusion profiles in the deepest aquitard revealed that DNAPL contamination down to the top of this aquitard occurred with minimal delay after DNAPL waste disposal began.The results highlight the necessity of high-resolution vertical profiling for assessing the presence of imperceptible features relevant to DNAPL migration and integrity of individual aquitards affecting organic contaminant source zone mass and phase distributions over decades.

Productivity, embryo and eggshell characteristics, and contaminants in bald eagles from the Great Lakes, USA, 1986 to 2000

Chlorinated hydrocarbon concentrations in eggs of fish-eating birds from contaminated environments such as the Great Lakes of North America tend to be highly intercorrelated, making it difficult to elucidate mechanisms causing reproductive impairment, and to ascribe cause to specific chemicals. An information- theoretic approach was used on data from 197 salvaged bald eagle (Haliaeetus leucocephalus) eggs (159 clutches) that failed to hatch in Michigan and Ohio, USA (1986-2000). Contaminant levels declined over time while eggshell thickness increased, and by 2000 was at pre-1946 levels. The number of occupied territories and productivity increased during 1981 to 2004. For both the entire dataset and a subset of nests along the Great Lakes shoreline, polychlorinated biphenyls (SigmaPCBs, fresh wet wt) were generally included in the most parsimonious models (lowest-Akaike's information criterion [AICs]) describing productivity, with significant declines in productivity observed above 26 microg/g SigmaPCBs (fresh wet wt). Of 73 eggs with a visible embryo, eight (11%) were abnormal, including three with skewed bills, but they were not associated with known teratogens, including SigmaPCBs. Eggs with visible embryos had greater concentrations of all measured contaminants than eggs without visible embryos; the most parsimonious models describing the presence of visible embryos incorporated dieldrin equivalents and dichlorodiphenyldichloroethylene (DDE). There were significant negative correlations between eggshell thickness and all contaminants, with SigmaPCBs included in the most parsimonious models. There were, however, no relationships between productivity and eggshell thickness or Ratcliffe's index. The SigmaPCBs and DDE were negatively associated with nest success of bald eagles in the Great Lakes watersheds, but the mechanism does not appear to be via shell quality effects, at least at current contaminant levels, while it is not clear what other mechanisms were involved.

Investigating the scale of structural controls on chlorinated hydrocarbon distributions in the fractured-porous unsaturated zone of a sandstone aquifer in the UK

Contaminant migration behaviour in the unsaturated zone of a fractured porous aquifer is discussed in the context of a study site in Cheshire, UK. The site is situated on gently dipping sandstones, adjacent to a linear lagoon historically used to dispose of industrial wastes containing chlorinated solvents. Two cores of more than 100 m length were recovered and measurements of chlorinated hydrocarbons (CHCs), inorganic chemistry, lithology, fracturing and aquifer properties were made. The results show that selecting an appropriate vertical sampling density is crucial both to providing an understanding of contaminant pathways and distinguishing whether CHCs are present in the aqueous or non-aqueous phase. The spacing of such sampling should be on a similar scale to the heterogeneity that controls water and contaminant movement. For some sections of the Permo-Triassic aquifer, significant changes in lithology and permeability occur over vertical distances of less than 1 m and samples need to be collected at this interval, otherwise considerable resolution is lost, potentially leading to erroneous interpretation of data. At this site, although CHC concentrations were high, the consistent ratio of the two main components of the plume (tetrachloroethene and trichloroethene) provided evidence of movement in the aqueous phase rather than in dense non-aqueous phase liquid (DNAPL).

Temporal and Spatial Trends in Chlorinated Hydrocarbon Concentrations of Mink in Canadian Lakes Erie and St. Clair

Mink (Mustela vison) carcasses were collected from local commercial trappers from fall 1998 to spring 2003 from tributaries and marshes within 4.8 km from the shores of Lakes Erie and St. Clair, including the Wheatley Harbour and St. Clair River Areas of Concern (AOCs), as well as from inland sites (8 to 40 km from shore). Liver concentrations, on a lipid weight basis, of chlorinated hydrocarbons were measured and compared among sites and to tissue concentrations of mink from two previous collections from similar sites over the past 25 years. Mink from the western Lake Erie sites, which included the Wheatley Harbour AOC, had significantly higher concentrations of sum PCBs and PCB Aroclors than those from the St. Clair corridor or inland sites, with concentrations from the rest of Lake Erie being intermediate. Dieldrin concentrations were also significantly higher in western Lake Erie than many other sites, and those of oxychlordane and mirex also tended to be higher (0.05 < p < 0.1). There were no differences in contaminant concentrations between the St. Clair River AOC and the downstream non-AOC Lake St. Clair site, with the exception of slightly higher levels of octachlorostyrene (OCS). Concentrations of PCBs and other chlorinated hydrocarbons in mink showed a general decrease over the past two decades. In contrast, PCBs and some organochlorine pesticides tended to increase, significantly so with oxychlordane, in western Lake Erie mink over the same time period. DDE declined at all sites. Currently, mink liver PCB concentrations are within the range associated with reproductive impairment, as determined from captive mink studies, in 11.7% of all animals collected from the Lakes Erie and St. Clair basin overall, but in almost 40% of individuals from western Lake Erie.

Monitoring trichloroethene remediation at an iron permeable reactive barrier using stable carbon isotopic analysis

Stable carbon isotopic analysis, in combination with compositional analysis, was used to evaluate the performance of an iron permeable reactive barrier (PRB) for the remediation of ground water contaminated with trichloroethene (TCE) at Spill Site 7 (SS7), F.E. Warren Air Force Base, Wyoming. Compositional data indicated that although the PRB appeared to be reducing TCE to concentrations below treatment goals within and immediately downgradient of the PRB, concentrations remained higher than expected at wells further downgradient (i.e. > 9 m) of the PRB. At two wells downgradient of the PRB, TCE concentrations were comparable to upgradient values, and δ 13C values of TCE at these wells were not significantly different than upgradient values. Since the process of sorption/desorption does not significantly fractionate carbon isotope values, this suggests that the TCE observed at these wells is desorbing from local aquifer materials and was present before the PRB was installed. In contrast, three other downgradient wells show significantly more enriched δ 13C values compared to the upgradient mean. In addition, δ 13C values for the degradation products of TCE, cis-dichloroethene and vinyl chloride, show fractionation patterns expected for the products of the reductive dechlorination of TCE. Since concentrations of both TCE and degradation products drop to below detection limit in wells within the PRB and directly below it, these downgradient chlorinated hydrocarbon concentrations are attributed to desorption from local aquifer material. The carbon isotope values indicate that this dissolved contaminant is subject to local degradation, likely due to in situ microbial activity.

Chlorinated Hydrocarbon Contaminants and Stable Isotope Ratios in Pelagic Seabirds From the North Pacific Ocean

Organochlorine pesticides, polychlorinated biphenyls (PCBs), and stable isotopes of nitrogen (delta15N) and carbon (delta13C) were determined in livers of eight seabird species (Diomedea immutabilis, D. nigripes, Fulmarus glacialis, Puffinus bulleri, P. carneipes, P. griseus, P. tenuirostris, and Fratercula corniculata) collected opportunistically from an experimental fishery in the North Pacific Ocean. Concentrations of P, P'-DDE were found in all samples but were highly variable among species, ranging over >2 orders of magnitude from 1.23 mg/kg (wet weight) in D. nigripes to 0.008 mg/kg in P. tenuirostris, whereas total PCBs ranged from 1.14 to 0.020 mg/kg in those same two species. Residues of hexachlorobenzene, trans-nonachlor, photo-mirex, mirex, beta-hexachlorocyclohexane, oxychlordane, and heptachlor expoxide were quantified at lower concentrations in all samples. There were significant positive regressions of lipid-normalized concentrations of DDE (r2 = 0.526), total PCBs (r2 = 0.566), CB-153 (r2 = 0.565), and mirex (r2 = 0.586) on the hepatic delta15N signature, indicating that trophic level accounted for approximately 50% of the variability in those contaminants among species. In some species, e.g., P. bulleri, concentrations were lower than expected based on delta15N, which was attributed to a dietary switch before sampling and therefore lack of concordance in the time scales integrated by hepatic chlorinated hydrocarbon concentrations compared with delta15N.

Assessing breeding potential of peregrine falcons based on chlorinated hydrocarbon concentrations in prey

Peregrine falcons ( Falco peregrinus) now breed successfully in most areas of North America from which they were previously extirpated. The loss during the mid-part of the last century of many of the world's peregrine populations was largely a consequence of impaired reproduction caused by the effects of DDE on eggshell quality and embryo hatchability. Population recovery has been attributed to re-introduction efforts, coupled with regulatory restrictions on the use of organochlorine pesticides. Peregrines have not returned to breed in some areas, such as the Okanagan Valley of British Columbia. That region has been extensively planted in fruit orchards which were treated annually with DDT during the early 1950s to the 1970s. Ongoing contamination of avian species, including potential peregrine prey, inhabiting orchards has been documented. In response to an initiative to release peregrines around the city of Kelowna in the Okanagan Valley, we collected potential peregrine prey species and analyzed whole bodies for chlorinated hydrocarbon residues. We used a simple bioaccumulation model to predict concentrations of DDE in peregrine eggs using concentrations in prey and estimates of dietary makeup as input. Peregrines would be expected to breed successfully only if they fed on a diet primarily of doves. Feeding on as little as 10% of other species such as starlings, robins, gulls and magpies would produce DDE concentrations in peregrine eggs greater than the threshold of 15 mg/kg. We also estimated the critical concentration of DDE in total prey to be about 0.5 mg/kg, one half of the previous most conservative criterion for peregrine prey. Concentrations of dieldrin and PCBs in peregrine prey are less than suggested critical levels.

Negative correlation between plasma thyroid hormone levels and chlorinated hydrocarbon levels accumulated in seals from the coast of Hokkaido, Japan

Chlorinated hydrocarbon (CHC) levels in the blubber of larga seals (Phoca largha) and ribbon seals (Phoca fasciata) collected from the coastal waters of Hokkaido, Japan, were determined in order to assess the hormonal effects of CHC exposure in free-ranging pinnipeds. Plasma thyroid hormone levels, including total thyroxine (T4), free thyroxine (free T4), total triiodothyronine (T3), and free triiodothyronine (free T3), were also measured. Higher concentrations of polychlorinated biphenyl congeners (PCBs), dichlorodiphenyltrichloroethane and its metabolites, and chlordane compounds were found in the range of 380 to 2,600 ng/g, 350 to 2,600 ng/g, and 120 to 760 ng/g on a wet-weight basis, respectively. Spearman rank correlation analyses showed that in larga seals, plasma total T3 and free T3 levels negatively correlated with levels of all the CHCs analyzed, although there was no such correlation between total or free T4 levels and CHC concentrations. In ribbon seals, total T3 levels significantly decreased with an increase of di-ortho PCB (PCB170 and 180) residues. These findings indicated that the plasma T3 deficiency could be associated with some CHC exposure in larga and ribbon seals and that the responses of plasma thyroid hormones may be useful biomarkers for CHC exposure in ribbon seals.

Cordierite monolith supported perovskite-type oxides — catalysts for the total oxidation of chlorinated hydrocarbons

The catalytic behaviour of LaMnO3, LaCoO3 and (La0.84Sr0.16)(Mn0.67Co0.33)O3 perovskites supported on cordierite monoliths was studied in the total oxidation of chlorinated hydrocarbons (CHC). By-products (higher chlorinated hydrocarbons, lower molecular coupling and cracking products) were formed in the low temperature range depending on the kind and concentration of CHC in the feed and the reaction conditions. The preparation method (impregnation or coating) influences catalytic activity and by-product formation. Addition of water, methane or propane to the feed diminishes the by-product formation significantly. In the case of monolith supported LaCoO3 perovskite, an irreversible catalyst deactivation was observed.

Environmental Contaminants in Colonial Waterbirds from Great Slave Lake, NWT: Spatial, Temporal and Food-chain Considerations

Great Slave Lake in the Northwest Territories, Canada, differs regionally in trophic status and local and regional inputs of contaminants. Spatial and temporal trends in contaminant levels in bioindicator species such as colonial waterbirds could offer insights into the potential for contaminant bioaccumulation in Great Slave Lake. Persistent chlorinated hydrocarbon contaminants, mercury (Hg), and selenium (Se) were examined in herring gull ( Larus argentatus ) eggs and livers collected from various locations on Great Slave Lake in 1995. Eggs were collected in May and June, and livers in May and August. Also, the relationship between contaminants and trophic level, as inferred from stable-nitrogen isotope analysis (delta 15N), was examined in four colonial waterbird species: herring gull, mew gull ( L. canus ), Caspian tern (Sterna caspia ), and black tern ( Chlidonias niger ). Finally, the co-accumulation of mercury and selenium was examined in eggs of these birds. There were no differences in chlorinated hydrocarbon concentrations among four sampling sites (colonies). Concentrations did not differ between herring gull adults collected in early May and those collected in early August. Chlorinated hydrocarbon concentrations in eggs of herring gull, mew gull, Caspian tern, and black tern were related to their trophic positions as inferred from their delta 15N values in their lipid-free egg yolks. Concentrations in these colonial waterbirds were much higher than those in fish from Great Slave Lake, but lower than those in their conspecifics from the Great Lakes. It is probable that a relatively large proportion of the chlorinated hydrocarbon contaminant load in colonial waterbird eggs on Great Slave Lake results from exposure to and storage of such contaminants at more heavily contaminated wintering and staging areas. This possibility limits the usefulness of colonial waterbirds as indicators of chlorinated hydrocarbon bioaccumulation in Great Slave Lake. Selenium and mercury concentrations in herring gull eggs differed significantly among the four breeding colonies, and concentrations in adults declined between May and August. Selenium and mercury were positively correlated in eggs of all species. Key words: black tern, Caspian tern, Great Slave Lake, herring gull, mew gull, mercury, organochlorines, selenium

Environmental specimen banking. Herring gull eggs and breams as bioindicators for monitoring longterm and spatial trends of chlorinated hydrocarbons

Abstract The German Environmental Specimen Bank (GESB) has been an important tool in contaminant monitoring and ecotoxicological research for more than one decade. The annual monitoring program provides a long-term database to determine trends in contaminant burdens in biota samples. Results of ten years of experience in the determination of chlorinated hydrocarbons (CHCs) in herring gull eggs collected in the North Sea and the Baltic Sea are presented. In addition, the study reports CHC concentrations in bream livers from the River Elbe between 1993-1997. Most of the compounds studied show a significant decline over time, especially in samples from East Germany. For specimens taken in West Germany, only small decreases or no changes of CHC levels were observed.

INCIDENCE OF PESTICIDE RESIDUES IN ADIPOSE TISSUE OF BEEF, PORK AND POULTRY FROM PLANTS LOCATED IN NORTHWESTERN MEXICO

ABSTRACT This study involved testing of adipose tissue from beef (208 samples), pork (112 samples) and poultry (39 samples) for pesticide residues, including nine different chlorinated hydrocarbons (CHC) and nine organophosphates (OP). Tissues were collected during a two‐year period (1996–1997) from plants located in the Northwestern Mexico, and determinations conducted by gas chromatography under international performance criteria. While none of the pork samples contained CHC residues, 17 (1996) and 11 (1997) beef samples contained either hexacholorobenzene, heptachlor, aldrin or dieldrin. Also, poultry samples (three in one year and four in the other) contained residues of either hexachlorobenzene, heptachlor or dieldrin. None of the tissues tested contained organophosphate residues above the detection limit. CHC incidences and concentrations were lower than those reported for other Mexican and Latin American regions, but higher than reports from the U.S. Based on the Mexican or U.S. tolerances, all concentrations of CHC found were nonviolative.

Levels and trends of PCBs, chlorinated pesticides and petroleum hydrocarbons in mussels from the NW Mediterranean coast: comparison of concentrations in 1973/1974 and 1988/1989

A mussel watch survey was conducted in 1988–1989 along the Mediterranean coast of France and Italy, between Sete and Genoa, in order to assess contamination by organochlorine pesticides, PCBs and petroleum hydrocarbons. Results show concentrations of DDTs (average 130 ng g −1 dry wt.) and PCBs (average 527 ng g −1 dry wt.) higher in coastal areas receiving river discharges and close to large cities. Concentrations of total aliphatics (average 470 μg g −1 dry wt.) and PAHs (average 233 μg g −1 dry wt.) were generally higher also near large harbours, namely Marseille, Toulon and Genoa. PAHs in mussel samples from Genoa and Monaco were mostly of pyrolytic sources, likely forest fires and exhaust gases from cars, whereas PAHs in other stations were mainly of petrogenic sources. Comparison of chlorinated hydrocarbon concentrations measured in 1988–1989 with those measured in a similar survey carried out at the same sites in 1973–1974, shows that DDTs and PCBs decreased by a factor of approximately 5 in 15 years. This decrease is in agreement with the ban on DDT implemented in 1975 in western Europe and gradual cessation of PCBs production in the 1970s and 1980s. Nevertheless, the residues of these compounds measured in mussels confirm the well-known long persistence of DDTs and PCBs, which are still present in relatively high concentrations in a few areas.

Chlorinated Hydrocarbons in Infertile Women

This study was conducted to investigate the hypothesis that chlorinated hydrocarbons (CHC) may affect fertility in women. In 489 infertile women, CHC levels were measured in whole blood. Different anamnestic and clinical parameters were obtained or investigated in order to detect possible associations to CHC concentrations. CHC levels were correlated to the women's age, body mass index, and nationality. Especially in women with uterine fibroids, endometriosis, miscarriages, persistent infertility, and hormonal disturbances, elevated concentrations of chlorinated hydrocarbons with long half-lives were observed. Chlorinated hydrocarbons may play a role in female infertility and may be an underlying factor in certain gynecological conditions.

Heavy metals and chlorinated hydrocarbon concentrations in the red fox in relation to some biological parameters

Heavy metals and organochlorine contamination were analyzed in tissues of red foxes (Vulpes vulpes) from the Province of Siena (central Italy). Mercury (Hg), cadmium (Cd) and lead (Pb) concentrations were assessed in liver tissues and the data were analyzed for differences in relation to sex and age. Overall Hg, Cd and Pb mean values were 0.16, 0.62 and 0.64 μg g_1 d.w., respectively. HCB, DDT and PCB concentrations were assayed in fatty tissues and muscle. The highest levels of those pollutants were found in muscle (0.47, 1.16 and 20.2 μg g_1 lipid basis of HCB, DDTs and PCBs respectively), rather than in fat (0.23, 0.49 and 7.2 μg g_1 l.b. of HCB, DDTs and PCBs respectively). Pollutant accumulation was analyzed in relation to sex, age and sexual maturity of females.

Distribution and mobility of organic micropollutants in river Elbe floodplains

Supercritical Fluid Extraction (SFE) methods have been developed to investigate the levels of chlorinated hydrocarbons (CHCs), polycyclic aromatic hydrocarbons (PAHs) and nitrogen- or phosphorus-containing pesticides (N/P-pesticides) in soils at river Elbe wetlands. Remarkably high concentrations of CHCs and PAHs were found and a mobilisation of contaminants seems probable at one location.

Some Dietary Predictors of Plasma Organochlorine Concentrations in an Elderly German Population

Associations between reported consumption of animal products and chlorinated hydrocarbon concentrations were examined in 297 elderly people who lived in Germany. Consumption of beef and lamb was correlated positively with hexachlorobenzene (HCB), beta-hexachlorocyclohexane (beta-HCH), total polychlorinated biphenyls (PCBs), and total dichloro-diphenyl-trichloroethane (DDT) (r = .13-.19, p < .05). Consumption of saltwater fish was correlated positively with alpha-HCH, dieldrin, and PCBs (r = .12-.26, p < .05). Other univariate predictors were body mass index, plasma cholesterol, pork consumption, poultry consumption, and age. Multivariate linear models of predictors of each chlorinated species were constructed, and some form of meat was used as the main predictor; the sum of all meats (exclusive of fish) was the best predictor of dieldrin and In(alpha-HCH) concentrations. Beef and lamb consumption was a positive predictor of HCB, heptachlor epoxide, total DDT, and beta-HCH. Saltwater fish was the major dietary predictor of PCBs.

Comparative bioaccumulation of chlorinated hydrocarbons from sediment by two infaunal invertebrates.

Bioaccumulation of chlorinated hydrocarbons (CHs) from field-contaminated sediments by two infaunal invertebrates, Rhepoxynius abronius (a non-deposit feeding amphipod) and Armandia brevis (a nonselective, deposit-feeding polychaete), was examined and species responses were compared. Sediments were selected over a large geographical area of the Hudson-Raritan estuary to assess the potential for bioaccumulation from a typical urban estuary. Unlike polycyclic aromatic hydrocarbons (PAHs) from these sediments, concentrations of CHs in interstitial water (IW) indicated that partition coefficients (Koc) were generally as expected, especially when based on predicted, nonsorbed, interstitial water CH concentrations (IWfree). Correlations between amphipod and polychaete tissue residues revealed that these species were responding similarly to a gradient of CH concentrations in sediment. While tissue residues and BAFloc (lipid/organic carbon normalized bioaccumulation factor) values for the trichlorobiphenyls were similar for both species, accumulation in the polychaete was three to 10 times higher for the more hydrophobic PCBs, which was attributed to differences in the route of exposure. A negative correlation between the bioaccumulation factor (BAF) and total organic carbon (TOC) was found for both species, which was expected according to equilibrium partitioning theory. Because it was assumed that the amphipod was not feeding in these tests and the polychaete was ingesting sediment, comparison of their tissue residues and bioaccumulation factors was useful for highlighting the importance of sediment ingestion, especially for short-term, nonequilibrium exposures. These results may also help elucidate the limitations associated with assessing bioaccumulation and the resultant toxic response in standard 10-day toxicity tests with similar invertebrates.

Chlorinated hydrocarbons in eggs of grey heron (Ardea cinerea L.) in France (Lac de Grandlieu)

Nineteen eggs of grey heron (Ardea cinera L.) were collected from nests in France (Lac de Grandlieu) for OCP and PCB residue analysis. α-HCH, δ-HCH, dieldrine, p,p′-DDD and p,p′-DDT were never detected in any of the eggs. In contrast, significant amounts of HCB, β-HCH, γ-HCH, HE, p,p′-DDE and PCBs were quantified by GC/ECD and identified by GC/MS in most of the eggs. Moreover, the two later pollutants were found in all samples analyzed. Nevertheless, chlorinated hydrocarbon concentrations in eggs of grey heron were lower than those associated with reproductive effects known in field and laboratory for other bird species.

Chemical contaminants in harbor porpoise ( Phocoena phocoena) from the North Atlantic coast: Tissue concentrations and intra- and inter-organ distribution

Concentrations of chlorinated hydrocarbons (CHs), such as polychlorinated biphenyls (PCBs), were measured in subsamples taken from different anatomical locations of blubber and liver of three apparently healthy harbor porpoises ( Phocoena phocoena) incidentally caught in a gill-net fishery along the northwest Atlantic coast; selected elements (e.g., mercury) were measured in subsamples of liver. The vertical distribution (skin to muscle) of contaminants within blubber was also determined. Additionally, the concentrations of CHs and elements were determined in individual samples of brain, lung, kidney, and testis to assess how the disposition of toxic chemicals may be dependent on the physiological characteristics of a specific organ. Statistical analyses of the results showed that the anatomical location of the blubber or liver sample had no significant effect on concentrations of either CHs in blubber and liver, or of selected elements in liver. However, there were statistical differences between strata of blubber (skin to muscle) for the concentrations of CHs. As expected, the results showed that the CH concentrations, based on wet weight, were considerably higher in the blubber than in the other tissues; however, the concentrations of CHs in the different tissues were more comparable when values were based on total lipid weight with the exception of the brain where lipid normalized concentrations were than in all other tissues. This low relative accumulation of lipophilic contaminants in the brain tissue may be due to the presence of the blood-brain barrier, or due to a lower proportion of neutral lipids, such as triglycerides, as analysis for percent lipid and for the proportion of specific lipid classes showed.