Sigma Polychlorinated Biphenyls Research Articles

Temporal trends of polychlorinated biphenyls in precipitation in Beijing, China

Temporal trend of polychlorinated biphenyls (PCBs) was determined in precipitation and monthly depositional fluxes were calculated in Beijing for the first time from February 2009 to March 2011. Total PCBs concentrations ranged from 7.00 to 993 ng L-1 in dissolved phase and from 1.00 to 133 ng L-1 in particulate phase, with a two orders of magnitude variation. Concentrations of PCBs were dominated by dissolved phase, which accounted for 82.5% of the total PCBs in precipitation, implying PCBs enrichment in rainwater due to efficient scavenging of highly contaminated gas phase and nonfilterable submicron particles which easily adsorbed organic contaminants in urban atmosphere. Highest concentrations of PCBs were measured in snow, which were about two times higher than those in rainwater, demonstrating more efficient scavenging of PCBs by snow. The sum of bi-, tri- and tetrachlorinated congeners accounted for 70.5% of total PCBs in precipitation, suggesting that PCBs mainly come from the historical usage of domestic PCB product, e.g., trichlorobiphenyl. PCBs concentrations in both dissolved and particulate phases showed slow rate of decline, with a half-life of 16.9 years in precipitation, suggesting that the atmospheric concentrations of PCBs were decreasing slowly in Beijing. The wet deposition flux of Sigma PCBs ranged from 0.240 to 6.55 mu g m(-2) month(-1) (mean: 1.41 mu g m(-2) month(-1)), indicating a relatively high level of PCBs contamination in Beijing atmosphere. (C) 2012 Elsevier Ltd. All rights reserved.

Tissue Distribution of Polychlorinated Biphenyls and Organochlorine Pesticides and Potential Toxicity to Alaskan Northern Fur Seals Assessed Using PCBs Congener Specific Mode of Action Schemes

The fur seal (Callorhinus ursinus) population has decreased in their primary breeding grounds in the Bering Sea; contamination is among suspected causes. Our goal was to better understand the extent of contamination of seal tissues with certain organochlorine compounds by measuring the concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in fur seal tissues from St. Paul Island, to gain a better perspective of tissue congener distribution and to evaluate the observed PCB levels against toxicologically significant levels for modes of action. Concentrations of 145 PCB congeners (Sigma(145)PCBs) and 12 OCPs were measured with gas chromatography-ion trap mass spectrometry in 8 different tissues of 10 male northern fur seals. The mean concentrations of SigmaOCPs [in ng/g lipid weight (lw)] were 1180 in blubber, 985 in the heart, 1007 in the liver, 817 in the kidney, 941 in muscle, 660 in reproductive tissues, 204 in the brain, and 322 in the lung. The mean concentrations of Sigma(145)PCBs (in ng/g lw) were 823 in blubber, 777 in the liver, 732 in the heart, 646 in reproductive tissues, 638 in muscle, 587 in the kidney, 128 in the lung, and 74.3 in brain tissues. Concentrations of PCBs affecting the aryl hydrocarbon receptor expressed as total PCB toxic equivalents (SigmaPCB-TEQs) ranged from 0.3 to 545 pg/g lw for the various tissues. The major contributors to SigmaPCB-TEQs are CB-118 in muscle, brain, lung, kidney, and liver, CB-126 in blubber, and CB-118 and CB-126 equally in the heart and reproductive tissues. Concentrations of PCBs affecting Ca(2+) homeostatsis expressed as the neurotoxic equivalent (NEQ) showed SigmaPCB-NEQs ranged from 17.7 to 215 ng/g lw in all tissues. Although no composite measure of perturbation of thyroid function is available, sufficient amounts of congeners with high binding to the thyroxine transport system were present to warrant consideration of this mode of action in future studies. Analyses of 145 PCBs and mode of action evaluation suggest that PCB contamination could potentially exert an effect on the Alaskan northern fur seal population although the PCB concentrations have been decreasing in the fur seals over the last decade.

Bioaccumulation and Biomagnification of Organochlorines in a Marine Food Web at a Pristine Site in Iceland

Organochlorine (OC) bioaccumulation and biomagnification were studied in a marine food web at a pristine site in Iceland. The species studied were the gastropod and grazer chink shell (Lacuna vincta), the filter feeding bivalve blue mussel (Mytilus edulis), the predators butterfish (Pholis gunnellus), and the seabird black guillemot (Cepphus grylle), all sampled and analysed in 1996-1997. Individual OC levels were generally low in chink shell and blue mussels, somewhat elevated in the fish, and an order of a magnitude higher in the top predator black guillemot, except for Sigma HCH (hexachlorocyclohexane isomers) and Sigma chlordane levels, which were similar in all organisms, ranging from 10 to 36 ng/g lipid weight (lw). In the molluscs and fish, mean concentrations of Sigma PCB (polychlorinated biphenyl) ranged from 111 to 377 ng/g lw, Sigma DDT (dichlorodiphenyltrichloroethane) ranged from 19 to 65 ng/g lw, and HCB (hexachlorobenzene) ranged from 21 to 30 ng/g lw. The levels of same OCs in the black guillemot were on average 2352, 361, and 283 ng/g lw, respectively. The OC tissue concentrations in blue mussel and black guillemot are comparable to levels in Arctic and sub-Arctic regions, but OC levels in blue mussel tissue were an order of magnitude lower than found in the North Sea and the Baltic Sea. The relative composition of OCs were generally similar among species with the PCB congeners emerging as the most abundant compounds with levels an order of magnitude higher than the other compounds in all species. Food web magnification factors (FWMFs) were determined for the OCs by using trophic levels determined from delta(15)N. FWMFs >1, indicating biomagnification, were found for Sigma PCB, penta- or higher chlorinated PCBs (e.g., PCB 101, 118, 138, 153, 180), beta-HCH, HCB, Sigma DDT, p,p-DDE, and transnonachlor. The highest FWMF was observed for PCB 180 at FWMF = 5.8.

Hybrid NAA method for assessment of the levels of organic halogen compounds in the atmosphere in China

Passive air samplers (polyurethane foam disks) were deployed at 25 urban sites and 66 rural sites over the period of July to October 2005, partly between October 2005 and January 2006 for about 120 days across China, and analyzed for extractable organo-chlorine /-bromine /-iodine (EOCI/EOBr/EOI) and polychlorinated biphenyls (PCBs) using hybrid neutron activation analysis (NAA) combined with gas chromatography-mass spectrometry (GC-MS). The average concentration of EOCI, EOBr, EOI and Sigma PCBs among all the sites were 173.7, 3.5, 1.0 and 0.74 ng/d, respectively. Higher values of EOCI/Br/I and PCBs were detected in the areas of high usage and high emission, which were linked to relatively high-income areas in China, while lower in the west ill-developed region of China, which indicated that these pollutants mainly came from industrial pollution. Higher EOCI contents in traffic areas stated that the exhaust emission from vehicle was another main source of organochlorines in the air. The relative proportions of the known organochlorines (84 PCB congeners) to total EOCI were 0.02-3.0%, which implied that most of EOCI measured in air were unknown.

Cryptorchidism at birth in Nice area (France) is associated with higher prenatal exposure to PCBs and DDE, as assessed by colostrum concentrations

Since fetal exposure to anti-androgenic and/or estrogenic compounds has adverse effect on animal reproduction, such exposure could be harmful to human fetus. Data are scarce on cryptorchidism and human exposure to endocrine disruptors. We performed a prospective case-control study to assess the incidence of cryptorchidism and fetal exposure to selected chemicals in the Nice area. One hundred and fifty-one cord bloods (67 cryptorchid, 84 tightly matched controls) and 125 colostrums (56 for cryptorchid and 69 for controls) were screened for xenobiotics, including anti-androgenic dichloro-diphenyl-trichloro-ethylene (DDE), polychlorinated biphenyls (PCBs), and dibutylphthalate (and metabolite monobutylphthalate, mBP). Median concentrations in colostrum were higher, although not statistically significantly, in cryptorchid versus controls. Cryptorchid boys were more likely to be classified in the most contaminated groups in colostrum for DDE, Sigma PCBs and the composite score PCB + DDE. The same trend, but again not statistically significantly was observed for mBP. Odds ratio for cryptorchidism was increased for the highest score of Sigma PCB, with a trend only for DDE and Sigma PCB + DDE versus the lowest score of those components. Our results support an association between congenital cryptorchidism and fetal exposure to PCBs and possibly DDE. Higher concentrations in milk could be a marker of higher exposure or for an impaired detoxification pattern in genetically predisposed individuals.

Concentrations, profiles and gas-particle partitioning of PCDD/Fs, PCBs and PBDEs in the ambient air of an E-waste dismantling area, southeast China

Polychlorinated diebenzo-p-dioxins (PCDDs), polychlorinated diebenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were monitored in the ambient air of Taizhou, an E-waste dismantling area of southeast China to evaluate their concentrations, profiles and gas-particle partitioning. The Delta PCDD/Fs concentrations ranged from 2.91 to 50.6 pg/m(3), with an average of 14.3 pg/m(3). The I-TEQs for PCDD/Fs were in the range of 0.20-3.45 pg/m(3), with an average of 1.10 pg/m(3). The Sigma PCBs concentrations and TEQs ranged from 4.23 to 11.35 ng/m(3), 0.050 to 0.859 pg(TEQ)/m(3), respectively. The concentrations of Sigma PBDEs ranged from 92 to 3086 pg/m(3), with an average of 894 pg/m(3). The pollution levels of PCDD/Fs, PCBs and PBDEs were higher than other urban sites, which may be associated with the E-waste dismantling activities. The PCDD/Fs were found exclusively in the particle phase whereas PCBs distributed dominantly in the gas phase. The gas-partilce partitioning was also assessed by correlating the gas-particle partition coefficient (K-p) with the subcooled liquid vapor pressure (P-L(0)). The measured particulate sorptions of PCDD/Fs, PCBs and PBDEs were compared with the predictions from Junge-Pankow model and K-oa absorption model. The Junge-Pankow model well estimated the particulate fractions of PCBs. However, it underestimated the sorptions of PCDD/Fs and overestimated the fractions of PBDEs. The predicted particulate fractions of PCDD/Fs and PCBs from K-oa model fitted well with the measured data.

Polychlorinated Biphenyls (PCBs) in Air and Seawater of the Atlantic Ocean: Sources, Trends and Processes

Air and seawater samples were collected on board the RV Polarstern during a cruise from Bremerhaven, Germany to Cape Town, South Africa from October-November 2005. Broad latitudinal trends were observed with the lowest sigma27PCB air concentration (approximately 10 pg m(-3)) in the South Atlantic and the highest (approximately 1000 pg m(-3)) off the west coast of Africa. Sigma(ICES)PCBs ranged from 3.7 to 220 pg m(-3) in air samples and from 0.071 to 1.7 pg L(-1) in the dissolved phase seawater samples. Comparison with other data from cruises in the Atlantic Ocean since 1990 indicate little change in air concentrations over the remote open ocean. The relationship of gas-phase partial pressure with temperature was examined using the Clausius-Clapeyron equation; significant temperature dependencies were found for all PCBs over the South Atlantic, indicative of close air-water coupling. There was no temperature dependence for atmospheric PCBs overthe North Atlantic, where concentrations were controlled by advection of contaminated air masses. Due to large uncertainties in the Henry's Law Constant (HLC), fugacity fractions and air-water exchange fluxes were estimated using different HLCs reported in the literature. These suggest that conditions are close to air-water equilibrium for most of the ocean, but net deposition is dominating over volatilization in parts of the transect. Generally, the tri- and tetrachlorinated homologues dominated the total flux (> 70%). Total PCB fluxes (28, 52, 118, 138, and 153) ranged from -7 to 0.02 ng m(-2) day(-1).

Effect of Municipal Sewage Treatment Plant Effluent on Bioaccumulation of Polychlorinated Biphenyls and Polybrominated Diphenyl Ethers in the Recipient Water

Water, sediment, and aquatic species including plankton, fish, and turtles were collected from a small lake in Beijing, which receives effluent discharged from a large sewage treatment plant (STP). The samples were examined to investigate polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) releases from a STP and their distributions in the lake. The accumulations of sigma 12PBDEs and BDE-209 in the sediment were 62.3 and 1150 ng/cm2, respectively, while that of sigma PCBs was 99.3 ng/cm2. BDE-209 was detected in more than 50% of the aquatic species. A strong linear correlation (R2 = 0.92) was found between sigma 12PBDEs and sigma PCBs levels in aquatic species but not in sediments. The different PBDE congener profiles in sediments and biota samples suggest metabolic debromination in the sampled fish. Bioaccumulations of PBDEs and PCBs were found in aquatic species.The logarithm bioaccumulation factor (BAF) decreases with the number of bromines in PBDEs molecules, while the log BAF versus the number of chlorines in PCBs appears to be parabolic. Biomagnifications of these compounds were not obvious in the food web by analysis of the relationship between sigma 12PBDEs or sigma PCBs levels and the trophic level of aquatic biota species.

Associations between organochlorine contaminant concentrations and clinical health parameters in loggerhead sea turtles from North Carolina, USA.

Widespread and persistent organochlorine (OC) contaminants, such as polychlorinated biphenyls (PCBs) and pesticides, are known to have broad-ranging toxicities in wildlife. In this study we investigated, for the first time, their possible health effects on loggerhead sea turtles (Caretta caretta). Nonlethal fat biopsies and blood samples were collected from live turtles for OC contaminant analysis, and concentrations were compared with clinical health assessment data, including hematology, plasma chemistry, and body condition. Concentrations of total PCBs (∑PCBs), ∑DDTs, ∑chlordanes, dieldrin, and mirex were determined in 44 fat biopsies and 48 blood samples. Blood concentrations of ∑chlordanes were negatively correlated with red blood cell counts, hemoglobin, and hematocrit, indicative of anemia. Positive correlations were observed between most classes of OC contaminants and white blood cell counts and between mirex and ∑TCDD-like PCB concentrations and the heterophil:lymphocyte ratio, suggesting modulation of the immune system. All classes of OCs in the blood except dieldrin were correlated positively with aspartate aminotransferase (AST) activity, indicating possible hepatocellular damage. Mirex and ∑TCDD-like PCB blood concentrations were negatively correlated with alkaline phosphatase (ALP) activity. Significant correlations to levels of certain OC contaminant classes also suggested possible alteration of protein (↑blood urea nitrogen, ↓albumin:globulin ratio), carbohydrate (↓glucose), and ion (↑sodium, ↓magnesium) regulation. These correlations suggest that OC contaminants may be affecting the health of loggerhead sea turtles even though sea turtles accumulate lower concentrations of OCs compared with other wildlife.

Determination of polychlorobiphenyls and polycyclic aromatic hydrocarbons in the atmospheric aerosol of the Venice Lagoon.

An analytical method for simultaneous determination of "particle"-associated and "gaseous"-phase concentrations of polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) in atmospheric aerosol samples obtained by high-volume samplers using polyurethane foam adsorbent (PUF) and quartz fibber filters (QFF) has been investigated. Quality control of the analytical procedure was carried out by blank control and by evaluating limits of detection, recoveries, accuracy, and repeatability. The proposed method was subsequently used to determine PAH and PCB in the "gaseous" and "particulate" phases of the aerosols that enter the Venice Lagoon atmosphere. The highest concentrations of sigma PCB and sigma PAH were predominantly in the "gaseous" phase. In both "particulate" and "gaseous" phases the penta-CB congeners dominated total PCB concentrations whereas phenanthrene, fluoranthene, and pyrene dominated the sigma PAH concentrations. Total ("gaseous" plus "particulate") PCB and PAH concentrations were higher at the site directly influenced by the industrial plants but the concentrations in marine aerosol samples were lower by a factor four only and must be taken into consideration when studying the chemical contamination of the Venice Lagoon.

Biomagnification factors (fish to Osprey eggs from Willamette River, Oregon, U.S.A.) for PCDDs, PCDFs, PCBs and OC pesticides.

A migratory population of 78 pairs of Osprey (Pandion haliaetus) nesting along the Willamette River in western Oregon was studied in 1993. The study was designed to determine contaminant concentrations in eggs, contaminant concentrations in fish species predominant in the Ospreys diet, and Biomagnification Factors (BMFs) of contaminants from fish species eaten to Osprey eggs. Ten Osprey eggs and 25 composite samples of fish (3 species) were used to evaluate organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). Mercury was also analyzed in fish. Geometric mean residues in Osprey eggs were judged low, e.g., DDE 2.3 microg g(-1) wet weight (ww), sigma PCBs 0.69 microg g(-1), 2,3,7,8-TCDD 2.3 ng kg(-1), and generally well below known threshold values for adverse effects on productivity, and the population was increasing. Osprey egg residue data presented by River Mile (RM) are discussed, e.g., higher PCDDs were generally found immediately downstream of paper mills and eggs from the Willamette River had significantly elevated PCBs and PCDDs compared to reference eggs collected nearby in the Cascade Mountains. Prey remains at nest sites indicated that the Largescale Sucker (Catostomus macrocheilus) and Northern Pikeminnow (Ptychocheilus oregonensis) accounted for an estimated 90.1% of the biomass in the Osprey diet, and composite samples of these two species were collected from different sampling sites throughout the study area for contaminant analyses. With the large percentage of the fish biomass in the Osprey diet sampled for contaminants (and fish eaten by Ospreys similar in size to those chemically analyzed), and fish contaminant concentrations weighted by biomass intake, a mean BMF was estimated from fish to Osprey eggs for the large series of contaminants. BMFs ranged from no biomagnification (0.42) for 2,3,7,8-TCDF to 174 for OCDD. Our findings for the migratory Osprey were compared to BMFs for the resident Herring Gull (Larus argentatus), and differences are discussed. We believe a BMF approach provides some basic understanding of relationships between contaminant burdens in prey species of fish-eating birds and contaminants incorporated into their eggs, and may prove useful in understanding sources of contaminants in migratory species although additional studies are needed.

Polychlorinated biphenyls and reproductive hormones in female polar bears at Svalbard.

High concentrations of polychlorinated biphenyls (PCBs) in polar bears from Svalbard have increased concern for that population's reproductive health. We examined whether there were associations between the plasma concentrations of PCBs and reproductive hormones [progesterone (P4)] and 17 beta-estradiol (E2)] in free-living female polar bears from Svalbard. Concentrations of P4 depended on reproductive status, and concentrations were lowest in females with offspring--females with cubs and females with yearlings. In these females, the P4 concentrations were positively correlated with plasma sigma PCBs (sum of all analyzed polychlorinated biphenyl congeners) concentrations. The sigma PCBs concentrations explained 27% of the variation in the P4 concentrations. There were no correlations between sigma PCBs and E2 and cortisol in any of the groups of polar bears, or between sigma PCBs and P4 in single polar bears. Although the sigma PCBs-P4 relationship in female polar bears with offspring is not evidence per se of a direct cause-effect association, the results indicate that PCBs may affect levels of P4 in polar bear females. There is a clear need to further assess the hormone balance and population health of polar bears at Svalbard.

Influence of trophic position on organochlorine concentrations and compositional patterns in a marine food web

The accumulation of polychlorinated biphenyls (PCBs), DDTs (p,p'-DDT [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane], o,p'-DDT [1,1,1-trichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl)ethane], p,p'-DDD [1,1,-dichloro-2,2-bis(4-chlorophenyl)ethane], o.p'-DDD [1,1-dichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl)ethane], and p,p'-DDE [1,1-dichloro-2,2-bis(4-chlorophenyl)ethene]), chlordanes (trans-chlordane, cis-chlordane, trans-nonachlor, cis-nonachlor and oxychlordane), hexachlorocyclohexanes (alpha-, beta-, and gamma-isomers), hexachlorobenzene, and mirex was investigated in a marine food web from southeastern Norway. The food web consisted of the polychaete Nereis diversicolor, lesser sandeel (Ammodytes tobianus), three species of gobys (Gobiusculus flavescens, Pomatoschistus sp., and Gobius niger), bullrout (Myoxocephalus scorpius), cod (Gadus morhua), herring gull (Larus argentatus), and harbor seal (Phoca vitulina). The results show that interspecies differences in organochlorine (OC) compositional patterns in the food web depend on several factors (allometric, biochemical, physical, and physicochemical) specific to both the chemicals and the organisms. The importance of dietary accumulation and metabolic capacity increases toward higher trophic levels, while the OC patterns are to a larger extent determined by the lipophilicity and water solubility of the compounds at lower trophic levels. Furthermore, stable nitrogen isotopes provided a continuous measure of trophic position, rendering us capable of quantifying the increases in the concentrations of sigma PCB, sigma dichorodiphenyltrichloroethane (DDT), and sigma chlordane (CHL) and the percentages of highly chlorinated PCBs through the food web. The information provided may be important for future modeling of the fate of organochlorine contaminants in marine food webs.

Pentachlorophenol and hydroxylated polychlorinated biphenyl metabolites in umbilical cord plasma of neonates from coastal populations in Québec.

Concentrations of polychlorinated biphenyls (PCBs), hydroxylated metabolites of PCBs (HO-PCBs) and octachlorostyrene (4-HO-HpCS), and pentachlorophenol (PCP) were determined in umbilical cord plasma samples from three different regions of Québec. The regions studied included two coastal areas where exposure to PCBs is high because of marine-food-based diets--Nunavik (Inuit people) and the Lower North Shore of the Gulf of St. Lawrence (subsistence fishermen)--and a southern Québec urban center where PCB exposure is at background levels (Québec City). The main chlorinated phenolic compound in all regions was PCP. Concentrations of PCP were not significantly different among regions (geometric mean concentration 1,670 pg/g, range 628-7,680 pg/g wet weight in plasma). The ratio of PCP to polychlorinated biphenyl congener number 153 (CB153) concentration ranged from 0.72 to 42.3. Sum HO-PCB (sigma HO-PCBs) concentrations were different among regions, with geometric mean concentrations of 553 (range 238-1,750), 286 (103-788), and 234 (147-464) pg/g wet weight plasma for the Lower North Shore, Nunavik, and the southern Québec groups, respectively. Lower North Shore samples also had the highest geometric mean concentration of sum PCBs (sum of 49 congeners; sigma PCBs), 2,710 (525-7,720) pg/g wet weight plasma. sigma PCB concentrations for Nunavik samples and southern samples were 1,510 (309-6,230) and 843 (290-1,650) pg/g wet weight plasma. Concentrations (log transformed) of sigma HO-PCBs and sigma PCBs were significantly correlated (r = 0.62, p < 0.001), as were concentrations of all major individual HO-PCB congeners and individual PCB congeners. In Nunavik and Lower North Shore samples, free thyroxine (T4) concentrations (log transformed) were negatively correlated with the sum of quantitated chlorinated phenolic compounds (sum PCP and sigma HO-PCBs; r = -0.47, p = 0.01, n = 20) and were not correlated with any PCB congeners or sigma PCBs. This suggests that PCP and HO-PCBs are possibly altering thyroid hormone status in newborns, which could lead to neurodevelopmental effects in infants. Further studies are needed to examine the effects of chlorinated phenolic compounds on thyroid hormone status in newborns.

POSSIBLE IMMUNOTOXIC EFFECTS OF ORGANOCHLORINES IN POLAR BEARS (URSUS MARITIMUS) AT SVALBARD

Associations between immunoglobulin G (IgG) levels and the organochlorine contaminants (OCs) polychlorinated biphenyls (PCBs), chlordanes, 1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene (DDE), hexachlorobenzene (HCB), and hexachlorocyclohexanes (HCHs) in blood plasma from polar bears caught at Svalbard were determined. The blood samples were collected from free-living polar bears of different age and sex between 1991 and 1994. The IgG concentration increased with age and was significantly higher in males than in females. IgG was negatively correlated with Sigma PCB level and with three individual PCB congeners, IUPAC numbers 99, 194, and 206. HCB was also negatively correlated with IgG. The significant negative OC correlation with IgG levels may indicate an immunotoxic effect.

Does lake size affect concentrations of atmospherically derived polychlorinated biphenyls in water, sediment, zooplankton, and fish?

Concentrations of 90 polychlorinated biphenyl (PCB) congeners were determined in water, surface sediment, zooplankton, and fish collected from eight remote lakes in northwestern Ontario. The lakes vary in surface area from 0.2 to 4848 km2 and receive PCBs only from atmospheric deposition. Systematic differences with lake size in concentrations of Sigma PCBs or in congener distributions were not detected in any of the sample sets, except sediment. Concentrations of Sigma PCBs in surface sediments increased in the largest lakes when expressed on an organic carbon basis because carbon content decreased with lake size. In general, there were few strong correlations among PCB concentrations in water, sediment, or biota and physical, chemical, or biotic conditions at the time of sampling. There was no strong biomagnification of PCBs up the food chain from plankton to piscivorous fish. The results of this study are surprising because many factors that are thought to affect PCB dynamics and bioaccumulation varied systematically with lake size (water temperature, dissolved organic carbon concentrations, particle residence times, food chain length, algal productivity).

Isomer-specific analysis of polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) in red fox and human adipose tissue from central Italy.

The general exposure of humans and foxes to polychlorinated biphenyls (PCBs) and DDT in Italy was determined by analysis of adipose tissue samples collected from 1991-1992. sigma PCB concentrations varied between 1.0 and 2.6 micrograms/g (wet wt.). sigma DDT concentrations ranged from 1.6 to 5.0 micrograms/g (wet wt.). About thirty-five PCB congeners were identified in most samples. PCB congeners of IUPAC Nos. 138, 153, and 180 were the most abundant compounds, accounting for an average of 50% of the sigma PCBs in humans and 64% in foxes. Generally, higher chlorinated biphenyls and those with a 2,4,5-chlorine substitution in one ring and at least one substitution in the 4-position of the other ring were preferentially accumulated. Coplanar PCB congeners were detected at considerable concentrations and there is no sign of decline in their concentrations with respect to previously reported data. IUPAC Nos. 118, 156 and 126 were the main contributors to toxicity in humans and foxes. The significant contribution of mono-ortho congeners in humans and non-ortho congeners in foxes suggests that differences in metabolic potential may affect the PCB toxicity pattern.

Organochlorines including polychlorinated biphenyls in muscle, liver, and ovaries of cod, Gadus morhua.

Twenty-three specific organochlorine contaminants and polychlorinated biphenyls (PCBs), measured as three Aroclor standards were analyzed in muscle, liver, and ovaries of cod, Gadus morhua, collected in the Northwest Atlantic. In general, contaminants were undetectable in muscle tissue, while concentrations were 10 times lower in ovaries than liver (wet weight). Comparison of results to other locations indicated a similarity between the ratio of the concentrations of p,p'-DDE, p,p'-DDD and p,p'-DDT, in liver of cod from the northern North Sea and from the Northwest Atlantic, although with lower levels in the present study. The ratio of alpha-HCH and gamma-HCH was between that of the central and northern North Sea. Similar ratios tend to indicate similar residence times in the atmosphere, from source to sampling area. Comparison of sigma PCB and sigma DDT in the liver of cod from various geographical locations showed the following general trend in concentrations: Arctic, Northwest Atlantic, West Atlantic, Norway < North Baltic, Nova Scotia, North Sea < South Baltic. It was observed that if the liver concentration of one compound was low (high), there was a tendency for all compounds to be low (high). Cluster analysis of organochlorines in liver pointed to the presence of four basic clusters, which could reflect similar physical chemical properties within a group. Concentrations of organochlorines in ovaries were below levels expected to affect egg and larval viability.

The relative contribution of individual polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-p-furans (PCDFs) to toxic equivalent values derived for bulked human adipose tissue samples from Wales, United Kingdom

Five bulked human adipose tissue samples were analyzed for individual polychlorinated biphenyl (PCB) congeners (including selected non-ortho-substituted compounds) and polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs). Mean sigma PCB and sigma PCDD/F (tetra-through octachlorinated homologues) concentrations were 0.75 microgram/g and 1.22 ng/g adipose tissue respectively. Both the congener patterns and levels detected were similar to those reported by laboratories in other industrialised countries. Each sample comprised of tissue taken from donors within a given locality. However, no obvious relationships were apparent between sampling area, absolute concentrations and congener pattern of PCBs and PCDD/Fs. The contribution of individual PCDD/F and non-ortho-(o), mono-o-, and di-o-substituted PCB congeners to the total calculated toxic equivalent values (sigma TEQ) was assessed for each sample. The main contributions to the sigma TEQ were the mono-o-substituted PCB congeners #118 (TEQ = 42.5 pg/g of lipid), #156 (TEQ = 24.8 pg/g) and #105 (TEQ = 20.7 pg/g), followed by 1,2,3,6,7,8-HxCDD (TEQ = 18.2 pg/g), 2,3,4,7,8-P5CDF (TEQ = 12 pg/g), 1,2,3,7,8-P5CDD (TEQ = 11.5 pg/g), and the non-o-substituted PCB congener #126 (TEQ = 11.3 pg/g). Collectively, these compounds accounted for 80% of the sigma TEQ values. Based on the TEFs proposed by Safe (1990), the overall TEQs calculated for the monitored PCBs, were twice those due to sigma PCDD/Fs.

Organochlorine compounds in adipose tissue of Greenlanders and southern Danes.

Abdominal fat tissue samples from the general population of Greenland and from southern Denmark were analyzed for o,p'-DDE and p,p'-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene], p,p,-DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)-ethane], o,p'-DDT and p,p'-DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethane], lindane (1,2,3,4,5,6-hexachlorocyclohexane), aldrin (1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro-endo-exo-1,4:5,8-dimethanonaphthalene), dieldrin (1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro-endo-exo-1,4:5,8-dimethanonaphthalene), heptachlor (1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methanoindene), heptachlor epoxide, and polychlorinated biphenyls (PCBs). Fat tissue from Greenlanders contained significantly higher amounts of p,p'-DDE (p less than or equal to 0.05), p,p'-DDT (p less than or equal to 0.01), and total DDT (SIGMA DDT, the sum of DDT and its metabolites) (p less than or equal to 0.01) than southern Danes. Lindane, aldrin-like residue, dieldrin heptachlor-like residue, heptachlor epoxide, and PCBs were present in adipose tissue of both groups and there were no significant differences between the groups. The p,p'-DDE level in Greenland was lower than that in the United States, eastern Europe, and India. Among Greenlanders of different ages the highest sigma DDT was found in the age group of 22-45 yr; the content of PCBs increased with age. Among southern Danes the highest sigma DDT was found in a higher age group than in Greenlanders. Among Greenlanders the content of aldrin-like residue decreased with age and that of dieldrin increased with age. A significant correlation was found (on the basis of wet weight) between p,p'-DDE and PCB content in southern Danes (p less than or equal to 0.02). The correlation between sigma DDT and PCB content was also significant in this population (p less than or equal to 0.01). These two relationships were not significantly correlated for the Greenlanders. The DDE/PCB and sigma DDT/PCB ratios were higher in Greenlanders than in southern Danes. These ratios are age-dependent and are highest in the age group 22-45 yr among the Greenlanders. A low DDE/PCB ratio and a low sigma DDT/PCB ratio have been proposed as markers for industrialization. In Greenlanders p,p'-DDE represented about 70% of sigma DDT. For southern Danes this level was about 90%. The data obtained are presented and discussed on the basis of both lipid and wet weight levels.