A mass spectroscopic method for analysis of AHH-inducing and other polychlorinated biphenyl congeners and selected pesticides in fish

The 209 polychlorinated biphenyl (PCB) congeners exhibit a wide range in toxicity to fish, birds, and mammals. This paper discusses the use of gas chromatography/mass spectrometry negative chemical ionization (GC/MS-NCI) to quantify congeners of highly suspected toxicity such as IUPAC #77 (3,3,4,4-tetrachlorobiphenyl) and #126 (3,3,4,4,5-pentachlorobiphenyl). GC/MS analysis time needed to produce the necessary resolution was reduced to 1 h per sample or standard, allowing an autosampler to inject 12 samples in 24 hours, plus 12 standards/QC samples. Identification and quantification of some 60+ congeners and several selected pesticides and estimation of total PCBs are also possible within the 1 h analysis. For congeners of high chlorination (penta through octa), the method exhibited excellent sensitivity, such that we could not locate a fish which exhibited PCB levels below our calibrated quantitation range. NCI was not as sensitive for mono through tri and for some tetrachlorinated PCB congeners, an exception being PCB #77, for which sensitivity was of the same order as for the more highly chlorinated biphenyls. Long term stability was excellent. Over a 6-mo period, results of replicate analyses for PCB congeners and pesticides in a composited sample of lake trout (Salvelinus namaycush) from Lake Michigan had a relative standard deviation of 12% of the mean. Over the same time period, mean recoveries for samples spiked at concentrations similar to those in Lake Michigan lake trout were 90–102%. Response was linear over a wide range of concentrations for each of the analyzed compounds. This method is now being used for routine analysis of PCB congeners and selected pesticides in our laboratory.Contribution 799 of the National Fisheries Research Center-Great Lakes, U.S. Fish and Wildlife Service, 1451 Green Road, Ann Arbor, MI 48105.     

Toxic potential of non-ortho and mono-ortho coplanar polychlorinated biphenyls in Aroclors®, seals,and humans

Mono-ortho and non-ortho coplanar polychlorinated biphenyls (PCBs) were analyzed in Aroclors^®, seals, and humans by graphitized carbon, a recently developed HPLC method (Hong et al. 1992b) and high-resolution gas chromatography with electron capture detection (HRGC/ECD). The concentration data were multiplied by potency factors derived from aryl hydrocarbon hydroxylase (AHH) induction to give 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents. The ability to separate coplanar PCBs from the majority of PCBs has allowed the use of TCDD toxicity equivalence to compare the relative dioxin-like potency of PCB residues in the complex mixtures. The most active mixtures, Aroclors^® 1254, 1248, and 1242, contained 42–54% by weight of chlorine. The results demonstrate that the apparent dioxin-like potency of PCB residues in Aroclors^®, seals, and humans is dominated by three congeners, 3,3,4,4-tetra-, 2,3,3,4,4-, and 3,3,4,4,5-pen-tachlorobiphenyl (IUPAC nos. 77, 105, 126).     

Embryotoxicity, teratogenicity, and aryl hydrocarbon hydroxylase activity in Forster's terns on Green Bay, Lake Michigan

Known reproductive problems, including congenital malformations and poor hatching success, exist for the state endangered Forster's tern (Sterna forsteri) in Green Bay, Wisconsin. Twenty Forster's tern eggs were collected from separate nests at a natural colony with documented reproductive problems, situated at Green Bay, Lake Michigan, and an inland colony at Lake Poygan (control) where reproduction was documented as normal. Eggs from the two locations were placed in the same laboratory incubator and candled throughout incubation. Hatching success of Green Bay eggs was 52% of that for controls. Several early embryonic deaths occurred, but most mortality occurred close to the time of hatching. Liver microsomal aryl hydrocarbon hydroxylase activity was elevated approximately threefold in Green Bay hatchlings compared to controls. Green Bay terns that hatched weighed less than controls, had an increased liver to body weight ratio, and had a shorter femur length. Two Green Bay embryos that failed to hatch had anomalies, one with a crossed beak and one with poor ossification of the foot. One Green Bay hatchling had an abnormally ossified ilium. These effects were observed in eggs where there were measureable levels of aryl hydrocarbon hydroxylase inducers including polychlorinated biphenyls and polychlorinated dibenzo-p-dioxins.     

Polychlorinated biphenyl congeners (PCBs),p,p′-DDE and hexachlorobenzene in human milk in three areas of upstate New York

Forty human milk samples from women in an urban and a rural vicinity on Lake Ontario (Rochester and Oswego) and a mixed urban and rural location on the Hudson River (Albany), New York, were analyzed for 74 PCB congeners,p,p-DDE, hexachlorobenzene, and mirex in order to determine the intake of breast-fed infants. All of the compounds were detected in the samples, but only eight PCB congeners andp,p-DDE accounted for 88% of the chlorinated hydrocarbons detected.p,p-DDE was the predominant pollutant (mean 78 ng/g wet weight), but the levels detected were low compared with the results from other parts of North America. Eight individual PCB congeners comprise 52% of the total PCB residue (mean 26.5 ng/g of whole milk); they ranged in mean concentration from 3.2 ng/g (2,4,5,2,4,5-hexachlorobiphenyl) to 1 ng/g (2,3,4,3,4-pentachlorobiphenyl). Statistical correlation analysis among PCB congeners indicates a possible higher exposure to less chlorinated congeners at Oswego than at Albany.     

Contaminant Exposure and Reproductive Success of Ospreys (<Emphasis Type="Italic">Pandion haliaetus</Emphasis>) Nesting in Chesapeake Bay Regions of Concern

Abstract:The Chesapeake Bay osprey population has more than doubled in size since restrictions were placed on the production and use of DDT and other toxic organochlorine contaminants in the 1970s. Ospreys are now nesting in the most highly polluted portions of the Bay. In 2000 and 2001, contaminant exposure and reproduction were monitored in ospreys nesting in regions of concern, including Baltimore Harbor and the Patapsco River, the Anacostia and middle Potomac rivers, and the Elizabeth River, and a presumed reference site consisting of the South, West, and Rhode rivers. A sample egg from each study nest was collected for contaminant analysis, and the fate of eggs remaining in each nest (n = 14–16/site) was monitored at 7- to 10-day intervals from egg incubation through fledging of young. Ospreys fledged young in regions of concern (observed success: 0.88–1.53 fledglings/active nest), although productivity was marginal for sustaining local populations in Baltimore Harbor and the Patapsco River and in the Anacostia and middle Potomac rivers. Concentrations of p,p-DDE and many other organochlorine pesticides or metabolites, total PCBs, some arylhydrocarbon receptor-active PCB congeners and polybrominated diphenyl ether congeners, and perfluorooctanesulfonate were often greater in sample eggs from regions of concern compared to the reference site. Nonetheless, logistic regression analyses did not provide evidence linking marginal productivity to p,p-DDE, total PCBs, or arylhydrocarbon receptor-active PCB congener exposure in regions of concern. In view of the moderate concentrations of total PCBs in eggs from the reference site, concerns related to new and emerging toxicants, and the absence of ecotoxicological data for terrestrial vertebrates in many Bay tributaries, a more thorough spatial evaluation of contaminant exposure in ospreys throughout the Chesapeake may be warranted.     

Measures of reproductive success and polychlorinated biphenyl residues in eggs and chicks of Forster's terns on Green Bay,Lake Michigan,Wisconsin—1988

Data on reproductive success of Forster's tern (Sterna forsteri) from Green Bay, Lake Michigan in 1983 are compared with data collected in 1988. In 1988 measures of reproductive performance (hatching success, number of young fledged, and length of incubation) were improved. Concentrations of total polychlorinated biphenyls (PCBs) and planar PCB congeners in the eggs were compared between years. Median total PCB residue was 67% lower in 1988 ( =7.3 μg/g). This corresponds to a 42% reduction in tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ) from 1983 to 1988. We suggest that contaminant reduction and improved reproductive performance were due to low river flows in 1988 and associated reduced PBC loading into Green Bay. Forty-two percent of the matured chicks died before fledgling, and their body weight growth curves were much lower than normal. Young accumulate total PCBs at a rate of 17.6 μg/day. A no-observable-adverse-effects level (NOAEL) of 40–84 μg/kg/day was estimated from the two year results using the least observable adverse effects level (LOAEL)/NOAEL rating values.     

Uptake of planar polychlorinated biphenyls and 2,3,7,8-substituted polychlorinated dibenzofurans and dibenzo-p-dioxins by birds nesting in the lower fox river and Green Bay,Wisconsin, USA

The uptake of persistent polychlorinated hydrocarbons (PCHs) by four avian species was investigated at upper trophic levels of two aquatic food chains of the lower Fox River and Green Bay, Wisconsin. Accumulation of total and specific planar polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxin (PCDDs), and H411E rat hepatoma cell bioassay-derived 2,37,8-tetrachlorodibenzop-dioxin equivalents (TCDD-EQ) was evaluated in Forster's tern (Sterna forsteri) and common tern (Sterna hirundo) chicks, and in tree swallow (Tachycineta bicolor) and red-winged blackbird (Agelaius phoeniceus) nestlings from colonies nesting in several locations within the watershed. Concentrations of the PCHs were greatest in eggs and chicks of the two tern species, less in the tree swallows and least in the red-winged blackbirds. Young of all four species accumulated total PCBs, PCB congeners 77, 105, 126, and 169, and TCDD-EQ. The young birds also accumulated small concentrations of several 2,3,7,8-sbustituted PCDF and PCDD congeners. Uptake rates for certain of the PCHs for the Forster's tern chicks were: 15 g/day for total PCBs, 70, 200, 6.5, and 0.14 ng/day for PCB congeners 77, 105, 126, and 169, respectively, and 270 g/day for TCDD-EQ. Principal components analysis revealed that the patterns of PCH concentrations in the samples were influenced by species of bird, their age (or length of exposure) and nesting location. Collectively, our findings demonstrate that exposure of avian species to contaminants derived from aquatic food chains can be characterized and quantified for the purposes of ecological risk assessment.     

Biochemical and toxicological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) congeners in female rats

The capability of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)² and six congeners to induce toxic and biochemical changes in rats was investigated. In addition to TCDD, the following compounds were administered at a dose of 40 or 400 g/kg/day for three days P.O.: 2,7-dichlorodibenzo-p-dioxin (DCDD); 1,2,4-trichlorodibenzo-p-dioxin (TrCDD); 1,2,3,4-tetrachlorodibenzo-p-dioxin; l,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin; 3,3,4,4,5-pentachlorobiphenyl (PCB); and 2,2,4,4,5,5-hexachlorobiphenyl (HCB). Six days after treatment the animals were killed. Lipid peroxidation and glutathione peroxidase (GSH-PX) activity were determined in liver and kidney. Hepatic aryl hydrocarbon hydroxylase (AHH) activity was determined 48 hr following the administration of 400 g/kg of each congener or 40 g/kg of TCDD. With the exception of PCB and TCDD, the other congeners produced no toxic or biochemical changes at the doses given as determined by the above parameters. PCB (400 g/kg) resulted in a 4-fold increase in lipid peroxidation and a 69% decrease in GSH-PX activity. These results were comparable to the effects of a 40 g/kg dose of TCDD. PCB treatment resulted in a 80% decrease in thymus weight, and a 3.8-fold increase in AHH activity which were comparable to the effects of TCDD. A correlation appears to exist between the ability to induce hepatic AHH activity, enhance lipid peroxidation. inhibit GSH-PX activity, and decrease body and thymus weights.Abbreviations include TCDD 2,7-dichlorodibenzo-p-dioxin - DCDD 1,2,4-trichlorodibenzo-p-dioxin - TrCDD 1,2,3,4,6,7,8,9-octachlorodibenzo-p-dioxin - OCDD 3,3,4,4,5-pentachlorobiphenyl - PCB 2,2,4,4,5,5-hexachlorobiphenyl - HCB malondialdehyde - MDA aryl hydrocarbon hydroxylase - AHH glutathione peroxidase - GSH-PX 8-aminolevulinic acid - ALA structure-activity relations     

Organochlorine Contaminants and Biomarker Response in Double-Crested Cormorants Nesting in Green Bay and Lake Michigan, Wisconsin, USA

Double-crested cormorant (Phalacrocorax auritus) eggs at pipping and sibling 10-day-old chicks were collected from two colonies in Green Bay, WI, one colony in Lake Michigan, WI, and reference colonies in South Dakota and Minnesota. Egg contents and chicks were analyzed for organochlorine contaminants including polychlorinated biphenyl (PCB) congeners. Livers of embryos and chicks were assayed for hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity. Eggshell thickness and the physical dimensions of embryo brains were measured. Concentrations of organochlorines, including p,p′-DDE (p,p′-dichlorodiphenyldichloroethylene), PCBs, and PCB congeners were generally an order of magnitude higher in eggs and chicks from Wisconsin than from reference locations. Total PCBs averaged 10–13 μg/g wet weight in eggs from three Wisconsin colonies compared to 0.9 μg/g PCBs from reference locations. Double-crested cormorant chicks accumulated on average 33–66 μg PCBs/day and 7–12 μg p,p′-DDE/day in the Wisconsin colonies compared to 0 μg PCBs/day and 1 μg p,p′-DDE/day in the reference colonies. At pipping, EROD activity in the livers of cormorant embryos was significantly higher in the Wisconsin colonies and significantly correlated with PCBs and the toxic equivalents (TEQs) of aryl hydrocarbon-active PCB congeners relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin. However, in 10-day-old chicks EROD activity was not consistently different among colonies and was not correlated with PCBs or TEQs. A significant negative relationship between embryo brain asymmetry and the size of the egg suggested that physical constraint might be an important factor influencing the response of this bioindicator. Thinner eggshells in two colonies located near Door County, Wisconsin, suggested that historic p,p′-DDE residues associated with orchards are still an important source of p,p′-DDE in the local environment. Received: 26 April 2000/Accepted: 18 July 2000     

Toxicity and persistence of PCB homologs and isomers in the avian system

This study reports the biotransformation and persistence of PCBs in the hen, her eggs, and chicks hatched from these eggs. Twelve White Leghorn hens and one rooster were given 50 µg/ml of the PCB mixture Aroclor 1254 in their drinking water (6.3 mg/kg body weight) for six weeks. The resultant concentration in the yolk of eggs laid during the following 20 weeks and in the tissues of surviving embryos and chicks was determined by thin-layer chromatography and gas chromatography. Mortality of embryos and deformity of chicks were found to be correlated with PCB content of the eggs. Moreover, after storage of the PCB mixture in the hen's body, the toxic potency of the PCB mixture deposited in the eggs more than doubled. It was shown that 3,4,2,3,6-pentachlorobiphenyl (peak 9) was cleared faster from the hen than 3,4,2,4,5-pentachlorobiphenyl (peak 12) and 2,3,4,2,4,5-hexachlorobiphenyl (peak 14) and that 4,4-chlorination is more important than degree of chlorination in determining persistence of chlorinated biphenyls in the hen, embryo, and chick.     

Isomer-specific analysis and toxic evaluation of polychlorinated biphenyls in striped dolphins affected by an epizootic in the western Mediterranean sea

Isomer-specific concentrations of polychlorinated biphenyls (PCBs) including planar, mono- and di-ortho congeners and concentrations of DDT were determined in striped dolphins affected by a morbillivirus epizootic in the western Mediterranean in 1990. Extremely high concentrations of PCBs ranging from 94 to 670 g/g (wet wt) were detected in the blubber. Similarly, DDT concentrations were high, between 22 and 230 g/g (wet wt). The concentrations of three non-ortho coplanar PCBs were 43 (3,3,4,4-T₄CB), 6.8 (3,3,4,4,5-P₅CB), and 7.8 (3,3,4,4,5,5-H₆CB) ng/g (wet wt), respectively, the highest residue levels reported to date. The estimated 2,3,7,8-TCDD toxic equivalents of non-, mono- and di-ortho PCB congeners in striped dolphins were several times higher than those observed for other marine mammals and humans. Mono-ortho congeners contributed greater 2,3,7,8-TCDD toxic equivalents than non-ortho members. The higher ratio of 3,3,4,4,5,5-H₆CB/3,3,4,4,5-P₅CB (IUPAC 169/126) suggested a strong induction of mixed function oxidase enzymes and highlighted the possibility of using this ratio as an index for risk assessment of PCB contamination in marine mammals. Elevated concentrations of PCBs may have played a role in the immune depression in striped dolphins, ultimately leading to the development of morbillivirus disease.     

Comparing Polybrominated Diphenyl Ether and Polychlorinated Biphenyl Bioaccumulation in a Food Web in Grand Traverse Bay,Lake Michigan

Levels of polybrominated diphenyl ethers (BDEs) in Great Lakes salmonids and ambient air have been recently reported, but few studies worldwide have examined the accumulation of BDEs within aquatic food webs. Here we report some of the first measurements of six BDE congeners that are common components of the pentaBDE commercial mixture within an entire Lake Michigan food web. BDEs were detected in all samples and the dominant BDE congener was 2,2,4,4-tetrabromodiphenyl ether (BDE 47). BDE 47 levels were consistently greater than those of the 2,2,4,4,5-pentabromodiphenyl ether (BDE 99), despite similar levels of these two compounds in commercial mixtures, suggesting differences in the bioavailability of the BDE congeners or differences in their ability to be metabolized. Additionally, congener composition was significantly different among deepwater sculpin, bloater chub, and lake trout, indicating differences in exposure or differences in biotransformation capacities. Total BDE concentrations in this food web were positively correlated (r = 0.94) with levels of PCBs previously measured in these samples (Stapleton et al. 2001a). Levels of BDE 47 and PCB 153, compounds with similar physicochemical properties, were compared to examine the relative exposure and bioaccumulation of these two classes of chemicals that have different environmental loading histories. Food web magnification factors calculated for these two congeners were 3.2 and 4.0 for BDE 47 and PCB 153, respectively, indicating a comparable potential for biomagnification in food webs.     

Polychlorobiphenyl congeners,p,p′-DDE,and sperm function in humans

170 seminal samples from fertile men, men with idiopathic oligospermia or azoospermia and men status post vasectomy were analyzed for 74 polychlorobiphenyl (PCB) congeners,p,p-DDE, mirex, and hexachlorobenzene using the technique of glass capillary gas chromatography with electron capture detection. Low concentrations of 32 PCB congeners were measured (mean total PCB residue of 5.8 ng/g wet weight). The application of multiple linear regression analysis to the data is described and the result is critically evaluated. There is a correlation between sperm motility and count. There are indications that the concentrations of three PCB congeners (2,4,5,245- and 2,4,5,234-hexachlorobiphenyl and 2,4,5,34-pentachlorobiphenyl) are inversely correlated with sperm motility index in samples with a sperm count less than 20 million cells/ml. The implications of the discerned associations are discussed.     

Accumulation and persistence of individual polychlorinated biphenyl congeners in liver,blood, and adipose tissue of rats following dietary exposure to Aroclor® 1254

Female F344/NCr rats were exposed continuously to Aroclor^® 1254 (1, 3.3, 10, 33, or 100 ppm in the diet) for 7, 28, or 84 days in order to assess the accumulation of polychlorinated biphenyls (PCBs) in liver, blood, and adipose tissue. The persistence of the individual PCB congeners which are detected in liver was examined in the three tissues of additional groups of rats exposed for 7 days followed by 21 days on control diet, or for 28 days followed by 56 days on control diet. Limited accumulation of PCB congeners with low chlorine substitution (tri- and tetrachlorobiphenyls) in the liver and blood, and preferential retention of highly substituted PCB congeners (penta-and hexachlorobiphenyls) were observed in rats continuously exposed to Aroclor. In these rats, time- and dose-dependent increases in the relative levels of two congeners which cause profound phenobarbital-type induction [2,2,3,4,4,5-hexachlorobiphenyl (BZ# 138) and 2,2,4,4,5,5-hexachlorobiphenyl (BZ# 153)] were detected in the liver and adipose tissue. Rats receiving control diet following Aroclor treatment displayed a time- and dose-dependent decrease in the relative levels in blood, adipose and hepatic tissue of 2,3,34,4-pentachlorobiphenyl (BZ# 105) and 2,3,4,4,5-pentachlorobiphenyl (BZ# 118), two of the major congeners showing both TCDD- and phenobarbital-type induction. These rats also displayed increases in the relative adipose levels of another relatively potent mixed-type inducer, 2,3,3,4,4,5-hexachlorobiphenyl (BZ# 156), and increases in adipose and hepatic levels of the pure phenobarbital-type inducer, 2,2,4,4,5-pentachlorobiphenyl (BZ# 99).     

Polychlorobiphenyis (PCBs) in sediments of Tokyo Bay,Japan

Sediment cores were collected from five sites in Tokyo Bay. The sediment age was estimated by the²¹⁰Pb method and the polychlorobiphenyls (PCBs)(2,5,2,4,5 — pentachlorobiphenyl,3,4,2,4, 5-pentachlorobiphenyl, 3,4,2,3,4-pentachlorobiphenyl, 2,3,6,2,3,6-hexachlorobiphenyl, 2,4, 5,2,4,5-hexachlorobiphenyl, and 2,4,5,2,3,4, 5-heptachlorobiphenyl) profiles in the sediments were determined quantitatively by gas chromatography. With respect to the horizontal distribution of PCBs, the levels were highest off Tokyo and Kawasaki, the inner western part of the bay off the mouths of the Tama and Arakawa Rivers, and declined in the direction of the eastern and southern parts of the bay. It was assumed that most of the PCBs supplied to the bay from the adjacent rivers and the industrial zones along the western coast were coprecipitated with suspended particles near the river mouths and the western coast, while PCBs adsorbed by fine particles are carried throughout the bay by the current. The accumulation rate of PCBs in Tokyo Bay sediments gradually increased, starting about 1936, and reached a maximum value in 1972 and declined moderately thereafter. The time-dependent changes in the quantity released into the environment were estimated from the amount of PCBs manufactured and used. The accumulation rate of PCBs in Tokyo Bay sediments was then compared with the estimated rate of release into the environment.     

Polychlorinated biphenyl congeners in Foxes in Germany from 1983 to 1991

Red foxes served as a biological indicator for the temporal development of environmental contamination with polychlorinated biphenyls (PCB). The concentration of PCB congeners nos. 28, 49, 52, 101, 138, 153, and 180 were analyzed in the body fat of 80 foxes (Canis vulpes) from Germany. The samples were from animals that had been submitted for examination in 1983, 1987, and 1991. Throughout this time period, a reduction was seen in the concentration of the highly chlorinated biphenyls 138, 153, and 180, whereas the concentration of the low-chlorinated congeners PCB nos. 28, 49, and 52 increased. No change in contamination with congener 101 was observed. These results show a trend toward reduction of environmental contamination with highly-chlorinated biphenyls since 1983, while contamination with low-chlorinated congeners is apparently increasing.An interesting observation is the disproportionately higher amount of 2,2,3,4,4,5,5-hepatachlorobiphenyl (PCB 180) over that of 2,2,4,4,5,5-hexachlorobiphenyl (PCB 153) in body-fat samples from all foxes analyzed. This phenomenon was also observed in 10 dogs examined as controls. Based on evidence from other authors of experimental toxicological studies on beagles, it appears that the fox possesses a similar cytochrome P-450 isoenzyme that can degrade 2,4,5-trichloro-substituted aromatic compounds. As a consequence, in canines, PCB 180 which is additionally meta-chloro substituted is accumulated to a greater degree than is PCB 153.This paper contains portions of the doctoral thesis of G. Bachour     

Congener-Specific Patterns and Toxic Assessment of Polychlorinated Biphenyls in Resident and Migratory Birds from Southern India and Lake Baikal in Russia

Concentrations of polychlorinated biphenyls (PCBs), including non-, mono-, and di-ortho congeners, were determined in migratory and resident birds collected from India and Lake Baikal in Russia. In the 11 different species examined, total PCBs concentrations were in the range of 11–4500 ng/g (wet wt). IUPAC 105, 118, 138, 153, and 180 were the predominant congeners in almost all the birds. White-cheeked tern collected from India and common tern collected from Lake Baikal showed high PCBs concentrations of 4400 ng/g (wet wt) and 4500 ng/g (wet wt), respectively, and accumulated relatively high ratios of penta-CBs (IUPAC 118, 105, 99). Toxic equivalents (TEQs) of non- and mono-ortho PCB congeners in birds collected from India and Lake Baikal were in the range of 1.5–56 and 2.8–370 pg/g wet wt, respectively. Toxic assessment results led by calculated TEQs of the transfer to eggs from female birds revealed that TEQs in most of migratory and resident birds were comparable to the lowest observable effect level (LOAEL) of chicken which is a highly sensitive species against dioxin-like compounds. Calculated transfer TEQs to eggs of common tern collected from Lake Baikal in autumn, however, exceeded the LOAEL of CYP1A induction in bald eagle embryos and ED₅₀ of that in pheasant embryos, suggesting that embryo toxicity by coplanar PCBs in some avian species breeding in Lake Baikal is possible.     

Concentrations and chromatographic profile of DDT metabolites and polychlorobiphenyl (PCB) residues in stranded beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary,Canada

The concentrations and high resolution gas Chromatographic profiles of DDT metabolites and polychlorobiphenyl (PCB) congeners were determined in blubber, liver, kidney and lung tissue and milk samples of stranded beluga whales (Delphinapterus leucas) collected at localities along the coasts of the Saint Lawrence Estuary, Canada from November 1983 through December 1984. The analyses indicate that the major PCB components of the tissues were 2,2,5,5-tétra-, 2,2,4,4,5-penta-, 2,2,3,4,4,5-hexa-, 2,2,4,4,5,5-hexa-, 2, 2,3,3,4,5-hexa-, 2,3,3,5,5,6-hexa-, 2,2,3,4, 5,5,6-hepta- and 2,2,3,4,4,5,5-heptachlorobiphenyls. Although the highest organochlorine chemical concentrations were found primarily in the blubber, concentrations of 1.72 g/g for PCB and 2.04 g/g for DDT were determined in one milk sample. No correlation was established between PCB,p,p-DDE and DDT concentrations and the fat content of the kidney liver and lung tissues. The Chromatographie patterns of the PCB congeners were similar from one tissue to another with the exception of the kidney; the profile indicates the retention of PCB congeners which are minor components in the other tissues. Relations of residue concentrations between tissue are described and the significance of congener-specific PCB analysis is discussed in terms of the structureactivity effects on PCB persistence and toxicity.Portions of this work were presented at the Sixth Biennial Conference on the Biology of Marine Mammals, Vancouver, British Columbia, November 22–26, 1985.     

Critical evaluation of polychlorinated biphenyl toxicity in terrestrial and marine mammals: Increasing impact of non-ortho and mono-ortho coplanar polychlorinated biphenyls from land to ocean

Residues of potentially toxic non-ortho chlorine substituted coplanar 3,3,4,4-tetra-,3,3,4,4,5-penta-, 3,3,4,4,5,5-hexachlorobiphenyl and their mono- and di-ortho analogs (2,3,4,4,5-penta-, 2,3,3,4,4-penta-, 2,3,3,4,4,5-hexa-and 2,2,3,3,4,4-hexa-, 2,2,3,4,4,5-hexa-chlorobiphenyl) were determined in humans, dogs, cats (terrestrial), a finless porpoise (Neophocoena phocoenoides-coastal), Dall's porpoises (Phocoenoides dalli,dalli), Baird's beaked whales (Berardius bairdii) and killer whales (Orcinus orca-open ocean). Among the coplanar polychlorinated biphenyl (PCB) congeners, the concentration of the di-ortho congeners was the highest and the non-ortho congeners was the lowest. However, all three coplanar PCBs occurred at significantly higher levels than toxic polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The relative bioconcentration and metabolic capacity of terrestrial and marine mammals to these chemicals, suggest that the toxic threat of coplanar PCBs increases from land to ocean, but the reverse is true for PCDDs and PCDFs. The toxic threat of coplanar PCBs to higher aquatic predators such as cetaceans was principally assessed by 2,3,7,8-T₄CDD Toxic Equivalent Analysis which is based on the induction of arylhydrocarbon hydroxylase (AHH) and ethoxyresorufinO-deethylase (EROD). Analysis indicates, in particular, that the bioaccumulation of toxic 3,3,4,4,5-penta- and 2,3,3,4,4-pentachlorobiphenyls in carnivorous marine mammals is a cause for considerable concern.     

Congener-specific data on polychlorinated biphenyls in tissues of common porpoise from Puck Bay,Baltic Sea

Individual congeners of polychlorinated biphenyls (PCBs), including the highly toxic non-ortho coplanar 3,3,4,4-tetrachlorobiphenyl (IUPAC No. 77), 3,3,4,4,5-pentachlorobiphenyl (IUPAC No. 126), and 3,3,4,4,5,5-hexachlorobiphenyl (IUPAC No. 169), and their mono- and di-ortho analogs, have been identified and quantified in the blubber, liver, and muscles of three female common porpoise Phocoena phocoena collected from the Puck Bay (inner Gulf of Gdask, Poland) in 1989–1990, to elucidate actual concentrations and toxic potential. The total 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalent for 13 coplanar PCBs in blubber was 1,500±470 pg/g wet wt. 2,3,4,4,5-Pentachlorobiphenyl (IUPAC No. 118) was the most contributing individual and occupied between 57 and 67% in total toxic equivalent of coplanar PCBs in blubber, while 2,2,4,4,5,5-hexachlorobiphenyl (IUPAC No. 153), 2,3,3,4,4-pentachlorobiphenyl (IUPAC No. 105) and 2,2,3,4,4,5-hexachlorobiphenyl (IUPAC No. 138) comprised between 9.5–14, 7.6–11.5, and 7.2–11.0%, respectively (totally 82–95%), and 2,3,3,4,4,5-hexachlorobiphenyl (IUPAC No. 156) was absent. A potentially most toxic non-ortho PCB members such as 3,3,4,4,5-pentachlorobiphenyl, 3,3,4,4,5,5-hexachlorobiphenyl and 3,3,4,4-tetrachlorobiphenyl were only minor contributors, altogether occupying between 1.0 and 14.5% in total TEQ of coplanar PCBs. Concentrations of total PCBs in lipids of the blubber ranged from 26 to 47 g/g and were comparable or lower than reported earlier for common porpoises from the Baltic Sea, North Sea, and North Atlantic by other authors.