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PubMed1999

Sex reversal effects of environmentally relevant xenobiotic concentrations on the red-eared slider turtle, a species with temperature-dependent sex determination.

Xenobiotics suspected of being estrogenic-the PCB aroclor 1242 and the pesticides toxaphene, dieldrin, p,p'-DDD, cis-Nonachlor, trans-Nonachlor, p,p'-DDE, and chlordane-were examined for their ability to override a male-producing incubation temperature and result in female hatchlings in the red-eared slider, a turtle with temperature-dependent sex determination. Compounds were assayed in the environmentally relevant concentrations detected in alligator eggs from Lake Apopka, Florida, singly, in concert with one another, and with estradiol. Compounds assayed alone and resulting in significant sex reversal were trans-Nonachlor, cis-Nonachlor, aroclor 1242, p,p'-DDE, and chlordane. When administered with estradiol, only one of the compounds, chlordane, caused sex reversal at significant levels. When applied together, however, the eight compounds assayed resulted in significant sex reversal.

Animals↗
PubMed2002

Estrogen mimics bind with similar affinity and specificity to the hepatic estrogen receptor in Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss).

A variety of organic chemicals have been documented to bind to and activate the estrogen receptor (ER) and consequently induce estrogenic effects in different animals. Although the function of the ER seems phylogenetically conserved in vertebrates, a considerable interspecies variation in the structure of the ER has been demonstrated. In this study, the hepatic ER from Atlantic salmon (Salmo salar) and rainbow trout (Oncorhunchus mykiss) were partly characterized, and the ligand-binding preference for a range of endogenous steroids and environmental estrogens (estrogen mimics) was determined by receptor-radio ligand studies. The results show that both Atlantic salmon and rainbow trout livers contain ERs that bind 1,2,4,6,7-[(3)H]estradiol ([(3)H]-E2) with high affinity and low capacity (K(d) = 2.5-4.4 nM and B(max) = 27-97 fmol/mg protein). The Atlantic salmon ER (asER) and rainbow trout ER (rtER) exhibit similar [(3)H]-E2 binding characteristics, although livers from female fish contained a two to three times higher amounts of ER than the males in the two species. In competition studies with [(3)H]-E2, the asER and rtER were found to bind both native steroids (E2 > estrone > 17 beta-estradiol 17-glucuronide >> testosterone and 11-ketotestosterone) and putative estrogen mimics (diethylstilbestrol, 4-hydroxytamoxifen, ethynylestradiol > genistein, zearalenone > 4-t-octylphenol, 4-n-nonylphenol, and o,p'-DDT). The pesticides toxaphen and dieldrin, which are proposed to bind to and activate the human ER, did not display significant binding affinity for the fish ER, however. In general, the asER and rtER were found to bind both native steroids and estrogen mimics with similar affinity and specificity. The present results suggest that closely related species such as Atlantic salmon and rainbow trout display similar ER ligand-binding requirements, although interspecies differences in ER affinity and specificity between divergent species such as fish and humans may exist.

Animals↗
PubMed1997

Vitamin E modulation of hepatic focal lesion growth in mice.

The effect of DL-alpha-tocopherol acetate (vitamin E) on hepatic focal lesion growth in male B6C3F1 mice previously treated with diethylnitrosamine (DEN) was investigated. After hepatic focal lesions were formed, mice were placed into one of the following dose groups: 0 mg vitamin E/kg NIH-07 diet, 50 mg vitamin E/kg NIH-07 diet (control diet), 250 mg vitamin E/kg NIH-07 diet, and 450 mg vitamin E/kg NIH-07 diet. Mice were euthanized after either 30 or 60 days of dietary treatment. In normal (nonlesion) liver, vitamin E deficiency (0 mg/kg diet) increased hepatic DNA synthesis. In addition, vitamin E supplementation (450 mg/kg diet) decreased the incidence of hepatic apoptosis, while vitamin E deficiency (0 mg/kg diet) increased the incidence of hepatic apoptosis. The effect of vitamin E-induced lesion growth was examined by measuring the number of focal lesions per liver and the relative focal lesion volume. High-dose vitamin E supplementation (450 mg/kg diet) appeared to enhance the growth of hepatic focal lesions. In particular, basophilic lesions appeared to be the most sensitive to high-dose vitamin E modulation (450 mg/kg diet) as evidenced by increased number, volume, and labeling index of hepatic focal lesions. Vitamin E deficiency also appeared to enhance the growth of hepatic focal lesions, though to a lesser extent than vitamin E supplementation (450 mg/kg diet). In the present study, both vitamin E supplementation (450 mg/kg diet) and deficiency (0 mg/kg diet) appeared to enhance focal lesion growth albeit neither treatment enhanced lesion growth as dramatically as known nongenotoxic hepatocarcinogens (e.g., phenobarbital and dieldrin). The data presented here suggest that oxidative stress in focal hepatocytes may be a component of the liver tumor promotion process.

Animals↗
PubMed2002

Assessment of interactions of diverse ternary mixtures in an estrogen receptor-alpha reporter assay.

This study used an MCF-7 cell based ER-alpha reporter gene assay to assess chemical interactions within the following ternary mixtures: (1) three synthetic pesticides, methoxychlor (MXC), o,p-DDT, and dieldrin; (2) three polyaromatic hydrocarbons, benzo[a]pyrene (BAP), 1,2-benzanthracene (BENZ), and chrysene (CHRY); and (3) an endogenous estrogen, [17beta-estradiol, (E(2))]; a phytoestrogen, genistein (GEN); and a synthetic estrogen, o,p-DDT. A full factorial design in which four concentrations of each chemical were assessed in all possible combinations (64 treatment groups) was utilized. In addition, mixtures were tested in both a low range (concentrations near the individual chemical response thresholds) and a high range ( approximately 2-10x higher) experiment. A response surface was estimated using a nonlinear mixed model, and the cumulative response in each mixture was evaluated for departure from additivity. The mixture of E(2), GEN, and DDT exhibited antagonistic interactions (p < 0.001) in both concentration ranges. However, specific interactions between E(2)/GEN and E(2)/DDT differed between the low and high range concentrations. The BAP/BENZ/CHRY mixture did not depart significantly from additivity (p = 0.66) in either concentration range, although response levels were generally low. The MXC/DDT/dieldrin mixture did not depart significantly from additivity in either the high (p = 0.065), or low dose range (p = 0.506), with generally minimal responses dominated by MXC and DDT. This methodology has allowed for a rigorous statistical evaluation of potential departures from additive interactions in endocrine active mixtures. In no case was a significantly greater-than-additive (synergistic) interaction observed.

Biological Assay↗
PubMed1994

Trophic transfer and biomagnification potential of contaminants in aquatic ecosystems.

This review summarizes information obtained from published literature to determine to what degree biomagnification of organic compounds and metals occurs in freshwater and marine food webs. This review was conducted by: (1) examining data from studies conducted in laboratory experiments to establish body burden ratios between trophic levels (trophic transfer coefficients; TTCs); (2) comparing laboratory-derived TTCs with data obtained from field studies; and (3) comparing biomagnification predictions described by published aquatic food-web models with data obtained in this review. It was determined that: (1) the majority of chemicals evaluated (both organic and metals) do not biomagnify in aquatic food webs; (2) for many of the compounds examined, considerable trophic transfer does occur in aquatic food webs; (3) DDT, DDE, PCBs, toxaphene, methyl mercury, total mercury, and arsenic have the potential to biomagnify in aquatic systems; (4) the lipid fraction of receptors directly influences biomagnification of lipophilic compounds; (5) the food web model reviewed provided similar estimates for most of the organic compounds examined (log Kow values between 5 and 7), with model predictions falling within the range of values of all compounds except dieldrin; (6) for many organic compounds, lack of information precludes assessing the relative importance of biomagnification for these contaminants; and (7) even those compounds for which evidence for biomagnification is strongest show considerable variability and uncertainty regarding the magnitude and existence of food-web biomagnification in aquatic systems.

Animals↗
PubMed1991

Transmitter-activated ion channels as the target of chemical agents.

The transmitter-activated ion channels are known to be important target sites of a variety of therapeutic and toxic agents. The GABA-activated chloride channel has been shown to be modulated by general anesthetics, alcohols, and the pyrethroid, cyclodiene and lindane insecticides. The general anesthetics halothane, enflurane and isoflurane greatly augmented the GABA-activated current before desensitization took place, and suppressed it after desensitization at clinically relevant concentrations equivalent to 1-2 minimum alveolar concentrations. The stimulating effect appears to be a mechanism of general anesthesia. It seems that general anesthetics have a specific affinity for the GABA receptor-channel complex. Ethanol also augmented the GABA-activated peak chloride current with little or no effect on the desensitized sustained current. Longer chain alcohols n-butanol, n-hexanol, n-octanol, and n-decanol also exerted the same type of effect, with the potency and efficacy increasing with lengthening of the carbon chain. The GABA receptor-channel complex has also been shown to be an important target site of certain insecticides. The type II pyrethroids deltamethrin and fenvalerate augmented the GABA-activated peak chloride current when applied concurrently with GABA, but the effect was diminished as the pyrethroids were applied for long periods of time prior to GABA application. The latter effect might explain the controversy in the literature regarding the pyrethroid action on the GABA system. The type I pyrethroid allethrin suppressed the GABA-activated peak chloride current when co-applied with GABA. Both types of pyrethroids suppressed the N-methyl-d-aspartate-induced current. Lindane and the cyclodienes dieldrin, endrin, heptachlor-epoxide, and isobenzan suppressed the GABA-activated chloride current. These effects can account for the convulsant action of lindane and the cyclodienes.

Alcohols↗
PubMed1986

Effects of tumor promoters, genotoxic carcinogens and hepatocytotoxins on mouse hepatocyte intercellular communication.

Intercellular communication via gap junctions may be an important mechanism of cellular growth control. Tumor promoters can inhibit intercellular communication between cultured cells, while genotoxic carcinogens apparently lack this capability. The inhibition of intercellular communication by tumor promoters may be an essential mechanism by which tumor promotion occurs in vivo. In this study, the liver tumor promoters phenobarbital, lindane (1,2,3,4,5,6-hexachlorocyclohexane, gamma-isomer), DDT (1,1-Bis[4-chlorophenyl]-2,2,2-trichloroethane), Aroclor 1254 (a polychlorinated biphenyl mixture) and dieldrin inhibited intercellular communication between male B6C3F1 mouse hepatocytes in primary culture. Intercellular communication was detected as the passage of [5-3H]uridine nucleotides from pre-labelled donor hepatocytes to non-labelled recipient hepatocytes. Mouse hepatocyte intercellular communication was also inhibited by the skin tumor promoter TPA (12-0-tetradecanoyl-phorbol-13-acetate), but not by the bladder tumor promoter saccharin. The genotoxic hepatocarcinogens dimethylnitrosamine, diethylnitrosamine, benzo[a]pyrene and 2-acetylaminofluorene, and the hepatocytotoxins bromobenzene, acetaminophen, carbon tetrachloride, chloroform and methotrexate had no effect on mouse hepatocyte intercellular communication at non-cytotoxic levels. These results suggest that the ability to inhibit mouse hepatocyte intercellular communication is an effect specific to tumor promoters.

Animals↗
PubMed1995

Organochlorine, organobromine, metal, and selenium residues in bottlenose dolphins (Tursiops truncatus) collected during an unusual mortality event in the Gulf of Mexico, 1990.

Polychlorinated biphenyls (PCBs), cis-chlordane, oxychlordane, heptachlor epoxide, mirex, hexachlorobenzene (HCB), lindane, octachlorostyrene (OCS), p,p'-DDE,p,p'-DDT, dieldrin, triphenylphosphate (TPP), polybrominated biphenyls (PBBs), and polybrominated diphenyl ethers (PB-DPEs) were measured in the blubber, and five metals (mercury, lead, cadmium, chromium, and manganese) and selenium were measured in the liver of bottlenose dolphins (Tursiops truncatus) obtained from the Gulf of Mexico during an unusual mortality event in 1990. The collection of animals included fetuses, sucklings (< 1 year old), immature dolphins (2-5 years old), and adults of both sexes. PCBs, p,p'-DDE, HCB, and PBDPEs were detected in the blubber of each animal. Mean concentrations of organic contaminants were generally highest in adult males. p,p'-DDE was the single component analyte measured at the highest concentration. Immature females had greater concentrations of most chlorinated organics than adult females. Mercury and cadmium concentrations in liver increased with increasing age-class. The correlation between mercury and selenium in all animals was r = 0.96, with a mole ratio of 0.90. Concentrations of lead, manganese, cadmium, and chromium did not follow any particular age-class trend.

Animals↗
PubMed1992

Organochlorine pesticide contaminations in human milk samples from women living in Amman, Jordan.

Concentration of 15 organochlorine pesticides were determined by capillary gas chromatography in 59 human milk samples collected from the general population during 1989/1990 in the Jordanian capital of Amman. In addition to hexachlorbenzene (HCB), three groups of organochlorine compounds namely, DDT and its metabolites, hexachlorcyclohexane (HCH-isomers) and the cyclopentadiene group (aldrin, dieldrin, endrin, heptachlor, and heptachlor epoxide) were analyzed. The results show that almost all samples contained HCB, beta-HCH, p,p'-DDE and p,p'-DDT, whereas p,p'-DDD, heptachlor, alpha-HCH, gamma-HCH and o,p'DDT were found in 42, 40, 33, 22 and 20 analyzed samples, respectively. The concentration of HCB, beta-HCH, p,p'-DDE, p,p'-DDT and heptachlor expressed on a milk-fat basis (median in mg/kg milk fat): 0.29, 0.4, 2.04, and 0.7 respectively. For the comparative purposes and in order to try to find the possible sources of mother-milk contaminations, different types of locally produced and imported cow milk samples were also analyzed for the same organochlorine compounds. Almost all types of tested milk were contaminated with p,p'-DDE.

Adult↗
PubMed1996

Organochlorine pesticide contamination in neotropical migrant passerines.

Organochlorine pesticide levels were determined in Neotropical migrant passerines which have populations reported to be declining. Pesticide residues ranging from 0.385 to 27.4 ng/g were found in 19 of 21 birds, including both Hatch Year (HY) and After Hatch Year (AHY) age classes of nine different species. Eighteen of the 19 birds contained p,p'-DDE, while dieldrin was found in 16 birds and heptachlor epoxide was present in 10 birds. There were no significant differences in pesticide levels between HY and AHY birds, suggesting that HY birds are exposed to pesticides in their diet on the breeding ground or that pesticides are acquired from contaminated mothers, or both. Pesticide levels were not related to gender. Although the effects of these low residue levels on passerine fecundity are unknown, their presence has potential conservation implications for passerines and for the raptorial birds that feed upon them.

Animals↗
PubMed1994

Evaluation of methods for monitoring the potential exposure of small children to pesticides in the residential environment.

A nine-home pilot study was conducted to evaluate monitoring methods in the field that may be used to assess the potential exposures of children aged 6 months to 5 years to pesticides found in the home environment. Several methods, some of which were newly developed in this study, were tested for measuring pesticide residues in indoor air, carpet dust, outdoor soil, and on the children's hands. Information was also collected on household characteristics, pesticides used and stored at the residence, and children's activities. Pesticides were detected at all nine study homes. With the exception of one home, at least one pesticide was detected in all matrices sampled at each house. Of the 30 target pesticides, 23 were detected during the study. The most frequently detected pesticides were chlordane, chlorpyrifos, dieldrin, hepatachlor, and pentachlorophenol. The greatest number of pesticides and highest concentrations were found in carpet dust. The results of these investigations will be discussed in terms of performance of the methods and the distribution of pesticides across the various media sampled.

Child, Preschool↗
PubMed1995

Modelling and monitoring organochlorine and heavy metal accumulation in soils, earthworms, and shrews in Rhine-delta floodplains.

In the Rhine-delta, accumulation of microcontaminants in floodplain foodwebs has received little attention in comparison with aquatic communities. To investigate organochlorine and metal concentrations in a terrestrial foodchain, samples of soil, earthworms (Lumbricus rubellus), and shrew (Crocidura russula, Sorex araneus) livers and kidneys were taken from two moderately to heavily polluted floodplains. Chlorobiphenyl residues in earthworm fat were 0.10 to 3.5 times the concentrations in soil organic matter, whereas ratios for other organochlorines varied between 0.87 and 8.8. These ratios are one order of magnitude lower than expected from laboratory experiments with earthworms, and laboratory and field studies on aquatic invertebrates. Bioconcentration ratios for heavy metals are in accordance with literature values for other locations, confirming the high potential for cadmium accumulation in Lumbricidae. Concentrations of organochlorines in shrew liver lipids were 1.0 to 13 times the residues in earthworm fat. These values are higher than lipid-corrected biomagnification ratios for laboratory rodents, but equal to those measured for benthivorous birds in the Rhine-delta. On a dry weight basis, kidney-earthworm ratios for cadmium were about one order of magnitude lower than previously reported values for insectivores. Soil concentrations of many compounds in both floodplains did not meet Dutch quality standards. Yet, hexachlorobenzene, chlorobiphenyl 153 (PCB153), gamma-hexachlorocyclohexane, sigma DDT, and dieldrin residues in earthworms and shrews did not exceed diet levels expected to be safe for endothermic species. An exception was noted for cadmium in worms and shrew kidneys. Heavy metal pollution in soil was close to levels that are critical to earthworms in laboratory studies. Cadmium concentrations in shrew kidneys were below levels suggested to be safe for Sorex araneus, but above those that were critical to the rat.

Animals↗
PubMed1992

Organochlorine pesticide residues in human milk in the Ribeirão Preto region, state of São Paulo, Brazil.

Thirty-seven samples of human milk (colostrum) from donors living in the Ribeirão Preto region were analyzed to determine the levels of organochlorine pesticide residues. Donors were classified into two groups, i.e., occupationally exposed and non-exposed to pesticides. Other factors such as age, previous lactations, race, smoking habit, occupation, family income and educational level were also considered. Analysis was performed by preliminary lipid extraction followed by fractional partition on a column and finally by gas chromatography with an electron capture detector. Lindane was found in 32% of the samples in amounts of less than 0.001 mg/kg; heptachlor was found in 65% of the samples at mean levels of 0.001 mg/kg, i.e., a level five-fold lower than that established by FAO/WHO (1970) for cow's milk. Aldrin and endrin were not detected in any of the samples. Dieldrin was detected in only one sample at a level of 0.038 mg/kg, which is considered high. DDT and DDE amounts are reported as total DDT and at least one of these compounds was present in every sample. Amounts detected in donors occupationally exposed to pesticides ranged from 0.008 to 0.455 mg/kg (mean, 0.149 mg/kg), i.e., three times the limit established by FAO/WHO (1970), while values for donors who had not been exposed ranged from 0.002 to 0.072 mg/kg (mean, 0.025 mg/kg), i.e., half the limit. Considering the level of acceptable daily intake proposed by FAO/WHO (1973), lactents ingested 1% of the acceptable intake of lindane (all donors), 30% of the acceptable intake of heptachlor (all donors), 60% of the acceptable intake of DDT (non-exposed donors), and 3.7 times the acceptable intake of DDT (exposed donors).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Organochlorine pesticides and polychlorinated biphenyls in the Arctic Ocean food web.

Polychlorinated biphenyls (PCBs), polychlorinated camphenes (PCCs) and isomers of DDT and DDE were the predominant organochlorine (OC) hydrocarbons measured in epontic particulate matter, zooplankton, pelagic and benthic amphipods and liver tissue from an abyssal fish collected in the Arctic Ocean. Chlordane, dieldrin and other cyclodienes and hexachlorocyclohexane (HCH) isomers were present at lower concentrations. Levels on a dry weight basis in plankton of various sizes less than 63 microns to 2 mm were similar to those in epontic particulate matter, but on a lipid weight basis, concentrations in smaller plankton were two to five times higher. Organochlorines in amphipods and liver from the glacial eelpout Lycodes frigidus exceeded levels in zooplankton by up to an order of magnitude. Large benthic lysianassid amphipods (Tmetonyx cicada, Anonyx nugax and Eurythenes gryllus) accumulated higher concentrations on a dry and lipid weight basis than small species (Onisimus spp. and Andaniexis spp.) or the under-ice gammaridean amphipod (Gammarus wilkitzkii). No significant differences in OC levels were measured in benthic amphipods collected at different times. However, concentrations in large zooplankton (greater than 500 microns) collected in August, dominated by adult copepods and ctenophores, contained concentrations of alpha-HCH, chlordane isomers and other cyclodienes that were two to four times higher than levels in May. Ratios of alpha-HCH: gamma-HCH (5 to 10) were similar to those in seawater collected simultaneously but there was no difference in ratios in various size categories of planktonic and benthic crustaceans indicating no selective accumulation or metabolic alteration of these isomers. Ratios of cis-chlordane:trans-chlordane concentrations were lower in all sizes of zooplankton (2 to 3) than in shelf amphipods (3 to 6) which corresponded to an increase in the ratio with depth. Higher ratios of DDT:DDE in plankton (2 to 6) than in amphipods (1 to 2) reflects the metabolism of DDT to the more stable DDE isomers in amphipods. Metabolites of trans-chlordane were also measured in plankton and benthic amphipods. Although some OCs are degraded or metabolically transformed, accumulation in lipid-rich tissues results in the highest total concentrations in long-lived large-bodied arctic marine organisms.

Animals↗
PubMed1994

Contaminants in fishes from Great Lakes-influenced sections and above dams of three Michigan rivers. I: Concentrations of organo chlorine insecticides, polychlorinated biphenyls, dioxin equivalents, and mercury.

Fishes of the Great Lakes contain hazardous chemicals such as synthetic halogenated hydrocarbons and metals. These fish can move from the lakes into the Great Lakes tributaries of Michigan. In doing so, they transport concentrations of contaminants which may represent a risk to wildlife. Concentrations of mercury (Hg), total polychlorinated biphenyls (PCBs), 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ), total DDT complex, aldrin, endrin, dieldrin, heptachlor, heptachlor epoxide, lindane, hexachlorobenzene, cis-chlordane, oxychlordane, endosulfan-I, methoxychlor, trans-chlordane, and trans-nonachlor were determined in composite samples of fishes from above and below Michigan hydroelectric dams, which separate the fishes which have access to the Great Lakes from fishes that do not. Mean concentrations of total PCBs, TCDD-EQ, DDT, and most of the other pesticides were greater in composite samples of six species of fishes from below than above the dams on the Au Sable, Manistee, and Muskegon Rivers. Concentrations of mercury, were the same or greater above the dams than below. However, this difference was statistically significant only on the Au Sable. Mercury concentrations ranged from less than 0.05 mg/kg to 0.73 mg Hg/kg, ww. Total concentrations of PCBs ranged from 0.02 to 1.7 mg/kg, ww. Concentrations of 2,3,7,8-tetrachlordibenzo-p-dioxin equivalents varied among fishes and locations. The concentrations of TCDD-EQ ranged from 2.4 to 71 micrograms/kg, ww, with concentrations in carp being the greatest. Concentrations of TCDD-EQ were greater than the concentrations which would be expected to occur, due solely to the presence of polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and technical mixtures of PCBs.

Animals↗
PubMed1992

Anodontites trapesialis: a biological monitor of organochlorine pesticides.

The mussel Anodontites trapesialis (Lam, 1819) was used as an indicator of organochlorine pollutants in the Pardo River, located in the municipality of Ribeirão Preto (21 degrees 07'S and 47 degrees 45'W), State of São Paulo, Brazil. Biological monitoring was performed for one year at the site of a sugar cane grove on the left bank of the river. Forty-three animals were placed in two aluminum enclosures on the river bottom at this site and 4 animals of each enclosure were sacrificed for pesticide analysis at 3-month intervals, each collection corresponding to one season of the year. The animals were found to have been exposed to DDT, lindane, heptachlor, aldrin and dieldrin. Endrin was not detected in any of the analyses.

Animals↗
PubMedDate not supplied

Organochlorine chemicals in human breast milk in Hong Kong.

The results of a small-scale survey of organochlorine contaminants in human breast milk are presented and compared to previous data from 1976 for Hong Kong, and to reported data from elsewhere. Concentrations of p,p DDT, dieldrin and hexachlorobenzene (HCB) in recent breast milk samples were slightly but significantly lower than those in samples taken a decade previously in Hong Kong. However, levels of gamma-HCH (hexachlorocyclohexane) were higher in the more recent samples. The concentrations of DDT, DDE and beta-HCH in Hong Kong breast milk remain among the highest reported in the literature. Probable routes of uptake of such contaminants include the ingestion of seafood, as these same compounds have previously been found at high concentrations in mussels from Hong Kong waters. Data for organochlorine levels in breast milk from other parts of Asia are not available, but trends in global pesticide usage suggest that significant contamination elsewhere in the continent is likely.

Adult↗
PubMed1991

Organochlorine levels in North Atlantic right whale (Eubalaena glacialis) blubber.

Polychlorinated biphenyls (PCBs), total DDT (DDT + DDE + DDD), dieldrin, heptachlor epoxide, chlordanes, and hexachlorobenzene (HCB) were found in blubber biopsies from endangered North Atlantic right whales (Eubalaena glacialis) in the Bay of Fundy and on Browns-Baccaro Banks. Analyses included four sex and age class composite samples from 1988, and 21 individual samples from 1989. Generally, PCBs demonstrated the highest wet weight residue levels (up to 1.9 micrograms/g), followed by total DDT (DDT + DDE + DDD) (trace to 0.47 micrograms/g). Relatively low residue levels in adult females suggest that transmammary organochlorine (OC) residue transfer occurs during lactation. The actual blubber residue loads may have been underestimated, because the samples were taken when the whales were depositing fat reserves and the samples may not have been representative of the remainder of the blubber.

Adipose Tissue↗