Organochlorine compounds in human adipose tissue from north Texas.

This paper reports a preliminary study that was conducted to determine the concentrations of organochlorine compounds in the adipose tissue of residents of North Texas. Thirty-five human adipose tissue samples were obtained during autopsy between 1987 and 1988 from persons who had no known occupational exposure to organochlorine pesticides. These samples were analyzed by electron-capture gas chromatographic methods for the presence of beta-benzene hexachloride, o,p'-DDE, p,p'-DDE, o,p'-DDT, p,p'-DDT, dieldrin, oxychlordane, and heptachlor epoxide. The findings indicate greater than 97% occurrence for each compound with the exception of o,p'-DDE and o,p'-DDT, each of which occurred in 54% of the population sampled. Statistical analyses of the data showed strong positive correlations between adipose tissue concentrations and age for oxychlordane, heptachlor epoxide, p,p'-DDT, p,p'-DDE, and total DDT (the normalized sum of DDT and its analogues) (p less than or equal to .05). Statistically significant differences (p less than or equal to .05) in geometric mean concentrations between all age groups were found for total DDT and p,p'-DDE. However, the group means comparison test was only significantly different between the 41-60 yr and 61 and over age groups for p,p'-DDT, oxychlordane, and heptachlor epoxide. No statistically significant difference was found between sexes in this study. The geometric means of pesticide concentrations in adipose tissue were compared with those reported in previous U.S. Environmental Protection Agency surveys for the general population. This comparison clearly indicates a declining temporal trend in environmental exposure for banned DDT analogues; however, a consistent temporal trend exists for oxychlordane and heptachlor epoxide--pesticides whose uses are currently restricted but not proscribed.     

Age at natural menopause and exposure to organochlorine pesticides in Hispanic women

A cross-sectional study was conducted to evaluate the relationship between exposure to selected organochlorine pesticides (OCP) (p,p'-DDT, p',p'-DDE, dieldrin, hexachlorobenzene, beta-hexachlorocyclohexane [beta-HCH], oxychlordane, trans' nonachlor) and age at natural menopause in a sample of 219 menopausal women participating in the Hispanic Health and Nutrition Examination Survey in 1982-1984. Information on age at menopause, reproductive history, demographic variables, and potential confounding variables was collected via interview. Analysis of variance was employed to compare adjusted mean age at natural menopause among women by category of serum OCP level. Serum levels of p,p'-DDT, p,p'-DDE, beta-HCH, and trans-nonachlor were associated with a younger age at menopause. In particular, women with exposure levels in the highest exposure categories (serum p,p'-DDT > or = 6ppb, beta-HCH > or = 4ppb, or trans-nonachlor > or = 2ppb) had an adjusted mean age at menopause on average 5.7, 3.4, and 5.2 yr earlier, respectively, than women with serum levels of these pesticides below the detection limit. Women with serum p,p'-DDE levels greater than 23.6 ppb (highest quintile) had an adjusted mean age at menopause 1.7 yr earlier than women with serump,p'-DDE levels less than 5.5 ppb (lowest quintile). However, no consistent dose-response effect was apparent across low, medium, and high exposure categories. Interactions were detected for p,p'-DDT in combination with beta-HCH, trans-nonachlor, or oxychlordane, as well as beta-HCH in combination with oxychlordane.     

Relation between the content of organochlorine compounds in Finnish human milk and characteristics of the mothers

Neutral organochlorine pesticide and PCB residues were analyzed by GC-MS technique in 183 human milk samples obtained in 1984-1985 from 165 women living in different parts of Finland. The effect of the donors' age, body mass, place of residence, number of children, dietary habits, smoking habits, occupational history, and weight loss on the organochlorine content of human milk were studied. Of all the milk samples analyzed, p,p'-DDE concentrations were above the detection limit in 99.5%, p,p'-DDD + p,p'-DDT in 57.9%, isomers of HCH in 30.0%, cis-chlordane in 4.9%, oxychlordane in 3.3%, trans-nonachlor in 6.0%, heptachlor in 12.0%, and heptachlor epoxide in 6.6%. Mirex was not found in any of the milk samples, whereas the signals of chlorinated terpenes (toxaphenes) were detected but could not be quantitatively determined. The mean fat adjusted residue levels above the detection limit in Finnish human milk samples of primipara mothers were 0.66 ppm for total DDT compounds, 0.08 ppm for HCB, 0.93 ppm for PCBs, 0.41 ppm for chlordane compounds, 0.20 ppm for isomers of HCH, and 0.10 ppm for heptachlor epoxide. The geometric means were 0.46, 0.06, 0.57, 0.02, 0.02, and 0.01 ppm, respectively. The age of the mothers positively correlated with the DDE concentrations in human milk. The residues of OC compounds in human milk did not differ in women living in plywood industry regions, those actually working in the industry, and other mothers. Small differences were detected in the levels of organochlorine compounds in different parts of Finland. No relation was found between the OC content and the fish consumption, smoking habits, weight loss, or social group of the donors.     

The presence of environmental pollutants in the follicular fluid of farm animals (cattle,sheep, goats,and pigs)

Organochlorine pesticides and polychlorinated biphenyls are widely used in agriculture and industry, respectively. The present study assessed the burden of environmental pollutants in the follicular fluid of farm animals (cattle, sheep, goats, and pigs). An analytical method combining a solid-phase extraction with (C(18)) for clean-up and GC-electron capture detection using a capillary column was implemented for isolation and determination of organochlorine pesticides and polychlorinated biphenyls (PCBs). Of the organochlorine pesticides, hexachlorobenzene (HCB), hexachlorocyclohexane (HCH, alpha-, beta-, and gamma-isomers), dieldrin, heptachlor epoxide, and the DDT-related chemicals (o,p'-DDE, p,p'-DDE, p,p'-DDD, p,p'-DDT) were detected and of the PCBs, the congeners PCB-52, -101, -138, -153, and -180 were detected. In all species of farm animals, the most frequently detected pollutant was gamma-HCH (90-100% of samples) followed by HCB (80-100%), and p,p'-DDE (75-90.91%). Species differences in the concentrations of HCB, beta-HCH, heptachlor epoxide, and DDT-related chemicals in follicular fluid were noted as well as differences in the concentrations of some pollutants within the same species.     

Determination of chlorinated hydrocarbon pesticides by solid-phase extraction and capillary GC with electron capture detection

Pesticides and their metabolites are extracted and concentrated from serum using C18 solid-phase extraction cartridges. The internal standard aldrin is added to 4 mL of serum or plasma, treated with 2 mL of methanol, and the resultant supernatant applied to the C18 cartridge. After several washes, pesticides are eluted from the column with isoctane and the eluate quantified with capillary gas chromatography using electron capture detection. Extraction efficiency is from 70 to 75% and the method detection limit ranges from 0.1-0.7 ng/mL depending on the analyte. Precision studies demonstrate that CVs range from 3.5 to 25.2%. Standard curves are linear to at least 7 ng/mL for lindane and chlordane isomers, heptachlor, heptachlor epoxide, oxychlordane, trans-nonachlor, dieldrin, dichlorodiphenyldichloroethylene (p,p'-DDE), dichlorodiphenyldichloroethane (p,p'-DDD), and dichlorodiphenyltrichloroethylene (p,p'-DDT).     

The presence of environmental pollutants in the semen of farm animals (bull,ram, goat,and boar)

Organochlorine pesticides and polychlorinated biphenyls are widely used in agriculture and industry, respectively, and may affect male reproduction function. Although several pollutants have been detected in human semen, similar studies in farm animals have not appeared. In the present study, the semen of bulls, rams, goats, and boars was assayed for the organochlorine pesticides hexachlorobenzene (HCB), hexachlorocyclohexane (HCH, alpha-, beta-, and gamma-isomers), dieldrin, and heptachlor epoxide, for DDT-related chemicals (o,p'-DDE, p,p'-DDE, p,p'-DDD, p,p'-DDT), and for the PCBs congeners (PCB-52, -101, -138, -150, and -180). In all species of farm animals, the most frequently detected pollutants were p,p'-DDE (80-100% of samples), HCB (73.9-100%), and gamma-HCH (69.6-100%). Species differences in the concentrations of HCB, alpha-, beta-, and gamma-HCH, dieldrin, p,p'-DDE, p,p'-DDD, and PCBs were noted as well as differences in the concentrations of some isomers of HCH, DDT-related chemicals, and PCB congeners in the same species.     

Assessing the estrogenic potential of organochlorine pesticides in primary cultures of male rainbow trout (Oncorhynchus mykiss) hepatocytes using vitellogenin as a biomarker

Many organochlorine pesticides are suspected of impairing natural hormonal function in organisms by mimicking endogenous estrogen. The aim of this study was to assess the estrogenic activity of the organochlorine pesticides o,p'-DDT, dieldrin, aldrin, heptachlor, mirex and DDT in rainbow trout hepatocyte cultures using vitellogenin (Vtg) as the biomarker. A wide range of pesticide concentrations (0.0001-100 microM) was evaluated. Among the pesticides tested, o,p'-DDT was the most potent inducer of Vtg. The lower potency of technical grade DDT relative to o,p'-DDT could be explained by the fact that this pesticide is a mixture of two different pesticides (18% o,p'-DDT and 77% p,p'-DDT). This suggests that o,p'-DDT is a stronger inducer of Vtg than p,p'-DDT. A simple hypothesis could be that pesticides mixed together competed for the same receptor to favor the formation of a complex with reduced activity towards EREs. If these compounds are classified according to the level of Vtg secreted, we observed the following decreasing order: 17beta-estradiol (E(2))>o,p'-DDT>dieldrin>aldrin>DDT. Non-toxic levels of these compounds competed with E(2) for binding to the estrogen receptor. Heptachlor and mirex did not induce Vtg. Since the latter compounds failed to stimulate Vtg production, the possibility that they could interfere with the estrogenic response by inhibiting E(2) action was tested. In the presence of heptachlor, Vtg production triggered by E(2) significantly decreased. The EC50 value for inhibition of ER binding by heptachlor was cytotoxic for hepatocytes in culture, and this could in part explain the lack of Vtg response observed with this compound at the concentrations tested. Our results indicate that organochlorine pesticides can act as positive or negative modulators of estrogenic function in rainbow trout.     

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.     

Extraction and clean-up procedure for analysis of organochlorine pesticide residues in ethoxylated lanolin

In the present study an evaluation was made of a method for the determination of organochlorine pesticide residues in ethoxylated lanolin. Samples were homogenized with Celite, transferred to chromatographic columns, prepacked with silica gel deactivated to 10%. The pesticide elution was processed with n-hexane-dichloromethane and the concentrated eluate was analyzed using gas-liquid chromatography (GC) with electron capture detection (ECD). The composition of the elution solvent was a significant factor for the recovery of the pesticides. Mean recoveries obtained for fortified samples ranged from 87 to 94% for p,p'-DDE, dieldrin, endrin, p,p'-DDD and p,p'-DDT. Optimization of the experimental conditions resulted in a small-scale method that combines extraction and cleanup in a single step.     

Organochlorine pesticide residues in human milk in the United Kingdom 1997 - 8

1 The concentrations of a range of organochlorine pesticide residues have been determined in 168 samples of human milk collected between January 1997 and May 1998 in the UK. 2 Of the 18 residues sought, only p,p'-DTT, p,p'-DDE, dieldrin, HCB, beta-HCH and gamma-HCH were detected. 3 The continuing trend of a reduction in the concentrations of these pesticide residues in human milk samples and in the percentage of human milk samples containing residues was seen. 4 Correlations between the concentrations of p,p'-DDE, dieldrin, HCB, beta-HCH and gamma-HCH and age were seen. 5 When compared to studies carried out in Europe over a similar time period, residues in this present study were shown to occur at similar or lower concentrations.     

Organochlorine pesticide residues in chicken eggs: a survey

One hundred and five chicken egg samples were taken from seven geographical locations in Kenya and analyzed for organochlorine pesticide residues using gas-liquid chromatography. Nine organochlorine compounds were detected: alpha- and gamma-HCH/BHC (hexachlorocyclohexane/benzene hexachloride), aldrin, dieldrin, p,p'-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene], p,p'-DDD (TDE) [2,2-bis(p-chlorophenyl)-1,1-dichloroethane] (tetrachlorodiphenylethane), o,p'-DDD [2-(o-chlorophenyl)-2-(p-chlorophenyl)-1,1-dichloroethane], o,p'-DDT [2-(o-chlorophenyl)-2-(p-chlorophenyl)-1,1,1-trichloroethane], and p,p'-DDT. Eighteen of the samples contained DDT levels exceeding the practical residue limit (0.5 ppm). The mean DDT residue content was 0.68 ppm, a result influenced greatly by the high contamination in the 18 samples. Both individual and mean residue levels for other organochlorine pesticides detected were well within the respective practical residue limits.     

Effects of estrogenic (o,p'-DDT; octylphenol) and anti-androgenic (p,p'-DDE) chemicals on indicators of endocrine status in juvenile male summer flounder (Paralichthys dentatus)

Laboratory experiments were conducted with male summer flounder to assess the value of selected measures of endocrine status in fish as indicators of exposure to endocrine-disrupting contaminants. Effects of 1,1,1-trichloro-2-(p-chlorophenyl)-2-(o-chlorophenyl) ethane (o,p'-DDT), octylphenol and 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p'-DDE) on hepatosomatic and gonadosomatic indices, plasma steroid hormone levels, vitellogenin production, and gonadal development were evaluated in laboratory-raised, juvenile male summer flounder. Flounder were injected twice with test chemical in a coconut oil carrier. Each chemical was tested at three different concentrations. Estrogenic (o,p'-DDT; octylphenol) and anti-androgenic (p,p'-DDE) chemicals were evaluated alone and in combination (octylphenol plus o,p'-DDT or p,p'-DDE). Additionally, some fish were treated with the natural ligand for the estrogen receptor, 17beta-estradiol. Blood and tissues from different fish in each treatment were sampled 4, 6 and 8 weeks after the first injection. Fish exposed to a combination of o,p'-DDT plus octylphenol were also sampled after 15 weeks. In all cases, responses of fish exposed to a test chemical were compared to control fish sampled at the same time. The following significant differences, relative to controls, were observed in at least one sampling time or at least one concentration of chemical. 17beta-Estradiol-treated flounder exhibited decreased gonadosomatic index (GSI), altered hepatosomatic index (HSI), elevated plasma estradiol, reduced plasma testosterone, and high levels of plasma vitellogenin. Fish treated with o,p'-DDT showed lower GSI, no change in HSI or plasma estradiol, depression of plasma testosterone, and induction of vitellogenesis. Octylphenol treatment resulted in lower GSI, no change in HSI, initially increased plasma estradiol and decreased testosterone, and no vitellogenin production. p,p'-DDE treatment did not significantly alter any indicator relative to controls. In experiments using combinations of chemicals, flounder receiving o,p'-DDT plus octylphenol had lower GSI after 8 weeks and elevated plasma estradiol after 15 weeks exposure. Fish treated with p,p'-DDE plus octylphenol for 8 weeks exhibited a significantly lower GSI. Overall, lower GSI and plasma testosterone levels, relative to controls, were consistent indicators of exposure to estrogenic chemicals in juvenile male flounder. No indicators were found that would identify exposure to the mammalian anti-androgen p,p'-DDE.     

Increased ErbB-2 tyrosine kinase activity, MAPK phosphorylation, and cell proliferation in the prostate cancer cell line LNCaP following treatment by select pesticides.

The oncogene erbB-2 codes for a receptor tyrosine kinase that functions as a key mitotic signal in a variety of cell types. Amplification or overexpression of erbB-2 occurs in many forms of cancer, such as of the breast, colon, and prostate, and is an indicator of poor prognosis in those diseases. In the human prostate cancer cell lines LNCaP and PC-3, erbB-2 kinase was activated by pesticides of different chemical classes: (1) the organochlorine insecticides beta-hexa-chlorocyclohexane (beta-HCH), o,p'-dichlorodiphenyltrichloroethane (o,p'-DDT), and heptachlor epoxide; (2) the pyrethroid insecticide trans-permethrin, and (3) the fungicide chlorothalonil. o,p'-DDT also causes phosphorylation of mitogen-activated protein kinase (MAPK) and cellular proliferation of the androgen-dependent LNCaP line. However, no proliferative effect was observed in the androgen-independent PC-3 line. The proliferative effect of o,p'-DDT in LNCaP could not be blocked by the androgen receptor antagonist p,p'-dichlorodiphenyldichloroethene (p,p'-DDE), indicating that this effect of o,p'-DDT does not occur through direct interaction with the androgen receptor. Together these data demonstrate a putative mechanism for the action of certain pesticides in hormonal carcinogenesis.     

Analysis of pesticides and PCB congeners in serum by GC/MS with SPE sample cleanup

This paper describes a simple procedure for the quantitative analysis of 25 polychlorinated biphenyl congeners (PCB) in serum. They are PCB 70, 74, 77, 87, 99, 101, 118, 126, 128, 138, 151, 153, 156, 169, 170, 180, 183, 187, 191, 194, 205, 206, 208 and 209. In addition, 15 pesticides are analyzed in the same extract: aldrin, p,p'-DDE, p,p'-DDT, dieldrin, endrin, endosulfan I, heptachlor, hexachlorobenzene, alpha-hexachlorocyclohexane, beta-hexachlorocyclohexane, lindane, methoxychlor, mirex, pentachlorobenzene, and 1,2,3,4-tetrachlorobenzene. The procedure involved sample cleanup using a combination of C18 and NH(2) solid phase extraction cartridges. The instrumental technique was gas chromatography/mass spectrometry with both electron ionization and negative chemical ionization in the selected ion monitoring mode. Concentration of sub-ng/ml level was attainable with 2 ml of serum sample.     

Dichlorodiphenyltrichloroethane suppresses neurite outgrowth and induces apoptosis in PC12 pheochromocytoma cells

It is well known that dichlorodiphenyltrichloroethane (DDT) is used as an insecticide and prevents many people in the tropical zone from devastating malaria. On the other hand, a number of reports have indicated that it may act as an endocrine disruptor and also has possible carcinogenic effects. However, the effects of DDT on the neural cells remain to be investigated. In this study, therefore, we observed the effects of p,p'-DDT, o,p'-DDT and its major metabolite p,p'-DDE on the differentiation and survival of PC12 pheochromocytoma cells. After stimulation with nerve growth factor, PC12 cells exhibited remarkable neurite outgrowth, suggesting that neuronal differentiation was induced by this growth factor. p,p'-DDT and o,p'-DDT suppressed this neurite outgrowth dose dependently, and p,p'-DDE also revealed a similar effect but to a lesser extent. Apoptotic cell death was induced within 3-6 h after treatment with p,p'-DDT and o,p'-DDT. Again p,p'-DDE showed a weaker apoptosis-inducing effect. In the organochlorine-treated PC12 cells phosphorylation of p44/42 mitogen-activated protein kinase (MAPK) was upregulated, whereas phosphorylation bands were not detected in any kinases of other MAPK groups such as p38 MAPK and SAPK/JNK. A kinase assay on p44/42 MAPK revealed that the extent of phosphorylation of Elk-1 substrates well correlated with the suppressive effect on neuronal differentiation and apoptosis-inducing activity. These results suggest that p,p'-DDT and o,p'-DDT exerted their effects on neuronal cells by the stimulation of p44/42 MAPK, and p,p'-DDE had less effects than the other two organochlorines.     

DDT and its metabolite DDE alter steroid hormone secretion in human term placental explants by regulation of aromatase activity

Placental explants were used to compare the effects of two isomers of DDT (1,1,1,-trichloro-2,2-bis(p-chlorophenyl)ethane), p,p'-DDT and o,p'-DDT and their metabolites p,p'-DDE and o,p'-DDE (1,1,-dichloro-2,2-bis(p-chlorophenyl)ethylene) on steroid hormone secretion (estradiol (E2) and progesterone (P4)). Explants were treated with 1, 10, 100ng/ml or 1microg/ml of each compound for 24h. We found that all investigated compounds at all doses caused reductions of estradiol secretion. Moreover, it was shown that the inhibition of estradiol secretion was due to direct action on aromatase activity. Twenty-four-hour exposure to p,p'-DDE, o,p'-DDT or o,p'-DDE at doses of 100ng/ml or 1microg/ml increased P4 secretion, suggesting that these compounds act on P450scc. The fluorometric assay confirmed that all investigated compounds inhibited aromatase activity at a concentration of 100ng/ml. Our findings suggest that by decreasing estradiol secretion with concomitant stimulation of progesterone secretion, DDT could be a factor that influences the outcome of pregnancy.     

Effects of two isomers of DDT and their metabolite DDE on CYP1A1 and AhR function in human placental cells

The aim of this study was to investigate the actions of two isomers of DDT (p,p'-DDT, o,p'-DDT) and DDE (p,p'-DDE, o,p'-DDE) on the human placenta. We studied the effects of DDT and its metabolite DDE on CYP1A1 activity and on CYP1A1 and aryl hydrocarbon receptor (AhR) protein expression in placental cells. We used explants from third-trimester human placental tissue and JEG-3 cells, which are first-trimester human placenta cells. The main finding of this study was that the activity of CYP1A1 in the human placenta, measured in terms of ethoxyresorufin-O-deethylase (EROD) activity, was suppressed by treatment of 1, 10, and 100 ng/ml p,p'-DDT, o,p'-DDT, p,p'-DDE and o,p'-DDE. Immunoblot analyses indicated that both isomers of DDT and DDE inhibited the expression of CYP1A1 most effectively at 48 h and/or 72 h after the treatment. Because CYP1A1 activity is mediated by AhR, we evaluated the expression of AhR in placental tissue exposed to DDT and DDE for 1 h to 72 h. Our data showed that DDT and DDE gradually decreased the level of AhR protein, starting at 3 h or 24 h after the start of the experiment. Our results strongly support the involvement of the AhR/CYP1A1 signaling pathway in the mechanism of action of DDT and DDE in the human placenta.     

Polychlorinated biphenyl (PCB) induction of CYP3A4 enzyme activity in healthy Faroese adults

The CYP3A4 enzyme is, along with other cytochrome P450 enzymes, involved in the metabolism of environmental pollutants and is highly inducible by these substances. A commercial polychlorinated biphenyl (PCB) mixture, 1,1,1,-trichloro-2-(o-chlorophenyl), 2-(p'-chlorophenyl)ethane (o,p'-DDT) and 1,1,-dichloro-2,2-bis (p-chlorophenyl)ethene (p,p'-DDE) are known to induce CYP3A4 activity through activation of nuclear receptors, such as the pregnane X receptor. However, this induction of CYP3A4 has not yet been investigated in humans. Thus, the aim of the study was to determine the variability of the CYP3A4 phenotype in regard to increased concentrations of PCBs and other persistent organohalogen pollutants (POPs) in healthy Faroese adults. In 310 randomly selected Faroese residents aged 18-60 years, the CYP3A4 activity was determined based on the urinary 6beta-hydroxycortisol/cortisol (6beta-OHC/FC) ratio. POP exposures were assessed by measuring their concentrations in serum lipid. The results showed a unimodal distribution of the 6beta-OHC/FC ratio with values ranging from 0.58 to 27.38. Women had a slightly higher 6beta-OHC/FC ratio than men (p=0.07). Confounder-adjusted multiple regression analysis showed significant associations between 6beta-OHC/FC ratios and summation PCB, PCB-TEQ and p,p'-DDE, o,p'-DDT and HCB, respectively, but the associations were statistically significant for men only.     

Bioaccumulation of DDT pesticide in cultured Asian seabass following dietary exposure

Bioaccumulation and metabolism of p,p'-DDT was studied in the marine carnivorous fish Lates calcarifer, Asian seabass, in a controlled aquaculture experiment. Over a 42-d period, seabass were fed pellets dosed with p,p'-DDT at environmentally realistic levels. Virtually all p,p'-DDT in pellets bioaccumulated in the fish with an uptake efficiency of 98%. The levels of p,p'-DDT and the metabolites p,p'-DDD and p,p'-DDE were analyzed in muscle, liver, visceral fat, brain, and remaining tissues. Partitioning of p,p'-DDT and its metabolites among the control, low-dose, and high-dose exposed seabass were 14.8% in muscle, 3.5% in liver, 37.1% in visceral fat, 0.11% in brain, and 45.5% in remaining tissues, where partitioning between tissues was a function of tissue lipid content. p,p'-DDT bioaccumulation increased linearly with exposure in visceral fat and muscle tissue. The metabolism of p,p'-DDT, which occurs mainly in the liver, resulted in the degradation of 2.5% of p,p'-DDT into p,p'-DDD. These new findings show that bioaccumulation processes at environmentally realistic ingestion exposure levels (ng/g) differ from previous DDT ingestion studies conducted at unrealistically high DDT levels (microg/g), highlighting the need to revise models on the transfer of persistent organic pollutants in the marine environment and aquaculture systems.     

Studies on concentration of halogen derivatives in herbal products from various regions of Poland

The studies covered evaluation of levels of halogen derivative pesticides (p,p'-DDT and its metabolites p,p'-DDD and p,p'-DDE, as well as HCH, DMDT, aldrin and dieldrin) in herbal raw materials picked up in various regions of Poland in 1983. Qualitative analyses have been carried out with the TLC method whereas for quantitative analyses the GLC method has been applied. It has been found that the most frequently occurring are p,p'-DDT and its metabolites. The highest concentrations of these compounds have been observed in herbs from Lower Silesia and from the Bydgoszcz regions. Also in the region of Bia?ystok concentrations of these compounds are generally higher than in other parts of Poland. Other pesticides have been found in a lesser number of herbal raw materials and in considerably lower concentrations.