Assessment of average exposure to organochlorine pesticides in southern Togo from water, maize (Zea mays) and cowpea (Vigna unguiculata)

Drinking water, cowpea and maize grains were sampled in some potentially exposed agro-ecological areas in Togo and analysed for their contamination by some common organochlorine pesticides. A total of 19 organochlorine pesticides were investigated in ten subsamples of maize, ten subsamples of cowpea and nine subsamples of drinking water. Analytical methods included solvent extraction of the pesticide residues and their subsequent quantification using gas chromatography-mass spectrometry (GC/MS). Estimated daily intakes (EDIs) of pesticides were also determined. Pesticides residues in drinking water (0.04-0.40 microg l(-1)) were higher than the maximum residue limit (MRL) (0.03 microg l(-1)) set by the World Health Organization (WHO). Dieldrin, endrin, heptachlor epoxide and endosulfan levels (13.16-98.79 microg kg(-1)) in cowpea grains exceeded MRLs applied in France (10-50 microg kg(-1)). Contaminants' levels in maize grains (0.53-65.70 microg kg(-1)) were below the MRLs (20-100 microg kg(-1)) set by the Food and Agriculture Organization (FAO) and the WHO. EDIs of the tested pesticides ranged from 0.02% to 162.07% of the acceptable daily intakes (ADIs). Population exposure levels of dieldrin and heptachlor epoxide were higher than the FAO/WHO standards. A comprehensive national monitoring programme on organochlorine pesticides should be undertaken to include such other relevant sources like meat, fish, eggs and milk.

Effects of perinatal combined exposure to 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) and tributyltin (TBT) on rat female reproductive system

1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) is the most prevalent metabolite of DDT used as a pesticide before and tributyltin (TBT) compounds are used primarily as antifouling agents on vessels, ships, and aqua culture facilities, as they exert biocidal actions. Currently, p,p'-DDE and TBT are ubiquitously distributed in the environment and bio-accumulated in marine products, especially fish or shellfish. Thus, oral p,p'-DDE and TBT intake through marine products is demonstrated to be rather high in Japan. Consequently, the fetus and neonate will be exposed to p,p'-DDE and TBT via mother. Therefore, effects of perinatal combined exposure to p,p'-DDE and TBT on the female reproductive system after maturation have been investigated in rat female offspring of dams ingesting 125ppm p,p'-DDE (approximately 10mg/kg) and 25ppm TBT (approximately 2mg/kg) during the perinatal period from gestation to lactation. In the present study, no deleterious reproductive outcomes were recognized in p,p'-DDE and/or TBT-treated dams. In contrast, growth retardation had developed in rat female offspring following perinatal exposure to TBT and sustained even after cessation of exposures. Further, reduced ovarian weights with elevated serum follicle-stimulating hormone (FSH) concentrations were observed in the reproductive system of matured female offspring following perinatal exposure to TBT. At present, biological relevance of these alterations remains unknown, but there is a possibility that these alterations lead to reproductive malfunctions in matured female offspring.

Effects of perinatal, combined exposure to 1,4-dichlorobenzene and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene on rat female reproductive system

Prenatal or early postnatal exposure to some synthetic chemicals may affect the later reproductive system of the offspring. 1,4-Dichlorobenzene (DCB) is used as an air freshener and a moth repellent and 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p'-DDE) is a persistent metabolite of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane that was used as a pesticide before. DCB concentrations of residential air and oral p,p'-DDE intake through marine products are demonstrated to be rather high in Japan. Such situations lead to high body burden of these pollutants in pregnant women. Consequently, foetuses and neonates will be exposed much more to DCB and p,p'-DDE via the mother. Therefore, the effects of the perinatal, combined exposure to DCB and p,p'-DDE on the female reproductive system have been investigated in mature rat female offspring of dams ingesting 25 p.p.m. DCB (approximately 2 mg/kg) and 125 p.p.m. p,p'-DDE (approximately 10 mg/kg) during the gestational and lactational period. Sexual maturation was fully developed in the rat female offspring perinatally exposed to DCB and/or p,p'-DDE through maternal exposure. The combined effect of DCB and p,p'-DDE was observed, and the ovarian weight was seen to decrease to approximately 80% of the control rat in matured female offspring following perinatal exposure to DCB and p,p'-DDE. This alteration might lead to reproductive dysfunction in matured female offspring. However, biological relevance of the alteration in the ovary remained uncertain in the present study. Further investigations concerning the reproductive function and mechanistic implication are required for elucidating the combined effects of perinatal exposure to DCB and p,p'-DDE on the later female reproductive system entirely.

Immunologic effects of perinatal exposure to dioxins, PCBs and organochlorine pesticides in Japanese infants

Effects of perinatal exposure to dioxins, PCBs and organochlorine pesticides on lymphocyte subsets were investigated in the peripheral blood from 101 Japanese infants with approximately 10 months of age. Perinatal exposure to these organochlorine compounds were estimated by their contamination levels in the breast milk of the mothers. Lymphocyte subsets such as CD16+, HLA-DR+, CD4+, CD4+8+, CD8+, CD3+ and CD20+ cells in peripheral venous blood were assessed in a subgroup of 92 infants. Greater exposures to HCE, chlordane and dioxins were significantly associated with the increase in the percentages of CD8+ and CD3+ T lymphocytes and CD4+/CD8+ T cell ratios, respectively. In addition, higher HCH exposure was also associated with a decrease in the percentage of HLA-DR+ T lymphocytes. Furthermore effects of dioxins, DDT and PCBs on the percentage of CD16+ T lymphocyte were more pronounced by the combined exposure of dioxins and PCBs or by the combined exposure of DDT and PCBs. Effects of HCE on the percentages of CD8+ T lymphocyte were also more pronounced by the combined exposure of HCE and chlordane. In conclusion, our study suggests that greater exposures to dioxins, PCBs and organochlorine pesticides determined in this study (except dieldrin) influence the immune system of Japanese infant, although the clinical significance of these changes is uncertain.

Analysis of the interaction of phytoestrogens and synthetic chemicals: an in vitro/in vivo comparison

In the evaluation of chemical mixture toxicity, it is desirable to develop an evaluation paradigm which incorporates some critical attributes of real world exposures, particularly low dose levels, larger numbers of chemicals, and chemicals from synthetic and natural sources. This study evaluated the impact of low level exposure to a mixture of six synthetic chemicals (SC) under conditions of co-exposure to various levels of plant-derived phytoestrogen (PE) compounds. Estrogenic activity was evaluated using an in vitro human estrogen receptor (ER) transcriptional activation assay and an in vivo immature rat uterotrophic assay. Initially, dose-response curves were characterized for each of the six SCs (methoxyclor, o,p-DDT, octylphenol, bisphenol A, beta-hexachlorocyclohexane, 2,3-bis(4-hydroxyphenyl)-propionitrile) in each of the assays. The six SCs were then combined at equipotent ratios and tested at 5-6 dose levels spanning from very low, sub-threshold levels, to a dose in which every chemical in the mixture was at its individual estrogenic response threshold. The SC mixtures also were tested in the absence or presence of 5-6 different levels of PEs, for a total of 36 (in vitro) or 25 (in vivo) treatment groups. Both in vitro and in vivo, low concentrations of the SC mixture failed to increase estrogenic responses relative to those induced by PEs alone. However, significant increases in response occurred when each chemical in the SC mixture was near or above its individual response threshold. In vitro, interactions between high-doses of SCs and PEs were greater than additive, whereas mixtures of SCs in the absence of PEs interacted in a less than additive fashion. In vivo, the SC and PE mixture responses were consistent with additivity. These data illustrate a novel approach for incorporating key attributes of real world exposures in chemical mixture toxicity assessments, and suggest that chemical mixture toxicity is likely to be of concern only when the mixture components are near or above their individual response thresholds. However, these data suggest that extrapolation from in vitro assays to in vivo mixture effects should be approached with caution.

Fish intake and serum levels of organochlorines among Japanese women

This study evaluates background serum levels of selected organochlorine compounds among Japanese women of reproductive age and investigates whether lifestyle factors, especially dietary factors, may be associated with these levels. A cross-sectional study was performed on 80 Japanese women, aged 26-43 years, who complained of infertility and were confirmed not to have endometriosis. The serum levels of total toxic equivalency (TEQ), 18 polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs), 4 coplanar polychlorinated biphenyls (cPCBs), 36 ortho-substituted polychlorinated biphenyls (PCBs), and 13 chlorinated pesticides or their metabolites were measured and data were collected on the women's age, residence, occupation, body mass index (BMI), smoking and alcohol habit and 6 dietary intakes (fish, meats, rice, vegetables, fruits and dairy products). The serum median level of total TEQ was 25.1 pg TEQ/g lipid, that of PCDDs/PCDFs/cPCBs was 11.5 pmol/g lipid, that of PCBs was 0.46 nmol/g lipid, and that of total pesticides was 1.32 nmol/g lipid. The serum levels of total TEQ, PCDDs/PCDFs/cPCBs, PCBs and pesticides were positively associated with age (P for trend=0.003, 0.01, 0.005 and 0.01, respectively) and frequent fish consumption (P for trend=0.002, 0.003, 0.0003 and 0.006, respectively). Other lifestyle factors were not associated with serum organochlorine levels. The present study suggests that Japanese women who consume fish frequently in their reproductive period tend to accumulate organochlorines in their bodies.

Canadian Total Diet Study in 1998: pesticide levels in foods from Whitehorse, Yukon, Canada, and corresponding dietary intake estimates

The Canadian Total Diet Study is a national survey to determine the level of chemical contaminants in the Canadian food supply. Food samples were collected from Whitehorse, Yukon, supermarkets as part of the study in 1998. Whitehorse was chosen as a sampling centre, despite its small population (n = 19,000), to determine if residue levels were different in foods available in northern communities relative to levels observed in previous studies in the more populated south. Foods were prepared as for consumption before pesticide residue analysis. Residue levels observed in most foods were similar to levels observed in samples from previous surveys from southern Canadian cities. Malathion and DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene), a transformation product of DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl(ethane), were the two most frequently detected compounds (26.4 and 25.8%, respectively). The majority of pesticides, however, had a detection frequency of < 5%. In general, pesticides in food composites were well below maximum residue limits established in the Canadian Food and Drug Regulations. Chlorpropham and captan had the highest dietary intakes (2.16 and 1.94 micrograms (kg body weight-day)-1, respectively), based on the results from Whitehorse. No dietary intakes above the acceptable daily intakes, however, were observed for any of the 39 pesticides investigated in any age-sex category, where an acceptable daily intake has been proposed.

Effects of bis(2-ethylhexyl) phthalate, γ-hexachlorocyclohexane, and 17β-estradiol on the fry stage of medaka (Oryzias latipes)

The effects of bis(2-ethylhexyl) phthalate (DEHP), γ-hexachlorocyclohexane (γ-HCH), and 17β-estradiol (E2) on the fry stage of medaka were investigated. The medaka fry were exposed to different concentrations (0.01, 0.1, 1, and 10μg/L) of these chemicals for 3 weeks after hatching. Then, mortality, body weight, sex ratio, and gonadosomatic index (GSI) of the matured fish (after 5 months) were measured. Mortality was increased significantly in the 10μg/L E2 group. Distortion of sex ratio was found in 1 and 10μg/L E2 groups. DEHP treated groups showed the GSI reduction only in male fish. All the γ-HCH and parts of the E2 treated groups showed the GSI reduction in both sexes. Exposure of DEHP, γ-HCH, and E2 during the fry stage affected normal maturation of medaka at the concentrations which had no impact on mortality or sex ratio.

Pesticide residues in the Canadian Market Basket Survey--1992 to 1996

Market basket food samples from six Canadian cities collected from 1992 to 1996 were analysed for pesticide residues. One hundred and thirty-six composites were prepared for each city, representing 99% of the Canadian diet. Residues were found most frequently in peanut butter and butter. DDE, malathion and captan occurred most frequently, while the fungicides chlorothalonil, dicloran and captan were present in the highest concentrations. Processed commodities contained fewer residues and at lower concentrations than the raw products. No residues were detected in either milk or soy-based infant formula. Of the infant foods sampled, fruit contained both the greatest number and highest concentrations of pesticides.

Automated sample clean-up and fractionation of chlorpyrifos, chlorpyrifos-methyl and metabolites in mussels using normal-phase liquid chromatography

An automated method based on normal-phase LC has been developed for the sample clean-up of mussel extracts prior to gas chromatographic analysis of residues of chlorpyrifos, chlorpyrifos-methyl and their metabolites chlorpyrifos-methyl-oxon and 3,5,6-trichloro-2-pyridinol. Pesticides were extracted by means of a high speed blender using acetonitrile-acetone (90:10, v/v). The extract obtained was filtered and concentrated using rotavapor and the residue was dissolved in hexane. One ml of the hexanoic extract was injected on the silica-gel column, using hexane as mobile phase. Pesticides and metabolites were eluted in fat-free fractions with different mixtures of hexane-ethyl acetate. Diode array detection allowed monitoring on-line the elution of lipids. Purified extracts were analyzed by GC using nitrogen-phosphorus detection for quantitation and MS for confirmatory purposes. The method is fully automated from the injection of the extract to the collection of fractions, which are directly injected into the GC system. In this way, neither further clean-up nor solvent exchange were necessary prior to GC analysis. Recoveries obtained from fortified mussel samples at two concentration levels-100 and 20 ng g-1 for parent pesticides and 200 and 40 ng g-1 for metabolites-were higher than 90%. Limits of detection of the whole procedure of analysis were lower than 1 ng g-1 for parent pesticides and than 10 ng g-1 for metabolites. This method has been successfully applied to bioconcentration studies with mussels exposed to chlorpyrifos. Chlorpyrifos and its metabolic derivative 3,5,6-trichloro-2-pyridinol were detected and confirmed by MS in analyzed samples.

Organochlorine pesticides and polychlorinated biphenyls in foodstuffs from Asian and oceanic countries

Public concern about the adverse environmental and human health impacts of organochlorine contaminants led to strict regulations on their use in developed nations two decades ago. Nevertheless, DDT and several other organochlorine insecticides are still being used for agriculture and public health programs in developing countries in Asia and the South Pacific. As a consequence, humans in this region are exposed to greater dietary levels of organochlorines. In this review, published information on organochlorine concentrations in foodstuffs from South and Southeast Asia and Oceanic countries has been compiled. Foodstuffs that contribute to human exposures and dietary intakes of organochlorines were examined, and the data compared with those reported from more developed nations. Among various developing countries in Asia, considerable information on organochlorines in foodstuffs has been available from India since the late 1960s. DDT and HCH were the major insecticides in Indian foodstuffs. Concentrations of these insecticides have declined more than two orders of magnitude in farm products, such as food grains and vegetables, in two decades. Milk and milk products are the major sources of dietary exposure to DDT and HCH in India. The residues of these insecticides in dairy products were close to or above the MRLs of the FAO/WHO. Dietary intake of DDT and HCH by Indians was > 100 fold that in more developed nations. Sporadic incidences of greater concentrations (> 1 microgram/g) of aldrin, dieldrin, and heptachlor have been measured in Indian vegetables. Untreated surface waters could be a potential source of DDT and HCH exposure. In most Southeast Asian countries DDT was the common contaminant in animal origin foodstuffs. The higher percentage of p,p'-DDT in meat and fish from Southeast Asian countries, except Japan and Korea, indicated the recent use of DDt in vector control operations. Dietary intakes of DDt and HCH in Southeast Asia were an order of magnitude less than those of Indians but 5- to 10 fold greater than in more developed nations. In addition to DDT, aldrin and dieldrin were prominent in meat collected from Thailand and Malaysia. Aquatic food products from more industrialized countries, such as Japan, South Korea, Hong Kong, and Taiwan, contained significant levels of PCBs. In South Pacific countries, particularly in Australia and New Zealand, chlordanes and PCBs were the most prevalent organochlorines in foodstuffs. Food contamination by DDT, HCH, aldrin, and dieldrin was less than in developing countries in Asia but greater than in the U.S. and Japan. Intake of PCBs in Australia was greater than in the U.S. Meat and fish were the major sources of organochlorine exposure by Australians. Human dietary intake of organochlorines has been declining more slowly in developing countries in Asia. Current intakes were at least 5- to 100 fold greater than those in more developed nations, suggesting a greater risk from organochlorine exposure. Factors such as malnutrition, common among rural poor in developing nations, can increase these risks. Of greatest concern is the magnitude of exposure to organochlorines to which infants and children are subjected through human and dairy milk. The estimated intake of DDT by infants was at least 100 fold greater than the ADI of the FAO/WHO. In addition to DDT, excessive exposures to HCH and dieldrin may cause potential health effects in infants because they are more vulnerable to toxic effects. The design and implementation of appropriate epidemiological studies and their integration with monitoring of human, food, and environmental samples would be a major step in assessing the risks of organochlorine residues in foods and controlling or eliminating them. With the continued globalization of trade in food products, and the concomitant risk that food contaminated through point-source pollution may be widely distributed, identification of sources and their control should be matters of