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DDT, a persistent organic pollutant, remains affecting human health worldwide. DDT and its most persistent metabolite (p,p'-DDE) negatively affect the immune response regulation and mechanisms involved in protecting against pathogens Such metabolite decreases the capability to limit intracellular growth of Mycobacterium microti and yeast. However, the effect on unstimulated (M0) and anti-inflammatory macrophages (M2) has been evaluated scanty. Herein, we evaluated the impact of p,p'-DDE at environmentally relevant concentrations (0.125, 1.25, 2.5, and 5 µg/mL) on bone marrow-derived macrophages stimulated with IFNγ+LPS to M1 or with IL-4 +IL-13 to M2. Thus we study whether the p,p'-DDE induces M0 to a specific phenotype or modulates activation of the macrophage phenotypes and explains, at least partly, the reported effects of p,p'-DDE on the M1 function. The p,p'-DDE did not affect the cell viability of M0 or the macrophage phenotypes. In M1, the p,p'-DDE decreased NO•- production and IL-1β secretion, but increasing cellular ROS and mitochondrial O 2 •-, but did not alter iNOS, TNF-α, MHCII, and CD86 protein expression nor affect M2 markers arginase activity, TGF-β1, and CD206; p,p'-DDE, did not affect marker expression in M0 or M2, supporting that its effects on M1 parameters are not dependent on M0 nor M2 modulation. The decreasing of NO•- production by the p,p'-DDE without altering iNOS levels, Arginase activity, or TNF-α, but increasing cellular ROS and mitochondrial O 2 suggests that p,p'-DDE interferes with the iNOS function but not with its transcription. The p,p'-DDE decreasing of IL-1β secretion, without any effect on TNF-α, suggest that an alteration of specific targets involved in IL-1β secretion may be affected and related to ROS induction. The p,p'-DDE effect on iNOS function and the IL-1β secretion process, as the NLRP3 activation, deserves further study., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Obesity has become a very important public health problem and is increasing globally. Genetics, individual and environmental factors play roles in the etiology of this complex disorder. Recently, several environmental pollutants have been suggested to have obesogenic activities. Peroxisome proliferator activating receptor gamma (PPARγ), uncoupling protein-1 (UCP1) and their expression in white adipose tissue (WAT) and brown adipose tissue (BAT) play key roles in adipogenesis. UCP3 and irisin were reported to play roles in non-shivering thermogenesis. Our primary aim was to investigate obesogenic effects of hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) in rats. In addition, thermoregulatory effects of HCB, DDT and DDE were also investigated by analyzing the levels of Ucp3 and irisin. Thirty-two adult male Sprague-Dawley rats were randomly divided into four groups as control, HCB, DDT and DDE. Animals were administered with organochlorine pesticides (OCPs; 5 mg/kg bw) by oral gavage every other day for five weeks. At the end of the experimental period, the animals were sacrificed, BAT and WAT samples were collected to analyze Pparγ, Ucp1 and Ucp3 levels. Moreover, skeletal muscle samples were collected to examine Ucp3 and irisin levels. Serum glucose, cholesterol and triglyceride levels were also determined. Body weight and core temperature of the animals were not significantly affected by any of the OCP administration. Serum glucose, cholesterol and triglyceride levels were similar among the experimental groups. Pparγ expression was significantly elevated by HCB administration only in WAT (p < 0.05). On the other hand, both Pparγ and Ucp1 expressions were diminished in WAT and BAT (p < 0.01) by DDT treatment, while in WAT, DDE significantly decreased Pparγ expression without altering its expression in BAT (p < 0.001). Ucp3 and irisin levels in skeletal muscle were not altered. Our findings show that both DDT and DDE reduce the browning of WAT by suppressing white adipocytes and thus may have obesogenic activity in male rats without altering thermoregulation. In addition, HCB, DDT and DDE-induced alterations in expression of Pparγ and Ucp1 in WAT implicates differential regulation of adipogenic processes., (Copyright © 2022. Published by Elsevier Inc.)

Background: Children are exposed to p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) through placental and lactational transfer. Some studies have suggested that early-life exposure to these compounds could lead to increased body mass index (BMI) during childhood. Our aim was to assess whether children's exposure during the first 2 years of life is associated with BMI z-score in Japanese children at 42 months of age., Methods: We used data from a birth cohort (n = 290) of the Tohoku Study of Child Development. p,p'-DDT and p,p'-DDE levels were measured in breast milk samples collected 1 month after birth, and levels in children were estimated using a toxicokinetic model for three exposure periods (0-6 months, 6-12 months, 12-24 months). Associations between exposure estimates and BMI z-score at 42 months of age were assessed using multivariate linear regression models., Results: We found no significant association between levels of p,p'-DDT measured in breast milk or estimated in children and BMI z-score. However, we observed associations between estimated p,p'-DDE levels in girls during all postnatal exposure periods and BMI z-score; for each log increase in the estimated p,p'-DDE levels, BMI z-score increased by 0.23 (C.I. 95%: 0.01, 0.45) for the 0-6 months exposure period, 0.26 (C.I. 95%: 0.06, 0.47) for the 6-12 months exposure period, and 0.24 (C.I. 95%: 0.05, 0.43) for the 12-24 months exposure period., Conclusion: In this study of Japanese children, estimated postnatal p,p'-DDE levels were associated with increased BMI z-score at 42 months of age, mostly in girls. These results are in line with previous studies supporting that early-life exposure to p,p'-DDE may be associated with higher BMI during childhood.

The Pine River downstream of the Velsicol Superfund site has been contaminated with various hydrophobic organic pollutants for more than 50 years. Remediation and sediment dredging near the site began in spring of 1999, and was completed in 2006. In 2011, the Michigan Department of Environmental Quality completed a baseline assessment report long-term monitoring plan for the Pine River. However, there has been limited assessment of the benthic community since this evaluation. The objective of this research was to evaluate the risk of Pine River sediment to aquatic macroinvertebrates downstream from the Superfund site after decades of degradation and dredging using the Triad approach. Three sites were selected downstream from the Superfund site, and an upstream reference site was used. At each site, macroinvertebrates surveys were conducted and sediments were collected for chemical analysis of DDT (1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane) and its degradation products and for laboratory toxicity testing for mortality and sublethal effects using Hyalella azteca and Chironomus dilutus. Sediment concentrations of DDT, DDD, and DDE were below levels expected to cause toxicity, and there was no observed toxicity in laboratory tests. Additionally, there were no statistically significant differences in richness, richness of Ephemeroptera, Plecoptera, and Trichoptera (EPT) species, total EPT abundance, percent EPT, or percent dominant taxa between the reference site and the downstream sites. There was an observed decrease in abundance of macroinvertebrate taxa at all downstream sites and a shift in macroinvertebrate structure when comparing the reference with most impaired sites. Although the sites downstream of the Superfund site remain different than the upstream control, there are improvements in species composition and abundance. However, more research is needed to evaluate the potential effects on ecosystem function.

Bioremediation of contaminated soils by a combinational approach using specific bacterial species together with ryegrass is a promising strategy, resulting in potentially highly efficient degradation of organic contaminants. The present study tested the combination of strain DXZ9 of Stenotrophomonas sp. with ryegrass to remove DDT and DDE contaminants from soil under natural conditions in a pot experiment. The strain DXZ9 was successfully colonized in the natural soil, resulting in removal rates of approximately 77% for DDT, 52% for DDE, and 65% for the two pollutants combined after 210 days. Treatment with ryegrass alone resulted in slightly lower removal rates (72 and 48%, respectively, 61% for both combined), while the combination of strain DXZ9 and ryegrass significantly (p < 0.05) improved the removal rates to 81% for DDT and 55% for DDE (69% for both). The half-life of the contaminants was significantly shorter in combined treatment with DXZ9 and ryegrass compared to the control. The remediation was mostly due to degradation of the contaminants, as the net uptake of DDT and DDE by the ryegrass accounted for less than 3% of the total amount in the soil. DDT is reductively dechlorinated to DDD and dehydrochlorinated to DDE in the soil; the metabolites of DDE and DDD were multiple undefined substances. The toxicity of the soil was significantly reduced as a result of the treatment. The present study demonstrates that the bioremediation of soil contaminated with DDT and DDE by means of specific bacteria combined with ryegrass is feasible.

The toxicity of p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), a contaminant and metabolite derivative of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] is partially mediated by reactive oxygen species. Protein cysteine-based regulatory switches and subsequent alterations of the overall hepatic metabolism are triggered by p,p'-DDE through the disruption of the cellular redox status. The consequences are reproductive impairment, metabolic disorders, diabetes, neurotoxicity and cancer. In recent years, the risk of p,p'-DDE exposure has increased worldwide, reflecting the rise of mosquito-borne diseases in tropical countries that produce and export contaminated foods. Selenium (Se) is an essential trace element in animal nutrition with antioxidant properties that protects against the toxicity of some xenobiotics. We analyzed the ability of diet Se-supplementation to prevent damages induced by p,p'-DDE in the liver of M. spretus mice, by using redox proteomics based on the determination of the redox status of protein Cys residues. Se selectively acted on specific target, restoring the redox status and functionality of some membrane proteins involved in mitochondrial functionality, protein transport, cell signaling and protein metabolism. However, the Se-enriched diet did not completely prevent the metabolic shift caused by p,p'-DDE exposure that leads to disturbed lipogenesis, hepatic steatosis and alterations in the synthesis of hormones and other cell signals., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: The prevalence of obesity is increasing in all countries, becoming a substantial public health concern worldwide. Increasing evidence has associated obesity with persistent pollutants such as the pesticide DDT and its metabolite p,p '-DDE., Objectives: Our objective was to systematically review the literature on the association between exposure to the pesticide DDT and its metabolites and obesity to develop hazard identification conclusions., Methods: We applied a systematic review-based strategy to identify and integrate evidence from epidemiological, in vivo , and in vitro studies. The evidence from prospective epidemiological studies was quantitatively synthesized by meta-analysis. We rated the body of evidence and integrated the streams of evidence to systematically develop hazard identification conclusions., Results: We identified seven epidemiological studies reporting prospective associations between exposure to p,p' -DDE and adiposity assessed by body mass index (BMI) z -score. The results from the meta-analysis revealed positive associations between exposure to p,p' -DDE and BMI z -score (β=0.13 BMI z -score (95% CI: 0.01, 0.25) per log increase of p,p' -DDE). Two studies constituted the primary in vivo evidence. Both studies reported positive associations between exposure to p,p' -DDT and increased adiposity in rodents. We identified 19 in vivo studies and 7 in vitro studies that supported the biological plausibility of the obesogenic effects of p,p' -DDT and p,p' -DDE., Conclusions: We classified p,p' -DDT and p,p' -DDE as "presumed" to be obesogenic for humans, based on a moderate level of primary human evidence, a moderate level of primary in vivo evidence, and a moderate level of supporting evidence from in vivo and in vitro studies. https://doi.org/10.1289/EHP527.

Objectives: Since the metabolism of the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT) is not fully known in humans, we evaluated if circulating levels of a major breakdown product of DDT, p,p'-DDE, were related to genome-wide genetic and methylation variation in a population-based sample., Methods: In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (1016 subjects all aged 70), circulating levels of p,p'-DDE were analyzed by high-resolution chromatography coupled to high-resolution mass spectrometry (HRGC/HRMS). Genetic variants were genotyped and imputed (1000 Genomes reference, March 2012 release). Methylation sites were assayed using the Illumina HumanMethylation450 array in whole blood. A genome-wide association study (GWAS) approach was applied., Results: Evidence for genome-wide significant association with p,p'-DDE levels was observed only for a locus at chromosome 19 corresponding to the CYP2B6 gene (lead SNP rs7260538). Subjects being homozygote for the G allele showed a median level of 472ng/g lipid, while the corresponding level for those being homozygote for the T allele was 192ng/g lipid (p=1.5×10 -31 ). An analysis conditioned on the lead SNP disclosed a distinct signal in the same gene (rs7255374, position chr19:41520351; p=2.2×10 -8 ). A whole-genome methylation analysis showed one significant relationship vs. p,p'-DDE levels (p=6.2×10 -9 ) located 7kb downstream the CYP2B6 gene (cg27089200, position chr19:41531976). This CpG-site was also related to the lead SNP (p=3.8×10 -35 ), but mediated only 4% of the effect of the lead SNP on p,p'-DDE levels., Conclusion: Circulating levels of p,p'-DDE were related to genetic variation in the CYP2B6 gene in the general elderly population. DNA methylation in this gene is not closely linked to the p,p'-DDE levels., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The use of 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT) in agriculture in the United States and Canada was prohibited in the early 1970s; however, it continued to be used restrictively in Mexico until 2000. Forty years later, 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p'-DDE), continues to be detected in eggs and bird carcasses in North America. The use of DDE has been associated with reproductive failure of several avian species, primarily through eggshell thinning. To assess the temporal and latitudinal distribution of p,p'-DDE in North America, the authors examined DDE concentrations reported in bird tissues in the scientific literature published between 1980 and 2009. Overall, the majority of supported models suggested that DDE concentrations in birds were greater in the upper mid-latitudes (38°-48°) than in other parts of North America. However, spatial trends of DDE seemed to be influenced by regions with large amounts of data, such as the Great Lakes area. Concentrations of p,p'-DDE in eggs averaged 2.5 μg/g, 3.2 μg/g, and 29.5 μg/g wet weight in 1980 and decreased to 1.64 μg/g, 0.87 μg/g, and 1.01 μg/g wet weight by the mid-2000s for the central, eastern, and western North America regions, respectively. The results indicate that, over time, all DDE residues observed in birds have decreased significantly in North America. Environ Toxicol Chem 2016;35:1340-1348. © 2016 SETAC., (© 2016 SETAC.)

Long-beaked common dolphins (Delphinus capensis) in the Gulf of California have been exposed to persistent contaminants that originated in large agricultural areas near the coast. Live common dolphins were sampled by remote dart biopsies to determine concentrations of tDDT in blubber. Life stage and initial gender identification was determined by field observations. Gender was confirmed by genetic analysis of the skin. Concentration of tDDT in blubber was analyzed by gas chromatography. The 16 samples collected consisted of: 2 adult males, 6 adult females, and 8 juveniles. 4,4'-DDE was detected in most of the samples with 4,4'-DDD and 4,4'-DDT under detection levels. Concentrations of DDE varied from non-detectable to 87.3 µg/g lipid weight with a median of 16 µg/g lipid weight. The highest concentration was detected in an immature female. No differences were detected between gender or life stage but this could be attributed to small sample size. We recommend continued sampling of D. capensis blubber biopsies from the Gulf of California in order to relate these levels with affected in vitro biomarkers such as mixed function oxidase activity.

Organochlorine pesticides have been used in Mexico in malaria control programs and against ectoparasites. The objective of this study was to compare the levels of organochlorine pesticides: HCB, α-β-γ-HCH, pp'-DDE, op'-DDT and pp'-DDT in adipose tissue of female inhabitants from three Mexican states: Veracruz, Puebla and Tabasco. Data analyses indicated higher β-HCH levels in Puebla inhabitants. When comparing the mean values of the pp'-DDE concentrations among the three states, no statistically significant differences were noted. A trend of increasing concentrations of op'-DDT from Veracruz to Puebla and Tabasco was observed. Significantly higher pp'-DDT concentrations in Veracruz as compared to Puebla and Tabasco were determined. Using factorial analysis of three age categories (>30, 31-50, <51) organochlorine pesticide concentrations increases with age of participants, indicating time of exposure as a principal factor of organochlorine pesticides accumulation in adipose tissue.

In a recent study, our group demonstrated that when peripheral blood mononuclear cells (PBMCs) were treated "in vitro" with p,p'-DDE, a DDT metabolite, an antioxidant response and biomarkers of inflammation were induced at the mRNA level, indicating a proinflammatory state. Thus, the aim of this study was to evaluate the induction of proinflammatory molecules at the protein level in PBMCs exposed to p,p'-DDE "in vitro". The main finding was that "in vitro" exposure to p,p'-DDE enhanced the expression of proinflammatory cytokines (TNF-α, IL-1β, IL-6) at the protein level in PBMCs. We also observed COX-2 induction at the protein level. Considering that p,p'-DDE has been identified as a persistent metabolite and is frequently found in the population, it is important to evaluate early inflammation biomarkers in populations exposed to DDT and to estimate the true risk of inflammatory disease development., (Copyright © 2012 Elsevier GmbH. All rights reserved.)

Resonance attachment of low-energy electrons to xenobiotic molecules, 2,4-dichlorophenoxyacetic acid (2,4-D), dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE), was investigated under gas-phase conditions by means of complementary experimental techniques. Electron transmission spectroscopy (ETS) and dissociative electron attachment spectroscopy (DEAS), in the 0-6 eV and 0-15 eV energy range, respectively, were applied with the aim of modeling the behavior of these pesticide molecules under reductive conditions in vivo. Formation of long-lived parent molecular anions and fragment negative ions was observed at incident electron energies very close to zero, in agreement with the results of density functional theory calculations. The gas-phase DEA process, analogous to dissociative electron transfer in solution, was considered as a model for the initial step which occurs in the intermembrane space of mitochondria when a xenobiotic molecule captures an electron "leaked" from the respiratory chain. A possible involvement of the fragments produced by DEA to the pesticides under investigation into cellular processes is discussed. It is concluded that the free radicals and potential DNA adducts formed by DEA are expected to be dangerous for mitochondrial functionalities, while several of the products observed could act as messenger molecules, thus interfering with the normal cellular signaling pathways.

3-Methylsulfonyl-DDE (MeSO₂-DDE) is a potent adrenal toxicant formed from the persistent insecticide DDT. MeSO₂-DDE is widely present in human plasma, milk and fat, and in tissues of marine mammals. In the present study, we investigated endocrine-disrupting properties of MeSO₂-DDE in primary neonatal porcine Leydig cells. Unstimulated and LH-stimulated cells were exposed to MeSO₂-DDE at concentrations ranging from 0.6 to 20 μM for 48 h. Cell viability, hormone secretion and expression of steroidogenesis related genes were recorded. Secretion of testosterone and estradiol was increased in a concentration-dependent fashion in unstimulated Leydig cells, while in LH-stimulated cells, secretion of testosterone, estradiol and progesterone was decreased. The expression of important steroidogenic genes was down-regulated both in unstimulated and LH-stimulated cells. Notably, no significant impairment of cell viability occurred at any exposure except the highest concentration (20 μM) in LH-stimulated cells. This indicated that the effects on hormone secretion and gene expression were not caused by cytotoxicity. We conclude that the adrenal toxicant MeSO₂-DDE disrupts hormone secretion in a complex fashion in neonatal porcine Leydig cells. The different endocrine responses in unstimulated and LH-stimulated cells imply that the endocrine disruptive activity of MeSO₂-DDE is determined by the physiological status of the Leydig cells., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Cucurbita pepo ssp pepo (zucchini) accumulates significant levels of persistent organic pollutants in its roots, followed by unexpectedly high contaminant translocation to the stems. Most other plant species, including the closely related C. pepo ssp ovifera (squash), do not have this ability. To investigate the mechanism of contaminant accumulation, two cultivars each of parental zucchini and squash, as well as previously created first filial (F1) hybrids and F1 backcrosses (BC) of those parental cultivars, were grown under field conditions in a soil contaminated with weathered chlordane (2.29 microg/g) and DDX residues (0.30 microg/g; sum of DDT, DDE, DDD). The parental zucchini had stem-to-soil bioconcentration factors (BCF, contaminant ratio of stem to soil) for chlordane and DDX of 6.23 and 3.10; these values were 2.2 and 3.7 times greater than the squash, respectively. Chlordane and DDX translocation factors, the ratio of contaminant content in the stems to that in the root, were 2.1 and 3.2 times greater for zucchini than for squash. The parental zucchini and squash also differed significantly in chlordane component ratios (relative amounts of trans-nonachlor [TN], cis-chlordane [CC], trans-chlordane [TC]) and enantiomer fractions for the chiral CC and TC. Hybridization of the parental squash and zucchini resulted in significant differences in contaminant uptake. For both the three separate component ratios (CR) and two sets of enantiomer fraction (EF) values, subspecies specific differences in the parental generation became statistically equivalent in the F1 hybrid zucchini and squash. When backcrossed (BC) with the original parental plants, the zucchini and squash F1 BC cultivars reverted to the statistically distinct CR and EF patterns. This pattern of trait segregation upon hybridization suggests either single gene or single locus control for persistent organic pollutant (POP) uptake ability by C. pepo ssp pepo.

The purpose of this study was to investigate the effect of 1,1,1-trichloro-2,2-bis-(chlorophenyl)ethane (DDT), 1,1-bis-(chlorophenyl)-2,2-dichloroethene (DDE), and 1,1-dichloro-2,2-bis(chlorophenyl)ethane (DDD) isomers on COX-2 expression in a human trophoblast-derived cell line. Cultured HTR-8/SVneo trophoblast cells were exposed to DDT isomers and its metabolites for 24 h, and COX-2 mRNA and protein expression were assessed by RT-PCR, Western blotting, and ELISA. Prostaglandin E₂ production was also measured by ELISA. Both COX-2 mRNA and protein were detected under control (unexposed) conditions in the HTR-8/SVneo cell line. COX-2 protein expression and prostaglandin E₂ production but not COX-2 mRNA levels increased only after DDE and DDD isomers exposure. It is concluded that DDE and DDD exposure induce the expression of COX-2 protein, leading to increased prostaglandin E2 production. Interestingly, the regulation of COX-2 by these organochlorines pesticides appears to be at the translational level., (© 2012 Wiley Periodicals, Inc.)

Orchard soils can contain elevated concentrations of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE), 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT), and heavy metals as a result of historical agrichemical applications. The bioavailability of p,p'-DDE, p,p'-DDT, As, Cd, Cu, and Pb from five field-aged New Zealand orchards and three grazing soils was assessed by using a 28-d bioassay with Aporrectodea caliginosa and chemical assays. Significant relationships were found between total soil and earthworm tissue concentrations for p,p'-DDE (p < 0.001), p,p'-DDT (p < 0.001), Cu (p < 0.001), and Pb (p < 0.01). Two neutral salt solutions, 0.01 M CaCl(2) and 1 M NH(4)NO(3), were used as surrogate measures of the bioavailability of heavy metals. Copper was the only heavy metal for which significant correlations were found between neutral-salt-extractable and earthworm tissue concentrations (p < 0.001). Up to 28% of the aged DDT residues were released from the soils by Tenax over a 24-h extraction period. Significant relationships (p < 0.01) between the Tenax-extractable and earthworm tissue concentrations for p,p'-DDE and p,p'-DDT showed that Tenax provides a good surrogate measure of the bioavailability of these compounds to A. caliginosa. Surprisingly, there was a similarly significant relationship (p < 0.001) between the total soil and earthworm tissue concentrations for p,p'-DDE and p,p'-DDT, suggesting that total soil concentrations alone were sufficient to predict uptake by A. caliginosa. These results demonstrate that the aged agrichemical residues in orchard soils, and particularly p,p'-DDE and p,p'-DDT, remain highly bioavailable to A. caliginosa despite decades of weathering and continue to present an environmental risk., (Copyright © 2012 SETAC.)

1,1-Dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p'-DDE) is the major metabolite of insecticide 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (p,p'-DDT) and a persistent organic pollutant (POPs) with concerns regarding its bioaccumulation and persistence in the environment and food chain. In the present study, an indirect competitive enzyme-linked immunosorbant assay (ic-ELISA) specific for the detection of p,p'-DDE is described. In hapten synthesis, 2,2'-bis(4-chlorophenyl)ethanol and glutaric anhydride were used as precursor and spacer arm, respectively. The hapten was then conjugated to bovine serum albumin (BSA) as immunogen for mouse immunization and also conjugated to ovalbumin as coating antigen for ELISA. The developed ic-ELISA was used for detecting p,p'-DDE in human milk samples and validated against the results from conventional gas chromatography-electron capture detection (GC-ECD). Coefficients of variation (%CV) of ELISA were 5.7-10.4% for intra-assay and 10.6-19.6% for interassay variations. The Pearson correlation coefficient of p,p'-DDE concentrations between ic-ELISA and GC-ECD was r = 0.766, which was in an acceptable range. The results indicate that the developed assay could be an alternative analytical tool for monitoring p,p'-DDE in lipimic matrices such as human milk.

Background: Computer-based modeling is part of a new approach to predictive toxicology., Objectives: We investigated the usefulness of an integrated computational systems biology approach in a case study involving the isomers and metabolites of the pesticide dichlorodiphenyltrichloroethane (DDT) to ascertain their possible links to relevant adverse effects., Methods: We extracted chemical-protein association networks for each DDT isomer and its metabolites using ChemProt, a disease chemical biology database that includes both binding and gene expression data, and we explored protein-protein interactions using a human interactome network. To identify associated dysfunctions and diseases, we integrated protein-disease annotations into the protein complexes using the Online Mendelian Inheritance in Man database and the Comparative Toxicogenomics Database., Results: We found 175 human proteins linked to p,p'-DDT, and 187 to o,p'-DDT.Dichlorodiphenyldichloroethylene (p,p'-DDE) was the metabolite with the highest number of links, with 52. We grouped proteins for each compound based on their disease annotations. Although the two data sources differed in linkage to diseases, integrated results predicted that most diseases were linked to the two DDT isomers. Asthma was uniquely linked with p,p'-DDT, and autism with o,p'-DDT. Several reproductive and neurobehavioral outcomes and cancer types were linked to all three compounds., Conclusions: Computer-based modeling relies on available information. Although differences in linkages to proteins may be due to incomplete data, our results appear meaningful and suggest that the parent DDT compounds may be responsible for more disease connections than the metabolites. The findings illustrate the potential use of computational approaches to toxicology.

Ionic liquids are a kind of environmentally friendly solvents which have drawn great attention in many fields. The potential of ionic liquid as dispersive liquidphase microextraction (DLPME) solvent for the enrichment of typical persistent organic pollutants, dichlorodiphenyltrichloroethane (DDT), and its metabolites including 1,1-dichloro-2,2-bis-(4'-chlorophenyl)ethane and 1,1-dichloro-2,2-bis-(4'-chlorophenyl)ethylene has been investigated. Parameters that may influence the extraction efficiency, such as the type and volume of ionic liquid, the type and volume of disperser solvent, extraction time, and sample pH, were investigated and optimized in detail. The experimental results showed the excellent linear relationship between peak area and the concentration of DDT and its metabolites over the range of 1-50 μg L⁻¹, and the precisions (RSDs) were 5.27-6.73% under the optimal conditions. The limits of detection could reach 0.33-0.63 μg L⁻¹. Satisfied results were achieved when the proposed method was applied to determine the target compounds in real-world water samples with spiked recoveries over the range 94.4-115.3%. All these facts indicated that ionic liquid DLPME coupled to HPLC was an environmentally friendly alternative for the rapid analysis of DDT and its metabolites at trace level in environmental water samples.

The DDT metabolite 3-methylsulfonyl-DDE (3-MeSO(2)-DDE) has been proposed as a lead compound for an improved adrenocortical carcinoma (ACC) treatment. ACC is a rare malignant disorder with poor prognosis, and the current pharmacological therapy o,p'-DDD (mitotane) has limited efficacy and causes severe adverse effects. 3-MeSO(2)-DDE is bioactivated by cytochrome P450 (CYP) 11B1 in mice and causes formation of irreversibly bound protein adducts, reduced glucocorticoid secretion, and cell death in the adrenal cortex of several animal species. The present study was carried out to assess similarities and differences between mice and humans concerning the adrenocorticolytic effects of 3-MeSO(2)-DDE. The results support previous indications that humans are sensitive to the adrenocorticolytic actions of 3-MeSO(2)-DDE by demonstrating protein adduct formation and cytotoxicity in the human adrenocortical cell line H295R. However, neither the irreversible binding nor the cytotoxicity of 3-MeSO(2)-DDE in H295R cells was inhibited by the CYP11B1 inhibitor etomidate. We also report biphasic responses to 3-MeSO(2)-DDE in cortisol and aldosterone secretion as well as in mRNA levels of the steroidogenic genes StAR, CYP11B1 and CYP11B2. Hormone levels and mRNA levels were increased at lower concentrations of 3-MeSO(2)-DDE, while higher concentrations decreased hormone levels. These biphasic responses were not observed with o,p'-DDD or with the precursor DDT metabolite p,p'-DDE. Based on these results, 3-MeSO(2)-DDE remains a viable lead compound for drug design, although the adrenocorticolytic effects of 3-MeSO(2)-DDE in human cells seem more complex than in murine cells., (Copyright 2009 Elsevier Inc. All rights reserved.)

The concentrations of the heavy metals lead (Pb) and cadmium (Cd) were determined in berries (blackberry, raspberry, bilberry, wild strawberry), and hazelnuts picked from plants in the wild as well as in fruit (blackberry, raspberry, blueberry) and hazelnuts picked from orchard-farmed plants in northeastern Poland. The levels of seven congeners of polychlorinated biphenyls (PCB(7)), gamma isomer of hexachlorocyclohexane (gamma-HCH), and sum of dichlorodiphenyl trichloroethane and its metabolites (SigmaDDT) were also measured in plants and nuts. In addition, the concentrations of Pb, Cd, PCB(7,) gamma-HCH, and SigmaDDT were determined in the surface samples of soil from the sites of fruit picking. The highest acceptable concentrations based upon Polish standards for Pb and Cd were not exceeded in forest fruit. In wild berries, Pb occurred at a level below the detection limit, whereas the concentration of Cd ranged from 6 to 49 microg/kg fresh weight. The levels were Cd 72 microg/kg fresh weight and Pb 290 microg/kg fresh weight in raspberries from orchard plants and exceeded the maximal acceptable limit of 50 microg/kg for Cd and 200 microg/kg for Pb. The level of Pb at 210 microg/kg fresh weight in hazelnuts from orchard plants also exceeded maximal acceptable limits. Individual samples of fruit, regardless of their origin, were found to contain trace amounts of organic pollutants such as 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (p,p'-DDE) and PCB congeners 101 and 118. All soil samples contained from 3.2 to 14.9 mg/kg dry weight concentrations of Pb and most soil samples also contained Cd. Further, individual soil samples were found to contain high levels of SigmaDDT (145 microg/kg), including p,p'-DDT at a concentration of 67 microg/kg. The concentrations of persistent organic pollutants (POP) in wild and orchard-farm-grown fruit in northeastern Poland were generally below threshold permissible limits, and no correlation was found between levels of contaminants in soils and POP concentrations in fruit.

Breast milk is considered the most important route in the elimination of deposited organochlorine pesticides in a mother’s body. The equilibrium of organochlorine pesticides in the human body considers the elements of internal transport processes, the equilibrium pattern between pesticides and tissue fat contents, and the mobilization of lipids and lipoproteins among body parts. The aim of this study was to determine organochlorine pesticide levels in breast milk samples from the 4th to the 30th day of lactation and the trend in their concentration time so as to forecast the time tendency of residue levels and the pesticide excretion pattern. Milk samples were taken from forty participants and analyzed by GLC-ECD. The organochlorine pesticide residues determined in the breast milk samples during lactation decreased: β-HCH from 0.095 to 0.066 mg/kg, pp′DDE from 1.807 to 1.423 mg/kg and pp′DDT from 0.528 to 0.405 mg/kg, at the characteristic rate for each compound. The obtained results compared with the calculated fits of forecasts were parallel and did not exhibit significant differences. The newborn baby exposed during lactation had organochlorine pesticide residues whose levels decreased permanently. The levels depended not only on the breast milk nutrition, but also on the total environmental exposures which included air pollution as a significant contamination source.

Dichlorodiphenyltrichloroethane (DDT) and its main metabolites, p,p'-DDD and p,p'-DDE (DDTs in this study included DDT, DDD and DDE), are frequently detected in agricultural soils even though its usage in agriculture was banned in 1980s or earlier. In this study, eleven plants including eight maize (Zea mays) cultivars and three forage species (alfalfa, ryegrass and teosinte) widely cultivated in China were grown in the soils spiked with DDTs to investigate their potential for removal of DDT from the contaminated soils. The plants varied largely in their ability to accumulate and translocate DDTs, with the bioconcentration factor (BCF; DDT concentration ratio of the plant tissues to the soils) ranging from 0.014 to 0.25 and the translocation factor (TF; DDT concentration ratio of the shoots to the roots) varying from 0.35 (Zea mays cv Chaotian-23) to 0.76 (Zea mays spp. mexicana). The amount of DDT phytoextraction ranged from 3.89mug (ryegrass) to 27.0mug (teosinte) and accounted for <0.1% of the total initial DDTs spiked in the soils. After 70d, the removal rates reached 47.1-70.3% of the total initial DDTs spiked in the soils with plants while that was only 15.4% in the soils without plant. Moreover, the higher removal rates of DDTs occurred at the first 20d of experiment, and then the removal rate decreased with time. The highest amount of DDTs phytoextracted was observed in teosinte, followed by Zea mays spp. mexicana, but the highest removal rate of DDTs was found in maize (Zea mays cv Jinhai-6). Even though phytoextraction is not the main removal process for DDTs, the plant species especially Zea mays cv Jinhai-6 showed high potential for removing DDTs from the contaminated soils.

This is the first study to evaluate the potential genotoxicity of p,p'-DDT (1,1,1-trichloro-2,2-bis-(chlorophenyl)ethane) and its metabolites (p,p'-DDD and p,p'-DDE) in the sentinel mollusc Zebra mussel (Dreissena polymorpha). DNA damage was measured using the single cell gel electrophoresis (SCGE) assay and the micronucleus test (MN test), which represent two of the more sensitive biomarkers for genotoxicity evaluation. Three different concentrations (0.1, 2, and 10 mug/L) of each compound were administered in water for 168 hr, maintaining mussels at constant laboratory conditions and collecting several specimens every 48 hr for biochemical analyses. At the same time, the bioaccumulation process and the concentration/effect relationship were checked by GC-MS/MS analyses of mussel soft tissues. The SCGE assay results showed a clear and significant (P < 0.05) relationship between DNA injuries and tested doses for all the homologues throughout the 7-day exposure period. The final DNA damage due to p,p'-DDE was almost double that of the other two homologues that showed the same toxicity pattern. The micronucleus frequency analysis confirmed the genotoxicity potential of the three homologues and p,p'-DDE showed the highest irreversible DNA damage. The capability of Zebra mussels to biotransform the administered compound in the other homologues was demonstrated by multiple regression analyses carried out between the MN frequencies and the concentrations of the different homologues in the mussel soft tissues. A greater genotoxic potential of the p,p'-DDE with respect to the other two chemicals was revealed., ((c) 2008 Wiley-Liss, Inc.)

We evaluated impact of DDT isomers, o, p'- DDT [1, 1-dichloro-2, 2-bis (p, p'-chlorophenyl) ethylene] and p, p'-DDT [1, 1, 1-trichloro-2, 2-bis (p-chlorophenyl) ethane], and their metabolites, o, p'-DDE and p, p'-DDE, on ovarian steroidogenesis. All these compounds, except for p, p'-DDT, demonstrated estrogenic effects on steroid secretion in co-cultures of porcine prepubertal granulosa and theca cells. p,p'-DDT decreased progesterone and estradiol release, which was reversed by the addition of testosterone. In contrast, o, p'-DDT inhibited progesterone secretion with parallel stimulation of basal and testosterone-stimulated estradiol release. DDEs stimulated progesterone and estradiol secretion. The fluorometric assay confirmed that p,p'-DDE, o,p'-DDT, and o,p'-DDE stimulated aromatase activity. Western blots indicated that o,p-DDT and o,p'-DDE diminished the expression of estrogen receptor beta (ERbeta). This study demonstrated the isomer-dependent action of DDT in pig ovarian cells. We propose that DDT could disrupt ovarian steroidogenesis either by interfering with main steroidogenic enzymes or affecting ERbeta.

Dynamics of DDMS and DDMU in soils with DDT application under rice and ryegrass planting by pot experiment in greenhouse was conducted. Results show that DDE/DDD is slightly increased, and only about 20 ng x g(-1) DDMU or DDMS could be found in ryegrass soil at the end of the experiment. However, the DDD, DDMS and DDMU are formed very rapidly in rice soil. By the 84th day of the experiment of rice planting, DDT residue is 70-80 ng x g(-1), about 2% of the concentration added at the first of the experiment, meanwhile, concentrations of DDD, DDMS and DDMU are increased to the highest level. Concentration of DDMS and DDMU is detected at 28 and 115 ng x g(-1) respectively. On the other hand, above phenomena are not observed in the aged DDT of soils, which implies that submerging could increase degradation of DDT added newly to DDD and DDMS/DDMU, but not for the aged DDT of soils.

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.

The benefits of nondestructive sampling techniques, such as plasma sampling, to directly measure contaminant exposure levels in at-risk or protected raptor populations are many. However, such assays are generally inconsistent with the most certain source of toxicity reference values, which are based on feeding studies and quantified as dietary or "in ovo" (egg-based) concentrations. An accurate conversion factor to translate nondestructive plasma-based contaminant concentrations to comparable egg-based concentrations will prove valuable to risk assessors investigating the potential effects of chemical exposures to raptors. We used databases describing the concentrations of total polychlorinated biphenyls (PCBs) in great horned owls (GHO; Bubo virginianus) and total PCBs and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) in bald eagles (Haliaeetus leucocephalus) from the Great Lakes region (Michigan, Wisconsin, USA) to develop a relationship to predict concentrations of PCBs and DDE in eggs. To develop a robust predictive relationship, all of the source data included concentrations of both total PCBs and/or DDE for nestling blood plasma and egg samples collected from within discrete active nesting territories and, in most instances, the same nest. The key characteristics (slope and elevation) of each relationship were tested for differences related to species and geographic region. Predicted variability of relationships were examined and compared to variability associated with natural systems. The results of statistical testing indicate that applying the conversion factors between species (GHO to bald eagle) and among geographic regions yields predicted egg concentrations that are not statistically dissimilar and are within the natural variability observed for residue concentrations among eggs of raptors within species and region.

Persistent organochlorine pesticides, such as dichlorodiphenyltrichloroethane (DDT), are lipophilic environmental pollutants which accumulate in the food chain. These chemicals have long half-lives and can be detected in human milk, serum, and some other tissues. These chemicals have recently been under scrutiny for their possible health hazards such as cancer and reproductive outcomes including low birth weight. The aim of our study was to investigate whether mothers with a higher contamination of pesticides were different from mothers with low contamination in relation to their offspring's birth outcomes such as birth weight, small for gestation age, prematurity, head circumference, sex ratio, and previous miscarriage or still birth. We used data collected as part of a cross-sectional study of organochlorines in breast milk. This study did not show any association between low birth weight or small for gestation age and organochlorine contamination when comparing the higher to the low exposure group. Weak, significant correlations (-0.1) were detected between low birth weight and contamination levels of dichlorodiphenyldichloroethylene (DDE) only in female offspring. There was a decrease in the percentage of female offspring for all chemicals in the high-contamination group. The baby's head circumference increased as the mother's contamination increased but the adjusted difference in means was not significant. We did not see any association between either miscarriage or stillbirth in the mother's previous pregnancies or prematurity of the first live (recent) baby when comparing the higher to the low exposure mothers. The organochlorines DDT and DDE were not found to be associated with adverse birth outcomes in contaminated mothers in the range of contamination of our population (<7.5 mg/kg lipid in maternal milk), although there is weak evidence that sex ratio may be affected.

Background, Aims and Scope: Although pp'DDT usage was strongly limited or banned in most parts of the world during the last three or four decades, the parent compound, its homologues and their metabolites still occur at levels which might pose a risk for many ecosystem components. A case of DDT pollution of industrial origin was discovered in 1996 in Lake Maggiore, the second largest (212 km2) and deepest (370 m) lake in Italy, causing concern for wildlife and human health. The extensive monitoring of many biotic and abiotic compartments which followed from 1998 in order to assess the pollution level and its trend in time, provided a great availability of data referring to DDT contamination of the different fish species of the lake. In this study, the recent contamination levels in selected fish species were compared to those measured in 1998 to evaluate the temporal pollution trend of the lake and its natural recovery, given that no remediation measures were carried out on the contaminated soils and sediments in this time span. Moreover, a modelling approach to test the equilibrium condition between water and pelagic fish species was used. Analytical results of pp'DDT and pp'DDE concentrations in lake water were used as input data in the bioenergetic model by Connolly & Pedersen (1988) to calculate concentrations in two fish species and to compare the predicted and the measured contamination., Methods: Sampling and analytical determination of DDT homologues in lake water: Five water sampling campaigns were carried out from May 2002 to February 2004 in three sampling sites of Lake Maggiore. Suspended and dissolved pollutants were determined separately. Quantitative DDT homologue analyses were performed by HRGC coupled with ECD detection by the external standard method. Single water extracts were put together in correspondence with the stratification zones of the water column inferred on the basis of the temperature profile to improve analytical sensitivity. Selection of fish data: Concentrations of DDT and DDE in fishes were selected from recent literature (CIPAIS 2003, 2004). Bioaccumulation model: The bioenergetic model proposed by Connolly & Pedersen (1988) was used to assess the bioaccumulation of pp'DDT and pp'DDE of Alosa fallax (landlocked shad) and Coregonus spp. (whitefish), selected among the different species as representative of a secondary consumer level., Results and Discussion: The average concentrations of pp'DDT and pp'DDE in water to be used as input data in the bioenergetic model were obtained considering all the concentrations measured at the three sampling stations in the epylimnion where the fish species considered in this study spend most of their life. The resulting values were 0.05 and 0.16 ng/L for pp'DDT and pp'DDE, respectively. Average measured pp'DDT and pp'DDE concentrations in landlocked shad were 0.81 +/- 0.39 and 1.69 +/- 0.71 mg/kg lipids, respectively, and were 0.29 +/- 0.12 and 1.06 +/- 0.41 mg/kg lipids for the whitefish. Calculated and measured values turned out to be in quite good agreement for pp'DDT, while measured pp'DDE concentrations were higher than expected on the basis of the bioenergetic model in both species. Probably metabolic transformations of pp'DDT accumulated in fish tissues in the past are responsible for the observed differences between calculated and expected pp'DDE concentrations in fish., Conclusions: Pelagic fishes of Lake Maggiore seem to maintain the DDT accumulated during their life time and the most efficient mechanism responsible for the fish population recoveries is probably their generation changes; for this reason, equilibrium models cannot be used until negligible pp'DDT concentrations are reached in fish tissues., Recommendations and Outlook: The limit proposed for pp'DDT in water by the EU Directive 2000/60, which will come in force in 2008, is 0.2 ng/L, four times higher than the average concentration measured in Lake Maggiore waters. Nevertheless, concentrations measured in Lake Maggiore fish were very close and sometimes exceeded the Maximum residue limits (MRLs) settled by the Italian legislation for foods (0.1 mg/kg w.w. for fish containing 5-20% lipid). It seems, therefore, that the 'environmental quality standard' of 0.2 ng/L cannot guarantee the suitability of fish for human consumption.

Several studies have evaluated cancer risk associated with occupational and environmental exposure to dichlorodiphenyltrichloroethane (DDT). Results are mixed. To further inquire into human carcinogenicity of DDT, we conducted a mortality follow-up study of 4,552 male workers, exposed to DDT during antimalarial operations in Sardinia, Italy, conducted in 1946 to 1950. Detailed information on DDT use during the operations provided the opportunity to develop individual estimates of average and cumulative exposure. Mortality of the cohort was first compared with that of the Sardinian population. Overall mortality in the cohort was about as expected, but there was a deficit for death from cardiovascular disease and a slight excess for nonmalignant respiratory diseases and lymphatic cancer among the unexposed subcohort. For internal comparisons, we used Poisson regression analysis to calculate relative risks of selected malignant and nonmalignant diseases with the unexposed subcohort as the reference. Cancer mortality was decreased among DDT-exposed workers, mainly due to a reduction in lung cancer deaths. Birth outside from the study area was a strong predictor of mortality from leukemia. Mortality from stomach cancer increased up to 2-fold in the highest quartile of cumulative exposure (relative risk, 2.0; 95% confidence interval, 0.9-4.4), but no exposure-response trend was observed. Risks of liver cancer, pancreatic cancer, and leukemia were not elevated among DDT-exposed workers. No effect of latency on risk estimates was observed over the 45 years of follow-up and within selected time windows. Adjusting risks by possible exposure to chlordane in the second part of the antimalarial operations did not change the results. In conclusion, we found little evidence for a link between occupational exposure to DDT and mortality from any of the cancers previously suggested to be associated.

The objective of the present study is to determine the levels of contamination by PCBs, DDT and its metabolites in dolphins failed on the coasts of the Mediterranean sea. Samples are represented by six Stenella coeruleoalba and a Tursiops truncatus collected in 2000 and 2003. The studies are achieved on the blubber, the heart, the liver, the kidney, the muscle and the lung. The concentrations of PCBs and DDT are very high in all tissues and organs analyzed. For the PCBs, the concentrations vary between 43,838 and 110,343 microg/kg lipid basis in the blubber, 601 and 39444 microg/kg dried weight in the liver, 1375 and 34512 microg/kg dried weight in the muscle, 3151 and 17082 microg/kg dried weight in the heart, 674 and 12365 microg/kg dried weight in the kidney and finally between 648 and 4118 microg/kg dried weight in the lung. These values are comparable to those previously obtained in our laboratory and by other authors during the years 1990 on the Mediterranean environment. Significant differences in concentrations are noted in tissues and organs, neither according to the age, nor according to the gender. In all the analyzed samples, the contents in PCBs are higher than those of DDT. The average ratios of pp'-DDE/SigmaDDT are close to 0.6 which shows the metabolization of these compounds along the years. The examination of the profiles of congeners shows that the hexachlorinated molecules are dominating in all tissues and organs which supposes the different animals were especially exposed to Pyralen-type compounds of transformer (Dp6).

Hong Kong and South China are the most developed regions within China. The industrialization in these areas has resulted in severe environmental problems. Sediment and biotic samples including tilapia (Oreochromis mossambicus), bighead carp (Aristichthys nobilis), grass carp (Ctenopharyngodon idellus), crucian carp (Carassius auratus) and mandarin fish/fresh water grouper (Siniperca chuatsi) were collected from different fishponds in the Pearl River Delta (Tanzhou, Sanjiao, Guangzhou, Shipai, Changan and Mai Po) for the analysis of polycyclic aromatic hydrocarbons (PAHs) and organochlorine (OC) pesticides. Mandarin fish, which belongs to the highest trophic level, accumulated the highest concentrations of PAHs and DDTs among all fish species. The levels of DDTs in fish samples ranged from 1.5 to 62ng g-1 (wet wt.), with more than 30% of the fish samples exceeding the limit of 14.4ng g-1 (wet wt.) for human consumption recommended by US EPA (2000). Levels of PAHs in fish samples ranged from 1.91 to 224.03ng g-1 (wet wt.), but the potency-weighted total concentrations of PAHs in all muscle tissues were below the guideline value of 0.67ng g-1 (wet wt.) for human consumption set by US EPA (2000). The guideline value calculated was based on a tissue consumption rate of 142.2g day-1 (4-5 meals per week), which is a more protective rate for populations with a high consumption of fish, like Chinese and Asians. The effect of lipid content in PAHs and DDTs accumulation in fish tissue was not significant in general.

Organochlorine concentrations (OCs) and stable isotopes were investigated in the blubber of common dolphins (Delphinus delphis) and striped dolphins (Stenella coeruleoalba) from the southwestern Mediterranean. Samples were obtained from dolphins entangled in fishing nets during the 1992-1994 fishing season and from biopsies taken in 1992. Intrapopulation variations were studied, but because most of the dolphins were juveniles or calves (90%), no significant differences were found on the basis of reproductive condition or sex. Only mature male common dolphins showed significantly higher levels of most of the compounds studied than immature individuals did. There were quantitative and qualitative interspecific differences in organochlorine compounds profile. As compared to common dolphins, striped dolphins carried higher concentrations of organochlorine concentrations (OCs), their %DDE/tDDT and PCB/tDDT ratios were significantly higher, and recalcitrant PCB congeners were more abundant. Distribution and information on composition of stomach contents would in principle support a higher exposure to OCs in common dolphins as compared to striped dolphins, thus apparently contradicting the observed results. However, stable isotopes showed that striped dolphins exploit a higher trophic level, thus explaining observed differences. Interspecific dissimilarities in metabolic capacity to handle OCs may be an added factor. Although in the two species OC concentrations exceeded levels considered to be ineffective in marine mammals, pollution-induced effects on populations could not be properly assessed.

The southern bent-wing bat (Miniopterus schreibersii bassanii) is an insectivorous, obligate cave dwelling species found in south-eastern South Australia and western Victoria, Australia. In recent times, the finger of blame for an apparent population decline at Bat Cave, Naracoorte (one of only two known maternity roosts for this species, the other being Starlight Cave, Warrnambool) has been pointed at pesticide use in the region, following the finding of organochlorine and organophosphate insecticide residues in bat guano. This study sampled juvenile southern bent-wing bats from Bat Cave and Starlight Cave, and determined DDT, DDD and DDE concentrations in liver, pectoral muscle, brain and back-depot fat tissues. DDT was detected in only three tissue samples (highest concentration, 126 microg kg(-1) (wet weight) in back-depot fat), DDD was detected only in brain tissue (highest concentration, 115 microg kg(-1) (wet weight)), but DDE was detected in most tissues (highest concentration, 24,200 microg kg(-1) (wet weight) in back-depot fat). A minimum DDE body burden was estimated for each bat, and then for each sex at each site, from the data from all tissues sampled. The DDE body burdens estimated were highest in male bats from Starlight Cave (114 microg kg(-1)), then females from Starlight Cave (54.5 microg kg(-1)), and males from Bat Cave (53.2 microg kg(-1)). Female bats at Bat Cave contained the lowest estimated body burden (24.2 microg kg(-1)). Comparisons of DDE concentrations between the sexes showed that contamination was not statistically different within each maternity site. The different chemical concentrations observed in the Bat Cave and Starlight Cave bats is suggestive of different feeding locations, and perhaps an emerging population split, further threatening a species already at risk as a result of landscape scale changes to land use across their range.

Orchards (n=13) were sampled as part of a larger survey investigating agrichemical residues (pesticides and trace elements) in cropping soils in the Auckland region, New Zealand. SigmaDDT concentrations in orchard soils ranged from <0.03 to 24.41 mg kg(-1). DDT (o,p'- and p,p'-) comprised at least 40% of the SigmaDDT residues in 67% of orchards in which DDT residues were detected. There was a highly significant negative correlation (-0.924, P<0.001) between copper concentration (21-490 mg kg-1) and the ratio of DDE:DDT (0.4-5.2) in pip and stonefruit orchard soils. In further investigations involving five pip and stone fruit orchard sites and one grazing paddock it was found that soil respiration and the ratio of soil microbial carbon to soil carbon (%Cmic/Org-C) in orchard soils decreased with increasing copper concentration. These findings are consistent with the conclusion that elevated soil copper concentrations in pip and stone fruit orchard soils in the Auckland region may have reduced the ability of the indigenous soil microbial community to degrade DDT to DDE

The organochlorine insecticide dichlorodiphenyltrichloroethane (DDT) was initially introduced for control of vector-borne discases It was banned in the United States by the Environmental Protection Agency in 1972 because of potential harmful effects on humans, wildlife and the environment. Since it is a potential human carcinogen, the United Nations Environmental Program (UNEP) has recently restricted the use of DDT in developing countries until alternative methods of vector control are sought. DDT and its metabolite, dichlorodiphenyltrichloroethylene (DDE) are lipid soluble, and bioaccumulate more in human adipose tissue, than breast milk and serum. This article is a review of DDT and DDE levels in human tissues from different countries in the world. Data on p,p'-DDT and p,p'-DDE levels in human adipose tissue, breast milk and serum were selected from more recent literature. It was discovered that countries in Africa, Asia, and Latin America with more recent exposure to DDT and DDE have higher levels in human tissue than in Europe and the United States. The global concern for DDT and DDE is the environmental spread and persistence in the food chain. Hypothetically, there is a potential risk of harmful effects of DDT and DDE to human health. UNEP has cautiously taken action to protect human health, the environment and the earth from further destruction by persistent organic pollutants. Further exposure to DDT should be prevented to achieve this goal.

Sediment borne pesticides are one of the major routes of transport of pesticides into the aquatic environment and could affect biota living closely in contact with it. Sediment residues of DDT were found to be easily adsorbed (95.0%) and were released in hard water (8.4%) and seawater (0.1%). DDT and DDE sediment residues were released into sterile and nonsterile brackish water indicating minimal role of micro-organisms. DDT was detected in oyster and in mussel with an average of 46-62% in the shell, 19-31% in the tissues and 19-23% in the fluids. Most of the sediment residues were extractable and released residues in water were in the form of DDT. In the presence oysters, bound was transformed into extractable DDT in sediment after 30 days equivalent to 26% of the total concentration. Most biota residues were extractable and an average of 46% was transformed to DDE. Uptake of residues depend on whether the source of contamination was by direct addition to the water or through sediment residues, if food was given or not, if the source of sediment residues were either aged or freshly treated and if residues were extractable or non-extractable.

Persistent organic pollutants (POPs) such as chlorinated pesticides are of global concern due to their widespread occurrence, persistence, bioaccumulation and toxicity to animals and human. This paper summarises recent research on 18 chlorinated pesticides in an important catchment in China, by determining their concentrations and behaviour in water, sediment, soil and plants. The concentrations of the total pesticides were in the ranges 187-893 ng l(-1) in river water, 8.53-210 ng g(-1) dry weight in soil, 2.66-13.45 ng g(-1) dry weight in river sediment, and 651-2823 ng g(-1) dry weight in plants. The predominance of beta-HCH as the major isomer of HCHs in all water, soil, sediment and plant samples was clearly observed, due to beta-HCH's resistance to biodegradation. On average beta-HCH accounted for 44%, 53%, 50%, and 46% of the total HCH concentration in water, soil, sediment and plant, respectively. Of the DDTs, DDE accounted for 48%, 43%, 53%, 55% of the total DDT, which suggested that DDT had been transformed to its metabolites, DDE and DDD, of which DDE was the more stable. The chlorinated pesticide levels in the River Wuchuan were generally below the guideline values in China, but some sites displayed levels in excess of EC Environmental Quality Standards for HCHs and DDTs. The results therefore provide important information on the current contamination status of a key agricultural watershed in China, and point to the need for urgent actions to evaluate the long-term fate and toxicity of such persistent compounds and an appropriate remediation strategy.

Background: DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) is highly effective against most malaria-transmitting mosquitoes and is being widely used in malaria-endemic areas. The metabolite, DDE (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene), has been linked to preterm birth in small studies, but these findings are inconclusive. Our aim was to investigate the association between DDE exposure and preterm birth., Methods: Our study was based on the US Collaborative Perinatal Project (CPP). From this study we selected a subset of more than 44000 eligible children born between 1959 and 1966 and measured the DDE concentration in their mothers' serum samples stored during pregnancy. Complete data were available for 2380 children, of whom 361 were born preterm and 221 were small-for-gestational age., Findings: The median maternal DDE concentration was 25 mg/L (range 3-178)-several fold higher than current US concentrations. The adjusted odds ratios (OR) of preterm birth increased steadily with increasing concentrations of serum DDE (ORs=1, 1.5, 1.6, 2.5, 3.1; trend p<0.0001). Adjusted odds of small-for-gestational-age also increased, but less consistently (ORs=1, 1.9, 1.7, 1.6, 2.6; trend p=0.04). After excluding preterm births, the association of DDE with small-for-gestational-age remained., Interpretation: The findings strongly suggest that DDT use increases preterm births, which is a major contributor to infant mortality. If this association is causal, it should be included in any assessment of the costs and benefits of vector control with DDT.

The potential for anaerobic biodegradation of 1,1,1-trichloro-2,2-bischlorophenylethane (DDT), 1,1-dichloro-2,2,-bischlorophenylethane (DDD), and dichlorodiphenylchloroethylene (DDE) in anoxic sediment slurries collected from the Keelung River was investigated in this study. o,p'- and p,p'-DDT were dechlorinated to o,p'- and p,p'-DDD, respectively, and then transformed to other compound(s). 1-Chloro-2,2-bis (p-chlorophenyl) ethylene (DDMU) and trace amount of dichlorobenzophenone (DBP) were detected in sediment slurries amended with p,p'-DDT or p,p'-DDD. DDMU was also detected in sediment slurries amended with p,p'-DDE. The relative transformation rates for both o,p'- and p,p'-isomers of DDT, DDD, and DDE were DDT>DDD>DDE. Re-addition of DDT, DDD, or DDE to the sediment slurries after initial removal enhanced the respective dechlorination rates. The transformation rates of the p,p'-isomers of both DDT and DDD were faster than those of the respective o,p'-isomers. p,p'-DDT dechlorination in the p,p'-DDT-adapted sediment slurries were inhibited by the addition of molybdate, or molybdate plus sulfate, but not inhibited by the addition of sulfate. Addition of bromoethane-sulfonic acid (BESA) slightly inhibited p,p'-DDT dechlorination. Non-adapted sediment slurries lost the ability to dechlorinate pentachlorophenol during adaptation to p,p'-DDT. p,p'-DDD was the major transformation product of p, p'-DDT in 3,4,4',5-tetrachlorobiphenyl-adapted sediment slurries, which suggested that the microbial community in the 3,4,4',5-CB-adapted sediment was unable to remove chlorine from the aromatic rings of p,p'-DDT.

The organochlorine pesticide 1,1,1-trichloro-2,2-bis (p-chlorophenyl)-ethane (DDT), is a well-known and widely dispersed "environmental estrogen" (World Health Organization Criteria no. 9; Geneva, Switzerland [1979]). Kelce et al. (Nature, 1995; 375:581-85) recently identified the DDT metabolite, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), has also recently been identified as a potent androgen receptor antagonist. The authors examined the relationship between serum levels of DDE and bone mineral density in 68 sedentary women who reported adequate dietary intake of calcium. Reduced bone mineral density was correlated significantly with age (r = -.36, p = .004), as well as with increases in the log of DDE levels in serum (r = -.27, p = .03). The authors also used multiple-regression analysis to examine the influence of other predictor variables on the relationship between log DDE and bone mineral density. The strongest model (p = .002) included log DDE (p = .018), age (p = .002), and years on hormone replacement therapy (p = .10) as predictor variables, and this model afforded prediction of 21% of bone mineral density variation. These results suggest that past community exposures to DDT may be associated with reduced bone mineral density in women.

Pressurised liquid extraction (PLE) was used to extract DDT [1,1,1,-trichloro-2,2-bis(p-chlorophenyl)ethane] and its metabolites, DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethane] and DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] from an aged, contaminated soil. Using three sequential static phases, PLE removed an equivalent quantity of DDT and its metabolites as Soxhlet extraction, in less time and with less solvent. Recovery was almost quantitative, implying appropriate sample work-up and manipulation.

A case-control study was conducted in Connecticut from 1994 to 1997 to investigate the relation between dichlorodiphenyldichloroethane (DDE) and dichlorodiphenyltrichloroethane (DDT) exposure and breast cancer risk. Cases and controls were women aged 40-79 years, who had breast-related surgery at the Yale-New Haven Hospital and from whose surgical specimen the authors could obtain at least 0.4 g of breast adipose tissue for chemical analyses. A total of 304 incident breast cancer cases (including 62 in situ carcinomas) and 186 benign breast disease controls were recruited into the study. Tissue levels of DDE and DDT were measured using gas chromatography. Statistical significance for comparisons of mean levels of DDE and DDT was calculated using analysis of variance and rank sum tests. A logistic regression model was used to estimate the association and to control confounding. The age-adjusted geometric mean tissue level of DDE for cases (736.5 ppb) was similar to that for the controls (784.1 ppb). DDT levels were also similar for cases (51.8 ppb) and controls (55.6 ppb). The adjusted odds ratio is 0.9 (95% confidence interval: 0.5, 1.5) for DDE and 0.8 (95% confidence interval: 0.5, 1.5) for DDT when the highest quartile was compared with the lowest. These results do not support an association between adipose tissue levels of DDE and DDT and breast cancer risk.

Capillary gas chromatography with atomic emission detection (GC-AED) was evaluated for the determination of DDT and metabolites in biological samples. Utilizing chlorine-selective detection at 479 nm, DDT, DDE, and DDD were quantified down to the 20 ng/g (fat weight) level (S/N = 10) in cod liver oil, while the detection, limit was 6 ng/g (S/N = 3). With splitless injection performed in the pressure programmed mode, DDT and related compounds were quantified based on a single chlorine calibration curve (universal calibration). The quantitative data obtained by GC-AED were in excellent accordance with similar results from capillary gas chromatography with electron capture detection (GC-ECD), while the procedure for calibration was simplified with the former technique.

The milk samples were collected from mothers who had lived in the area for at least 5 years, healthy and breast feeding their first, second or third child. Of the 175 mothers' milk samples analysed, the organochlorine pesticide residues were detected in the following order of frequency: pp-DDE, 100%, pp-DDT 98%; and sum PCB, 53%. Of all the seven areas analysed the Kariba area and the highest mean level of sum DDT--25,259 ng/g milk fat and the lowest mean level of sum DDT of 1607 ng/G milk fat was found in Esigodini which is a rural area. The major DDT metabolite was pp-DDE. The ratio of pp-DDT/pp-DDE was highest in Kariba (0.6) suggesting recent pollution by DDT in that area. The results show that the vector control programmes (extensive pesticide spraying of disease-carrying pests, such as mosquitoes and tsetse flies), agricultural activities and dietary habits were the main contributing factors towards the high levels of pesticides in most of the areas. Kadoma area had the highest mean level of sum-PCB (60 ng/g milk fat).