Dichlorodiphenyltrichloroethane Research Articles

Estrogenic Activity of Persistent Organic Pollutants and Parabens Based on the Stably Transfected Human Estrogen Receptor-α Transcriptional Activation Assay (OECD TG 455)

Screening of estrogenic activity on dichloro diphenyl trichloroethane (DDT), dichloro diphenyl dichloro ethylene (DDE), dieldrin, heptachlor, aldrin, chlordane, lindane, polybrominated diphenyl ethers (PBDE) and parabens was compared using Organization for Economic Cooperation and Development (OECD) test guideline 455 (TG455). The estrogenic activity of DDT was 58,000-fold (PC50, 1.67 × 10−6 M) less than 17β-estradiol(E2) (PC50, 2.88 × 10-11 M) but DDE, dieldrin, heptachlor, aldrin, chlordane, lindane and PBDE did not show any estrogenic activity in this assay system. In the case of paraben compounds, the rank of relative transcriptional activation (logRTA) was butyl paraben −1.63752 (PC50, 1.25 × 10−7M) > isobutyl paraben −2.34008 (PC50, 6.3 × 10−7M) > ethyl paraben −2.64016 (PC50, 1.26 × 10−6 M) > isopropyl paraben −2.73993 (PC50, 1.58 × 10−6M) > propyl paraben −2.84164 (PC50, 2.0 × 10−6 M). Our data suggest that OECD test guideline TG455 may be useful as a screening tool for potential endocrine disruptors.

Insecticide Resistance in Bedbugs in Thailand and Laboratory Evaluation of Insecticides for the Control ofCimex hemipterusandCimex lectularius(Hemiptera: Cimicidae)

Bedbugs are found in many countries around the world, and in some regions they are resistant to numerous insecticides. This study surveyed bedbugs in Thailand and determined their resistance to insecticides. The surveys were carried out in six provinces that attract large numbers of foreign tourists: Bangkok, Chonburi, Chiang Mai, Ubon Ratchathani, Phuket, and Krabi. Bedbugs were collected from hotels and colonized in the laboratory to evaluate their resistance to insecticides. Cimex hemipterus (F.) was found in some hotels in Bangkok, Chonburi, Phuket, and Krabi, whereas Cimex lectularius L. was found only in hotels in Chiang Mai. No bedbugs were found in Ubon Ratchathani. The colonized bedbugs showed resistance to groups of insecticides, including organochlorines (dichlorodiphenyl trichloroethane, dieldrin), carbamates (bendiocarb, propoxur), organophosphates (malathion, fenitrothion), and pyrethroids (cyfluthrin, deltamethrin, permethrin, lambda-cyhalothrin, etofenprox) in tests using World Health Organization insecticide-impregnated papers. The new insecticides imidacloprid (neonicotinoid group), chlorfenapyr (pyrrole group), and fipronil (phenylpyrazole group) were effective against the bedbugs; however, organophosphate (diazinon), carbamates (fenobucarb, propoxur), and pyrethroids (bifenthrin, cypermethrin, esfenvalerate, etofenprox) were ineffective. Aerosols containing various pyrethroid insecticides with two to four different active ingredients were effective against the bedbugs. The results obtained from this study suggested that both species of bedbugs in Thailand have developed marked resistance to various groups of insecticides, especially those in the pyrethroid group, which are the most common insecticides used for pest control. Therefore, an integrated pest management should be implemented for managing bedbugs in Thailand.

Select chemical and engineering properties of wastewater biosolids

The select chemical and engineering characteristics of biosolids produced at a wastewater treatment plant in Eastern Australia were investigated to assess its suitability as structural fill material in road embankments. Results of comprehensive set of geotechnical experimentation including compaction, consolidation, creep, hydraulic conductivity and shear strength tests implied that biosolids demonstrate behavior similar to highly organic clays with a higher potential for consolidation and settlement. Results of chemical study including heavy metals, dichloro diphenyl trichloroethane (and derivatives) and organochlorine pesticides, indicate that biosolids samples are within the acceptable limits which allows their usage under certain guidelines. Results of tests on pathogens (bacteria, viruses or parasites) also indicated that biosolids were within the safe acceptable limits. Technical and management suggestions have been provided to minimize the possible environmental risks of using biosolids in road embankment fills.

The Missing Piece: Sediment Records in Remote Mountain Lakes Confirm Glaciers Being Secondary Sources of Persistent Organic Pollutants

After atmospheric deposition and storage in the ice, glaciers are temporary reservoirs of persistent organic pollutants (POPs). Recently, the hypothesis that melting glaciers represent secondary sources of these pollutants has been introduced by investigations of the historical trend of POPs in a dated sediment core from the proglacial Alpine Lake Oberaar. Here, the hypothesis is further confirmed by the comparison of sediment data gathered from two Alpine lakes with a glaciated and a nonglaciated hydrological catchment. The two lakes (Lake Engstlen and Lake Stein in the Bernese Alps in Switzerland) are situated only 8 km apart at similar altitude and in the same meteorological catchment. In the nonglacial lake sediment of Lake Engstlen, PCBs and DDT (polychlorinated biphenyls and dichlorodiphenyl trichloroethane) levels culminated with the historic usage of these chemicals some 30-50 years ago. In the glacial Lake Stein, this peak was followed by a reincrease in the 1990s, which goes along with the accelerated melting of the adjacent glacier. This study confirms the hypothesis of glaciers being a secondary source of these pollutants and is in accordance with the earlier findings in Lake Oberaar.

Potential Occupational Exposures in the Reiss-Engelhorn-Museen Mannheim/Germany

The Reiss-Engelhorn-Museen in Mannheim, Germany requested support from a toxicological laboratory in evaluating occupational exposures before a cleanup and renovation period in 2006. Samples of dust and dirt and scrapings of exhibits were collected from several locations. Following toxicologically relevant compounds could be identified by gas chromatography - mass spectrometry (GC/MS) by comparison with a mass spectra library: dichlorodiphenyl trichloroethane (DDT) and its breakdown product dichlorodiphenyl dichloroethane (DDD) as well as dichlorodiphenyl dichlorethylene (DDE), methoxychlor, nicotine, and camphor. In recent times various insecticides have been used to protect museum artefacts against moths, woodborers and other insect pests. Caution has to be made because the presence of hazardous compounds can result in security problems for museum staff as well as for visitors.

Sociodemographic, reproductive and dietary predictors of organochlorine compounds levels in pregnant women in Spain

Organochlorine pesticides and polychlorinated biphenyls (PCBs) are consistently found in human tissues. Serum levels of organochlorine compounds (OC) in pregnant women in particular have raised concern about possible harm to humans in the early phases of physical and behavioural development. The objective of the present study was to evaluate the association between concentration of OCs in serum of two cohorts of pregnant women from Gipuzkoa and Sabadell in Spain and socioeconomic, reproductive and dietary variables. Concentration of polychlorinated biphenyls (PCBs: 28, 52, 101, 118, 138, 153 and 180), hexachlorobenzene (HCB), beta and gamma-hexachlorocyclohexane ( β-HCH and γ-HCH), heptachlor epoxide, dichlorodiphenyl dichloroethylene ( p,p′-DDE) and dichlorodiphenyl trichloroethane ( p,p′-DDT) were measured in the serum of 1259 pregnant women. Associations between OCs and potential predictor variables were assessed using linear regression models adjusted for potential confounders. The compounds most commonly found in the serum were p,p′-DDE (99% of the samples) and PCB-153 (95% of the samples). Geometric means of serum concentrations (ng g −1 lipid) of organochlorine pesticides were 110.0, 19.1, and 33.5 for p,p′-DDE, β-HCH, and HCB respectively, while the geometric means of PCBs were 21.8, 38.9 and 26.9 for PCB 138, 153, and 180 respectively. The levels of all OCs increased with age. BMI was positively associated with the concentration of organochlorine pesticides but inversely related to PCB concentrations. The serum levels of OCs fell only after a cumulative period of breastfeeding of over a year. Levels of PCBs were related to fish intake, but in general dietary factors did not improve the explained variability of the concentrations of OCs. Overall, the levels of OCs found in the study are at the lower end of the range reported in Spain and other countries.

Nanoscale fabrication of a peptide layer in cell chip to detect effects of environmental toxins on HEK293 cells

A cysteine-terminated C(RGD)(4) peptide film was fabricated on a gold electrode for improving the attachment of cells. The electrochemical signals of cyclic voltammogram from cells on a C(RGD)(4) deposited electrode was enhanced from 0.27 to 0.49 μA compared to a bare electrode. The developed cell-based sensor determined the effect of bisphenol-A (BPA) and dichlorodiphenyltrichloroethane (DTT) on the viability of HEK-293 cells by detecting decrease of reduction peaks (1.12-0.15 μA for BPA and 0.81-0.29 μA for DDT) after the treatment of environmental chemicals. This developed system can be a powerful tool for the monitoring of environmental toxicants.

Determination of Lead, Cadmium, and Persistent Organic Pollutants in Wild and Orchard-Farm-Grown Fruit in Northeastern Poland

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 (PCB7), γ isomer of hexachlorocyclohexane (γ-HCH), and sum of dichlorodiphenyl trichloroethane and its metabolites (ΣDDT) were also measured in plants and nuts. In addition, the concentrations of Pb, Cd, PCB7, γ-HCH, and ΣDDT 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 μg/kg fresh weight. The levels were Cd 72 μg/kg fresh weight and Pb 290 μg/kg fresh weight in raspberries from orchard plants and exceeded the maximal acceptable limit of 50 μg/kg for Cd and 200 μg/kg for Pb. The level of Pb at 210 μg/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 ΣDDT (145 μg/kg), including p,p'-DDT at a concentration of 67 μg/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.

Multiresidue Pesticide Analysis of Ginseng Powders Using Acetonitrile- or Acetone-Based Extraction, Solid-Phase Extraction Cleanup, and Gas Chromatography−Mass Spectrometry/Selective Ion Monitoring (GC-MS/SIM) or −Tandem Mass Spectrometry (GC-MS/MS)†

A multiresidue method for the analysis of 168 pesticides in dried powdered ginseng has been developed using acetonitrile or acetone mixture (acetone/cyclohexane/ethyl acetate, 2:1:1 v/v/v) extraction, solid-phase extraction (SPE) cleanup with octyl-bonded silica (C(8)), graphitized carbon black/primary-secondary amine (GCB/PSA) sorbents and toluene, and capillary gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM) or -tandem mass spectrometry (GC-MS/MS). The geometric mean limits of quantitation (LOQs) were 53 and 6 microg/kg for the acetonitrile extraction and 48 and 7 microg/kg for the acetone-based extraction for GC-MS/SIM and GC-MS/MS, respectively. Mean percent recoveries and standard deviations from the ginseng fortified at 25, 100, and 500 microg/kg using GC-MS/SIM were 87 +/- 10, 88 +/- 8, and 86 +/- 10% from acetonitrile extracts and 88 +/- 13, 88 +/- 12, and 88 +/- 14% from acetone mixture extracts, respectively. The mean percent recoveries from the ginseng at the 25, 100, and 500 microg/kg levels using GC-MS/MS were 83 +/- 19, 90 +/- 13, and 89 +/- 11% from acetonitrile extracts and 98 +/- 20, 91 +/- 13, and 88 +/- 14% from acetone extracts, respectively. Twelve dried ginseng products were found to contain one or more of the following pesticides and their metabolites: BHCs (benzene hexachlorides, alpha-, beta-, gamma-, and delta-), chlorothalonil, chlorpyrifos, DDT (dichlorodiphenyl trichloroethane), dacthal, diazinon, iprodione, quintozene, and procymidone ranging from <1 to >4000 microg/kg. No significant differences were found between the two extraction solvents, and GC-MS/MS was found to be more specific and sensitive than GC-MS/SIM. The procedures described were shown to be effective in screening, identifying, confirming, and quantitating pesticides in commercial ginseng products.

Organochlorine Residues in South American Sea Lions, Otaria flavescens (Shaw, 1800): Bioaccumulation and Time Trends

Blubber from stranded South American sea lions (Otaria flavescens) was sampled between 1991 and 2005 on the Peninsula Valdés in Argentina and analyzed for organochlorine (OC) pollutants. Mean blubber concentrations, expressed on an extractable basis, were 686 (SD = 1,060) ng g(-1) for dichlorodiphenyl trichloroethane (tDDT) and 735 (SD = 787) ng g(-1) for polychlorinated byphenils (PCB). The OC levels were well below those associated with adverse sublethal effects and lethality in mammals. OC concentrations showed statistically significant associations with age that were positive in males and negative in females. These trends are consistent with the majority of marine mammal populations studied. There were no trends in the levels of tDDT or PCB over time. In spite of the low levels detected, OC contamination was present consistently over the 14-year period, suggesting continuous inputs from geographic redistribution.

Release of Legacy Pollutants from Melting Glaciers: Model Evidence and Conceptual Understanding

Recently, increasing concentrations of persistent organic pollutants (POPs) have been observed in the sediment of glacier-fed Lake Oberaar, Switzerland. Melting glaciers have been suggested as a secondary source of POPs released to Alpine lakes. Here we further investigate whether climate warming may accelerate the release of POPs previously deposited to Alpine glaciers ("glacier hypothesis"). To test this hypothesis, a dynamic multimedia mass balance model is developed for the catchment area of Lake Oberaar and is applied to polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dichlorodiphenyl trichloroethane (DDT). This lake model is combined with two other models. The first is a dynamic multimedia mass balance model parametrized for the Swiss lowlands that is used to calculate (on the basis of historical emission data) the atmospheric concentrations that are an advective input into the model of the lake catchment. The second is a flow model of Oberaar Glacier that determines the residence time of persistent chemicals in the glacier after their deposition to the glacier surface. According to results from these three models in combination, the release of POPs by the glacier is currently increasing and accounts for the observed increase in concentrations in the lake sediment. The models indicate that approximately half of the amount of PCBs, PCDD/Fs, and DDT initially incorporated into the glacier ice is still stored in the glacier. Under the assumption that the climate is warming, accelerated release of POPs is to be expected for the future; in a model run where no climate warming is assumed, the period of time required for release of the same amount of chemicals is longer by several decades than in the scenario with a changing climate.

Xeno-oestrogens and phyto-oestrogens are alternative ligands for the androgen receptor

The androgen receptor (AR) plays a critical role in prostate cancer development and progression. This study aimed to use a computerized docking approach to examine the interactions between the human AR and phyto-oestrogens (genistein, daidzein, and flavone) and xeno-oestrogens (bisphenol A, 4-nonylphenol, dichlorodiphenyl trichloroethane [DDT], diethylstilbestrol [DES]). The predicted three-dimensional structure of AR and androgens was established using X-ray diffraction. The binding of four xeno-oestrogens and three phyto-oestrogens to AR was analysed. The steroids estradiol and dihydrotestosterone (DHT) were used as positive controls and thyroxine as negative control. All the ligands shared the same binding site except for thyroxine. The endogenous hormones DHT and 17beta-oestradiol showed the strongest binding with the lowest affinity energy (< -10 kcal mol(-1)). All three phyto-oestrogens and two xeno-oestrogens (bisphenol A and DES) showed strong binding to AR. The affinities of flavone, genistein, and daidzein were between -8.8 and -8.5 kcal mol(-1), while that of bisphenol A was -8.1 kcal mol(-1) and DES -8.3 kcal mol(-1). Another two xeno-oestrogens, 4-nonylphenol and DDT, although they fit within the binding domain of AR, showed weak affinity (-6.4 and -6.7 kcal mol(-1), respectively). The phyto-oestrogens genistein, daidzein and flavone, and the xeno-oestrogens bisphenol A and DES can be regarded as androgenic effectors. The xeno-oestrogens DDT and 4-nonylphenol bind only weakly to AR.

The saviour who turned villain: dichlorodiphenyl-trichloroethane, children and the environmint in Swaziland

The saviour who turned villain: dichlorodiphenyl-trichloroethane, children and the environmint in Swaziland

Identification of Methylmercury Tolerance Gene Candidates in Drosophila

Methylmercury (MeHg) is a ubiquitous environmental contaminant that preferentially targets the developing nervous system. Variable outcomes of prenatal MeHg exposure within a population point to a genetic component that regulates MeHg toxicity. We therefore sought to identify fundamental MeHg tolerance genes using the Drosophila model for genetic and molecular dissection of a MeHg tolerance trait. We observe autosomal dominance in a MeHg tolerance trait (development on MeHg food) in both wild-derived and laboratory-selected MeHg-tolerant strains of flies. We performed whole-genome transcript profiling of larval brains of tolerant (laboratory selected) and nontolerant (control) strains in the presence and absence of MeHg stress. Pairwise transcriptome comparisons of four conditions (+/-selection and +/-MeHg) identified a "down-down-up" expression signature, whereby MeHg alone and selection alone resulted in a greater number of downregulated transcripts, and the combination of selection + MeHg resulted in a greater number of upregulated transcripts. Functional annotation cluster analyses showed enrichment for monooxygenases/oxidoreductases, which include cytochrome P450 (CYP) family members. Among the 10 CYPs upregulated with selection + MeHg in tolerant strains, CYP6g1, previously identified as the dichlorodiphenyl trichloroethane resistance allele in flies, was the most highly expressed and responsive to MeHg. Among all the genes, Turandot A (TotA), an immune pathway-regulated humoral response gene, showed the greatest upregulation with selection + MeHg. Neural-specific transgenic overexpression of TotA enhanced MeHg tolerance during pupal development. Identification of TotA and CYP genes as MeHg tolerance genes is an inroad to investigating the conserved function of immune signaling and phase I metabolism pathways in MeHg toxicity and tolerance in higher organisms.

Contaminant pattern and bioaccumulation of legacy and emerging organhalogen pollutants in the aquatic biota from an e‐waste recycling region in South China

Legacy pollutants, polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), and some emerging organhalogen pollutants, such as polybrominated diphenyl ethers (PBDEs), hexabromobenzene (HBB), pentabromotoluene (PBT), 2,3,4,5,6-pentabromoethyl benzene (PBEB), 1,2-bis (2,4,6-tribromophenoxy) ethane (BTBPE), and dechlorane plus (DP), were detected in an aquatic food chain (invertebrates and fish) from an e-waste recycling region in South China. Polychlorinated biphenyls, DDTs, PBDEs, and HBB were detected in more than 90% of the samples, with respective concentrations ranging from not detected (ND)-32,000 ng/g lipid weight, ND-850 ng/g lipid weight, 8 to 1,300 ng/g lipid weight, and 0.28 to 240 ng/g lipid weight. Pentabromotoluene, PBEB, BTBPE, and DP were also quantifiable in collected samples with a concentration range of ND-40 ng/g lipid weight. The elevated levels of PCBs and PBDEs in the organisms, compared with those in non-e-waste regions in South China, suggest that these two kinds of pollutants derived mainly from e-waste recycling practices. Hexabromobenzene was significantly correlated with PBDEs, implying that HBB come from the release of e-waste along with PBDEs and/or the pyrolysis of BDE209. Most of the compounds whose trophic magnification factor (TMF) could be calculated were found to biomagnify (TMF > 1). Hexabromobenzene was also found, for the first time, to biomagnify in the present food web, with a TMF of 2.1.

Understanding the accumulation features of POPs in squid from the offshore waters of southeast Korea

In this study we investigated the current contamination status and accumulation features of POPs in Korean offshore waters using Japanese common squid as a biomonitoring organism. Concentrations of organochlorine compounds (OCs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), and hexachlorocyclohexanes (HCHs) were determined in different organs of squid of both sexes and of various sizes caught in the offshore waters of southeast Korea in July and October, 2005. Most of the compounds showed their highest concentrations in liver among the organs analyzed. The concentrations of PCBs, DDTs, CHLs and HCHs in liver were in the ranges of 116–206 ng/g (mean: 146), 158–325 ng/g (238), 20.6–37.3 ng/g (28.2), and 1.68–12.3 ng/g (7.79) on a dry weight basis, respectively. There was no relationship between squid size and OC concentrations, while the levels of all of the compounds were significantly correlated with lipid content. Due to its relatively high lipid content, the concentration of OCs in squid liver was higher than other organs of the squid. Therefore, OCs in female squid may be redistributed from the liver to the gonad. These results showed that male squid liver is a useful organ for monitoring OCs in Korean offshore waters, regardless of its size.

Electrical Property and Application of Au Electrodes Passivated with DDT Molecules

We report the passivation characteristics of dodecanethiol (DDT) molecules on gold electrodes of field effect transistor bio-sensors. The leakage current between the electrolyte and the electrode can be as small as 3pA when 7 mM of DDT passivation is performed. The DDT layer is also shown to resist the attack of acid up to 120 mins.

Organochlorine Compounds, Iodine Intake, and Thyroid Hormone Levels during Pregnancy

The effect of organochlorine compounds (OCs) on thyroid function, as well as the potential confounding effect of iodine intake, was studied in a large sample of pregnant women from two population-based cohort studies in Sabadell (n = 520) and Gipuzkoa (n = 570), Spain. Thyroid hormones (free T4 and total T3), thyrotropin, and polychlorinated biphenyls (PCB congeners 118, 138, 153, and 180), hexachlorobenzene (HCB), beta-hexachlorocyclohexane (beta-HCH), dichlorodiphenyl dichloroethylene (p'p'-DDE) and dichlorodiphenyl richloroethane (p'p-DDT) were measured in serum samples collected at first trimester of pregnancy. Urinary iodine concentration (UIC) was measured and iodine intake from diet, iodized salt, and supplements were estimated from a food frequency questionnaire. Levels of HCB and PCBs congeners 180, 153, and 138 were related to lowe rtotal T3 levels (adjusted coefficient (SE): -4.0(1.1), -6.1(1.6), -5.5(1.6), and 3.8(1.4), respectively) and higher free T4 levels (adjusted coefficient (SE): 0.013(0.05), 0.017(0.007), 0.016(0.007), and 0.007(0.006), respectively). These associations were homogeneous in both cohorts, especially for PCBs and total T3 (p-value forthe interaction between cohorts >0.8). Iodine intake and UIC did not affect the association between OCs and thyroid hormones. Our results indicate that exposure to OCs during pregnancy can alter TH levels.

Biochemical endpoints on juvenile Solea senegalensis exposed to estuarine sediments: the effect of contaminant mixtures on metallothionein and CYP1A induction

Juvenile Solea senegalensis were exposed to fresh sediments from three stations of the Sado estuary (Portugal) in 28-day laboratory assays. Sediments revealed distinct levels of total organic matter, fine fraction, redox potential, trace elements (arsenic, cadmium, chromium, copper, nickel, lead and zinc) and organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls and a pesticide: dichloro diphenyl trichloroethane). Organisms were surveyed for contaminant bioaccumulation and induction of two hepatic biochemical biomarkers: metallothionein (MT) and cytochrome P450 (CYP1A), as potential indicators of exposure to metallic and organic contaminants, respectively. Using an integrative approach it was established that, although bioaccumulation is in general accordance with sediment contamination, lethality and biomarker responses are not linearly dependent of the cumulative concentrations of sediment contaminants but rather of their bioavailability and synergistic effects in organisms. It is concluded that metals and organic contaminants modulate both MT and CYP1A induction and it is suggested that reactive oxygen species may be the link between responses and effects of toxicity.

Serum levels of organochlorine pesticides in healthy adults from five regions of Spain

The aim of this study was to measure of serum levels of p,p′-dichlorodiphenyl trichloroethane ( p,p′-DDT), p,p′-dichlorodiphenyl dichlorethylene ( p,p′-DDE), β-hexachlorocyclohexane (β-HCH), and hexachlorobenzene (HCB) in healthy adults in Spain. Furthermore, we also analyzed these levels according to dietary, other lifestyle factors and anthropometric characteristics. We measured the concentrations of such organochlorine pesticides (OCPs) in serum samples collected during 1992–1996 from 953 subjects aged 35–64 years, they were residents of five Spanish regions, they were randomly selected from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. OCPs were determined by means of gas chromatography with electron-capture detection (GC-ECD). The most frequent compound found in serum was p,p′-DDE, present in 98% of the samples, followed by HCB and β-HCH, found in 89% and 77% of samples, respectively, while p,p′-DDT could be measured only in 26% of subjects. The geometric means of serum concentrations (ng/g lipid) were 822 for p,p′-DDE, 167 for β-HCH, and 379 for HCB. The concentrations of all OCPs were positively associated with age and body mass index, and decreased along the period of blood collection. No association was found between OCPs levels and dietary factors. The concentrations of p,p′-DDE and β-HCB were higher in Murcia, one of southern regions, most likely associated with intensive past use of pesticides related to agricultural practices, while higher levels of HCB were found in Navarra, located in the north, maybe due to industrial use rather than agricultural application.