Determination of endocrine-disrupting pesticides and polychlorinated biphenyls in human serum by GC-ECD and GC-MS-MS and evaluation of contributions to the uncertainty of the results

Cross-sectional associations of persistent organic pollutants measured in adipose tissue and metabolic syndrome in clinically diagnosed middle-aged adults

INTRODUCTION

Although often overlooked in clinical settings, accumulation of persistent organic pollutants (POPs) in visceral adipose tissue (VAT) is thought to be a relevant risk factor for metabolic syndrome (MetS).

METHODS

One hundred and seventeen patients undergoing non-oncological surgery were randomly recruited and classified as MetS + if presented 3 out of the 5 MetS components: waist circumference (WC), systolic and diastolic blood pressure (SBP and DBP, respectively), serum glucose, insulin, triglycerides (TG) and high-density lipoprotein (HDL) cholesterol levels, according International Diabetes Federation (IDF) criteria. Seventeen organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were measured in adipose tissue samples. Linear, logistic and weighted quantile sum (WQS) regression models, adjusted for age and sex, were performed.

RESULTS

One third of the participants were males (36.8%) with a median age of 44 years, showing clinical evidences of MetS (35.0%). Adjusted linear regression models showed that WC correlated positively with all OCP concentrations. Higher fasting serum glucose levels were related to higher HCB and γ-HCH concentrations. The remaining OCPs and PCBs were not associated with this MetS component. HCB was inversely associated with HDL cholesterol levels, while PCB-180 was positively associated. HCB and γ-HCH concentrations were also positively correlated with DBP and SBP levels. PCB-138 was also positively associated with SBP. Adjusted logistic models revealed that exposure to HCB and γ-HCH were associated with increased odds of MetS [ORs (95%CI) 1.53 (1.22-1.92) and 1.39 (1.10-1.76) respectively; p < 0.01]. No associations were observed for the remaining POPs. WQS models showed a positive and significant mixture effect of POPs on the odds of MetS (exp [beta] = 2.34; p < 0.001), with γ-HCH (52.9%), o,p'-DDT (26.9%) and HCB (19.7%) driving the association.

CONCLUSIONS

Our findings support that POPs accumulated in VAT, specifically HCB and (gamma)-HCH, are associated with both isolated components and clinically diagnosed SMT.

Differential Bioaccumulation Patterns of α, β-Hexachlorobenzene and Dicofol in Adipose Tissue from the GraMo Cohort (Southern Spain)

To identify bioaccumulation patterns of α-, β- hexachlorocyclohexane (HCH) and dicofol in relation to sociodemographic, dietary, and lifestyle factors, adipose tissue samples of 387 subjects from GraMo cohort in Southern Spain were analyzed. Potential predictors of these organochlorine pesticides (OCP) levels were collected by face-to-face interviews and assessed by multivariable linear and logistic regression. OCPs were detected in 84.2% (β-HCH), 21.7% (α-HCH), and 19.6% (dicofol) of the population. β-HCH levels were positively related to age, body mass index (BMI), mother's occupation in agriculture during pregnancy, living in Poniente and Alpujarras, white fish, milk and water consumption, and negatively related to being male, living near to an agricultural area, working ≥10 years in agriculture, and beer consumption. Detectable α-HCH levels were positively related to age, BMI, milk consumption, mother's occupation in agriculture during pregnancy, and negatively with residence in Poniente and Alpujarras, Granada city, and Granada Metropolitan Area. Residence near to an agricultural area, smoking habit, white fish and water consumption, and living in Poniente and Alpujarras, Granada city and Granada Metropolitan Area were negatively associated with detectable dicofol levels. Our study revealed different bioaccumulation patterns of α, β-HCH and dicofol, probably due to their dissimilar period of use, and emphasize the need for assessing the exposure to frequently overlooked pollutants.

Trace-level analysis of polychlorinated biphenyls, organochlorine pesticides and polycyclic aromatic hydrocarbons in human plasma or serum by dispersive liquid-liquid microextraction and gas chromatography-tandem mass spectrometry

A method to determine 8 polychlorinated biphenyls (PCBs), 23 organochlorine pesticides (OCPs) and 16 polycyclic aromatic hydrocarbons (PAHs) was described using dispersive liquid-liquid microextraction (DLLME) of a small amount of plasma or serum sample and gas chromatography-tandem mass spectrometry (GC-MS/MS). The appropriate selection of the extraction solvent and dispersing solvent contributes to a high extraction yield and a clean extract. To verify the developed method, the interference, linearity of the calibration curve, detection limit, precision and accuracy were evaluated. The calibration curves were linear by 2-3 orders of magnitude with correlation coefficients above 0.997 in all cases. The LODs of PCBs, OCPs and PAHs were measured in the ranges of 0.0006-0.0029, 0.001-0.029 and 0.0002-0.012 ng/ml. The intraday precision achieved by this method was 2.19-10.3% (PCBs), 1.65-14.3% (OCPs) and 0.91-12.8% (PAHs), and the intraday accuracy 1.56-7.37% (PCBs), 2.34-19.6% (OCPs) and 1.49-15.7% (PAHs). The advantage of this method is that the analysis of PCBs, OCPs, and PAHs can be performed in a single chromatographic run, and the low detection limit enables monitoring of target substances in low exposure general public samples, and the analysis procedure is relatively simple and fast.

Associations of residential and occupational history with the distribution of persistent pollutant mixtures in adipose tissue samples

This research aims to explore clusters of a mixture of 15 Persistent Toxic Substances (PTSs) in the adipose tissue of 227 individuals of an adult cohort from Granada Province (Southern Spain). Information about residence and occupation during participants lifetime was gathered by means of validated questionnaires. Clusters of pollutants in the study population were identified by Principal Component Analyses (PCA). PCA analyses revealed three major clusters of pollutants: PC1, representing predominantly an assortment of metal(loid)s, namely aluminium, arsenic, chromium, nickel and lead; PC2, including mostly Organochlorine Pesticides (OCPs), such as HCB, β-HCH and p,p'-DDE; and PC3, gathering mainly a mixture of Polychlorinated Biphenyls (PCB-138, PCB-153 and PCB-180) and metals (cadmium, cobalt and chromium). The patterns of distribution of individual pollutants and their mixtures were explored through Geographic Information Systems and multivariable linear regression models. Living in rural areas was associated with decreased levels of the mixture of PCBs and metals. Residents of industrial and heavy traffic areas showed increased levels of the mixture of metal(loid)s. Those living in rural and semi-rural areas at recruitment had decreased levels of the OCP mixture. Occupational history related to agriculture and food industry was associated with increased levels of the mixture of metal(loid)s, whereas those who had been involved in motor and industrial activities showed increased levels of the OCP mixture. Participants who had worked in cleaning and housekeeping activities for long periods showed decreased levels of the mixture of PCBs and metals. Our research revealed suggestive clusters of exposure, that emphasized the need for further epidemiological studies to address the effect of environmental pollutants from a mixture perspective. Results also highlight the potential of adipose tissue as a matrix for exposure assessment to combinations of different families of contaminants.

Biomonitoring Organochlorine Pesticides in Didelphis virginiana from Yucatan, Mexico by GC-ECD

The aim of the present work was to apply a validated methodology for the detection of organochlorine pesticides in Didelphis virginiana (Virginia opossum) serum samples collected in Yucatan, Mexico. Recent studies performed to investigate the presence of Organochlorines (OCLs) in water, human blood and milk, and animal tissues from Yucatan have shown that the OCLs concentrations are high and can be associated with potential human health risk. Since opossum is considered an important synanthropic species in Yucatan, 40 opossum serum samples were analyzed by gas chromatography with electron capture detector. The most common OCLs found in opossum sera were lindanes, chlordanes, drines, and endosulfan. Heptachlor, heptachlor epoxide, and lindanes were found at the highest concentrations, while dichlorodiphenyl trichloroethane and its metabolites were found at the lowest concentrations in the samples. The good linearity, precision, and accuracy obtained in the evaluated parameters in the extraction and chromatographic methods support its application for the monitoring of OCLs pesticides in populations of opossums and other wild species in Yucatan.

Contribution of Persistent Organic Pollutant Exposure to the Adipose Tissue Oxidative Microenvironment in an Adult Cohort: A Multipollutant Approach

Despite growing in vitro and in vivo evidence of the putative role of persistent organic pollutants (POPs) in the induction of oxidative damage in cell structures, this issue has been poorly addressed from an epidemiologic perspective. The aim of this study was to explore associations between adipose tissue POP concentrations and the in situ oxidative microenvironment. A cross-sectional study was conducted in a subsample (n = 271) of a previously established cohort, quantifying levels of eight POPs and four groups of oxidative stress biomarkers in adipose tissue. Associations were explored using multivariate linear regression analyses adjusted for potential confounders. We assessed the combined effect of POPs on oxidative stress/glutathione system biomarkers using weighted quantile sum regression (WQS). Increased concentrations of p,p'-DDE, HCB, β-HCH, dicofol, and PCBs (congeners -138, -153, and -180) were predominantly associated with higher lipid peroxidation (TBARS) [exp(β) = 1.09-1.78, p < 0.01-0.04)] and SOD activity [exp(β) = 1.13-1.48, p < 0.01-0.05)] levels. However, only a few associations were observed with glutathione system biomarkers, e.g., PCB-180 with total glutathione [exp(β) = 1.98, p = 0.03]. The WQS index was found to be positively associated with SOD activity, and PCB-138, PCB-180, and β-HCH were the main contributors to the index. Likewise, the WQS index was positively associated with TBARS levels, with the three PCBs acting as the main contributors. This is the first epidemiological evidence of the putative disruption by POPs of the adipose tissue oxidative microenvironment. Our results indicate that POP exposure may enhance alternative pathways to the glutathione detoxification route, which might result in tissue damage. Further research is warranted to fully elucidate the potential health implications.

Associations of maternal o,p'-DDT and p,p'-DDE levels with birth outcomes in a Bolivian cohort

This study examined the potential association of maternal serum levels of o,p'-DDT and p,p'-DDE with gestation time and with anthropometric measurements and thyroid-stimulating hormone (TSH) levels of newborns in a Bolivian birth cohort. Two hundred mothers were consecutively recruited between January and March 2013 at the "Hospital de la Mujer Dr. Percy Boland" in Santa Cruz de la Sierra. Potential confounders were derived from an ad hoc questionnaire. o,p'-DDT and p,p'-DDE were quantified in cord serum by high-resolution gas chromatography coupled with mass spectrometry. Multivariable linear regression analyses were performed, with POP concentrations as independent variables and log-transformed newborn birth outcomes (newborn weight, gestational age, head circumference, birth height, ponderal index, and TSH levels) as dependent variables. o,p'-DDT was detected in 82.5% of samples at median concentration of 0.22ng/mL and p,p'-DDE in 86.5% of samples at median concentration of 1.01ng/mL. Opposite associations with birth weight were found for p,p'-DDE (β=0.012, p=0.006) and o,p'-DDT (β=-0.014, p=0.039), and these associations were stronger when both chemicals were entered in the same model. p,p'-DDE was negatively associated with gestation time (β=-0.004, p=0.012), and o,p'-DDT was borderline negatively associated with newborn head circumference (β=-0.004, p=0.054). We observed no relevant changes in the magnitude of the coefficients or in statistical significance after adjustment for newborn TSH levels. This study indicates a possible impact of prenatal exposure to o,p'-DDT and p,p'-DDE on newborn anthropometric measurements in a population showing evidence of recent exposure to the pesticide DDT.

Effects of maternal diet and environmental exposure to organochlorine pesticides on newborn weight in Southern Spain

An appropriate eating pattern is essential during childbearing years and pregnancy to ensure a healthy pregnancy and newborn. Our group developed a Mediterranean Diet Score for Pregnancy (MDS-P) based on the MD and the specific need of pregnant women for Fe, Ca, and folic acid. Humans are daily exposed to endocrine disruptors, which may alter body weight and hormone system regulation. This study analyzed the relationship of maternal diet and in utero exposure to organochlorine pesticides (OCPs) with newborn weight in mothers and newborns from Southern Spain. Higher MDS-P score, folic acid supplementation, and greater in utero exposure to endosulfan-diol and endosulfan-1 were related to higher newborn weight. MDS-P score was not associated with maternal weight gain during pregnancy (above or below 12 Kg). Residues from one or more OCPs were detected in 96.5% of umbilical cord serum samples from 320 newborns. The most frequent residues were endosulfans (96.5%). The presence of endosulfan-diol, endosulfan-I, p-p´DDT, folic acid supplementation, and a higher MDS-P (>8) were predictive factors for newborn overweight (>3500 g). Conversely, smoking during pregnancy, shorter gestation time (32-36 vs. 37-39 weeks), and lesser maternal weight gain during pregnancy predicted lower newborn weight (<2500 g). These results indicate prenatal exposure to OCPs in Southern Spain and its possible impact on the weight of healthy full-term newborns. Further studies are warranted to interpret the consequences of this exposure and identify preventive measures. Adherence to the MD and folic acid supplementation during pregnancy emerged as predictive factors for overweight in newborns.

Serum and adipose tissue as matrices for assessment of exposure to persistent organic pollutants in breast cancer patients

The aim of this study was to assess differences between two biological matrices (serum and breast adipose tissue) in the evaluation of persistent organic pollutant (POP) exposure in breast cancer patients. The study population consisted of 103 women undergoing surgery for newly diagnosed breast carcinoma in a public hospital in Granada, Southern Spain. Independent variables were gathered from questionnaires and clinical records. POP concentrations were quantified in breast adipose tissue and serum samples. Spearman correlation tests were performed between pairs of POP concentrations and stepwise multivariable linear regression analyses were conducted to assess predictors of concentrations in the two matrices. p,p'- Dichlorodiphenyldichloroethylene (p,p'-DDE) showed the the highest median concentration in both matrices (194.34 and 173.84 ng/g lipid in adipose tissue and serum, respectively). Median wet-basis adipose tissue:serum ratios ranged from 109.34 to 651.62, while lipid-basis ratios ranged from 0.88 to 4.34. In general, we found significant positive correlation coefficients between pairs of POPs in adipose tissue and in serum, which were always higher in adipose tissue. We found positive and statistically significant correlations between serum and adipose tissue concentrations of p,p'-DDE and hexachlorobenzene (HCB) but not of polychlorinated biphenyls (PCBs). Age was positively associated with most POPs in adipose tissue and serum, while the body mass index was positively associated with adipose tissue HCB concentrations and negatively associated with serum PCB-153 and PCB-138 concentrations. Recent weight loss was inversely associated with POP residues in adipose tissue and positively associated with POP residues in serum. Serum HCB and PCB-180 concentrations were lower in patients who had received preoperative chemotherapy. According to our results, serum and adipose tissue POP concentrations in breast cancer patients may be differentially affected by external predictors. Taken together, these findings indicate the need to take account of the individual POP(s) under study and the biological matrix used when relating internal POP exposure to breast cancer disease and to make a careful selection of covariates for adjusting the model.

Associations of accumulated exposure to persistent organic pollutants with serum lipids and obesity in an adult cohort from Southern Spain

The aim of this research was to study the association of the accumulated human exposure to persistent organic pollutants with serum lipid levels and obesity, in a cohort of 298 adults. In the multivariable analyses, HCB concentrations evidenced a significant quadratic association with levels of total cholesterol, HDL, LDL, and total serum lipids. Likewise, PCBs 138 and 180 were associated with triglycerides and total serum lipids, and PCB 153 with LDL. HCB, p,p'-DDE, and β-HCH showed quadratic associations with BMI. All quadratic models showed a positive trend at low exposure levels, while the slope decreased or even became negative at higher exposure levels. Additionally, PCB 138 was positively associated with BMI but in a linear manner. Our results suggest a potential relationship between historical POP exposure and serum lipids/obesity, which followed a non-linear pattern in most cases.

Simultaneous determination of polybrominated diphenyl ethers and polychlorinated biphenyls by gas chromatography-tandem mass spectrometry in human serum and plasma

Sensitive and reliable methods for simultaneous determination of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in limited volumes of human serum or plasma need to be further documented especially when they accumulate at low levels that are still capable of disrupting endocrine and immune functions, and affecting neurodevelopment and reproduction. The objective of this study was to develop and validate a sensitive and quantitative method that simultaneously quantifies PBDEs and PCBs in 0.5 ml of human serum or plasma. We optimized a solid-phase extraction (SPE) method and used silica particle purification for the extraction of PBDEs and PCBs. Two multiple reactions monitoring (MRM) transitions were optimized for each congener. The sum of the transitions was used for quantification, and their abundance ratios were used for identification. The combined method optimization techniques resulted in limits of detection from 3 to 145 pg/ml for 10 PBDEs and 1-12 pg/ml for 15 PCBs. Method was solidly validated by analyzing serum fortified with a certified PBDE and PCB standard mixture from the National Institute of Standards and Technology (NIST). The accuracy was 88-118% and day-to-day precision was within 19%. The method was successfully applied to quantify native concentrations of PBDE and PCB in commercially available human serum. The sensitivity and selectivity of the GC/EI-MS/MS analysis enables it to be the method of choice for investigations of exposures to PBDE and PCB congeners, especially when sample volume is limited.

Human exposure to p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) in urban and semi-rural areas in southeast Spain: a gender perspective

p,p'-Dichlorodiphenyldichloroethylene (p,p'-DDE) is the main metabolite of pesticide dichlorodiphenyltrichloroethane and a marker of past exposure to this organochlorine pesticide. p,p'-DDE is considered a persistent organic pollutant with potential adverse effects on human health. The aims of the present study were to assess p,p'-DDE levels in serum and adipose tissue from a cohort of adults in southern Spain and to explore the predictors of exposure from a gender perspective. Chemical analyses were performed using gas chromatography-coupled mass spectrometry in tandem mode. The study population (n=387) was intraoperatively recruited in two areas of Granada Province (southern Spain), and data on potential predictors of these concentrations were gathered by questionnaire. The statistical analysis was performed by means of multivariable linear regression models. All participants showed detectable concentrations of p,p'-DDE in both serum and adipose tissue, with median concentrations of 175.7 and 93.0 ng/g lipid, respectively (p<0.001), and the two measurements showed positive correlations. Women showed higher concentrations than men (115.8 and 66.2 ng/g lipid, respectively, p<0.001). Concentrations in both matrices were positively associated with fatty food consumption, as well as with age and BMI, the latter only in adipose tissue. The multivariate model showed that, among women, adipose tissue concentrations were approximately 40% higher in those residing in the semi-rural area and 2-fold higher in those whose mothers had participated in agricultural activities during the pregnancy. In this study population, gender and place of residence play a key role in human exposure to p,p'-DDE and can be used to identify subjects at special risk of long-term exposure.

Serum concentrations of p,p'-dichlorodiphenyltrichloroethane (p,p'-DDE) in a sample of agricultural workers from Bolivia

Organochlorine pesticide p,p'-dichlorodiphenyltrichloroethane (DDT) is still used for vector control in several tropical and subtropical areas of South America and there is evidence of recent illegal use in agriculture. Its main breakdown product in the environment and living organisms is p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), which is considered a marker of past exposure to DDT. The aim of the present study was to assess human exposure to p,p'-DDE in a sample of agricultural farmers from three rural communities in eastern Bolivia. In addition, o,p'-DDT was analyzed as a surrogate of a potential ongoing exposure to the pesticide. Face-to-face questionnaires were performed, and serum samples were analyzed by high-resolution gas chromatography with mass spectrometry. p,p'-DDE was found in 100% of the samples, with a median concentration of 19.7ngmL(-1) (4788.7ng/g lipid), while o,p'-DDT was detected in 3 samples (4.3%). Serum p,p'-DDE concentrations were associated with time of residence in the study area, personal hygiene after work, and body mass index in adjusted multinomial logistic regression models with tertiles of p,p'-DDE as the dependent variable. The present results revealed high levels of exposure to p,p'-DDE, which might be derived from a heavily polluted local environment and past occupational exposure. These findings deserve further attention due to the potential associated health risks and point to the need for the continuous monitoring of these populations.

Adipose tissue concentrations of persistent organic pollutants and prevalence of type 2 diabetes in adults from Southern Spain

There is increasing evidence that environmental factors play an important role in the development of type 2 diabetes. Several persistent organic pollutants are suspected to contribute to the increasing prevalence and risk of type 2 diabetes. The aim of this study was to investigate the association of the body burden of three organochlorine pesticides and three polychlorinated biphenyls and the overall estrogenic activity with the risk of type 2 diabetes in a sample of adults from Southern Spain. Samples of adipose tissue and serum were obtained from 386 subjects undergoing non-cancer-related surgery and were extracted using validated methodologies. Residues of persistent organic pollutants were analyzed by means of high-resolution gas chromatography with a mass spectrometry detector in tandem mode. The overall estrogenicity of the adipose tissue extracts was measured by using the total effective xenoestrogen burden (TEXB) biomarker. Data on lifestyle, dietary habits, and health status were gathered from face-to-face interviews and clinical records. Statistical analyses were performed with unconditional logistic regression and different adjustment levels. In the models adjusted for adipose tissue origin, sex, age, and body mass index, the 2nd and 3rd tertiles of adipose tissue concentrations of p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) were positively associated with the risk of diabetes [odds ratios (95% confidence interval)=3.6 (0.8-17.3) and 4.4 (1.0-21.0), respectively]. A positive association with β-hexachlorocyclohexane was also found when body mass index and adipose tissue origin were removed from the models, with odds ratios (95% confidence interval) of 3.3 (1.0-10.4) and 5.5 (1.7-17.3), for the 2nd and 3rd tertiles of exposure, respectively. In addition, a statistically significant interaction was observed between p,p'-DDE and body mass index, such that the risk of diabetes increased with tertiles of exposure in a linear manner in non-obese subjects but not in the obese, in whom an inverted U-shape pattern was observed.

Factors influencing combined exposure to three indicator polychlorinated biphenyls in an adult cohort from Bolivia

Polychlorinated biphenyls are persistent organic pollutants that have been used for decades in several industrial applications. Although production of polychlorinated biphenyls was restricted from the 1970s in most countries, substantial amounts remain in old equipment and buildings and they have been detected in various environmental and biological matrices. The main objective of this study was to analyze predictors of the combined exposure to three non-dioxin-like polychlorinated biphenyls (congeners 138, 153 and 180) in serum and adipose tissue from an adult cohort (n=112) living in the city of Santa Cruz de la Sierra (Bolivia) and surrounding towns/villages. A second aim was to identify modifiers that might influence the statistical associations found, using crude, partially-adjusted, and global multiple linear regression models. Main predictors of serum concentrations were occupation and fatty food consumption, while those for adipose tissue concentrations included age, smoking habit, fatty food consumption, and residence. The differences between the two matrices might be derived from their biological meaning, given that adipose tissue concentrations are an indicator of chronic exposure to polychlorinated biphenyls while serum levels are a good predictor of ongoing exposure and the mobilization of polychlorinated biphenyls stored in fatty tissues. Body mass index was found to be an important modifier of these associations.

Contribution of sociodemographic characteristics, occupation, diet and lifestyle to DDT and DDE concentrations in serum and adipose tissue from a Bolivian cohort

The organochlorine pesticide p,p'-Dichlorodiphenyltrichloroethane (DDT) was widely used in the early 1960s-70s for vector control in tropical and subtropical areas of South America. Due to its persistence, DDT has a high potential to bioaccumulate in the food chain and living organisms and is a major public health concern, especially in South America. The main purpose of the present study was to investigate predictors of serum and adipose tissue concentrations of p,p'-DDT and its main metabolite, p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), in an adult cohort (n=112) from Santa Cruz de la Sierra, Bolivia, using multiple linear regression models. These models explained 29.3-47.8% of the variability in adipose tissue concentrations of p,p'-DDT and p,p'-DDE, respectively, and 32.9-47.0% of that in serum. Main exposure predictors included age, occupational class, residence, diet, smoking habit, and accumulated breastfeeding time. This is one of the few studies to explore predictors of human exposure to these chemicals using a multivariate approach in a South American population. Results show that predictors of human exposure to p,p'-DDT and p,p'-DDE in Santa Cruz de la Sierra may diverge from those found in other populations of the world, due to particular sociodemographic and lifestyle characteristics of this region.

Multivariate models to predict human adipose tissue PCB concentrations in Southern Spain

The use of Polychlorinated biphenyls (PCBs) has been severely restricted due to their high toxicity and persistency in the environment. However, the presence of PCBs in human tissues nowadays is still been reported worldwide. Background exposure predictors of the human PCB body burden require more precise understanding. In the present study, PCB congeners 138, 153, and 180 were quantified in adult adipose tissue samples (n=387) from Granada Province (Southern Spain) and data on potential predictors of PCB concentrations were gathered by questionnaire. Chemical analysis of the selected congeners was done by gas chromatography and mass spectrometry, and multivariate analyses were performed stratifying by gender. PCB residues were quantified in 92% (PCB 153), 90% (PCB 180), and 86% (PCB 138) of the population. Geometric mean concentrations were 161.65+/-4.41 ng/g lipid for PCB 153, 111.62+/-6.27 ng/g lipid for PCB 180, and 38.41+/-8.61 ng/g lipid for PCB 138. Multivariate models explained 30-36% of the variability in PCB concentrations. Age and body mass index (BMI) predicted exposure in both males and females and were positively correlated with the concentration of the three PCB congeners. Occupation and diet predicted exposure in the males, whereas only dietary predictors were observed in the females. Further in-depth studies are required to investigate the influence of dietary habits on the bioaccumulation of PCBs and to evaluate the impact of policies aimed at reducing human exposure.

Endosulfan, a global pesticide: a review of its fate in the environment and occurrence in the Arctic

This review investigates the fate and behaviour of endosulfan, a current-use organochlorine pesticide, in temperate environments and the Arctic. Usage data and patterns, physical-chemical properties, environmental partitioning and degradation, environmental levels, global distribution and temporal trends are evaluated and discussed in the context of criteria that designate a substance as a persistent organic pollutant. Endosulfan is one of the most abundant OC pesticides in the global atmosphere and is capable of undergoing long range transport to remote locations such as the Arctic. Degradation of the two isomers, alpha- and beta-endosulfan, does occur in temperate/tropical soil and aquatic systems, both by abiotic and biotic processes, although this is highly dependent on the prevailing environmental conditions. Endosulfan sulfate is the major metabolite and this recalcitrant compound has been detected in air and is present in remote mountain lake sediments, although in comparison to alpha-endosulfan, data for this compound in the wider environment are lacking. Temporal trends from ice/snow cores as well as mountain lake sediments reveal a marked increase in endosulfan accumulation from the 1980s onwards. Furthermore, unlike other 'legacy' OC pesticides, levels of alpha-endosulfan do not show a decline in atmospheric monitoring data, reflecting ongoing use of this pesticide in the northern hemisphere. Endosulfan is present at low concentrations (relative to the pesticide, lindane) in surface Arctic Ocean waters, with the atmosphere likely to be the major contemporary source. Residues of endosulfan have been detected in marine biota for different geographical regions of the Arctic, with higher bioaccumulation factors (>10(3)-10(7)) for zooplankton and various species of fish, compared to studies in warmer/temperate systems. Endosulfan is present in marine mammals, although there is uncertainty in the various Arctic biota datasets due to differences in analytical techniques. For some biota, biomagnification factors for alpha-endosulfan are >1, notably from fish to seal, although there is a wide variability in values between the same species for different regions of the Arctic. There is little if any evidence of trophic magnification of alpha-endosulfan in well-defined marine foodwebs, with some evidence of bio-dilution at higher trophic levels, presumably due to increased metabolism. Endosulfan does fulfil several of the criteria under the UNEP Stockholm Convention for designation as a persistent organic pollutant. The alpha- and beta-isomer have similar physical-chemical properties and environmental behaviour to some of the obsolete organochlorine pesticides, although an assessment of their persistence and toxicity should be viewed alongside endosulfan sulfate, as 'Sigmaendosulfan'. Persistence of 'Sigmaendosulfan' coupled to ongoing use of endosulfan pesticides, will ensure continued long-range transport and contamination of remote environments.

Estimating uncertainty in analytical procedures based on chromatographic techniques

Chromatographic techniques are very frequently used in analytical procedures for the separation, determination and identification of a wide spectrum of analytes present in samples with complex and sometimes variable matrices. However, the estimation of uncertainty of the final results does not include the uncertainties associated with the actual chromatographic process. In effect, such results cannot always be treated as a reliable source of analytical information. In this paper we present the basic terms, sources of uncertainty, and methods of calculating the combined uncertainty that any presentation of final determinations should include.

Exposure of mother-child and postpartum woman-infant pairs to DDT and its metabolites in Tianjin, China

1,1,1-trichloro-2,2'-bis(4-chlorophenyl)ethane (DDT) exhibits its long persistence in the environment, unusual bioaccumulation, effects on wildlife, and the possibility of long-term adverse effects on human health, especially reproductive toxicity. Despite the prohibition of most persistent organochlorine pesticides in China, the presence of organochlorine residue, including DDT, has been widely indicated in environmental substance. However, scarce information is available about accumulative levels of DDT in human tissues in China. To evaluate levels of DDT and its potential effects on women and children's health in a Chinese pesticide-exposed area, we recruited 50 pairs of mother-child and 50 postpartum women, and determined the levels of total DDT and its four main metabolites (p,p'-DDE, p,p'-DDT, p,p'-DDD, o,p'-DDT) in venous blood, breast milk and umbilical blood cord by gas chromatography. Accordingly, data on reproductive outcomes of mothers and postpartum women and healthy status of children and infants were gathered through a questionnaire and medical examinations. Furthermore, we also assayed the DDT levels of some environmental samples (soil, food, milk, et al.). The levels of DDT in children's blood were higher than that in the women's. As compared to breast milk, the umbilical blood cord and the ventral fat individually demonstrated a significantly lower and higher level of DDT in the postpartum women. DDT was lower in milk and crucian carp than in the soil near the chemical plant. p,p'-DDT and p,p'-DDE were the main metabolites of DDT. Our findings suggested the cumulative effect of DDT in human body in Tianjin, China.

Organochlorine pesticide exposure in children living in southern Spain

Despite the prohibition of most persistent organochlorine (OC) pesticides in Spain, their presence has been widely documented in adult human tissues. However, scarce information is available on the exposure of children. The aim of the present study was to investigate the presence of 16 OC pesticide residues in 52 fat samples collected from boys with a mean age of 7yr (0-15yr) living in Southern Spain and to assess the association between OC pesticide levels and child characteristics. No pesticide was found in more than 50% of samples, except for p,p'-DDE (79% of samples; median, 710ng/g lipid). After this compound, the most frequent pesticides were o,p'-DDT (17%; median, 330ng/g lipid) and o,p'-DDD (15%; median, 1510ng/g lipid). No statistically significant association was found between p,p'-DDE or SigmaDDTs and the birth year, birth weight, gestational age, infant feeding history or the age, weight, height or Quetelet Index at the time of sampling. The lack of correlation between the presence of the main metabolite p,p'-DDE and that of the parent compounds, o,p'-DDT and p,p'-DDT, suggests that children were exposed mainly to the metabolite rather than to the commercial pesticide, which was banned 30yr ago. In contrast, among currently used OCs, endosulfan was positively correlated with the presence of its metabolites, suggesting exposure to the commercial products. Further research is warranted to investigate the health consequence in children resulting from exposure to chemicals suspected of endocrine-disrupting effects.

Exposure of young men to organochlorine pesticides in Southern Spain

It has been hypothesized that endocrine disruptors and especially synthetic estrogenic environmental contaminants (xenoestrogens) are etiologic factors in the global decrease of sperm counts and other problems of the male reproductive tract, including cryptorchidism, hypospadias, and testicular cancer. This possibility has prompted research into the current and historical incidence of these diseases. The largest area of intensive greenhouse agriculture in Europe is near the Mediterranean coast of Southern Spain, where this activity has greatly expanded since the 1960s. We determined and compared levels of 14 organochlorine pesticides in the blood of 220 young males in Southern Spain. Aldrin, dieldrin, endrin, lindane, methoxychlor, endosulfans, and DDT and its metabolites were identified. Detectable concentrations of p,p'-DDE were found in 96% of serum samples. Among the remaining DDTs, o,p'-DDD was the most prevalent, detected in 65% of serum samples. Detectable concentrations of endosulfan I or II or their metabolites endosulfan-diol, or -sulfate were found in all samples; endosulfan-diol was the most frequently detected metabolite (92%) followed by sulfate. Results indicate that men of reproductive age in Southern Spain have been and are exposed to organochlorine pesticides. Because many of these chemicals have estrogenic and anti-androgenic activity, further research is warranted to interpret the male reproductive health consequences of this exposure.

Environmental and lifestyle factors for organochlorine exposure among women living in Southern Spain

Southern Spain has the largest area of intensive greenhouse agriculture in Europe, and may constitute a special case of occupational and female exposure, because this type of farming requires considerable pesticide use and employs many women. We measured adipose tissue levels of 14 organochlorine pesticides in 458 women living in this area and analyzed the relationship between pesticide level/presence and sociodemographic characteristics, reproductive history or life-style factors that may influence this exposure. Pesticide presence was determined by gas chromatography with electron-capture detector. All fat samples were positive for 1 residue. DDT or metabolites were found in 98.25%, with mean value of 660 ngg(-1) of lipid. p,p'-DDE level was higher in women who were older, with lower educational level or obese. Almost 70% had measurable levels of endosulfan and/or metabolites, with a mean total value of 38.8 ngg(-1) of lipid. Endosulfan-I exposure was higher in women with shorter residence in rural settings and more frequent in women with 3 children. 52.62% were exposed to 1 of aldrin-dieldrin-endrin group. Endrin was more frequent in women who were younger, with higher educational level or no agricultural working experience; dieldrin was more frequent in women who were older, with lower educational level or more children. Finally, lindane residues were found in 39.30%. Lindane levels were higher in women who breastfed longer or had more children. Research is required on women occupationally exposed to a selected group of organochlorine pesticides, especially those of reproductive age, as a basis for preventive action.

Relative concentrations of organochlorines in adipose tissue and serum among reproductive age women

Much of the available literature focusing on organochlorine exposure and human health effects has relied upon serum for quantifying exposure despite adipose tissue being the purported "gold standard". The accuracy of exposure status is dependent upon serum being a valid and reliable proxy for adipose tissue regardless of compound under study and served as the impetus for study. Serum and omentum fat concentrations for 62 polychlorinated biphenyls (PCBs) and 7 organochlorine pesticides (OCPs) were determined using gas chromatography with electron capture and compared to assess their relative abundance and correlation among 15 women aged 18-40 years undergoing laparoscopy. The relation between concentration in serum and fat was determined by linear regression. Of the 20 organochlorines (OCs) (29%) present in both serum and fat samples, moderate linear correlations (r > 0.6) were observed between lipid-adjusted serum and fat concentrations for PCBs #138, 153, 180, 188, 194, 206, and DDE. Forty-nine OCs were present in adipose samples but measured below the LOD in serum samples. Our findings underscore the potential for discrepant human health results associated with OC exposure on the basis of medium used for quantification purposes, especially for less ubiquitous compounds or when study samples include individuals with relatively low exposures. These data support earlier findings and argue for concerted methodological work aimed at developing standardized laboratory methods for epidemiologic studies.

Exposure of women to organochlorine pesticides in Southern Spain

Organochlorine pesticides are lipophilic compounds that persist in the environment. Because of their lipid solubility and resistance to metabolism, some of these chemicals accumulate in human tissues. The largest area of intensive greenhouse agriculture in Europe is near the Mediterranean coast of Southern Spain, where this type of farming has greatly expanded since the 1960s. We determined and compared the levels of 15 organochlorine pesticides in the adipose tissue and blood of 200 women living in Southern Spain. Aldrin, dieldrin, endrin, lindane, methoxychlor, endosulfans, and DDT and its metabolites were identified. Detectable concentrations of p,p'-DDE were found in 100% of adipose tissue and serum samples. Among the remaining DDTs, p,p'-DDT was the most common, being detected in 39% of adipose tissue and 76.5% of serum samples, followed by endosulfans I and II, which also were found in both adipose tissue and serum samples but at lower concentrations. Endosulfans were followed in frequency by lindane, aldrin, and dieldrin. Endrin and methoxychlor were present at a much lower frequency compared to those of the other organochlorines. Serum concentrations of p,p'-DDE o,p'-DDD, and endosulfan -I, -sulfate, -lactone, and -diol were significantly correlated with their adipose tissue concentrations. No significant relationships were found between the serum and adipose tissue concentrations of the remaining nine compounds determined, raising doubts about the equivalent use of fat/serum samples for the exposure assessment of some pesticides in epidemiological studies. The results suggested that women of reproductive age in Southern Spain have been and are currently exposed to organochlorine pesticides. Because many of these chemicals can mobilize during pregnancy and lactation, further research is warranted to interpret the health consequences for the children of such exposure.

Determination of Low-level Pesticide Residues in Agricultural Products by Ion-trap GC/MS/MS

The objective of this study was to elucidate the utility of ion-trap GC/MS/MS for the analysis of pesticides in extracted matrices from various agricultural products. Identification and quantitative analysis of pesticides in matrices were performed by quadrupole GC/MS and ion-trap GC/MS/MS. Chlorpyrifos was added to the matrix of spinach, soybean in the pod or corn, and aldrin, dieldrin, endrin, alpha-BHC, beta-BHC, gamma-BHC, delta-BHC, p,p'-DDD, p,p'-DDE, o,p'-DDT and p,p'-DDT were added to each matrix of green tea, black tea or oolong tea. Although most of the pesticides in the matrix could not be determined by quadrupole GC/MS-Scan analysis at 0.1 microgram/mL, every pesticide was identified from the mass spectrum using ion-trap GC/MS/MS at the same concentration. The quantitation limit of every pesticide in each matrix by ion-trap GC/MS/MS analysis was higher than that by GC/MS-SIM analysis. The calibration curves obtained by GC/MS/MS were linear in the range of 0.01-0.25 microgram/mL of each pesticide. The recoveries of each pesticide from four kinds of samples spiked at the levels of 0.01 ppm to 0.02 ppm in extracts were 61.2-138.3% with SD values in the range from 1.2 to 15.4%. This study revealed that ion-trap GC/MS/MS was useful for the identification and quantitative analysis of low-level pesticides residues in matrices of agricultural products.