Concentrations of organochlorine pesticides in pooled human serum by age and gender

Organochlorine pesticides and risk of papillary thyroid cancer in U.S. military personnel: a nested case-control study

BACKGROUND

The effects of organochlorine pesticide (OCP) exposure on the development of human papillary thyroid cancer (PTC) are not well understood. A nested case-control study was conducted with data from the U.S. Department of Defense Serum Repository (DoDSR) cohort between 2000 and 2013 to assess associations of individual OCPs serum concentrations with PTC risk.

METHODS

This study included 742 histologically confirmed PTC cases (341 females, 401 males) and 742 individually-matched controls with pre-diagnostic serum samples selected from the DoDSR. Associations between categories of lipid-corrected serum concentrations of seven OCPs and PTC risk were evaluated for classical PTC and follicular PTC using conditional logistic regression, adjusted for body mass index category and military branch to compute odds ratios (OR) and 95% confidence intervals (CIs). Effect modification by sex, birth cohort, and race was examined.

RESULTS

There was no evidence of associations between most of the OCPs and PTC, overall or stratified by histological subtype. Overall, there was no evidence of an association between hexachlorobenzene (HCB) and PTC, but stratified by histological subtype HCB was associated with significantly increased risk of classical PTC (third tertile above the limit of detection (LOD) vs. Collapse

Key Words

• Hexachlorobenzene
• Hexachlorocyclohexane
• Organochlorine pesticides
• Papillary thyroid cancer

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MESH Headings

• Male
• Humans
• Female
• Military Personnel
• Thyroid Cancer, Papillary/epidemiology
• Hexachlorobenzene
• Case-Control Studies
• Pesticides
• Hydrocarbons, Chlorinated
• Thyroid Neoplasms/chemically induced
• Thyroid Neoplasms/epidemiology
• Hexachlorocyclohexane

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Grants

• R01ES020361 NIH HHS
• R01ES020361 NIH HHS
• National Institutes of Health
• Murtha Cancer Center Research Program
• Oak Ridge Associated Universities
• National Cancer Institute Intramural Research Program

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Affiliation(s) Collapse

Cross-sectional and longitudinal associations of dichlorodiphenyltrichloroethane (DDT) metabolites exposure with lung function alternation in the Chinese general adults

Exposure of dichlorodiphenyltrichloroethane (DDT) pesticide was suggested to be associated with adverse effects on the respiratory system. However, the effects of DDT exposure on lung function remain unclear. Our objectives were to investigate the potential associations of internal levels of DDT and its metabolites including dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD) with lung function. Serum DDT, DDE, and DDD concentrations and lung function were measured among 3968 general adults from the Wuhan-Zhuhai cohort. The cross-sectional and longitudinal associations of serum DDT and its metabolites with lung function were assessed using linear mixed models. The results showed negative dose-response relationships of serum DDT, DDE, and DDD levels with forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). In the cross-sectional analyses, each 1-unit increase in natural log-transformed values of p,p'-DDE, o,p'-DDT, o,p'-DDE, or p,p'-DDD was significantly associated with a 25.77-, 44.84-, 51.13-, or 43.44-mL decrease in FVC, respectively. Each 1-unit increase in natural log-transformed values of o,p'-DDT, o,p'-DDE, o,p'-DDD, or p,p'-DDD was significantly associated with a 35.72-, 31.87-, 29.54-, or 36.80-mL decrease in FEV1, respectively. In the three-year longitudinal analyses, each 1-unit increase in natural log-transformed serum p,p'-DDT and p,p'-DDE was significantly associated with a 35.10 mL and 36.38 mL decrease in FVC, and a 26.32 mL and 32.37 mL decrease in FEV1, respectively. In conclusion, DDT and its metabolites exposure were associated with lung function decline in the general Chinese adult population.

Advances in Microfluidics Techniques for Rapid Detection of Pesticide Residues in Food

Food safety is a significant issue that affects people worldwide and is tied to their lives and health. The issue of pesticide residues in food is just one of many issues related to food safety, which leave residues in crops and are transferred through the food chain to human consumption. Foods contaminated with pesticide residues pose a serious risk to human health, including carcinogenicity, neurotoxicity, and endocrine disruption. Although traditional methods, including gas chromatography, high-performance liquid chromatography, chromatography, and mass spectrometry, can be used to achieve a quantitative analysis of pesticide residues, the disadvantages of these techniques, such as being time-consuming and costly and requiring specialist staff, limit their application. Therefore, there is a need to develop rapid, effective, and sensitive equipment for the quantitative analysis of pesticide residues in food. Microfluidics is rapidly emerging in a number of fields due to its outstanding strengths. This paper summarizes the application of microfluidic techniques to pyrethroid, carbamate, organochlorine, and organophosphate pesticides, as well as to commercial products. Meanwhile, the study also outlines the development of microfluidics in combination with 3D printing technology and nanomaterials for detecting pesticide residues in food.

Cellulose Nanocrystals Induced Loose and Porous Graphite Phase Carbon Nitride/Porous Carbon Composites for Capturing and Determining of Organochlorine Pesticides from Water and Fruit Juice by Solid-Phase Microextraction

Herein, novel, loose, and porous graphite phase carbon nitride/porous carbon (g-C₃N₄@PC) composites were prepared by decorating cellulose nanocrystals (CNCs). The characterization results demonstrate that the as-prepared composites presented high specific surface areas, porous structures, and abundant chemical groups, with the modification of CNCs. In view of the unique advantages, g-C₃N₄@PC was used as the coating material for the solid-phase microextraction (SPME) of organochlorine pesticides (OCPs) in water and juice samples. The g-C₃N₄@PC-coated fibers showed better extraction efficiencies than commercial fibers (100/7 μm PDMS and PA) toward the OCPs, with the enrichment factors of the g-C₃N₄@PC-coated fibers 5-30 times higher than the latter. Using a gas chromatography-mass spectrometry (GC-MS) instrument, the g-C₃N₄@PC-coated fibers exhibited a gratifying analytical performance for determining low concentrations of OCPs, with a wide linear range (0.1-1600 ng L^-1 for water; 0.1-1000 ng L^-1 for juice), low limits of detection (0.0141-0.0942 ng L^-1 for water; 0.0245-0.0777 ng L^-1 for juice), and good reproducibility and repeatability in optimal conditions. The established method showed good sensitivity and recovery in the determination of OCPs in the water and fruit juice samples, which displayed broad prospects for analyzing organic pollutants from environmental samples.

Biomonitoring of organochlorine pesticides and cancer survival: a population-based study

Organochlorine pesticides (OCPs) are endocrine-disrupting chemicals (EDCs) that even at very low levels can cause cancer by increasing the activity of tumor cells and suppressing the immune system. There is also little information on OCPs and survival after diagnosis. The aim of this study was to monitor the concentration of OCPs in the blood serum of cancer patients and its relationship with their socio-demographic characteristics and ultimately that impact on survival time and hazard ratio (HR). This cross-sectional study included 89 diagnosed patients with cancer in Isfahan, Iran. 12 types of OCPs were measured in serum by gas chromatography (7GC) with an electron capture detector and equipped with mass spectrometer (MS). Also, participants' questionnaire was completed to collect information. T-test, ANOVA, and Chi-square tests were used to evaluate the association between serum levels of OCPs and quantitative and qualitative information of patients. Survival analysis was also examined based on Kaplan-Meier method, log-rank test, and Cox model. The mean of total OCPs in patients' serum was calculated to be 1.82 ± 1.36 μg/L. Concentration of 2,4' DDE had a significant relationship with body mass index (BMI) (kg/m²) (P < 0.05). In addition, gender revealed a significant correlation in estimating survival time (P < 0.05). Non-exposure to OCPs showed a positive effect on increasing the life expectancy of patients. Lindane and endosulfan increased the risk of death by 16% and 37%, respectively, with insignificant P value (P > 0.05). The findings of the present study showed adverse effects of OCPs on patients' survival time and increased mortality of HR. Moreover, as the first research conducted in the study area, it is suggested management of environmental, individual and social factors that could be influenced the biological accumulation of OCPs in humans and cause health promotion.

Organochlorine pesticides and polycyclic aromatic hydrocarbons in serum of Beijing population: Exposure and health risk assessment

Organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants, but large-scale human biomonitoring and health risk assessment data on these contaminants remain limited. In this study, concentrations of 6 OCPs and 5 PAHs were determined by GC-MS/MS in 1268 human serum samples which were collected from the participants in 2017 Beijing Chronic Disease and Risk Factor Surveillance. The detection frequencies of OCPs and PAHs ranged from 64.7 % to 96.5 % and 89.4 % to 99.6 %, respectively. The most abundant contaminants in OCPs and PAHs were pentachlorophenol (PCP) and pyrene (Pyr) with median concentrations reaching up to 3.13 and 8.48 μg/L, respectively. Nonparametric tests were employed to assess the correlations among contaminants levels, demographic characteristics (age, gender, body mass index, residence) and serum biochemical indexes. Significantly higher serum levels of all PAHs were observed in suburb residents than that in urban residents (P < 0.001). Binary logistic regression analysis demonstrated that exposure to benzo(a)pyrene (OR 2.17 [1.29, 3.63]), phenanthrene (OR 1.06 [1.02, 1.11]), fluoranthene (OR 1.04 [1.02, 1.07]) and Pyr (OR 1.02 [1.01, 1.03]) might increase the occurrence of hyperglycemia, and exposure to hexachlorobenzene (HCB) (OR 1.53 [1.05, 2.22]) and pentachlorobenzene (OR 1.14 [1.02, 1.27]) were positively associated with hyperlipidemia. Furthermore, the hazard quotients (HQs) for serum HCB, PCP and p,p'-dichlorodiphenyldichloroethylene were calculated based on health-based guidance values to predict health risks. 0.2 % and 4.3 % of serum samples showed HQ values exceeding 1 for HCB and PCP, respectively, in case of the non-carcinogenic risk, while 23.1 % of HQs for HCB were above 1 in case of the carcinogenic risk for a risk level 10^-5. Our study reveals that the body burden of the Beijing general population relative to OCPs and PAHs was nonnegligible. The past exposure of HCB and PCP might adversely affect the health status of the Beijing population.

Simultaneous determination of 35 organochlorine pesticides and polychlorinated biphenyls in the serum of the general population in Wuhan by solid phase extraction-gas chromatography-tandem mass spectrometry

有机氯农药(OCPs)和多氯联苯(PCBs)是两类重要的持久性有机污染物,可在环境介质中长期存在,并通过多种途径进入人体,导致人体的高暴露风险。OCPs和PCBs对人体存在诸多健康危害,精准定量人体内OCPs和PCBs的暴露水平是健康效应评价的关键。该研究基于固相萃取-气相色谱-串联质谱联用技术(SPE-GC-MS/MS)建立了同时检测100 μL血清中35种OCPs和PCBs的分析方法。血清样品经尿素沉淀蛋白后,采用Oasis^® HLB小柱净化,正己烷-二氯甲烷混合溶液(1∶1, v/v)洗脱,氮吹近干,正己烷定容,多反应监测(MRM)模式检测,内标法定量分析。结果表明,OCPs和PCBs在0.05~50.0 ng/mL范围内线性关系良好,检出限在1.2~71.4 ng/L之间。35种目标分析物的加标回收率在72.6%~142%之间,相对标准偏差小于25%。利用所建立的方法检测了武汉市普通人群血清样本中OCPs和PCBs的浓度水平,结果表明武汉市普通人群广泛暴露于OCPs和PCBs,且以OCPs为主。有8种OCPs和7种PCBs检出率高于50%,其中p,p'-滴滴伊、p,p'-滴滴滴和甲氧滴滴涕检出率达100%,非类二噁英PCBs是PCBs的主要成分。血清中OCPs浓度随年龄增长呈升高趋势,在60岁以上存在性别差异;不同性别、年龄人群血清中PCBs浓度无统计学差异。该方法样本用量少,操作简便,具有较高的准确度和精密度,适用于环境健康研究中大量人群血清样本中痕量OCPs和PCBs的生物监测。

Temporal Trends of Exposure to Organochlorine Pesticides in the United States: A Population Study from 2005 to 2016

The current study aimed to investigate temporal trends of serum organochlorine pesticide (OCP) concentrations in the general United States population, approximately 30 years after the prohibition of OCP usage, by using National Health and Nutrition Examination Survey data. The least square geometric means and percent change in OCP concentrations were calculated by a survey weighted multiple linear regression model. Over 2005–2016, OCP concentrations showed significant downward temporal trends. Females had substantially higher concentrations of β-Hexachlorocyclohexane (β-HCH), p,p′-DDE and p,p′-DDT, but lower concentrations of Hexachlorobenzene (HCB) and trans-nonachlor. In addition, females had a more rapid decrease in p,p′-DDT levels over time than males. The overall OCP concentrations increased with age, and the two oldest age groups (aged 40–59 and 60+ years) had substantially lower rates of decrease than the younger age groups (aged 12–39 years). Concentrations and declines in OCPs (except for trans-nonachlor) were higher in Mexican Americans than both non-Hispanic Whites and non-Hispanic Blacks. There is a particular need for the ongoing monitoring of these banned chemicals, and measures should be taken to mitigate the exposure of vulnerable populations, including adults aged over 60, Mexican Americans, females for β-HCH, p,p′-DDE and p,p′-DDT, and males for HCB and trans-nonachlor.

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.

Monitoring temporal trends of dioxins, organochlorine pesticides and chlorinated paraffins in pooled serum samples collected from Northern Norwegian women: The MISA cohort study

The ubiquitous presence of legacy and emerging persistent organic pollutants (POPs) in the environmental matrices poses a potential hazard to the humans and creating public health concerns. The present study aimed to evaluate dioxins, dioxin-like polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and chlorinated paraffins (CPs) concentrations in serum of women (postpartum, pregnant and non-pregnant) from Northern Norway to better understand their exposure and contamination status as well as temporal trends across 2007-2009 (MISA 1) to 2019 (MISA 2). Sixty-two blood samples from the MISA 1 cohort and 38 samples from MISA 2 were randomly selected in this study (n = 100). Ninety samples from postpartum (MISA 1) and pregnant women (MISA 2) were randomly combined into 9 pools, with 9-11 individual samples contributing to each pool keeping the groups of pregnant and postpartum women. Remaining 10 samples from non-pregnant women (MISA 2) were allocated into separate group. Geometric mean, minimum and maximum were used to describe the serum concentrations of pooled POPs in MISA cohort. Mann-Whitney U test and independent sample t-test were applied for trend analysis of blood levels of POPs between MISA 1 and MISA 2. We found the serum concentrations of selected POPs in this study to be at lower range. Serum concentrations of dibenzo-p-dioxins (PCDDs) (p = 0.010), polychlorinated dibenzofurans (PCDFs) (p = 0.002), dioxins-like PCBs (p = 0.001), hexachlorobenzene (HCB) (p < 0.001) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) (p = 0.002) were decreased between the studied time. In contrast, the serum concentrations of medium chain chlorinated paraffins showed an increasing trend between 2007 and 2009 and 2019 (p = 0.019). Our findings report a particular concern of emerging contaminant medium chain chlorinated paraffin exposure to humans. Future observational studies with repeated measurements of chlorinated paraffins in general populations worldwide and large sample size are warranted.

Health risk assessment of exposure to organochlorine pesticides in the general population in Seoul, Korea over 12 years: A cross-sectional epidemiological study

This study evaluated the 12-year trends in serum levels of 28 organochlorine pesticides (OCPs) in 880 adults living in Seoul, Korea. The OCP levels decreased from 2006 to 2017, and p,p'-dichlorodiphenyldichloroethylene was a predominant compound. OCP levels were higher in females than in males, and showed positive associations with BMI and age. The OCP concentrations had inverted U-shaped associations with low-density lipoprotein cholesterol and total cholesterol. Concentrations of β-hexachlorocyclohexane were significantly higher in patients with hypertension than in participants that were normotensive. OCP levels showed positive associations with uric acid, creatinine, and thyroid-stimulating hormone, but negative associations with free thyroxine. Participants with diabetes had significantly higher OCP levels than those without it. Principal component analysis suggested possible differences in disease manifestation depending on the composition of OCPs. These results suggest that OCPs might disturb renal transport and thyroid homeostasis. To our knowledge, the inverted U-shaped associations of heptachlor epoxide and endosulfan with cholesterol, the epidemiological associations of trans-nonachlor and endosulfan with thyroid hormones, and the association of p,p'-DDE with hyperuricemia have not been previously reported in general population. This is the first long-term study to show trends of 28 OCPs in serum and associations with various health indicators in Korea.

Biomonitoring of 89 POPs in blood serum samples of Czech city policemen

In this biomonitoring study, we evaluated the concentrations of 8 polychlorinated biphenyls (PCBs), 11 organochlorinated pesticides (OCPs), 33 brominated flame retardants (BFRs), 7 novel brominated and chlorinated flame retardants (novel FRs) and 30 per- and polyfluoroalkylated substances (PFAS) in human serum samples (n = 274). A total of 89 persistent organic pollutants (POPs) were measured in blood serum samples of city policemen living in three large cities and their adjacent areas (Ostrava, Prague, and Ceske Budejovice) in the Czech Republic. All samples were collected during the year 2019 in two sampling periods (spring and autumn). The identification/quantification of PCBs, OCPs, BFRs, novel FRs and PFAS was performed by means of gas chromatography coupled to (tandem) mass spectrometry (GC-MS/(MS)) and ultra-high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UHPLC-MS/MS). The most frequently detected pollutants were perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorooctanesulfonate (PFOS), perfluorohexanesulfonate (PFHxS), 2,2',3,4,4',5'-hexachlorobiphenyl (CB 138), 2,2',4,4',5,5'-hexachlorobiphenyl (CB 153), 2,2',3,3',4,4',5-heptachlorobiphenyl (CB 170), 2,2',3,4,4',5,5'-heptachlorobiphenyl (CB 180), hexachlorobenzene (HCB), and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) quantified in 100% of serum samples. In the serum samples, the concentrations of determined POPs were in the range of 0.108-900 ng g^-1 lipid weight (lw) for PCBs, 0.106-1016 ng g^-1 lw for OCPs, <0.1-618 ng g^-1 lw for FRs and <0.01-18.3 ng mL^-1 for PFAS, respectively. Locality, sampling season, and age were significantly associated with several POP concentrations. One of the important conclusions was that within the spring sampling period, statistically significant higher concentrations of CB 170 and CB 180 were observed in the samples from Ostrava (industrial area) compared to Prague and Ceske Budejovice. Older policemen had higher concentrations of five PCBs and two OCPs in blood serum.

Evaluating the Level of Pesticides in the Blood of Small-Scale Farmers and Its Associated Risk Factors in Western Ethiopia

BACKGROUND

The presence of agricultural pesticide residue can cause adverse health effects.The main objective of this study was to evaluate the level of pesticides in the blood of small-scale farmers (SSFs) and associated risk factors in western Ethiopia.

METHODS

Across sectional study was conducted in June 2020 using 240 blood samples, 140 from the exposed small-scale farmers (ESSFs) and 100 from non-exposed small-scale farmers (NESSFs). The blood sample analysis was mad for 5 organochlorines (OCs) and 3 synthetic pyrethroids (SPs) pesticides by gas-liquid chromatography with an electron capture detector (GC-ECD) methods. Extraction, and clean up of the samples were made by using standard analytical methods. To define the relationships between the outcomes and explanatory variables, logistic regression models were used.

RESULTS

The results shows that p,p'-DDT, heptachlor and deltamethrin were the most frequently detected pesticides with 96.4%, 95%, and 100% in both ESSFs and NESSFs, respectively. The ESSFs blood samples have shown the highest mean concentrations of permethrin and p,p'-DDT(1.26 ± 0.15) and (0.28 ± 0.4) mgL^-1, respectively. SSFs under the age of 40 were 21% less likely to be exposed to permethrin than those above the age of 40 (Adjusted Odd Ratio, AOR, 0.21; 95% CI: 0.1-0.44). Male SSFs were 17 times more likely to be exposed to heptachlor than females (AOR, 17.36; 95%CI: 7.34-41.09) and farmers with no formal education were 18 times more likely to be exposed to deltamethrin than those with primary schools and beyond (AOR, 18.1; 95 %CI: 4.53-72.06). Furthermore, SSFs that did not use PPE appropriately were 3.6 and 6.21 times more likely to be exposed to cypermethrin (AOR, 3.6; 95%CI: 1.94-6.54) and p,p'-DDE(AOR, 6.21; 95%CI: 3.38-11.41) blood levels than those who did, respectively. SSFs that perform different activities like eating and drinking (11%), chewing (10%), and diverse activities (8%) were more likely to be exposed to p,p'-DDT than those farmers who didn't use pesticides.

CONCLUSIONS

This study identified a high concentration p,p'-DDE, p,p'-DDT, heptachlor, cypermethrin, permethrin, and deltamethrin in the blood of small scale farmers. The older age, less education, and farmers with inappropriate PPE use are more likely exposed to pesticides.

The pesticide chlorpyrifos promotes obesity by inhibiting diet-induced thermogenesis in brown adipose tissue

Obesity results from a caloric imbalance between energy intake, absorption and expenditure. In both rodents and humans, diet-induced thermogenesis contributes to energy expenditure and involves the activation of brown adipose tissue (BAT). We hypothesize that environmental toxicants commonly used as food additives or pesticides might reduce BAT thermogenesis through suppression of uncoupling protein 1 (UCP1) and this may contribute to the development of obesity. Using a step-wise screening approach, we discover that the organophosphate insecticide chlorpyrifos suppresses UCP1 and mitochondrial respiration in BAT at concentrations as low as 1 pM. In mice housed at thermoneutrality and fed a high-fat diet, chlorpyrifos impairs BAT mitochondrial function and diet-induced thermogenesis, promoting greater obesity, non-alcoholic fatty liver disease (NAFLD) and insulin resistance. This is associated with reductions in cAMP; activation of p38MAPK and AMPK; protein kinases critical for maintaining UCP1 and mitophagy, respectively in BAT. These data indicate that the commonly used pesticide chlorpyrifos, suppresses diet-induced thermogenesis and the activation of BAT, suggesting its use may contribute to the obesity epidemic.

Differential mitochondrial dysregulation by exposure to individual organochlorine pesticides (OCPs) and their mixture in zebrafish embryos

Organochlorine pesticides (OCPs) have been reported to cause mitochondrial dysfunction. However, most studies reported its mitochondrial toxicity with respect to a single form, which is far from the environmentally relevant conditions. In this study, we exposed zebrafish embryos to five OCPs: chlordane, heptachlor, p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), β-hexachlorocyclohexane (β-HCH), and hexachlorobenzene (HCB), as well as an equal ratio mixture of these OCPs. We evaluated mitochondrial function, including oxygen consumption, the activity of mitochondrial complexes, antioxidant reactions, and expression of genes involved in mitochondrial metabolism. Oxygen consumption rate was reduced by exposure to chlordane, and β-HCH, linking to the increased activity of specific mitochondrial complex I and III, and decreased GSH level. We found that these mitochondrial dysfunctions were more significant in the exposure to the OCP mixture than the individual OCPs. On the mRNA transcription level, the individual OCPs mainly dysregulated the metabolic cycle (i.e., cs and acadm), whereas the OCP mixture disrupted the genes related to mitochondrial oxidative phosphorylation (i.e., sdha). Consequently, we demonstrate that the OCP mixture disrupts mitochondrial metabolism by a different molecular mechanism than the individual OCPs, which warrants further study to evaluate mitochondrial dysregulation by chronic exposure to the OCP mixture.

The decomposition and ecological risk of DDTs and HCHs in the soil-water system of the Meijiang River

This research project was designed to study the residues of OCPs (organochlorine pesticides) in the sediments of the Meijiang River Basin. Samples from the Meijiang River Basin were analyzed by gas chromatography-mass spectrometry after being pretreated by Soxhlet extraction, and their compositions, distributions and sources were evaluated. The current study presents the distribution of OCPs in the soils and sediments of the Meijiang River Basin. The results demonstrate that OCPs contamination is an important environmental concern due to the excessive use of these compounds in the agricultural and industrial sectors. The ratios of α-HCH/γ-HCH, (DDE + DDD)/∑DDTs, p,p-DDT/o,p-DDT, and DDD/DDE were used as indices for identifying the possible pollution sources and assessing the decomposition of the parent compounds and the recent γ-HCH and DDT inputs. At the XY (Xiyang) and DSGYY (Dongshenggongyeyan) sites, the pollutants had industrial origins. At other sites (QTH (Qutianhu), LXC (Longxichun), ZJC (Zhenjiaochun), HKC (Hekouchun), GS (Guangshan) and RGQ (Raogongqiao)), the pollution was caused by dissolved organic matter. The SHB site was polluted by transportation and upstream pollutants. At the SXC (Shixichun), YZX (Youzhihe), DSH (Dongshihe) and ZGG (Zhegupai) sites, the metabolite was p,p'-DDD and was produced in an environment with anaerobic conditions. At the FJC (Fujiangkou), QTH (Qiutianhu), GS (Guangshang) and MX (Meixi) sites, the metabolite was DDE and was produced under aerobic conditions. In view of the health risks, the risk quotients for these contaminants were evaluated, and all risk quotients were less than 1 under the best-case scenario. This result suggests that the investigated pollutants may pose little hazard to the local ecosystem. The sediments containing toxic pesticides had a less than 55% ecological risk, indicating that the ecological risk of HCHs in the soils from the Meijiang River Basin is low.

Implication of human drug transporters to toxicokinetics and toxicity of pesticides

Human membrane drug transporters are recognized as major actors of pharmacokinetics. Pesticides also interact with human drug transporters, which may have consequences for pesticide toxicokinetics and toxicity. The present review summarizes key findings about this topic. In vitro assays have demonstrated that some pesticides, belonging to various chemical classes, modulate drug transporter activity, regulate transporter expression and/or are substrates, thus bringing the proof of concept for pesticide-transporter relationships. The expected low human concentration of pesticides in response to environmental exposure constitutes a key-parameter to be kept in mind for judging the in vivo relevance of such pesticide-transporter interactions and their consequences for human health. Existing data about interactions of pesticides with drug transporters remain, however, rather sparse; more extensive and systematic characterization of pesticide-transporter relationships, through the use of high throughput in vitro assays and/or in silico methods, is, therefore, required. In addition, consideration of transporter polymorphisms, pesticide mixture effects and physiological and pathological factors governing drug transporter expression may help to better define the in vivo relevance of pesticide-transporter interactions in terms of toxicokinetics and toxicity for humans. © 2019 Society of Chemical Industry.

Mother-child transfer rates of organohalogen compounds up to four years of age

BACKGROUND

Breastfed children absorb persistent and toxic chemicals such as organohalogen compounds (OHCs) during the entire lactation period. Nursing is a main contributor to the burden of these pollutants in the first years of life, hence further assessments on the OHC load processes are needed.

OBJECTIVES

To identify the determinants of OHC increase in children at four years of age, considering concentration gains, maternal venous concentrations and breastfeeding time.

METHODS

Concentrations of 19 organochlorine compounds (OCs) and 14 polybrominated diphenyl ethers (PBDEs) were analyzed in maternal venous (n = 466), cord blood (n = 326) and children venous serum at four years of age (n = 272) in the Asturias INMA cohort representing the Spanish general population. Data were evaluated considering the socio-demographic and individual information collected at recruitment and follow up surveys, as well as the OHC physical-chemical constants.

RESULTS

The four years-old children concentration gains of the most abundant OHCs showed strong correlations (R² = 0.65-0.93) with the maternal concentrations during pregnancy and lactation period. The child gain/maternal transfer rates of most correlated pollutants were similar.

DISCUSSION

Between 65 and 93% of the variance of OCs in four years-old children was explained by the maternal concentrations during pregnancy and the lactation period. The compounds with log(Kow) > 3.7 (hydrophobic) showed analogous child gain/maternal transfer rates indicating similar processes of membrane lipid dissolution and passive diffusion from the epithelial cells into the milk. Molecular weight of these pollutants did not influence on these rates. Compounds with low log(Koa) such as hexachlorobenzene are more volatile and less retained, involving lower child gain/maternal transfer rates. These results may be useful to anticipate the increase of the concentrations of OCs in children using the maternal concentration of these compounds during pregnancy and the planned lactation period and to implement prophylactic measures in mothers with high venous pollutant concentrations.

Application of ensemble methods to analyse the decline of organochlorine pesticides in relation to the interactions between age, gender and time

Organochlorine pesticides (OCPs) are toxic chemicals that persist in human tissue. Short and long term exposure to OCPs have been shown to have adverse effects on human health. This motivates studies into the concentrations of pesticides in humans. However these studies typically emphasise the analysis of the main effects of age group, gender and time of sample collection. The interactions between main effects can distinguish variation in OCP concentration such as the difference in concentrations between genders of the same age group as well as age groups over time. These are less studied but may be equally or more important in understanding effects of OCPs in a population. The aim of this study was to identify interactions relevant to understanding OCP concentrations and utilise them appropriately in models. We propose a two stage analysis comprising of boosted regression trees (BRTs) and hierarchical modelling to study OCP concentrations. BRTs are used to discover influential interactions between age group, gender and time of sampling. Hierarchical models are then employed to test and infer the effect of the interactions on OCP concentrations. Results of our analysis show that the best fitting model of an interaction effect varied between OCPs. The interaction between age group and gender was most influential for hexachlorobenzene (HCB) concentrations. There was strong evidence of an interaction effect between age group and time for β-hexachlorocyclohexane (β-HCH) concentrations in >60 year olds as well as an interaction effect between age group and gender for HCB concentrations for adults aged >45 years. This study highlights the need to consider appropriate interaction effects in the analysis of OCP concentrations and provides further insight into the interplay of main effects on OCP concentration trends.

Human biomonitoring in Australian children: Brominated flame retardants decrease from 2006 to 2015

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD) were used intensively as flame retardants, worldwide. They have been detected in human serum samples and PBDEs have been found to be elevated in young children. Commercial Penta- and Octa-PBDE mixtures were banned in Australia in 2005, while HBCDD was banned worldwide in 2013. We investigated PBDE and HBCDD concentrations in serum collected from young children. We also investigated temporal trends in PBDE concentration 10 years after their Australian ban. Surplus human blood serum samples were collected through a pathology clinic (n = 800), in 2014/15, stratified by age (0-6, 6-12, 12-18, 18-24, 24-30, 30-36, 36-42, 42-48, 48-54 and 54-60 months) and sex and pooled for analysis of PBDEs (BDEs -28, -47, -99, -100, -153, -154, -183) and HBCDD. In 2014/15, the geometric mean concentration of the sum of all PBDEs measured (ΣPBDEs) was 4.5 ng/g lipid (median: 4.6 ng/g lipid, range: 0.88-26 ng/g lipid). A positive association between BDE-47 concentration and age was observed (R = 0.41, p = 0.008), however there were no trends between other PBDE congeners or HBCDD and age. There were no significant differences between genders for PBDEs (t-test, p = 0.802) or HBCDD (t-test, p = 0.740).The highest concentrations observed were in pools from the females 30-36 month (26 ng/g lipid) and Males 6-12 month (21 ng/g lipid) categories. BDEs -47 and -99 were the predominant congeners with a combined average contribution of 75% of ΣPBDEs. PBDEs showed a significant reduction in children aged 0-4 years over an eight year period. In 2014/15, the mean (range) concentration of BDE-47 is 2.8 (0.23 to 11) ng/g lipid compared to pools in 2006/07 at 19 (3-55) ng/g lipid (p < 0.0001) and for BDE-153 is 0.73 (<0.1 = -2.9) ng/g lipid compared to pools in 2006/07 at 4.7 (2-10) ng/g lipid (p < 0.0001). HBCDD concentrations were lower than PBDEs with a mean concentration of 0.45 ng/g lipid. There were no temporal trends observed for HBCDD when compared to samples collected in 2012. The dominant stereoisomer was α-HBCDD (mean = 0.38 ng/g lipid) with an average contribution of 65% towards ΣHBCDD. Levels of PBDEs in young Australian children have significantly decreased since the bans of commercial Penta- and Octa-BDE in 2005. There has been no observed decrease in HBCDD levels in Australian children since its ban in 2012.

Concentrations of organochlorine pesticides in cord serum of newborns in Wuhan, China

Organochlorine pesticides (OCPs) had been widely used in China before they were banned decades ago due to the concern of the toxicology to human. Previous reports showed that OCPs were still often detectable in human bodies. However, there is limited study concerning the body burden of OCPs in infants and fetus in China. In this study, the prenatal exposure to OCPs was evaluated by measuring OCPs in cord serum. A total of 1046 cord serum samples were collected in Wuhan during 2014 and 2015, and analyzed for the concentrations of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), dichlorodiphenyldichloroethanes (DDDs) and dichlorodiphenyldichloroethylenes (DDEs) by using gas chromatography-tandem mass spectrometry (GC-MS/MS). The median levels of ∑HCHs and ∑DDTs were 10.1 ng/g lipid (with the range from <LOD to 1910 ng/g lipid) and 35.5 ng/g lipid (with the range from 0.18 to 11,100 ng/g lipid), respectively. β-HCH and p,p'-DDE were found to be the major OCPs presenting in the cord serum samples. A minor positive association between the serum levels of α-HCH and β-HCH was observed, and the concentrations of o,p'- and p,p'-DDT isomers were found positively associated. The OCP exposure levels obtained in this study were comparable to those data from other areas in China and much lower than some of highly polluted countries. The prenatal exposure to OCPs would be of concern since fetuses were more vulnerable than adults and the cord serum is an accurate non-invasive matrix for monitoring of prenatal exposure.

Serum concentrations of organochlorine compounds and predictors of exposure in children living in agricultural communities from South-Eastern Spain

BACKGROUND

Information on exposure levels to organochlorine compounds (OCs) in child population is limited, despite their greater vulnerability to the adverse health effects of these chemicals.

OBJECTIVE

To determine serum concentrations of 10 OCs (including organochlorine pesticides and polychlorinated biphenyls -PCBs-) in children living in agricultural communities from Almería (South-Eastern Spain), and to identify the main predictors of exposure related to socio-economic characteristics, diet and lifestyle.

METHODS

A cross-sectional study was conducted on 133 children aged 6-11 years selected from public schools of the study area. OCs compounds were determined in serum samples by GC/ECD. Anthropometric measures were obtained during sample collection. Information on sociodemographic characteristics, parental occupation, residential history, lifestyle and frequency of food consumption, among other relevant factors, was obtained by questionnaires administered to the mothers.

RESULTS

Geometric means of serum concentrations (ng/ml) were 0.11 for β-hexachloro-cyclohexane (β-HCH), 0.09 for endosulfan, 0.20 for endosulfan-ether, 0.51 for hexachorobenzene (HCB), 0.08 for mirex, 0.06 for oxychlordane, 0.36 for p,p'-DDE, 0.20 for PCB 138, 0.36 for PCB 153, and 0.45 for PCB 180. Percentage of samples above the limit of detection (0.05 ppb) ranged from 32 (β-HCH) to 100 (HCB). A high variability in OC levels depending on the compound was observed between our results and others found in similar studies carried out in children. Variables related to fish consumption were found to be the major dietary determinant of PCB 138, p,p´-DDE, endosulfan-α, β-HCH, mirex and oxychlordane levels.

CONCLUSIONS

Children participating in this study showed detectable levels of many OC, despite these compounds are no longer used. Their presence in children serum can be explained by their high lipophilicity and environmental persistence, leading to contamination of fatty food. In this line, fish consumption seemed to be the most relevant determinant of OC levels found in our study.

Association between Organochlorine Pesticide Levels in Breast Milk and Their Effects on Female Reproduction in a Taiwanese Population

Only few studies have focused on organochlorine pesticides (OCPs) in breast milk and the related health risks for women in Taiwan. Our goal is to examine breast milk OCPs and their associations with female reproductive function (infertility, gynecological diseases, and menstruation characteristics) as well as their correlation with sociodemographic parameters (age, pre-pregnant body mass index (BMI), annual incomes, population, birth year, and parity) and dietary habit. The breast milk samples were collected in southern Taiwan (n = 68) from 2013 to 2016 and the OCP residues were analyzed using high resolution gas chromatography with low resolution mass spectrometry (HRGC/LRMS). The results show that the most abundant OCP residues in the breast milk was ΣDDT with the geometric mean ± standard deviation of 9.81 ± 7.52 ng⁻¹ lipid⁻¹ followed by ΣHCH (0.539 ± 0.557 ng⁻¹·lipid⁻¹). In the principal component analysis, cis-chlordane (cis-CHL) and γ-HCH were found to be related to participants who received medical treatment for infertility, and 4,4′-DDT was associated with those who received gynecological surgery. The logistic regression showed that the odds ratio (OR) of log γ-hexachlorocyclohexane (γ-HCH) was higher for mothers who had received medical treatment for infertility than for the normal group (OR = 25.6, p = 0.035) after adjustments for age, pre-pregnant BMI, annual income, population (i.e., native-born Taiwanese), birth year, and parity. Cow milk and beef consumption as well as menstruation characteristics such as average menstrual period (>5 days), shortest menstrual period (<3 days), and women who had taken hormonal drugs were significantly associated to several OCP residues in the breast milk. In addition, ΣHCH including β-HCH and γ-HCH was correlated with annual family income and gravidity as well as cow milk and beef consumptions. Overall, γ-HCH exhibited a probable association with the infertility diseases of Taiwanese women, and dietary habit might play an important role in the female Taiwanese exposure to OCPs.

Chlorinated persistent organic pollutants in serum of New Zealand adults, 2011-2013

A national survey was conducted in 2011-2013 to assess serum concentrations of persistent organic pollutants (POPs) in adult New Zealanders. Participants were randomly selected from the 2010 Electoral Roll within 64 demographic strata according to 4 age groups, 4 regions, 2 ethnic groups (Māori/non-Māori) and gender. Eligible subjects (n=734) donated up to 30ml of blood, after which serum was pooled (n=49) according to demographic strata prior to analysis by GC-HRMS. Associations between demographic variables (age, region, ethnicity, gender) and serum POPs were assessed using linear regression. The weighted geometric mean (GM) of PCDD/Fs was 5.3pg/g lipid toxic equivalents using the WHO 2005 toxic equivalence factors (TEQ₀₅), which increased by age (3.2, 4.4, 4.8, and 8.1pg/g lipid for the 19-24, 25-34, 35-49, and 50-64year age groups, respectively). The weighted GM of dioxin-like PCBs was 1.4pg TEQ₀₅/g lipid which also increased by age (0.82, 0.86, 1.4, and 2.3pg/g lipid for the same age groups, respectively). Of the detected OCPs, the highest concentration was observed for p,p'-DDE (weighted GM, 220ng/g lipid) followed by hexachlorobenzene (HCB; 7.3ng/g lipid), beta-HCH (7.0ng/g lipid), and dieldrin (4.7ng/g lipid). For most Cl-POPs, concentrations were lowest in the youngest age group, and were similar for men and women and Māori and non-Māori. Serum Cl-POPs were, on average, 50% lower than those measured 15years earlier in 1997. This survey provides evidence of declining serum concentrations of chlorinated POPs in the New Zealand adult population. Age was the most important determinant of POPs concentrations. Body burdens of PCDD/Fs and PCBs in New Zealand are relatively low by international comparison, while for OCPs they are similar or lower compared to those reported for other developed countries.

Urinary metabolites of organophosphate esters: Concentrations and age trends in Australian children

There is growing concern around the use of organophosphate esters (OPEs) due to their suspected reproductive toxicity, carcinogenicity, and neurotoxicity. OPEs are used as flame retardants and plasticizers, and due to their extensive application in consumer products, are found globally in the indoor environment. Early life exposure to OPEs is an important risk factor for children's health, but poorly understood. To study age and sex trends of OPE exposures in infants and young children, we collected, pooled, and analysed urine samples from children aged 0-5years from Queensland, Australia for 9 parent OPEs and 11 metabolites. Individual urine samples (n=400) were stratified by age and sex, and combined into 20 pools. Three individual breast milk samples were also analysed to provide a preliminary estimate on the contribution of breast milk to the intake of OPEs. Bis(1-chloroisopropyl) phosphate (BCIPP), 1-hydroxy-2-propyl bis(1-chloro-2-propyl) phosphate (BCIPHIPP), bis(1,3-dichloroisopropyl) phosphate (BDCIPP), dibutyl phosphate (DBP), diphenyl phosphate (DPHP), bis(2-butoxyethyl) phosphate (BBOEP), bis(2-butoxyethyl) 3-hydroxyl-2-butoxyethyl phosphate (3OH-TBOEP), and bis(2-butoxyethyl) hydroxyethyl phosphate (BBOEHEP) were detected in all urine samples, followed by bis(methylphenyl) phosphate (80%), and bis(2-ethylhexyl) phosphate (BEHP, 20%), and bis(2-chloroethyl) phosphate (BCEP, 15%). Concentrations of tris(2-chloroethyl) phosphate (TCEP), BCEP, tris(2-ethylhexyl) phosphate (TEHP), and DBP decreased with age, while bis(methylphenyl) phosphate (BMPP) increased with age. Significantly higher concentrations of DPHP (p=0.039), and significantly lower concentrations of TEHP (p=0.006) were found in female samples compared to males. The estimated daily intakes (EDIs) via breastfeeding, were 4.6, 26 and 76ng/kg/day for TCEP, TBP and TEHP, respectively, and were higher than that via air and dust, suggesting higher exposure through consumption of breast milk.

Use of a simple pharmacokinetic model to study the impact of breast-feeding on infant and toddler body burdens of PCB 153, BDE 47, and DDE

Several studies have examined the role of breast milk consumption in the buildup of environmental chemicals in infants, and have concluded that this pathway elevates infant body burdens above what would occur in a formula-only diet. Unique data from Australia provide an opportunity to study this finding using simple pharmacokinetic (PK) models. Pooled serum samples from infants in the general population provided data on PCB 153, BDE 47, and DDE at 6-month increments from birth until 4 years of age. General population breast-feeding scenarios for Australian conditions were crafted and input into a simple PK model which predicted infant serum concentrations over time. Comparison scenarios of background exposures to characterize formula-feeding were also crafted. It was found that the models were able to replicate the rise in measured infant body burdens for PCB 153 and DDE in the breast-feeding scenarios, while the background scenarios resulted in infant body burdens substantially below the measurements. The same was not true for BDE 47, however. Both the breast-feeding and background scenarios substantially underpredicted body burden measurements. Two possible explanations were offered: that exposure to higher BDE congeners would debrominate and form BDE 47 in the body, and/or, a second overlooked exposure pathway for PBDEs might be the cause of high infant and toddler body burdens. This pathway was inhalation due to the use of PBDEs as flame retardants in bedding materials. More research to better understand and quantify this pathway, or other unknown pathways, to describe infant and toddler exposures to PBDEs is needed.