Dichlorodiphenyldichloroethylene Research Articles

Screening levels spatial interpolation of lifetime carcinogenic risk by organochlorine pesticides across catchments of river chenab

The present study has employed an advanced GIS based statistical technique for spatial interpolation of lifetime carcinogenic risk to OCPs in water and sediments from tributaries of River Chenab. The findings revealed that among all detected isomers, DDT exhibited the highest concentrations (mean 14.41 ng/l: range 9.33 – 20.21 ng/l and mean 16.47 ng/l: range 10.55 – 21.24 ng/g) for water and sediment, respectively. Results of OCPs fingerprints revealed the presence of dicofol confirmed fresh input of OCPs isomers along with the DDTs (Dichloro-diphenyl trichloroethane) historical usages in water bodies. The evaluation of ecological risk to benthic organisms’ fish, daphnia and green algae (RQ 2 × 102) indicated that DDTs (DDD, DDE) pose potential hazardous risks (>1) to fish species across all the studied sites. Moreover, Spatial interpolation of the lifetime carcinogenic risk denoted the sites along downstream zone surpassed the permissible limit. The non-carcinogenic risk (∑HQ) ranged from 2 × 10-3 – 1.0 with the highest value for DDT, indicating DDT as a potential hazard through oral exposure (∑HQ≥1). In the case of sediments results of SQGQs (Sediment Quality Guideline Quotient) levels for DDE (Dichloro-diphenyldichloromethane) and DDD (Dichloro-diphenyl dichloroethylene) denoted a severe biological risk to ecological integrities. The findings comprehend the more inclusive monitoring of OCPs usage and distribution in the studied region to reduce risks ecological integrities and to promote good health and wellbeing’s.

Association between prenatal exposure to indoor residual spraying insecticides and infection rates among South African children participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE)

In 2021, 53 countries conducted indoor residual spraying (IRS), the application of insecticides such as dichlorodiphenyl trichloroethane (DDT) or pyrethroids to the walls of homes to control malaria. Animal studies show that these insecticides can increase susceptibility to infections but only one human study was conducted in a population from an area where IRS is applied. The aim of the present study was thus to investigate whether maternal exposure to DDT, its breakdown product dichlorodiphenyl dichloroethylene (DDE) or pyrethroid insecticides is associated with symptoms of infection among children living in a region of South Africa were IRS is conducted annually. As part of the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) we measured maternal serum concentrations of DDT and DDE, and urinary concentrations of four pyrethroid metabolites in peripartum samples. Poisson regression models with robust variance estimates were used to investigate associations with the rates of infection symptoms between ages 3.5–5 years among 629 children as assessed based on caregiver interviews. Multiple pyrethroid metabolites were associated with infection symptoms. For instance, cis-DBCA was associated with increased rates of ear infection (Incidence Rate Ratio for a 10-fold increase (IRR10) = 1.4; 95 % Confidence Interval (CI) = 1.0, 2.1) and persistent diarrhea (IRR10 = 2.1; 95 % CI = 1.2, 3.9), trans-DCCA was associated with increased rates of colds in children (IRR10 = 1.3; 95 % CI = 1.0, 1.6) and persistent fever (IRS10 = 1.4; 95 % CI = 1.0, 2.0), and 3-PBA was associated with increased rates of persistent fever (IRR10 = 1.8; 95 % CI = 1.0, 3.0). We found limited evidence of association between maternal DDE and DDT serum concentrations and infection symptoms. Results suggest that prenatal exposure to pyrethroid insecticides may be associated with infections among children from an area where IRS is conducted.

Effects of mixtures of polychlorinated biphenyls (PCBs) and three organochlorine pesticides on cognitive function differ between older Mohawks at Akwesasne and older adults in NHANES

BackgroundAkwesasne Mohawks has been exposed to high concentrations of polychlorinated biphenyls (PCBs) and background levels of organochlorine pesticides, hexachlorobenzene (HCB), dichlorodiphenyl dichloroethylene (DDE), and mirex. We have previously reported relative contributions to the mixture of low- and high-chlorinated PCBs, HCB, and DDE on cognitive decrements in Mohawks of various ages. ObjectiveThis study examines differences in the mixture effects of PCB congener groups, HCB, DDE, and mirex on cognitive function in older Mohawks and less PCB-exposed older adults from the National Health and Nutrition Examination Survey (NHANES) 1999–2002 cycles. MethodsWe used Bayesian kernel machine regression (BKMR) to evaluate the mixture effects of different PCB congener groups, HCB, DDE, and mirex on cognitive function in both populations. Models were adjusted for age, sex, education levels, and race/ethnicity focusing on individuals 60 years and older. ResultsOlder Mohawks had 3-fold higher mean total PCB concentrations and 1.8-fold higher mirex, but slightly lower mean DDE and HCB levels than NHANES older adults. Higher mixture concentrations were significantly associated with greater cognitive decline. In older Mohawks, low- and high-chlorinated PCBs, HCB, and DDE contributed to the cognitive score decline. In contrast, score decline in older NHANES adults were primarily from high-chlorinated PCBs and DDE with a threshold dose of approximately 2.08–2.27 ng/g and 2.02–2.40 ng/g, respectively. ConclusionMixtures of PCBs and organochlorine pesticides increase the risk of cognitive decline in both older Mohawks and NHANES older adults. However, contributions to these mixture effects show significant differences. In older Mohawks, high- and low-chlorinated PCBs, DDE, and HCB are the primary contributors, while high-chlorinated PCBs and DDE are important contributors in NHANES older adults. Due to chronic heavy exposures to PCBs, older Mohawks had a significantly increased risk of cognitive decline compared to general older adults from NHANES.

Prenatal organochlorine pollutant exposure and risk of schizophrenia in a national birth cohort

Non-genetic prenatal exposures have been associated with schizophrenia risk. However, the role of prenatal exposure to environmental neurotoxicants in offspring schizophrenia risk has been studied in only limited instances. Polychlorinated biphenyls (PCBs) and the pesticide metabolite p,p′-dichlorodiphenyl dichloroethylene (DDE) have been linked to neurodevelopmental outcomes, including impairments implicated in schizophrenia. To determine whether prenatal maternal levels of organochlorine pollutants including PCBs or DDE are associated with schizophrenia in the offspring, an investigation was conducted in the Finnish Prenatal Study of Schizophrenia (FIPS-S), a case-control study nested in a national birth cohort. Cases were born in 1987–1991 and had at least two diagnoses of schizophrenia (ICD-10 F20; ICD-9 295) or schizoaffective disorder (ICD-10 F25; ICD-9 295.7) recorded in the national Care Register for Health Care. Each case was individually matched to a control on sex, date of birth, and residence in Finland on the date of case diagnosis. In 500 case-control pairs, PCB congeners 74, 99, 118, 138, 153, 156, 170, 180, 183, 187, and some widespread organochlorine pesticides or their metabolites including DDE were measured in archived prenatal maternal sera using gas chromatography - high triple quadrupole mass spectrometry. Maternal total PCBs were quantified as the sum of concentrations of the measured congeners. Associations with schizophrenia were examined using conditional logistic regression. Maternal PCB or DDE levels greater than the 75th percentiles of the control distributions showed no evidence of association with offspring schizophrenia (PCBs: adjusted odds ratio (aOR) = 1.13, 95 % CI = 0.85–1.50), p = 0.41; DDE: aOR = 1.08, 95 % CI = 0.80–1.45; p = 0.63). Maternal levels of either pollutant dichotomized at the 90th percentile or considered as a continuous variable also did not show evidence for association with offspring schizophrenia. This study found a lack of evidence that prenatal maternal levels of the organochlorine pollutants DDE and PCBs are associated with offspring risk of schizophrenia.

Polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, pesticides, and diabetes in the Anniston Community Health Survey follow-up (ACHS II): single exposure and mixture analysis approaches

Dioxins and dioxin-like compounds measurements were added to polychlorinated biphenyls (PCBs) and organochlorine pesticides to expand the exposure profile in a follow-up to the Anniston Community Health Survey (ACHS II, 2014) and to study diabetes associations. Participants of ACHS I (2005–2007) still living within the study area were eligible to participate in ACHS II. Diabetes status (type-2) was determined by a doctor's diagnosis, fasting glucose ≥125 mg/dL, or being on any glycemic control medication. Incident diabetes cases were identified in ACHS II among those who did not have diabetes in ACHS I, using the same criteria. Thirty-five ortho-substituted PCBs, 6 pesticides, 7 polychlorinated dibenzo-p-dioxins (PCDD), 10 furans (PCDF), and 3 non-ortho PCBs were measured in 338 ACHS II participants. Dioxin toxic equivalents (TEQs) were calculated for all dioxin-like compounds. Main analyses used logistic regression models to calculate odds ratios (OR) and 95 % confidence intervals (CI). In models adjusted for age, race, sex, BMI, total lipids, family history of diabetes, and taking lipid lowering medication, the highest ORs for diabetes were observed for PCDD TEQ: 3.61 (95 % CI: 1.04, 12.46), dichloro-diphenyl dichloroethylene (p,p’-DDE): 2.07 (95 % CI 1.08, 3.97), and trans-Nonachlor: 2.55 (95 % CI 0.93, 7.02). The OR for sum 35 PCBs was 1.22 (95 % CI: 0.58–2.57). To complement the main analyses, we used BKMR and g-computation models to evaluate 12 mixture components including 4 TEQs, 2 PCB subsets and 6 pesticides; suggestive positive associations for the joint effect of the mixture analyses resulted in ORs of 1.40 (95% CI: -1.13, 3.93) for BKMR and 1.32 (95% CI: -1.12, 3.76) for g-computation. The mixture analyses provide further support to previously observed associations of trans-Nonachlor, p,p’- DDE, PCDD TEQ and some PCB groups with diabetes.

Putative interactions between transthyretin and endosulfan II and its relevance in breast cancer

The unregulated use of organochlorine pesticides (OCPs) has been linked to spread of breast cancer (BC), but the underlying biomolecular interactions are unknown. Using a case-control study, we compared OCP blood levels and protein signatures among BC patients. Five pesticides were found in significantly higher concentrations in breast cancer patients than in healthy controls: p′,p′ dichloro diphenyl trichloroethane (DDT), p′p′ dichloro diphenyl dichloroethane (DDD), endosulfan II, delta-hexachlorocyclohexane (dHCH), and heptachlor epoxide A (HTEA). According to the odds ratio analysis, these OCPs, which have been banned for decades, continue to raise the risk of cancer in Indian women. Proteomic analysis of plasma from estrogen receptor-positive breast cancer patients revealed 17 dysregulated proteins, but transthyretin (TTR) was three times higher than in healthy controls, which is further validated by enzyme-linked immunosorbent assays (ELISA). Molecular docking and molecular dynamics studies revealed a competitive affinity between endosulfan II and the thyroxine-binding site of TTR, pointing towards the significance of the competition between thyroxin and endosulfan, resulting in endocrine disruption leading to breast cancer. Our study sheds light on the putative role of TTR in OCP-mediated BC, but more research is needed to decipher the underlying mechanisms that can be used to prevent the carcinogenic effects of these pesticides on women's health.

Organochlorine pesticide residues in water, sediments and Nile tilapia (Oreochromis niloticus) of Lake Nakuru, Kenya and implications for its fishery

AbstractThe present study was conducted to assess the levels of selected organochlorine pesticide (OCP) residues in water, sediments and Nile tilapia, as well as the potential health risks to humans who consume the fish of Lake Nakuru. Nine composite water and nine sediment samples, as well as 30 fish specimens, were collected from five representative sampling sites within Lake Nakuru. The OCPs targeted in the present study included p,p′‐Dichlorodiphenyl dichloroethane (p,p′‐DDD), p,p′‐dichlorodiphenyldichloroethylene (p,p′‐DDE), p,p′‐dichlorodiphenyltrichloroethane (p,p′‐DDT), heptachlor, heptachlor epoxide, α endosulfan (1), β endosulfan (2), endosulfan sulphate, endrin, lindane, aldrin, dieldrin, methoxychlor and hexachlorocyclohexanes (alpha; beta; gamma; delta). Except for aldrin, all 16 OCPs targeted in the present study were detected. The OCP residue levels ranged from below detection limit (BDL) to 7.44 ± 0.66 μg/L, BDL to 6.39 ± 1.10 μg/kg ww and BDL to 319.74 ± 66.94 μg/kg ww in water, sediment and fish samples respectively. Some OCP concentrations exhibited significant differences across the sampling sites (p < .05). The residue level of endosulfan was above the European Union standard, whereas the target hazard quotient of heptachlor epoxide was above 1, therefore being unsafe for human consumption. The present study results indicate that most of organochlorine pesticides though banned in Kenya are still detected in the environment, posing potential long‐term health hazards to humans. Accordingly, environmental monitoring programme and mitigation strategies of reducing pollutant inputs into the lake is recommended, as well as an immediate ban on harvesting and consumption of fish from Lake Nakuru.

Maternal serum persistent organic pollutant exposure and offspring diagnosed ADHD in a national birth cohort

BackgroundEvidence implicates environmental factors in attention-deficit/hyperactivity disorder (ADHD) risk. Prenatal exposures to polychlorinated biphenyls (PCBs) and the pesticide metabolite p,p’-dichlorodiphenyl dichloroethylene (DDE) have been linked to lower cognitive ability, increased impulsivity, and attention related deficits in the offspring. However, information on the relationship of these exposures to the risk of clinically diagnosed ADHD is limited. ObjectivesTo determine whether prenatal maternal levels of PCBs or DDE are associated with ADHD diagnosis in the offspring. MethodsThe investigation was conducted in the Finnish Prenatal Study of ADHD (FIPS-ADHD), a case-control study nested in a national birth cohort. Cases were born in 1998 or 1999 and diagnosed with ADHD (ICD-9 314x or ICD-10 F90. x) according to the national Care Register for Health Care. Each case was individually matched to a control on sex, date, and place of birth. PCB congeners (PCB 74, 99, 118, 138, 153, 156, 170, 180, 183, 187) and DDE were quantified from archived prenatal maternal sera from 359 matched case-control pairs using gas chromatography - high triple quadrupole mass spectrometry. Maternal total PCBs were quantified as the sum of concentrations of the measured congeners. Associations with ADHD were examined using conditional logistic regression. ResultsMaternal PCB or DDE levels greater than the 75th percentiles of the control distributions showed no evidence of association with offspring ADHD (PCBs: adjusted odds ratio (aOR) = 1.01, 95% CI = 0.63, 1.60), p = 0.98; DDE: aOR = 1.13, 95% CI = 0.71, 1.81; p = 0.60). Maternal levels of either pollutant dichotomized at the 90th percentile or considered as a continuous variable also did not show evidence for association with offspring ADHD diagnosis. DiscussionThis study did not find evidence for association of maternal prenatal levels of PCBs or DDE with clinical diagnosis of offspring ADHD; however, this does not rule out the possibility of an impact on subclinical phenotypes.

Prenatal exposure to a mixture of organochlorines and metals and internalizing symptoms in childhood and adolescence

BackgroundAlthough prenatal chemical exposures influence neurobehavior, joint exposures are not well explored as risk factors for internalizing disorders through adolescence. ObjectiveTo evaluate associations of prenatal organochlorine and metal exposures, considered individually and as a mixture, with mid-childhood and adolescent internalizing symptoms. MethodsParticipants were 468 children from a prospective cohort recruited at birth (1993–1998) in New Bedford, Massachusetts. Organochlorines (hexachlorobenzene, p,p'-dichlorodiphenyl dichloroethylene, polychlorinated biphenyls) and metals (lead, manganese) were analyzed in cord blood. Internalizing symptoms (anxiety, depressive, somatic) were assessed via multiple informants on the Conners' Rating Scale (CRS) at 8-years and Behavior Assessment System for Children, Second Edition (BASC-2) at 15-years; higher T-scores indicate greater symptoms. Overall and sex-specific covariate-adjusted associations were evaluated using Bayesian Kernel Machine Regression (BKMR) and five-chemical linear regression models. ResultsThe cohort was socioeconomically diverse (35% household income <$20,000; 55% maternal ≤ high school education at birth). Most chemical concentrations were consistent with background levels [e.g., median (range) cord blood lead: 1.1 (0–9.4) μg/dL]. BKMR suggested linear associations and no interactions between chemicals. The overall mixture was positively associated with Conners’ Parent Rating Scale (CPRS) and BASC-2 Self Report of Personality (SRP) anxiety and depressive symptoms, and negatively with somatic symptoms. Prenatal lead was positively associated with adolescent anxiety symptoms [1.56 (95% CI: 0.50, 2.61) BASC-2 SRP Anxiety score increase per doubling lead]. For CRPS and BASC-2 SRP, a doubling of cord blood manganese was positively associated with internalizing symptoms for girls [e.g., 3.26 (95% CI: 0.27, 6.25) BASC-2 SRP Depression score increase], but not boys. Organochlorine exposures were not adversely associated with internalizing symptoms. DiscussionLow-level prenatal lead exposure was positively associated with adolescent anxiety symptoms, and prenatal manganese exposure was positively associated with internalizing symptoms for girls from mid-childhood through adolescence. In utero neurotoxicant metal exposures may contribute to the emergence of anxiety and depression.

Immobilised TiO2 application for pesticides degradation using a solar still

Pesticides are recalcitrant contaminants, which are bioaccumulative in nature. A good number of pesticides, particularly organochlorines, have been listed among the Persistent Organic Pollutant list of Stockholm convention. Organochlorine pesticides were significantly used in the past, however, their footprints still exist in environmental matrices. In the present study, degradation of pesticides using a solar still, with immobilised TiO 2 , is performed. Existing solar remediation systems have a limitation of utilizing ultraviolet portion of solar energy and the thermal energy remains unutilized in most cases. Solar distillation with a TiO 2 photocatalysis enhances the purification properties of the solar still in terms of treatment of recalcitrant pollutants. Organochlorine pesticides like isomers of Hexachlorocyclohexane (HCH), Endosulphan and Dichlorodiphenyltrichloroethane (DDT) can be significantly degraded using a thermo-photocatalytic solar still described in the study. Besides this, degradation of synthetic pyrethroids like fenpropathrin, cyhalothrin, cyfluthrin, cypermethrin and fenvalerate is also studied. Combination of solar distillation and photocatalysis was effective for the treatment of water contaminated with pesticides, achieving more than 21–82% degradation for the studied pesticides. For Organochlorine pesticides, pp DDE’ was the compound which showed least degradation (21.4%) and maximum degradation was achieved for Alpha HCH (82.9%). In the synthetic pyrethroid group, fenpropathrin showed least degradation among all the compounds (60.4%) and fenvalerate showed a maximum degradation (96.4%). Solar photocatalytic distillation can find application in recycling of wastewater generated from agriculture-intensive areas and pesticide manufacturing industries.

Ensuring the purity of water resources in the Don River basin

Uncontrolled levels of persistent organic pollutants (POPs), which are prohibited for use under the POPs Convention, are the environmental concerns and, when applied on a large scale, will disrupt entire ecosystems. The identification of their impact on the purity of water resources is relevant and affects the planning of water supply for the population and the economy, the justification of water management measures and the redistribution of water resources within the basin. The aim of the research was to identify the content of hazardous pesticides in the surface waters of water bodies of the river basin Don. The data on the concentrations of α-, γ-hexochlorocyclohexane (HCCH), dichlorodiphenyl trichloroethane (DDT), dichlorodiphenyl dichloroethane (DDE), trifluralin, parathion methyl, karbofos, and fosalon were analyzed in surface waters and bottom sediments. It is noted that organochlorine pesticides (OCPs) are found in most places (up to ’100%) and in the number of samples in the bottom sediments of the surface waters of the Don River. It is significant that in the water of water bodies of the Don basin, including in the Don River, the detection frequency of the most active γ-HCCH is detected more often than α-HCCH. In the context of the projected increase in fresh water consumption in the Don River Basin, measures are being discussed to protect water resources from pollution.

Effects of prenatal exposure to persistent organic pollutants on neonatal Outcomes:A mother-child cohort (Shanghai, China)

Persistent organic pollutants (POPs), known as common environmental pollutants, which have adverse effects on neurobehavioral development, are widely applied in industry and agriculture. However, evidence about neurodevelopmental toxicity of POPs in humans is limited. This study aimed to explore the relationship between prenatal exposure to POPs and birth outcome of the newborn including birth length, weight, and head circumference. In this study, 1522 mother-child pairs were included in this study and cord blood samples were collected, which were detected to determine exposure level of 37 POPs in total. After delivery, the neonatal anthropometric indices detection (birth length, weight, and head circumference) was performed. According to the multivariate linear regression, the newborn with high detection rates (≥75 percentile) of hexachlorobenzene (HCB), beta-hexachlorocyclohexane (β-HCH), p,p’-dichlorodiphenyl dichloroethylene (p,p’-DDE) in the umbilical cord blood were demonstrated negative relationship with birth head circumference after adjusting for confounding factors, but not related with birth length and weight. After confirming that there was a nonlinear relationship between HCB and birth head circumference based on sex stratification through the generalized additive model (GAM), further two-piecewise linear regression model was conducted to explore the saturation threshold effect between HCB and birth head circumference, which showed cord serum HCB concentration greater than 0.5 μg/L was negatively associated with birth head circumference in girls. Our study provided evidence for the adverse influence of HCB, β-HCH and p,p'-DDE exposure during pregnancy on the birth head circumference of offspring. Although HCB induced reduction of birth head circumference was found in girls, the mechanism of gender difference remained unclear. Further studies are needed to explore the effect of POPs on the growth and development of offspring based on in vivo or in vitro experimental models.

Plasma concentrations of chlorinated persistent organic pollutants and their predictors in the general population of Algiers, Algeria

BackgroundPersistent organic pollutants (POPs) are subject of particular attention and in-depth studies which demonstrate their toxicity towards humans and biotope in general. POPs are therefore addressed by the Stockholm Convention globally with human milk or blood as matrix for effectiveness evaluation. ObjectivesThe objective of this study was to assess plasma concentrations of certain chlorinated POPs in subjects from the urban population in Algiers. MethodsA total number of 207 adult subjects were recruited in Algiers and plasma concentrations of Hexachlorobenzene (HCB), p,p’Dichlorodiphenyl DichloroEthylene (4,4′DDE) and Polychlorinated Biphenyls (PCBs) were determined by gas chromatography with mass spectrometry detection (GC-MS). ResultsThe nanogram per gram of lipids (ng g−1 lipids) geometric means of plasma concentrations of studied compounds were: 6.09 for HCB, 131.60 for 4,4′DDE, 8.61 for PCB153, 7.95 for PCB138 and 8.39 for PCB180. PCB 180, PCB 153 and PCB 138 showed a high correlation with each other (r > 0.5). 4,4′DDE concentrations were significantly higher in women and in subject with low educational level, whereas POPs were higher in older participants (> 65 years old). Organochlorine pesticides (OCPs) and PCB153 concentrations were higher in overweight and obese subjects. There was no significant difference between POPs concentrations according to breastfeeding history, smoking status or fish consumption. ConclusionsChlorinated POPs were detected in the blood plasma of adults living in Algiers. Plasma concentrations were consistent with those of several studies in the world. However, further investigations are needed to assess the exposure profile of subjects living near contaminated sites.

Exposure to environmental contaminants and risk of pregnancy induced hypertension and gestational diabetes mellitus

Introduction: Persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB), are ubiquitously found in the environment and resistant to degradation. POPs, along with persistent organochlorine pesticides including p,p'-dichlorodiphenyl dichloroethylene (DDE) and heavy metals have been associated with various pregnancy outcomes but results are inconsistent.Objective: We assessed the associations between prenatal exposures to organochlorines and heavy metals and the development of gestational diabetes mellitus (GDM) and pregnancy induced hypertension (PIH). Methods: We used existing exposure models to predict prenatal levels of PCBs (using the sum of 4 prevalent congeners), DDE, HCB, lead (Pb) and mercury (Hg) for all pregnant women living in southeast Massachusetts between 1993-1998 (n=10,270). Outcome and covariate data were obtained from Massachusetts birth records. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for GDM and PIH were estimated using multivariable logistic regression models. Results: Approximately 1.8% of women in this study population developed GDM and 1.9% of women developed PIH. PCBs, DDE and HCB were strongly associated with the development of GDM, while no associations were observed for Pb and Hg exposure. After adjusting for weight gain during pregnancy, smoking during pregnancy, parity, race, and socioeconomic factors, the effects of PCBs (OR: 1.56; 95% CI: 1.10-2.22) and DDE (OR: 2.84; 95% CI: 1.90-4.25) on GDM remained. However, the risk associated with HCB exposure was no longer significant after adjusting for confounders. Associations with PIH were null.Conclusions: These results suggest that women with high prenatal levels of PCBs and DDE may have a higher risk of developing GDM. We found no associations between PIH and exposures to organochlorines and heavy metals.

Prenatal exposure to mixtures of environmental chemicals and adolescent internalizing behaviors in the New Bedford Cohort

Background/Aim: Exposure to combinations of chemical neurotoxicants has not been well explored as a risk factor for mental health difficulties. We evaluated associations of prenatal exposure to mixtures of organochlorines and metals with adolescent internalizing behaviors.Methods: Participants were 397 socioeconomically (32% household income &lt;$20,000) and racially (31% non-White) diverse children from a prospective birth cohort recruited at birth (1993-1998) in New Bedford, Massachusetts. Organochlorines [hexachlorobenzene, p,p'-dichlorodiphenyl dichloroethylene, polychlorinated biphenyls] and metals [manganese, lead] were analyzed in cord blood. Internalizing behaviors (anxiety, depression, somatization) at age ~15 years were assessed via teacher, parent, and self-report using the Behavior Assessment System for Children, 2nd Edition (BASC-2). Adjusted for sociodemographic predictors of exposures and internalizing behaviors, multi-chemical linear regression and Bayesian Kernel Machine Regression (BKMR) were used to explore overall and sex-specific associations between prenatal chemical exposures and BASC-2 T-scores [standardized to mean (standard deviation) of 50 (10)].Results: Chemical concentrations were consistent with background exposure levels [e.g., mean (range) cord blood lead: 1.50 (0-17.45) g/dL]. Although there was some variability in magnitude and precision, across all three reporters, lead was associated with higher anxiety, depression, and somatization behaviors in adolescents of both sexes. For example, in linear regression, a doubling of lead was associated with a 1.6-point higher (95% confidence interval: 0.6, 2.7) parent-reported anxiety T-score. There was suggestive evidence of increased susceptibility to lead among boys for parent-reported behaviors. The direction of associations of organochlorines and manganese with internalizing behaviors varied, depending on the reporter. BKMR analysis supported linear regression results, with no evidence of interactions between chemicals or non-linear associations.Conclusions: Low-level prenatal lead exposure was consistently associated with adolescent internalizing behaviors. In utero chemical exposures, particularly lead, may contribute to the emergence of anxiety and depression symptoms during this vulnerable developmental stage.[Funding: NIEHS/NIH P42ES005947, R01ES014864; CDC/NIOSH T42OH008416].

Prenatal environmental exposures and associations with teen births.

Background:Children’s prenatal exposure to multiple environmental chemicals may contribute to subsequent deficits in impulse control, predisposing them to risk-taking.Objective:Our goal was to investigate associations between prenatal exposure mixtures and risk of teen birth, a manifestation of high-risk sexual activity, among 5,865 girls (1st generation) born in southeast Massachusetts from 1992-1998.Methods:Exposures included prenatal modeled polychlorinated biphenyls (PCBs), ρ,ρ′-dichlorodiphenyl dichloroethylene (DDE), hexachlorobenzene (HCB), lead (Pb), and mercury (Hg). We fit adjusted generalized additive models with multivariable smooths of exposure mixtures, 1st generation infant’s birth year, and maternal age at 1st generation birth. Predicted odds ratios (ORs) for teen birth were mapped as a function of joint exposures. We also conducted sensitivity analyses among 1st generation girls with measured exposure biomarkers (n=371).Results:The highest teen birth risk was associated with a mixture of high prenatal HCB, Hg, Pb, and PCB, but low DDE exposure, with similar associations in sensitivity analyses. The highest OR predicted for girls born in 1995 to mothers of median age (26 years) was at the 95th percentile of the HCB and PCB exposure distributions (OR=3.09; 95% confidence interval: 0.29, 32.4). Additionally, girls born earlier in the study period or to teen mothers were at increased risk of teen birth.Significance:Prenatal environmental chemical exposures and sociodemographic characteristics may interact to substantially increase risk of teen births.

Associations between prenatal exposure to DDT and DDE and allergy symptoms and diagnoses in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), South Africa

Dichlorodiphenyl trichloroethane (DDT) is an organochlorine insecticide that is banned internationally except for use as part of Indoor Residual Spraying (IRS) programs to control malaria. Although animal studies show that DDT and its breakdown product dichlorodiphenyl dichloroethylene (DDE) affect the immune system and may cause allergies, no studies have examined this question in populations where IRS is conducted. The aim of our study was to investigate whether prenatal exposure to DDT and DDE is associated with allergy symptoms and diagnose among South African children living in an area where IRS is conducted. To accomplish this aim, we used data from the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), an ongoing birth cohort study of 752 children born between 2012 and 2013 in the rural Vhembe district of Limpopo, South Africa. We measured maternal peripartum serum concentrations of DDT and DDE, and administered a questionnaire to the caregivers of 658 children aged 3.5 years to collect information on allergy symptoms and diagnoses as well as potential confounders using validated instruments. Using multiple logistic regression models, we found positive associations between DDT and DDE serum concentrations and most of the allergy symptoms and diagnoses. Maternal DDT (Odds Ratio [OR] = 1.5 per 10-fold increase, 95% Confidence interval, CI = 1.0, 2.3) and DDE (OR = 1.4, 95% CI = 0.8, 2.4) serum concentrations were most strongly associated with caregiver report of wheezing or whistling in the chest. Concentrations of DDT and/or DDE were also associated with increased odds of children's chests sounding wheezy during or after exercise, itchy rashes coming and going for at least six months, diagnosis of food allergy, and diagnosis of dust or dust mites allergy but confidence intervals crossed the null. Results suggest that prenatal exposure to DDT, and possibly DDE, is associated with elevated odds of wheezing among children from an IRS area.

Sex and poverty modify associations between maternal peripartum concentrations of DDT/E and pyrethroid metabolites and thyroid hormone levels in neonates participating in the VHEMBE study, South Africa

Indoor Residual Spraying (IRS), the application of insecticides on the inside walls of dwellings, is used by 84 countries for malaria control. Although effective in preventing malaria, this practice results in elevated insecticide exposure to >100 million people, most of whom are Africans. Pyrethroid insecticides and dichlorodiphenyl trichloroethane (DDT) are currently used for IRS. Animal and in vitro studies suggest that pyrethroids and DDT interfere with thyroid hormone homeostasis but human studies are inconsistent and no prior study has investigated this question in a population residing in an area where IRS is conducted. Our objective was thus to evaluate whether prenatal exposure to pyrethroids, DDT or DDT's breakdown product dichlorodiphenyl dichloroethylene (DDE) is associated with altered thyroid hormone levels among neonates from Limpopo, South Africa, where pyrethroids and DDT are used annually to control malaria. We measured serum DDT/E and urinary pyrethroid metabolite concentrations in maternal peripartum samples from 717 women participating in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), a birth cohort study conducted in Limpopo's Vhembe district. We measured total thyroxine (T4) and thyroid-stimulating hormone (TSH) in dried blood spots collected via heel stick. We found that all pyrethroid metabolites were positively associated with TSH; trans-DCCA and 3-PBA showed the strongest associations with a 12.3% (95%CI = 3.0, 22.3) and 14.0% (95%CI = 0.5, 30.2) change for each 10-fold increase in biomarker concentration, respectively. These associations were substantially stronger among children from households below the South African food poverty line. DDT and DDE were associated with lower total T4 among boys only (β = −0.27 μg/dL per 10-fold increase; 95%CI = −0.47, −0.04). Results suggest that prenatal exposure to DDT, DDE and pyrethroid insecticides is associated with changes in neonatal thyroid hormones consistent with hypothyroidism/hypothyroxinemia and that sex and poverty modify associations. Further research is needed to confirm these findings and examine whether they have implications for child development.

Breast Cancer and Exposure to Organochlorines in the CECILE Study: Associations with Plasma Levels Measured at the Time of Diagnosis and Estimated during Adolescence.

Exposure to environmental chemicals with hormonal effects, such as organochlorine compounds (OCs), during developmental periods of breast cells may have an impact on the incidence of breast cancer later in life. However, the assessment of exposure to these chemicals that occurred in early life at the time of breast cancer development in adult women is a difficult challenge in epidemiological studies. Plasma levels of the OCs p,p’-dichlorodiphenyl dichloroethene (DDE) and polychlorinated biphenyl congener 153 (PCB153) were measured in 695 cases and 1055 controls of a population-based case-control study conducted in France (CECILE study). Based on these values, we used a physiologically-based pharmacokinetic (PBPK) model to estimate PCB153 levels at age 11–20 years when the women were adolescents. Overall, there was no clear association between breast cancer risk and measured levels of DDE and PCB153 at the time of diagnosis, but there was a trend of decreasing odds ratios of breast cancer with increasing DDE and PCB153 levels in women aged 50 years and over. The PBPK model revealed that PCB153 concentrations estimated during adolescence were highest in the youngest women born after 1960 who reached adolescence at a time when environmental contamination was maximum, and very low in the oldest women who attained adolescence before the contamination peak. Negative associations between breast cancer and PCB153 estimates during adolescence were also found. The negative associations between DDE and PCB153 levels measured at the time of diagnosis or estimated during adolescence in our study were unexplained. Further investigations are needed to clarify whether this finding is real or related to study artifacts. However, this study suggests that using PBPK models in epidemiological studies to back-estimate OC exposures during early life stages may be useful to address critical questions on cancer development.

Using Birth Cohort Data to Estimate Prenatal Exposures for All Births around the New Bedford Harbor Superfund Site in Massachusetts

Introduction: Children born near New Bedford, Massachusetts, USA have been prenatally exposed to environmental chemicals, in part due to an older housing stock, high fish consumption rates, and proximity to the New Bedford Harbor (NBH) Superfund site. Chemical exposure measures are not available for the general population, limiting epidemiologic investigations and potential interventions. Our objective was to leverage available sociodemographic and biomonitoring data from the New Bedford Cohort (NBC) to retrospectively estimate prenatal exposures for all 10,273 births between 1993-1998 in the 4 towns neighboring the NBH Superfund site.Methods: The NBC, a population-based cohort of 788 mother-infant pairs born between 1993-1998 near the NBH, collected questionnaire data and prenatal exposure biomarkers including cord serum polychlorinated biphenyls (PCB), &amp;#961;,&amp;#961;&amp;#8242;-dichlorodiphenyl dichloroethylene (DDE), hexachlorobenzene (HCB), cord blood lead (Pb), and maternal hair mercury (Hg). We used bootstrapped samples of the NBC data to build prenatal exposure models, with multivariable smooths of birth location, birth year, maternal age at birth, and other NBC maternal sociodemographic characteristics as predictors.Results: Maternal country of birth was the strongest exposure predictor across all exposures with women from the Azores and Cape Verde having the highest levels. Maternal age, education, and marital status also were important predictors. The PCB, DDE, HCB, Pb, and Hg exposure models explained 55%, 53%, 41%, 43% and 38% of the variance, respectively.Conclusions: Our analyses suggest that multiple prenatal exposures can be estimated at the population level by modeling available data for a subset of the population. Predictive models using multivariable smoothing explained reasonable amounts of variance. Other exposure models with comparable performance have been used successfully in epidemiologic investigations to characterize exposure-outcome associations.