Metabolite 3-phenoxybenzoic Acid Research Articles

Exposure to biocides and their potential exposure sources among adults: A nationwide population-based study in South Korea

Biocides are present in personal care (including preservatives or antibacterials), pest control, and disinfectant products (including non-agricultural insecticides, fungicides, and disinfectants), and their long-term exposure may induce adverse health effects in humans. Therefore, in this study, we assessed the exposure levels and major exposure predictors of biocides among nationally representative Korean adults. The target group included adults (≥19 years) participating in the Korean National Environmental Health Survey (KoNEHS) 2015–2020. We employed survey-weighted multiple regression analysis and conditional inference trees analysis to assess the associations between demographic characteristics, behavioral sources (including personal care product use, pesticide use, and dietary patterns), and urinary levels of phenol (triclosan [TCS]), parabens (methyl paraben [MP], ethyl paraben [EP], propyl paraben [PP], and butyl paraben [BP]), and the pyrethroid insecticide metabolite (3-phenoxybenzoic acid [3-PBA]). Urinary EP, BP, and 3-PBA levels were higher in South Korean adults compared with those in Western countries. Major exposure predictors for MP, EP, and PP included the use of personal care products such as sunscreen, makeup, and hair care products in KoNEHS 2018–2020. Major exposure predictors for TCS and BP were vegetable consumption, and those for 3-PBA were mosquitocide use during summer in KoNEHS 2018–2020. However, these predictors were not observed in KoNEHS 2015–2017. Collectively, our findings suggest that biocide exposure predictors vary according to changes in product use and diet habits of individuals. Therefore, developing strategies to mitigate biocide exposure based on the demographic and behavioral characteristics of the general population is imperative.

Association of pyrethroids exposure with asthma in US children and adolescents: a nationally representative cross-sectional study.

Pyrethroids (PYR) are among the most widely used insecticides in households, leading to substantial exposure. Children and adolescents, especially during growth spurts, have a reduced capacity to effectively metabolize these insecticides. The relationship between PYR exposure and asthma in these age groups remains poorly understood, highlighting the need for further research.We used data from the 2007-2014 National Health and Nutrition Examination Survey, which included 1181 children aged 6-11years and 1258 adolescents aged 12-19years. The concentration of the PYR metabolite 3-phenoxybenzoic acid (3-PBA) in urine was quantified using solid-phase extraction-high-performance liquid chromatography-heated electrospray ionization tandem mass spectrometry. Asthma was defined based on self-reported doctor diagnoses from the questionnaire. PYR exposure was measured using urine samples collected simultaneously with the questionnaire. We explored the association between PYR exposure and asthma using multiple logistic regression analyses, adjusting for potential confounders.Multiple logistic regression analyses revealed no significant association between PYR exposure and asthma in children and adolescent boys (all P > 0.05). In contrast, PYR exposure was significantly associated with asthma in adolescent girls aged 12-19years. Specifically, for "ever asthma," the odds ratios (ORs) were 2.49 (95% CI = 1.03-5.97) in the second quartile of PYR exposure and 2.48 (95% CI = 1.04-5.91) in the third quartile, each in comparison to the first quartile. For "current asthma," in comparison to the first quartile, the ORs were 3.99 (95% CI = 1.55-10.26) in the second quartile of PYR exposure, 3.39 (95% CI = 1.32-8.70) in the third quartile, and 2.93 (95% CI = 1.24-6.90) in the fourth quartile.Conclusions:Our study found a significant association between PYR exposure and asthma in adolescent girls, whereas no significant association was observed in children and adolescent boys. These findings suggest potential sex and age differences in susceptibility to PYR exposure. Further research is warranted to confirm these results and elucidate the underlying mechanisms.

Association of pesticide exposure with respiratory health outcomes and rhinitis in avocado farmworkers from Michoacán, Mexico

BackgroundA growing literature suggests associations between occupational pesticide exposure and respiratory health. In this study, we aimed to examine the association of exposure to insecticides, fungicides, and herbicides, individually and as a mixture, with respiratory health outcomes and rhinitis in avocado farmworkers from Michoacán, Mexico. Material and methodsWe conducted a cross-sectional study of 105 avocado farmworkers between May and August 2021. We quantified 12 insecticide, fungicide, and herbicide metabolites in urine samples collected during two study visits (8–10 weeks apart). We collected survey data on self-reported pesticide use during the 12 months prior to the baseline survey and estimated annual exposure-intensity scores (EIS) using a semi-quantitative exposure algorithm. We also assessed respiratory symptoms, including wheezing, chest tightness, wheezing after exercise, and night cough. We used generalized linear regression models to examine associations of individual urinary metabolite concentrations and annual EIS with respiratory health outcomes and rhinitis. Mixture effects were assessed using Bayesian Weighted Quantile Sum (BWQS) regression. ResultsAfter adjusting for multiple comparisons, we observed mostly null associations of individual pesticide metabolite concentrations and annual EIS with the outcomes of interest. However, in BWQS analyses, we found evidence of a mixture association of urinary pesticide metabolites with increased odds of night cough (OR: 5.34, 95 % CrI: 1.67, 20.62). Pyrethroid metabolites 3-phenoxybenzoic acid and cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid were the main contributors to this association (43 %). ConclusionsOur findings indicate that exposure to a mixture of pesticides, particularly pyrethroid insecticides, may be associated with night cough in avocado farmworkers.

A Novel Approach to Integrate Human Biomonitoring Data with Model Predicted Dietary Exposures: A Crop Protection Chemical Case Study Using Lambda-Cyhalothrin.

The appropriate use of human biomonitoring data to model population chemical exposures is challenging, especially for rapidly metabolized chemicals, such as agricultural chemicals. The objective of this study is to demonstrate a novel approach integrating model predicted dietary exposures and biomonitoring data to potentially inform regulatory risk assessments. We use lambda-cyhalothrin as a case study, and for the same representative U.S. population in the National Health and Nutrition Examination Survey (NHANES), an integrated exposure and pharmacokinetic model predicted exposures are calibrated to measurements of the urinary metabolite 3-phenoxybenzoic acid (3PBA), using an approximate Bayesian computing (ABC) methodology. We demonstrate that the correlation between modeled urinary 3PBA and the NHANES 3PBA measurements more than doubled as ABC thresholding narrowed the acceptable tolerance range for predicted versus observed urinary measurements. The median predicted urinary concentrations were closer to the median measured value using ABC than using current regulatory Monte Carlo methods.

Toxic effect and mechanism of β-cypermethrin and its chiral isomers on HTR-8/SVneo cells

Beta-cypermethrin (β-CYP) consists of four chiral isomers, acting as an environmental estrogen and causing reproductive toxicity, neurotoxicity, and dysfunctions in multiple organ systems. This study investigated the toxic effects of β-CYP, its isomers, metabolite 3-phenoxybenzoic acid (3-PBA), and 17β-estradiol (E2) on HTR-8/SVneo cells. We focused on the toxic mechanisms of β-CYP and its specific isomers. Our results showed that β-CYP and its isomers inhibit HTR-8/SVneo cell proliferation similarly to E2, with 100 μM 1S-trans-αR displaying significant toxicity after 48 h. Notably, 1S-trans-αR, 1R-trans-αS, and β-CYP were more potent in inducing apoptosis and cell cycle arrest than 1R-cis-αS and 1S-cis-αR at 48 h. AO/EB staining and flow cytometry indicated dose-dependent apoptosis in HTR-8/SVneo cells, particularly at 100 μM 1R-trans-αS. Scratch assays revealed that β-CYP and its isomers variably reduced cell migration. Receptor inhibition assays demonstrated that post-ICI 182780 treatment, which inhibits estrogen receptor α (ERα) or estrogen receptor β (ERβ), β-CYP, its isomers, and E2 reduced HTR-8/SVneo cell viability, whereas milrinone, a phosphodiesterase 3 A (PDE3A) inhibitor, increased viability. Molecular docking studies indicated a higher affinity of β-CYP, its isomers, and E2 for PDE3A than for ERα or ERβ. Consequently, β-CYP, its isomers, and E2 consistently led to decreased cell viability. Transcriptomics and RT-qPCR analyses showed differential expression in treated cells: up-regulation of Il24 and Ptgs2, and down-regulation of Myo7a and Pdgfrb, suggesting the PI3K-AKT signaling pathway as a potential route for toxicity. This study aims to provide a comprehensive evaluation of the cytotoxicity of chiral pesticides and their mechanisms.

Factors influencing occupational exposure to pyrethroids and glyphosate: An analysis of urinary biomarkers in Malaysia, Uganda and the United Kingdom

BackgroundLong-term exposure to pesticides is often assessed using semi-quantitative models. To improve these models, a better understanding of how occupational factors determine exposure (e.g., as estimated by biomonitoring) would be valuable. MethodsUrine samples were collected from pesticide applicators in Malaysia, Uganda, and the UK during mixing/application days (and also during non-application days in Uganda). Samples were collected pre- and post-activity on the same day and analysed for biomarkers of active ingredients (AIs), including synthetic pyrethroids (via the metabolite 3-phenoxybenzoic acid [3-PBA]) and glyphosate, as well as creatinine. We performed multilevel Tobit regression models for each study to assess the relationship between exposure modifying factors (e.g., mixing/application of AI, duration of activity, personal protective equipment [PPE]) and urinary biomarkers of exposure. ResultsFrom the Malaysia, Uganda, and UK studies, 81, 84, and 106 study participants provided 162, 384 and 212 urine samples, respectively. Pyrethroid use on the sampling day was most common in Malaysia (n = 38; 47%), and glyphosate use was most prevalent in the UK (n = 93; 88%). Median pre- and post-activity 3-PBA concentrations were similar, with higher median concentrations post-compared to pre-activity for glyphosate samples in the UK (1.7 to 0.5 μg/L) and Uganda (7.6 to 0.8 μg/L) (glyphosate was not used in the Malaysia study). There was evidence from individual studies that higher urinary biomarker concentrations were associated with mixing/application of the AI on the day of urine sampling, longer duration of mixing/application, lower PPE protection, and less education/literacy, but no factor was consistently associated with exposure across biomarkers in the three studies. ConclusionsOur results suggest a need for AI-specific interpretation of exposure modifying factors as the relevance of exposure routes, levels of detection, and farming systems/practices may be very context and AI-specific.

Mediating role of host metabolites in strontium's effect on osteoporosis among older individuals: Findings from Wuhan, China.

Strontium is receiving widespread attention due to its remarkable biological qualities in preventing bone resorption and fostering osteogenesis. However, the chemical processes behind strontium's dual activities on bone cells are not yet fully understood. This study used the metabolomic technique to identify and examine potential biomarkers between strontium exposure and osteoporosis (OP) risk. A total of 806 participants were recruited for the detection of plasma strontium content via inductively coupled plasma-mass spectrometry. Plasma metabolites were profiled in 254 participants through an untargeted metabolomics technique. Generalized linear models were primarily used to analyze associations among plasma strontium, metabolites, and OP. The mediating effects of metabolites on the strontium-OP association were further investigated. A total of 31 differential metabolites were observed, 10 of which were upregulated and 21 were downregulated in the OP group compared with the non-OP group. Five metabolites (3-phenoxybenzoic acid, Cer (t18:0/16:1), HexCer(t16:1/12:1(2OH)), HexCer(t14:2/18:1(2OH)), and TG(16:0-18:1-24:4)) were selected as potential mediators based on their significant association with OP risk and with femoral neck and lumbar spine bone mineral density (BMD). Moreover, all except TG(16:0-18:1-24:4) were involved in the OP discrimination model with excellent power combined with several traditional variables. 3-Phenoxybenzoic acid and Cer(t18:0/16:1) had significant indirect effects on the strontium-OP association. The five candidate metabolites mediated 83.79% of the strontium-OP association. Plasma strontium level was associated with reduced OP risk in the Han population in Wuhan. Thus, plasma metabolite profiling revealed five BMD/OP-associated metabolites that acted as mediators in the strontium-OP association. Our findings provided evidence of the mediating role of host plasma metabolites in strontium's effect on OP pathology.

Assessment of Preschool Children's Exposure Levels to Organophosphate and Pyrethroid Pesticide: A Human Biomonitoring Study in Two Turkish Provinces.

Pesticides are products developed to prevent, destroy, repel or control certain forms of plant or animal life that are considered to be pests. However, now they are one of the critical risk factors threatening the environment, and they create a significant threat to the health of children. Organophosphate (OP) and pyrethroid (PYR) pesticides are widely used in Turkey as well as all over the world. The main focus of this presented study was to analyze the OP and PYR exposure levels in urine samples obtained from 3- to 6-year-old Turkish preschool children who live in the Ankara (n:132) and Mersin (n:54) provinces. In order to measure the concentrations of three nonspecific metabolites of PYR insecticides and four nonspecific and one specific metabolite of OPs, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses were performed. The nonspecific PYR metabolite 3-phenoxybenzoic acid (3-PBA) found in 87.1% of samples (n = 162) and the specific OP metabolite 3,5,6-trichloro-2-pyridinol (TCPY) found in 60.2% of samples (n = 112) were the most frequently detected metabolites in all urine samples. The mean concentrations of 3-PBA and TCPY were 0.38 ± 0.8 and 0.11 ± 0.43ng/g creatinine, respectively. Although due to the large individual variation no statistically significant differences were found between 3-PBA (p = 0.9969) and TCPY (p = 0.6558) urine levels in the two provinces, significant exposure differences were determined both between provinces and within the province in terms of gender. Risk assessment strategies performed in light of our findings do not disclose any proof of a possible health problems related to analyzed pesticide exposure in Turkish children.

Determination of the pyrethroid inseticide metabolite 3-phenoxybenzoic acid in wastewater using polar organic integrative samplers and LC-MS/MS analysis

Wastewater-based epidemiology (WBE) is a methodological approach that aims to obtain epidemiological information through wastewater analysis, by identifying endogenous metabolism products. Pyrethroid insecticides are commonly used but just a few studies evaluated concentrations of pyrethroid metabolites in wastewater. A cost-effective and efficient sampling strategy for WBE studies is the use of polar organic chemical integrative samplers (POCIS). This study aimed to develop and evaluate a method for estimating the concentration of the pyrethroid insecticide 3-phenoxybenzoic acid (3-PBA) using POCIS sampling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The sampler sorbent was extracted with methanol, followed by a double solid phase extraction (SPE) clean-up. The extraction procedure had yields in the range of 95.7–100.4 %. There were 27 collection cycles, with POCIS samplers changed every 14 days. The analyte 3-PBA was measured in all collections. The concentration of 3-PBA in the POCIS sorbent was 208.6–2456.9 ng g−1. The sampling rate was 0.096 L/day and the resulting estimated concentration in wastewater was 24.3 to 335.2 ng/L. This is the first study evaluating POCIS sampling to measure a pyrethroid metabolite in water or wastewater samples.

Exposure to mixtures of phenols, phthalate metabolites, parabens, and pesticide and BMI and lipid profiles in adolescents age 12-18

Background and aim Endocrine disrupting chemicals (EDCs) interfere endocrine system and lead to the imbalance in the regulation of lipid metabolism and body weight. Some recent studies suggest that EDCs may increase the risk for obesity or dyslipidemia, but most previous studies have evaluated the health effects of individual EDCs in isolation. We evaluated the association of combined exposure of EDCs with body mass index (BMI) and lipid profiles in a representative sample of a general population from Korea. Methods Urinary concentrations of exposures including three phenols (bisphenol A, bisphenol F, bisphenol S), eight phthalate metabolites (mono- (2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl-5-oxohexyl) phthalate, mono-n-butyl phthalate, monobenzyl phthalate, mono-(2-ethyl-5-carboxypentayl) phthalate, mono-(carboxyoctyl) phthalate, mono-(carboxynonyl) phthalate, mono(3-carboxylpropyl) phthalate), three parabens (methyl paraben, ethyl paraben, propyl paraben), and pyrethroid pesticides metabolite (3-phenoxybenzoic acid) and outcomes of interest including BMI, triglycerides (TG), total cholesterol, and high-density lipoprotein cholesterol (HDL-c) were measured in 891 adolescents. Age, sex, monthly household income, mother’s education level, frequency of fast-food, physical activity, smoking status, and alcohol consumption were adjusted. The association was examined using Bayesian Kernel Machine Regression (BKMR), and the analyses were stratified by sex to assess the potential effect modification. Results BMI, TG to HDL-c ratio (TG/HDL), and total cholesterol to HDL ratio (TC/HDL) showed significant increasing trends when all the chemicals were at different levels from 25th percentile to 75th percentile, although the confidence intervals were wide. And the overall effects were more significant among males compared to female. For BMI, parabens showed the highest group posterior inclusion probability (PIP). On the other hand, for TG/HDL and TC/HDL, phthalate metabolites showed the highest group PIP. Conclusions Our findings suggest that higher exposure to EDCs mixture is associated with higher BMI, TG/HDL, TC/HDL, particularly in male adolescents. Key workds endocrine disrupting chemicals, mixture, BKMR, BMI, TG, HDL, total cholesterol, adolescents

Highly efficient degradation of cypermethrin by a co-culture of Rhodococcus sp. JQ-L and Comamonas sp. A-3.

Cypermethrin is an important synthetic pyrethroid pesticide that widely used to control pests in agriculture. However, extensive use has caused its residue and the metabolite 3-phenoxybenzoic acid (3-PBA) to seriously pollute the environments and agricultural products. In this study, a highly efficient cypermethrin-degrading bacterial consortium was acclimated from long-term pyrethroid-contaminated soil. Two strains, designated JQ-L and A-3, were screened from the consortium, and identified as Rhodococcus sp. and Comamonas sp., respectively. Strain JQ-L transformed 100 mg/L of cypermethrin to 3-PBA within 60 h of incubation; however, 3-PBA could not be further degraded by the strain. Strain A-3 utilized 3-PBA as sole carbon for growth, and completely degraded 100 mg/L of 3-PBA within 15 h of incubation. Co-culture of JQ-L and A-3 completely degraded 100 mg/L of cypermethrin within 24 h of incubation. Furthermore, a complete catabolic pathway of cypermethrin and the metabolite 3-PBA by the co-culture was proposed. This study provided a promising strategy for efficient elimination of cypermethrin residue-contaminated environments and agricultural products.

Prenatal Pesticide Exposure Is Associated With Lower Cognitive, Language, and Motor Development Scores in Children 20–40 Months of Age Rural Bangladesh

ObjectivesPesticides are an often-overlooked dietary exposure, especially in low- and middle-income countries (LMICs). Evidence from high-income settings indicates that pesticide exposure during pregnancy can adversely affect early childhood development (ECD). However, evidence from LMICs is limited. Our objective was to quantify the associations between prenatal pesticide exposure and ECD in rural Bangladesh. MethodsWe used data from 284 mother-child pairs participating in a birth cohort established in 2008. Eight pesticide biomarkers were assessed in urine collected in early pregnancy (<16 weeks’ gestation). Urinary pesticide biomarkers capture all exposure routes. In our sample, 0% of women and 23% of their husbands were employed in agriculture, and indoor residual spraying is rare in this part of Bangladesh. Thus, we hypothesised that the primary pesticide exposure route was dietary intake. ECD was assessed at 20–40 months of age using the Bayley Scales of Infant and Toddler Development, Third Edition. Associations between creatinine-adjusted pesticide levels and child development raw scores were estimated using multivariable generalised linear models. Results3,5,6-trichloro-2-pyridinol (TCPY) and 4-nitrophenol, metabolites of frequently used organophosphates, were detected in 98% and 100% of women, respectively. The metabolites 3-phenoxybenzoic acid (3-PBA, a pyrethroid metabolite) and 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMPY, an organophosphate metabolite) were detected in 19.8% and 16.1% of women, respectively. Higher IMPY concentrations were associated with lower language (–0.67 points [95% CI –1.31, –0.04]) and motor development (–0.40 points [95% CI –0.71, –0.09]). Higher TCPY concentrations were associated with lower cognitive development, though the association was small: –0.01 points (95% CI –0.02, 0.00). We observed no associations between 4-nitrophenol and 3-PBA and child development. ConclusionsExposure to organophosphates, which are acetylcholinesterase inhibitors, in early pregnancy may adversely affect ECD. Interventions to reduce children’s pesticide exposure in LMICs are needed. Funding SourcesFunding was provided by UK Research and Innovation, (removed to allow blinded review), and the National Institutes of Health (NIEHS).

Literature review on pyrethroid common metabolites

A systematic literature review has been performed on the toxicological profiles of the pyrethroid common metabolites 3-phenoxybenzoic acid (PBA), 3-(4’-hydroxyphenoxy)benzoic acid (PBA(OH)) and 3-phenoxybenzaldehyde (PBAld). Following the definition of appropriate search strings 1031 publications were screened by abstract, title and keywords followed by a screening of full texts of 82 publications. From these 20 publications could be identified to provide data relevant for the toxicological profile(s) of one or more of the metabolites. As one publication covered in vitro and in vivo studies those data have been assessed twice – so that the total number of publications was considered to be 21. Overall, the studies identified in the literature focused on effects related to reproductive toxicity, immunotoxicity, endocrine disruption, hepatotoxicity, cardiovascular toxicity, and neurotoxicity. Following a risk of bias (ROB) assessment, the majority (n=13) was considered to have low ROB, while two studies were assessed to have a high ROB. Seven publications could not be allocated to Tier 1 (low risk of ROB) or Tier 3 (high risk of ROB) and thus were grouped as Tier 2 studies. The Tier 1 studies provided evidence that PBA does not appear to produce any effects on sperm motility. However, based on the Tier 1 studies, all of which were in vitro, there are some indications that PBA, PBAld and PBA(OH) may interact with the endocrine system. In addition, also based on in vitro data, PBA and PBAld were shown to produce cell cycle arrest, inhibition of cell differentiation, and generation of reactive oxygen species, indicating the potential for immunotoxicity. PBA was also associated with apoptosis and replicative DNA synthesis in hepatocytes, while PBA along with PBAld damage in heart cells. © European Food Safety Authority, 2021

Prenatal exposure to pyrethroid and organophosphate insecticides and language development at age 20-36 months among children in the Odense Child Cohort.

Prenatal exposure to organophosphate and pyrethroid insecticides has been associated with impaired neurodevelopment. Few longitudinal studies have investigated associations with early language development in populations with mainly low dietary exposure. To investigate associations between biomarkers of maternal gestational exposure to organophosphate and pyrethroid insecticides and the child's language development at age 20-36 months in the prospective Odense Child Cohort. Metabolites of organophosphate and pyrethroid insecticides were measured in maternal urine samples collected at gestational week 28. Language development was assessed among 755 singletons at age 20-36 months using the Vocabulary and Complexity scores of the MacArthur-Bates Communicative Development Inventories, standardized into age and sex specific percentile scores according to a Danish reference study. Multiple logistic regression models were used to estimate the odds of scoring below the 15th percentile scores in relation to maternal urinary insecticide metabolite concentrations after adjustment for confounders. The generic pyrethroid metabolite 3-phenoxybenzoic acid (3-PBA) and the chlorpyrifos metabolite 3,5,6-trichloro-2-pyridinol (TCPY) were detectable in more than 90% of the urine samples analyzed. Likewise, 82.2% had detectable concentrations of diethyl phosphates (DE) and 58.4% of dimethyl phosphates (DM), both of which are common metabolites of organophosphate insecticides. None of the metabolites was associated with higher odds of delayed results below the 15th percentile language scores. In contrast, reduced probability for scoring below the 15th percentile Vocabulary score was seen for the highest tertile of 3-PBA in boys and for the upper tertile of TCPY and DE in girls. In this prospective cohort, with predominantly dietary insecticide exposure, we found no evidence that gestational exposure to organophosphate or pyrethroid insecticides adversely affected early language development in the children. The observed indication of a positive effect of insecticides on language development may be explained by residual and unmeasured confounding from socioeconomic factors and dietary habits. Follow-up of these children should include assessment of more complex cognitive functions in later childhood, as well as associations with their own postnatal insecticide exposure.

Synthetic pyrethroids common metabolite 3-phenoxybenzoic acid induces caspase-3 and Bcl-2 mediated apoptosis in human hepatocyte cells

Synthetic pyrethroids are a group of insecticides frequently used in public health and agriculture, and 3-PBA is a common metabolite of them. Although the liver is the primary organ responsible for metabolizing many compounds including pesticides, to the authors’ knowledge there have been no studies on the direct hepatotoxic effects of 3-PBA. Therefore, this study aimed to investigate the possible hepatotoxic effects of 3-PBA on a Human Hepatoma Cell Line (HepG2) and the underlying apoptotic mechanisms. Firstly, an LC50 of 1041.242 µM was calculated for 3-PBA by using the WST-1 test with concentrations ranging between 1 µM and 10 mM. Following that, the HepG2 cells in the experimental group were exposed to 3 different concentrations of 3-PBA (1/5 LC50, 1/10 LC50 and 1/20 LC50) for 24 hours. The apoptotic mechanism was evaluated by using flow cytometry, and immunofluorescence assays for Caspase 3 and Bcl-2. In the flow cytometry assay, the total number of apoptotic cells increased in a dose dependent manner (p < 0.05). In the immunofluorescence assay, the Caspase 3 protein showed strong immunoreactivity in the experimental groups, while the reaction to the Bcl-2 protein was minimal. These results demonstrated that 3-PBA has a significant hepatotoxic effect on HepG2 cells and induces apoptosis via the regulation of Caspase-3 and Bcl-2. Furthermore, our results could further the understanding of the fundamental molecular mechanisms of 3-PBA hepatotoxicity. More studies are needed to determine the effects of long-term exposure to 3-PBA and also the molecular mechanisms underlying hepatotoxicity.

Pyrethroid exposure among children residing in green versus non-green multi-family, low-income housing.

Background:There is growing concern about children’s chronic low-level pesticide exposure and its impact on health. Green building practices (e.g. reducing leakage of the thermal and pressure barrier that surrounds the structure, integrated pest management, improved ventilation) have the potential to reduce pesticide exposure. However, the potential impact of living in green housing on children’s pesticide exposure is unknown.Objective:To address this question, a longitudinal study of pyrethroid metabolites (3-phenoxybenzoic acid [3-PBA], 4-fluoro-3-phenoxybenzoic acid [4-F-3-PBA], trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid [trans-DCCA]) in first morning void urine, collected from 68 children from New Orleans, Louisiana residing in green and non-green housing was conducted.Methods:Children were followed for one year with three repeated measures of pesticide exposure. Generalized Estimating Equations examined associations between housing type (green v non-green) and urinary pyrethroid metabolite concentrations adjusting for demographic and household factors over the year.Results:Ninety-five percent of samples had detectable concentrations of 3-PBA (limit of detection [LOD]: 0.1 μg/L); 8% of 4-F-3-PBA (LOD: 0.1 μg/L), and 12% of trans-DCCA (LOD: 0.6 μg/L). In adjusted models, green housing was not associated with statistically significant differences in children’s 3-PBA urinary concentrations compared to non-green housing.Significance:In this study, green building practices had no impact on children’s pyrethroid urinary concentrations. Further studies with larger sample sizes are needed to confirm these findings.

In utero pyrethroid pesticide exposure in relation to autism spectrum disorder (ASD) and other neurodevelopmental outcomes at 3 years in the MARBLES longitudinal cohort

BackgroundWe assessed the relationships between prenatal pyrethroid pesticide exposure and autism spectrum disorders (ASD) or non-typical development (non-TD) at 3 years. MethodsParticipants were mother-child pairs (n = 201) in the MARBLES (Markers of Autism Risk in Babies-Learning Early Signs) cohort. Because familial recurrence risk is high, MARBLES enrolls pregnant women with a family history of ASD. Children from these pregnancies were clinically assessed at 3 years of age and classified into 3 outcome categories: ASD, typically developing (TD), or non-TD (neither TD or ASD). Repeated maternal second and third trimester urine samples were analyzed for pyrethroid metabolite 3-phenoxybenzoic acid (3-PBA). Multinomial logistic regression was used to obtain relative risk ratios (RRR) linking 3-PBA concentrations averaged across each trimester and over pregnancy with child's outcome: ASD or non-TD vs. TD. Models were adjusted for specific gravity, maternal pre-pregnancy BMI, prenatal vitamin use, birth year, home-ownership, and pregnancy concentrations of TCPy (3,5,6-trichloro-2-pyridinol, a metabolite of chlorpyrifos). ResultsThe median specific gravity corrected 3-PBA concentration of all samples was 1.46 ng/mL. Greater second trimester 3-PBA concentrations were associated with a relative risk ratio (RRR) for ASD of (RRR: 1.50 (95% CI 0.89 to 2.51), p = 0.12). There were no differences between non-TD and TD. ConclusionsThis study found no evidence for differences in 3-PBA comparing non-TD with TD. A modestly elevated RRR was found comparing second trimester urinary 3-PBA concentrations for ASD versus TD; however, the confidence interval was wide and hence, these findings cannot be considered definitive.

Hypospadias in boys born to mothers exposed to dichlorodiphenyltrichloroethane and pyrethroid insecticides

PDS 72: Environmental health issues in LMIC, Exhibition Hall (PDS), Ground floor, August 28, 2019, 10:30 AM - 12:00 PM Background: Hypospadias is the ectopic opening of the male urethra and related in vivo to maternal estrogenic and/or anti-androgenic exposures. We examined the relationship between maternal exposure to DDT and pyrethroids and hypospadias in a malaria endemic area. Dichlorodiphenyltrichloroethane (DDT) and the pyrethroids cypermethrin and deltamethrin are used to control malaria. In vitro, DDT is estrogenic and its breakdown product, dichlorodiphenyldichloroethylene (DDE) is anti-androgenic. Cypermethrin, and permethrin are metabolized to cis-3-and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane carboxylic acid (cis- and trans-DCCA) and the most common pyrethroid metabolite 3-phenoxybenzoic acid (3-PBA). Deltamethrin breaks down to the metabolites 3-PBA and cis-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cis-DBCA). DCCA and 3-PBA are anti-androgenic. Methods: We measured peripartum levels of DDT and DDE in maternal blood and the pyrethroid metabolites cis- and trans-DCCA, 3-PBA and cis-DBCA in maternal urine in a birth cohort and examined boys at age one year for hypospadias (n=359). Due to the high prevalence of phimosis (n=291, 81.1%), which prevented examination for hypospadias, we restricted analyses to boys without phimosis (n= 68). Results: Hypospadias was observed in 32 boys. Maternal cis-DCCA, trans-DCCA and 3-PBA urinary concentrations were significantly associated with increased relative risks (RR) of having a boy with hypospadias (RR 1.90 (95% CI: 1.31, 2.75), 1.82 (95% CI: 1.27, 2.63) and 1.85 (95% CI: 1.06, 3.22), respectively). There were no significant associations between DDT, DDE and DBCA and hypospadias. Conclusions: Boys examined had very high prevalence of phimosis and hypospadias. Mothers with high urinary concentrations of 3-PBA and DCCA had significantly greater risks of having a son with hypospadias. This is the first study to report associations between maternal pyrethroid exposure and hypospadias. Hormonal mechanisms might be involved in the etiology. Given the extensive global use of pyrethroids, our findings raise health concerns for other populations with high usage for malaria control, home use or agricultural purposes.

Pesticide interactions and risks of sperm chromosomal abnormalities.

Disentangling the separate and synergistic effects of chemicals poses methodological challenges for accurate exposure assessment and for investigating epidemiologically how chemicals affect reproduction. We investigated combined exposures to ubiquitous contemporary use pesticides, specifically organophosphates (OP) and pyrethroids (PYR), and their association with germ cell abnormalities among adult men. Fluorescence in situ hybridization was used to determine disomy in sperm nuclei and urine was analyzed for concentrations of PYR metabolites (3-phenoxybenzoic acid; 3PBA) and OP dialkyl phosphate (DAP) metabolites. Incidence rate ratios using Poisson models were estimated for each disomy type by exposure quartile of DAP metabolites and 3PBA, controlling for confounders. The shape of the associations between PYRs, OPs and disomy were frequently nonmonotonic. There were consistent interactions between OP and PYR metabolite concentrations and the risk for sperm abnormalities. Taking both chemicals into account simultaneously resulted in quantitatively different associations than what was reported previously for OPs and PYRs separately, demonstrating the importance of modeling multiple concentrations simultaneously. Methods investigating interactions using Poisson models are needed to better quantify chemical interactions and their effects on count-based health outcomes, the importance of which was shown here for germ cell abnormalities.

Monitoring of organophosphate and pyrethroid metabolites in human urine samples by an automated method (TurboFlow™) coupled to ultra-high performance liquid chromatography-Orbitrap mass spectrometry

There is a growing concern to pesticide exposure in humans, being the organophosphate (OP), carbamate and pyrethroid the most commonly used insecticides. Therefore, a fast, simple and automated screening method based on ultra-high performance liquid chromatography coupled to Orbitrap high resolution mass spectrometry (UHPLC-Orbitrap-MS) has been developed to determine six OPs metabolites (3,5,6-trichloro-2-pyridinol “TCPy”, 2-isopropyl-6-methyl-4-pyrimidinol “IMPY”, 4-nitrophenol “PNP”, 4-nitrophenol-d4 “PNP-d4″, 3-chloro-7-hydroxy-4-methylcoumarin “CMHC” and 2-diethylamino-6-methylpyrimidin-4ol “DEAMPY”) and three pyrethroid metabolites (3-phenoxybenzoic acid “3-PBA”, 4-fluoro-3-phenoxybenzoic acid “4-F-3-PBA” and 3-(2,2-dichlorovinyl)-2,2-dimethyl-1-cyclopropanecarboxylic acid “cis/trans-DCCA”) in human urine samples. Off-line solid phase extraction (SPE), on-line SPE and turbulent flow chromatography (TurboFlow™) extraction methodologies were compared, obtaining better results when TurboFlow™ was applied, achieving a total analysis time of 13.83 min. Several validation parameters were tested, obtaining suitable results for all studied compounds. Recoveries ranged from 70 to 116%, meanwhile repeatability and reproducibility were lower than or equal to 7% and 13%, respectively. The limits of quantification (LOQs) were set in the range from 1 μg/L to 5 μg/L (except for DCCA at 10 μg/L). Finally, thirty seven urine samples from women and men living near the agricultural areas of Almeria (Spain) were analyzed to know and control the contamination on the human health. PNP, DEAMPY and IMPY were detected in six urine samples at trace levels except IMPY, which was detected at 3.44 μg/L in one of the samples. Additionally, a post-targeted and untargeted analysis were carried out in the samples, identifying eleven insecticides such as bensulide or cinerin II, one insecticide metabolite, fipronil sulfone, one drug metabolite, carboxyibuprofen and two nicotine metabolites, cotinine and 2-(1-pyrrolidinyl)isonicotinic acid, in several samples.