Review of pesticide urinary biomarker measurements from selected US EPA children's observational exposure studies

Development and validation of multiresidue analysis method for biomonitoring of pesticides and metabolites in human blood and urine by LC-QToF-MS

The widespread use of pesticides and their consequential presence in the environment is a growing concern due to the harmful health effects associated with pesticide exposure. For clinical and toxicology laboratories, a method for simultaneously determining these compounds and their metabolic products in body fluids, such as blood and urine, is important. In the present study, a rapid, sensitive and simultaneous LC-QToF-MS method for detecting multiclass pesticides and metabolites in blood and urine samples has been developed and validated. Four sample preparation procedures, protein precipitation and three different variants of QuEChERS-based extraction were evaluated to find a suitable, simple, and effective sample pretreatment technique. The final optimized sample preparation method (acetonitrile; 400 μl, MgSO4; 40 mg and NaCl; 10 mg) was validated for accuracy, precision, matrix effect, recovery, stability, carryover, and dilution integrity. Analyte recoveries ranged from 75.40 to 113.54 % while accuracy was evaluated in the range of 71.41-108.26 % and precision (%RSD) in the range of 0.01 %-16.85 %. The limit of quantification (LOQ) for all compounds was established in the range of 0.82-7.05 ng mL-1. The developed reliable, robust, and sensitive method was successfully applied for the quantification of target pesticides and metabolites in human blood and urine samples. Evaluated samples resulted in detection of eleven analytes (seven pesticides and four metabolites).

Characterization of pesticide exposures and their associations with asthma morbidity in a predominantly low-income urban pediatric cohort in Baltimore City

BACKGROUND

Pesticides may impact respiratory health, yet evidence of their impact on pediatric asthma morbidity is limited, particularly among urban children.

OBJECTIVE

To characterize pesticide biomarker concentrations and evaluate their associations with pediatric asthma morbidity among predominantly low-income, Black children in Baltimore City, USA.

METHODS

We measured urinary concentrations of 10 biomarkers for pyrethroid insecticides (cyfluthrin:4F-3PBA, permethrin:3PBA), organophosphate insecticides (chlorpyrifos:TCPY, malathion:MDA, parathion:PNP, diazinon:IMPY), and herbicides (glyphosate:AMPA, GPS; 2,4-dicholorphenoxyacetic acid:2,4-D; 2,4,5-tricholorphenoxyacetic acid:2,4,5-T) among 148 children (5-17 years) with established asthma. Urine samples and asthma morbidity measures (asthma symptoms, healthcare utilization, lung function and inflammation) were collected every three months for a year. Generalized estimating equations were used to examine associations between pesticide biomarker concentrations and asthma morbidity measures, controlling for age, sex, race, caregiver education, season, and environmental tobacco smoke. In sensitivity analyses, we assessed the robustness of our results after accounting for environmental co-exposures.

RESULTS

Frequently detected (≥90% detection) pesticide biomarker concentrations (IMPY, 3PBA, PNP, TCPY, AMPA, GPS) varied considerably within children over the follow-up period (intraclass correlation coefficients: 0.1-0.2). Consistent positive significant associations were observed between the chlorpyrifos biomarker, TCPY, and asthma symptoms. Urinary concentrations of TCPY were associated with increased odds of coughing, wheezing, or chest tightness (adjusted Odds Ratio, aOR, TCPY:1.60, 95% Confidence Interval, CI:1.17-2.18). Urinary concentrations of TCPY were also associated with maximal symptom days (aOR:1.38, CI:1.02-1.86), exercise-related symptoms (aOR:1.63, CI:1.09-2.44), and hospitalizations for asthma (aOR:2.84, CI:1.08-7.43). We did not observe consistent evidence of associations between the pesticide exposures assessed and lung function or inflammation measures.

CONCLUSION

Among predominantly Black children with asthma, we found evidence that chlorpyrifos is associated with asthma morbidity. Further research is needed to assess the contribution of pesticide exposures to pediatric respiratory health and characterize exposure sources among vulnerable populations to inform targeted interventions against potentially harmful pesticide exposures.

Associations between Neonicotinoid, Pyrethroid, and Organophosphate Insecticide Metabolites and Neurobehavioral Performance in Ecuadorian Adolescents

Background

Organophosphate and pyrethroid insecticides can affect children's neurodevelopment and increase inflammation. Limited evidence exists among adolescents and on whether inflammation may mediate pesticide-neurobehavior associations. We examined the associations between insecticide metabolite concentrations and neurobehavior among adolescents in Ecuadorian agricultural communities.

Methods

We included 520 participants aged 11-17 years. We measured urinary insecticide metabolites (mass spectrometry) and neurobehavior (NEPSY-II). Associations were adjusted for socio-demographic and anthropometric characteristics. The associations of insecticide mixtures with neurobehavior were evaluated using PLS regression, and mediation by inflammatory biomarkers (TNF-α, IL-6, CRP, SAA, sICAM-1, sVCAM-1 and sCD-14) was conducted.

Results

Among organophosphates, para-nitrophenol (PNP) and 3,5,6-Trichloro-2-pyridinol (TCPy) were inversely associated with Social Perception (score difference per 50% increase [β 50% ] = -0.26 [95%CI: - 1.07, -0.20] and -0.10 [-0.22, 0.01], respectively). PNP and TCPy also had significant inverse associations with Attention/Inhibitory Control at concentrations >60 th percentile (β 50% = -0.26 [95%CI: -0.51, -0.01] and β 50% = -0.22 [95%CI: -0.43, -0.00], respectively). The pyrethroid, 3-phenoxybenzoic acid (3-PBA), was inversely associated with Language (β 50% = -0.13 [95%CI: -0.19, -0.01]) and had a negative quadratic association with Attention/Inhibitory Control. The neonicotinoid 5-Hydroxy imidacloprid (OHIM) was positively associated with Memory/Learning (β 50% = 0.20 [95%CI: 0.04, 0.37]). Mixtures of all insecticides were significantly negatively related to all domains, except for Memory/Learning, which was positively associated. No mediation by inflammatory markers on these associations was observed.

Conclusions

Concurrent organophosphate, pyrethroid, and the mixtures of all metabolites were associated with lower performance in all domains except for Memory/Learning. Neonicotinoids were positively associated with Memory/Learning and Social Perception scores.

Exploring noninvasive matrices for assessing long-term exposure to phthalates: a scoping review

The phthalic acid esters (PAEs) are one class of the most abundant and frequently studied pseudo-persistent organic pollutants. Noninvasive urine is an effective substrate for evaluating PAE exposure, but repeated sampling is needed to overcome this bias. This adds much work to on-site collection and the cost of detection increases exponentially. Therefore, the aim of this study was to conduct a scope review to describe the detection methods and validity of the use of other noninvasive matrices, such as nails and hair, for assessing long-term exposure to PAEs. The PubMed, Web of Science and China National Knowledge Infrastructure (CNKI), electronic databases were searched from 1 January 2000 to 3 April 2024, and 12 studies were included. Nine and three studies used hair and nails, respectively, as noninvasive matrices for detecting PAE exposure. Five articles compared the results of nail or hair and urine tests for validity of the assessment of PAE exposure. The preprocessing and detection methods for these noninvasive samples are also described. The results of this review suggest that, compared with nails, hair may be more suitable as a noninvasive alternative matrix for assessing long-term exposure to PAEs. However, sample handling procedures such as the extraction and purification of compounds from hair are not uniform in various studies; therefore, further exploration and optimization of this process, and additional research evidence to evaluate its effectiveness, are needed to provide a scientific basis for the promotion and application of hair detection methods for assessing long-term PAE exposure levels.

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.

Dietary Predictors of Urinary Biomarkers of Pyrethroids in the General Population - A Scoping Review

BACKGROUND

Pyrethroid pesticides are ubiquitous environmental contaminants, contributing to chronic and potentially harmful exposure among the general population. Although studies have measured pesticide residues on agricultural products, the link between food intake and concentrations of pyrethroid biomarkers in urine remains unclear.

OBJECTIVE

This scoping review aims to analyze peer-reviewed publications investigating dietary predictors of pyrethroid exposure through urinary biomarkers. We assess existing evidence, identify research gaps, and highlight current limitations.

METHODS

We conducted a comprehensive search using PubMed and Google Scholar. Eligible studies examined associations between diets, food items or dietary components, and measured urinary pyrethroid biomarkers. No geographical restriction was applied to our search. Results were summarized in themes referring to study characteristics, relevant outcomes, biomarker measurement, dietary assessment and statistical analyses.

RESULTS

We identified 20 relevant articles. Most studies presented evidence on associations between the consumption of organic diets or food items and reduced concentrations of 3-phenobenzoic acid metabolites in urine. There was less evidence for diet affecting other pyrethroid-specific biomarkers. Dietary assessment methodologies and recall periods varied, as did the number and timing of urine collections. Many studies did not control for potential alternative pyrethroid sources, exposure to other pesticides, or demographic and socioeconomic characteristics.

CONCLUSION

Researchers should consider standardized dietary assessment, chemical analyses of foods consumed, adequate recall time, and food preparation methods. Consistency in biomarker measurement, including urine collection time and corrections for specific gravity or creatinine, is needed. Ensuring the validity of such studies also requires larger samples and appropriate control for confounders.

Investigating the prevalence of erectile dysfunction among men exposed to organophosphate insecticides

INTRODUCTION

Erectile dysfunction (ED) poses a significant disease morbidity and contributor to male infertility, where an estimated 20-40% of men are affected annually. While several risk factors have been identified in the etiology of ED (e.g., aging, heart disease, diabetes, and obesity), the complete pathogenesis remains to be elucidated. Over the last few decades, the contribution of environmental exposures to the pathogenesis of ED has gained some attention, though population studies are limited and results are mixed. Among environmental contaminants, organophosphate (OP) insecticides represent one of the largest chemical classes, and chlorpyrifos is the most commonly used OP in the U.S. OP exposure has been implicated in driving biological processes, including inflammation, reactive oxygen species production, and endocrine and metabolism disruption, which have been demonstrated to adversely affect the hypothalamus and testes and may contribute to ED. Currently, studies evaluating the association between OPs and ED within the U.S. general population are sparse.

METHODS

Data were leveraged from the National Health and Nutrition Examination Survey (NHANES), which is an annually conducted, population-based cross-sectional study. Urinary levels of 3,5,6-trichloro-2-pyridinol (TCPy), a specific metabolite of the most pervasive OP insecticide chlorpyrifos, were quantified as measures of OP exposure. ED was defined by responses to questionnaire data, where individuals who replied "sometimes able" or "never able" to achieve an erection were classified as ED. Chi-square, analysis of variance (ANOVA), and multivariable, weighted linear and logistic regression analyses were used to compare sociodemographic variables between quartiles of TCPy exposure, identify risk factors for TCPy exposure and ED, and to analyze the relationship between TCPy and ED.

RESULTS

A total of 671 adult men were included in final analyses, representing 28,949,379 adults after survey weighting. Approximately 37% of our cohort had ED. Smoking, diabetes, aging, Mexican-American self-identification, and physical inactivity were associated with higher ED prevalence. Analysis of TCPy modeled as a continuous variable revealed nonsignificant associations with ED (OR = 1.02 95% CI [0.95, 1.09]). Stratification of total TCPy into quartiles revealed increased odds of ED among adults in the second and fourth quartiles, using the first quartile as the reference (OR = 2.04 95% CI [1.11, 3.72], OR = 1.51 95% CI [0.58, 3.93], OR = 2.62 95% CI [1.18, 5.79], for quartiles 2, 3, and 4, respectively).

CONCLUSIONS

The results of our study suggest a potential role for chlorpyrifos and other OPs the pathogenesis of ED. Future studies are warranted to validate these findings, determine clinical significance, and to investigate potential mechanisms underlying these associations.

Urinary pesticide mixture patterns and exposure determinants in the adult population from the Netherlands and Switzerland: Application of a suspect screening approach

INTRODUCTION

Non-occupational sources of pesticide exposure may include domestic pesticide usage, diet, occupational exposure of household members, and agricultural activities in the residential area. We conducted a study with the ambition to characterize pesticide mixture patterns in a sample of the adult population of the Netherlands and Switzerland, using a suspect screening approach and to identify related exposure determinants.

METHODS

A total of 105 and 295 adults participated in the Dutch and Swiss studies, respectively. First morning void urine samples were collected and analyzed in the same laboratory. Harmonized questionnaires about personal characteristics, pesticide-related activities, and diet were administered. Detection rates and co-occurrence patterns were calculated to explore internal pesticide exposure patterns. Censored linear and logistic regression models were constructed to investigate the association between exposure and domestic pesticide usage, consumption of homegrown and organic foods, household members' exposure, and distance to agricultural and forest areas.

RESULTS

From the 37 detected biomarkers, 3 (acetamiprid (-CH2), chlorpropham (4-HSA), and flonicamid (-C2HN)) were detected in ≥40% of samples. The most frequent combination of biomarkers (acetamiprid-flonicamid) was detected in 22 (5.5%) samples. Regression models revealed an inverse association between high organic vegetable and fruit consumption and exposure to acetamiprid, chlorpropham, propamocarb (+O), and pyrimethanil (+O + SO3). Within-individual correlations in repeated samples (summer/winter) from the Netherlands were low (≤0.3), and no seasonal differences in average exposures were observed in Switzerland.

CONCLUSION

High consumption of organic fruit and vegetables was associated with lower pesticide exposure. In the two countries, detection rates and co-occurrence were typically low, and within-person variability was high. Our study results provide an indication for target biomarkers to include in future studies aimed at quantifying urinary exposure levels in European adult populations.

Association of Prenatal Exposure to Organophosphate, Pyrethroid, and Neonicotinoid Insecticides with Child Neurodevelopment at 2 Years of Age: A Prospective Cohort Study

BACKGROUND

Widespread insecticide exposure might be a risk factor for neurodevelopment of our children, but few studies examined the mixture effect of maternal coexposure to organophosphate insecticides (OPPs), pyrethroids (PYRs), and neonicotinoid insecticides (NNIs) during pregnancy on child neurodevelopment, and critical windows of exposure are unknown.

OBJECTIVES

We aimed to evaluate the association of prenatal exposure to multiple insecticides with children's neurodevelopment and to identify critical windows of the exposure.

METHODS

Pregnant women were recruited into a prospective birth cohort study in Wuhan, China, from 2014-2017. Eight metabolites of OPPs (mOPPs), three metabolites of PYRs (mPYRs), and nine metabolites of NNIs (mNNIs) were measured in 3,123 urine samples collected at their first, second, and third trimesters. Children's neurodevelopment [mental development index (MDI) and psychomotor development index (PDI)] was assessed using the Bayley Scales of Infant Development at 2 years of age (N = 1,041 ). Multivariate linear regression models, generalized estimating equation models, and weighted quantile sum (WQS) regression were used to estimate the association between the insecticide metabolites and Bayley scores. Potential sex-specific associations were also examined.

RESULTS

Single chemical analysis suggested higher urinary concentrations of some insecticide metabolites at the first trimester were significantly associated with lower MDI and PDI scores, and the associations were more prominent among boys. Each 1-unit increase in ln-transformed urinary concentrations of two mOPPs, 3,5,6-trichloro-2-pyridinol and 4-nitrophenol, was associated with a decrease of 3.16 points [95% confidence interval (CI): - 5.59 , - 0.74 ] and 3.06 points (95% CI: - 5.45 , - 0.68 ) respectively in boys' MDI scores. Each 1-unit increase in that of trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid (trans-DCCA; an mPYR) was significantly associated with a decrease of 2.24 points (95% CI: - 3.89 , - 0.58 ) in boys' MDI scores and 1.90 points (95% CI: - 3.16 , - 0.64 ) in boys' PDI scores, respectively. Significantly positive associations of maternal urinary biomarker concentrations [e.g., dimethyl phosphate (a nonspecific mOPP) and desmethyl-clothianidin (a relatively specific mNNI)] with child neurodevelopment were also observed. Using repeated holdout validation, a 1-quartile increase in the WQS index of the insecticide mixture (in the negative direction) at the first trimester was significantly associated with a decrease of 3.02 points (95% CI: - 5.47 , - 0.57 ) in MDI scores among the boys, and trans-DCCA contributed the most to the association (18%).

CONCLUSIONS

Prenatal exposure to higher levels of certain insecticides and their mixture were associated with lower Bayley scores in children, particularly in boys. Early pregnancy may be a sensitive window for such an effect. Future studies are needed to confirm our findings. https://doi.org/10.1289/EHP12097.

How safe is our food we eat? An electrochemical lab-on-kitchen approach towards combinatorial testing for pesticides and GMOs; A case study with edamame

In our daily life, as consumers we are constantly made aware of the impact of pesticides and other modifications to food products derived from genetically modified organisms (GMO's) that have an impact on human health. In our connected world, there is an immense interest for on-demand information about food quality prior to consumption. The gold standard method to detect pesticides or GMOs residues in food is complex and is not amenable to rapid consumer use. In this study, we demonstrate the feasibility of an electrochemical portable sensing approach for the simultaneous direct detection of spiked pesticides chlorpyrifos (Chlp) and GMOs protein Cry1Ab in real edamame soy matrix. The immunoassay based two-plex sensing platform was fabricated using respective antibody's Chlp on one side and Cry1Ab on other side. A simple lab-on-kitchen level preparation of matrix has been demonstrated and sensor response was tested using non-faradaic electrochemical impedance spectroscopy (EIS), which showed a linear response in Cry1Ab/Chlp concentrations from 0.3 ng/mL to 243 ng/mL with limit of detection 0.3 ng /mL for both the target antigens (Cry1Ab and Chlp) respectively. The spiked and recovery test results fall within ± 20% error in real sample matrix which demonstrates the performance of the our platform with maximum residue limit (MRL) for the given targets. Such electrochemical portable multi-analyte direct sensing tool with simple matrix processing protocol can be a future commercial field-testing tool for use at everyday consumer level.

Assessment of Dermal and Inhalation Exposure to Permethrin During Field Treatment of Military Uniforms

INTRODUCTION

Permethrin is a common pesticide spray-applied to civilian clothing and military uniforms for protection against biting arthropods in an effort to reduce risks to arthropod-borne diseases. During mass clothing spray events, exposure is possible through the dermal, inhalation, and ingestion routes. The potentially exposed population during a spray event includes the pesticide applicator(s) and working party (personnel who handle clothing/uniforms by positioning on the ground, flipping, and removing after spraying is complete). Previous investigation is limited regarding permethrin exposure via multiple routes of entry. Additionally, most exposure assessments are limited to pesticide applicators rather than working party that support applicator personnel. The purpose of this investigation was to conduct a multi-route exposure assessment for all personnel normally participating in mass permethrin military uniform treatments.

MATERIALS AND METHODS

The protocol and Informed Consent Document were approved by the Uniformed Services University of the Health Sciences (USUHS) Institutional Review Board (IRB) before fieldwork initiation (IRB number: USUHS.2019-032). Sampling occurred during routine spray events performed by 14 U.S. Navy personnel (3 applicators and 11 working party) over 2 days. Personal exposures were measured with dermal sampling, and airborne concentrations were measured with area air sampling. Permethrin area air sampling and analysis were conducted using OSHA Versatile Sampler-2 sampling media (n = 36). Dermal exposure was measured using dosimeter gloves (n = 26) and a dermal patch (n = 26) worn by study participants.

RESULTS

All air samples were reported below the 0.4 µg limit of quantification. Glove sample results ranged from 45 to 120,000 µg and patch results ranged from 0.57 to 45 µg. A repeated-measures ANOVA showed non-statistically significant differences in dermal concentrations (P-value = .8340) between the applicators and working party in patches and gloves.

CONCLUSIONS

Results suggest dermal contact is the primary route of exposure compared to inhalation when mass spraying clothing with permethrin. Similar dermal exposures between these two occupations may necessitate reconsidering risk assessment procedures, training and personal protective equipment (PPE) requirements for mass spray uniform treatments. Specifically, while PPE requirements for applicators are highly regulated by the Armed Forces Pest Management Board and include items such as Tyvek suits, chemical protective gloves, and air-purifying respirators, PPE was not regulated for working party personnel before this investigation.

Diurnal variability in urinary volatile organic compound metabolites and its association with oxidative stress biomarkers

Volatile organic compounds (VOCs) are ubiquitous environmental pollutants that are associated with birth defects, leukemia, neurocognitive deficits, reproductive impairment and cancer in humans exposed to these compounds. Exposure to VOCs can be assessed by measuring their metabolites in urine. Little is known, however, about the temporal variability in urinary VOC metabolite (VOCM) concentrations within- and between-individuals. In this study, we determined the variability in the concentrations of 38 VOCMs in urine samples collected from 19 healthy individuals across a period of 44 days. We also measured seven biomarkers of oxidative stress (lipid, protein and DNA damage) in urine to assess the relationship of VOC exposure to oxidative stress. Seventeen VOCMs had detection frequencies (DFs) of >60% in urine, and we limited further data analysis to those compounds. The creatinine-adjusted geometric mean concentrations of VOCMs ranged from 2.70 μg/g to 327 μg/g in spot and 2.60 μg/g to 551 μg/g in first morning void (FMV) urine samples. Calculation of the intra-class correlation coefficients (ICCs) for 17 VOCM concentrations to assess their predictability and repeatability in urinary measurements showed ranges of 0.080-0.425 in spot and 0.050-0.749 in FMV urine samples, revealing notable within-individual variability. Our results suggest that taking only single measurements of VOCM concentrations in urine in epidemiological investigations may lead to exposure misclassification. In addition, VOCM concentrations were significantly and positively correlated with oxidative stress biomarkers. This study thus provides important information for formulating sampling strategies in the biomonitoring of VOC exposure in human populations.

Elements to increase translation in pyrethroid epidemiology research: A review

Pyrethroid insecticides have been the subject of numerous epidemiology studies in the past two decades. We examined the pyrethroids epidemiology literature published between 2016 and 2021. Our objective with this exercise was to inform interested readers regarding information on methodological elements that strengthen a study's use for translation (i.e., use in risk assessment) and to describe aspects of future research methods that could improve utility for decision-making. We focused on the following elements: (i) study design that provided evidence that pyrethroid exposure preceded the outcome, (ii) evidence that the method used for exposure characterization was reliable and sufficiently accurate for the intended purpose, and (iii) use of a robust approach for outcome ascertainment. For each of the 74 studies identified via the literature search, we categorized the methodological elements as Acceptable or Supplemental. A study with three Acceptable elements was considered Relevant for risk assessment purposes. Based on our evaluative approach, 18 (24%) of the 74 publications were considered to be Relevant. These publications were categorized as Acceptable for all three elements assessed: confirmed exposure (N = 24), confirmed outcome (N = 64), exposure preceded the outcome (N = 44). Three of these studies were birth cohorts. There were 15 Relevant publications of adults which included 10 Agricultural Health Study cohort publications of self-reported permethrin. Overall, the majority of the reviewed studies used methods that did not permit a determination that pyrethroid exposure preceded the outcome, and/or did not utilize robust methods for exposure assessment and outcome ascertainment. There is an opportunity for investigators and research sponsors to build on the studies reviewed here and to incorporate more translational approaches to studying exposure/outcome associations related to pesticides and other chemicals.

Spatio-temporal assessment of pregnant women exposure to chlorpyrifos at a regional scale

BACKGROUND

The aim of this study was to use an integrated exposure assessment approach, combining spatiotemporal modeling of environmental exposure and fate of the chemical to assess the exposure of vulnerable populations. In this study, chlorpyrifos exposure of pregnant women in Picardy was evaluated at a regional scale during 1 year. This approach provided a mapping of exposure indicators of pregnant women to chlorpyrifos over fine spatial and temporal resolutions using a GIS environment.

METHODS

Fate and transport models (emission, atmospheric dispersion, multimedia exposure, PBPK) were combined with environmental databases in a GIS environment. Quantities spread over agricultural fields were simulated and integrated into a modeling chain coupling models. The fate and transport of chlorpyrifos was characterized by an atmospheric dispersion statistical metamodel and the dynamiCROP model. Then, the multimedia model Modul'ERS was used to predict chlorpyrifos daily exposure doses which were integrated in a PBPK model to compute biomarker of exposure (TCPy urinary concentrations). For the concentration predictions, two scenarios (lower bound and upper bound) were built.

RESULTS

At fine spatio-temporal resolutions, the cartography of biomarkers in the lower bound scenario clearly highlights agricultural areas. In these maps, some specific areas and hotspots appear as potentially more exposed specifically during application period. Overall, predictions were close to biomonitoring data and ingestion route was the main contributor to chlorpyrifos exposure.

CONCLUSIONS

This study demonstrated the feasibility of an integrated approach for the evaluation of chlorpyrifos exposure which allows the comparison between modeled predictions and biomonitoring data.

Development of an analytical method based on solid-phase extraction and LC-MS/MS for the monitoring of current-use pesticides and their metabolites in human urine

Pyrethroids, organophosphorus pesticides and fipronil have been listed as priority chemicals in human biomonitoring studies because of their wide use and potential health effects in humans. The determination of 13 pesticides, including pyrethroids (deltamethrin, cypermethrin, permethrin, cyfluthrin, bifenthrin), organophosphorus (chlorpyrifos, chlorpyrifos-methyl, and malathion), fipronil, neonicotinoids (imidacloprid, acetamiprid and thiacloprid) and triazole (prothioconazole), together with 13 corresponding metabolites in human urine samples was achieved by solid-phase extraction and analysis by liquid chromatography coupled to tandem mass spectrometry. All targeted compounds, except malathion dicarboxylic acid, were measured with a mean within-accuracy (n = 5) of 71%-114% (RSD: 1%-14%) and between-run (n = 15) accuracy of 80%-118% (RSD: 2%-14%). Limits of quantitation of the targeted analytes ranged from 0.1 to 16 pg/mL. The detection result of urine samples from 25 volunteers indicated that the detection frequencies of 3,5,6-trichloro-2-pyridinol (median: 448 pg/mL), 6-chloropyridine-3-carboxylic acid (median: 193 pg/mL), 2-methyl-3-phenylbenzoic acid (median: 181 pg/mL), 3-phenoxybenzoic acid (median: 99 pg/mL), 2-isopropyl-6-methyl-4-pyrimidinol (median: 77 pg/mL), cyfluthrin (median: 59 pg/mL), cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (cis-DCCA, median: 53 pg/mL), trans-DCCA (median: 25 pg/mL), prothioconazole (median: 21 pg/mL), imidacloprid (median: 7 pg/mL), and prothioconazole-desthio (median: 1 pg/mL) were > 50%. The obtained results show that the validated method is suitable for the human biomonitoring of these current-use pesticides and their metabolites.

The Residential Population Generator (RPGen): Parameterization of Residential, Demographic, and Physiological Data to Model Intraindividual Exposure, Dose, and Risk

Exposure to chemicals is influenced by associations between the individual's location and activities as well as demographic and physiological characteristics. Currently, many exposure models simulate individuals by drawing distributions from population-level data or use exposure factors for single individuals. The Residential Population Generator (RPGen) binds US surveys of individuals and households and combines the population with physiological characteristics to create a synthetic population. In general, the model must be supported by internal consistency; i.e., values that could have come from a single individual. In addition, intraindividual variation must be representative of the variation present in the modeled population. This is performed by linking individuals and similar households across income, location, family type, and house type. Physiological data are generated by linking census data to National Health and Nutrition Examination Survey data with a model of interindividual variation of parameters used in toxicokinetic modeling. The final modeled population data parameters include characteristics of the individual's community (region, state, urban or rural), residence (size of property, size of home, number of rooms), demographics (age, ethnicity, income, gender), and physiology (body weight, skin surface area, breathing rate, cardiac output, blood volume, and volumes for body compartments and organs). RPGen output is used to support user-developed chemical exposure models that estimate intraindividual exposure in a desired population. By creating profiles and characteristics that determine exposure, synthetic populations produced by RPGen increases the ability of modelers to identify subgroups potentially vulnerable to chemical exposures. To demonstrate application, RPGen is used to estimate exposure to Toluene in an exposure modeling case example.

Body fluids from the rat exposed to chlorpyrifos induce cytotoxicity against the corresponding tissue-derived cells in vitro

BACKGROUND

This study aims to establish an in vitro monitoring approach to evaluate the pesticide exposures. We studied the in vitro cytotoxicity of three different body fluids of rats to the respective corresponding tissue-derived cells.

METHODS

Wistar rats were orally administrated daily with three different doses of chlorpyrifos (1.30, 3.26, and 8.15 mg/kg body weight/day, which is equal to the doses of 1/125, 1/50, and 1/20 LD50, respectively) for consecutive 90 days. Blood samples as well as 24-hour urine and fecal samples were collected and processed. Then, urine, serum, and feces samples were used to treat the correspondent cell lines, i.e., T24 bladder cancer cells, Jurkat lymphocytes, and HT-29 colon cancer cells respectively, which derived from the correspondent tissues that could interact with the respective corresponding body fluids in organism. Cell viability was determined by using MTT or trypan blue staining.

RESULTS

The results showed that urine, serum, and feces extract of the rats exposed to chlorpyrifos displayed concentration- and time-dependent cytotoxicity to the cell lines. Furthermore, we found that the cytotoxicity of body fluids from the exposed animals was mainly due to the presence of 3, 4, 5-trichloropyrindinol, the major toxic metabolite of chlorpyrifos.

CONCLUSIONS

These findings indicated that urine, serum, and feces extraction, especially urine, combining with the corresponding tissue-derived cell lines as the in vitro cell models could be used to evaluate the animal exposure to pesticides even at the low dose with no apparent toxicological signs in the animals. Thus, this in vitro approach could be served as complementary methodology to the existing toolbox of biological monitoring of long-term and low-dose exposure to environmental pesticide residues in practice.

Exposure to permethrin used as a home insecticide: A case study comparing model predictions and excretion of metabolites

Pyrethroids have been widely used as an active ingredient in home insecticide products since the 1960 s. Although their occurrence in indoor environments has been studied, the contribution of home insecticide application to the aggregate exposure to pyrethroids is not well known. The objective of this study was to estimate the consumer exposure to permethrin, a representative pyrethroid, via the use of home insecticide spray during the summer season using biomonitoring and personal exposure modeling. Exposure to permethrin was assessed by analyzing its urinary metabolites, 3-phenoxybenzoic acid (3-PBA) and cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropan carboxylic acid (cis/trans-DCCA), for a group of consumers (n = 27). The levels of metabolites were also compared with those predicted by a screening exposure model considering personal exposure parameters. The levels of metabolites in 15 participants increased significantly (p < 0.05) with the application of home insecticide products, thereby suggesting that the heavy use of home insecticides during summer could be an important exposure route of permethrin in addition to other sources, such as food consumption. The total amount of excreted 3-PBA and cis/trans-DCCA was lower than the amount estimated by the exposure model for most participants by a factor of 0.9-861.0. These differences could be attributed to the rapid loss of permethrin after application, including sorption to indoor surfaces, reaction with indoor substances, individual biological variations, and ventilation during application. However, the screening exposure model used for the initial safety assessment of biocidal products generally performed well because it did not underestimate the personal exposure to permethrin during the application of home insecticide spray.

Validation of exposure indexes to pesticides through the analysis of exposure and effect biomarkers in ground pesticide applicators from Argentina

The characterization of the population exposed to pesticides and the use of effective biomarkers to evaluate potential health effects are determinant to identify vulnerable groups, understanding the causality of diverse pathologies and propose prevention policies. This is particularly important in countries where intensive agricultural practices had an explosive expansion in last decades. The aim of this study was assessing the usefulness of two exposure indexes questionnaire-based: Intensity Level of the pesticide Exposure (ILE) and Cumulative Exposure Index (CEI) and their scales, in terrestrial applicators of pesticide from the Province of Córdoba (Argentina). The analysis was performed contrasting ILE and CEI results with perceived symptomatology, in addition to effect and exposure biomarkers. A cross-sectional study was designed to compare pesticides body burdens and effect biomarkers between subjects occupationally (OE) and non-occupationally exposed (NOE) to pesticides. Prevalence of perceived symptomatology and genotoxicity damage was higher in the OE group. The exposure condition was the only variable explaining these differences. Significant associations were found between CEI and neurologic symptomatology (p < 0.05) and between ILE and plasmatic cholinesterase (p < 0.1). However, residues of HCB, β-HCH, α-endosulfan, pp'DDE, endrin, β-endosulfan, pp'DDT, endosulfan sulfate and mirex were found in blood samples from both groups. To our knowledge, this is the first report on pesticides body burdens in occupational exposure settings in Argentina. So far, our current results indicate that the occupational condition affects the health of the workers. Significant associations found between symptomatology and biomarkers with scales of CEI and ILE suggest their usefulness to verify different levels of exposure. Further research is necessary to propose these indexes as an affordable tool for occupational health surveillance in areas with difficult access to health care centres.

Urinary metabolites of non-persistent pesticides and serum hormones in Spanish adolescent males

OBJECTIVE

To assess the relationship of urinary concentrations of ethylenethiourea (ETU), the main degradation product of ethylene bis-dithiocarbamate fungicides, 3-phenoxybenzoic acid (3-PBA), a common metabolite of many pyrethroids, and 1-naphthol (1N), a metabolite of the carbamate insecticide carbaryl, with hormone concentrations in adolescent males; and to examine interactions between pesticide metabolites and polymorphisms in xenobiotic metabolizing enzymes, including CYP2C19 and CYP2D6, in relation to hormone concentrations.

METHODS

A cross-sectional study was conducted in 134 males from the Spanish Environment and Childhood (INMA)-Granada cohort. Urine and serum samples were collected from participants during the same clinical visit at the age of 15-17 years. First morning urine void was analyzed for concentrations of ETU, 3-PBA, and 1N. Serum was analyzed for concentrations of reproductive hormones (testosterone, 17β-estradiol [E₂], dehydroepiandrosterone sulfate [DHEAS], sex hormone binding globulin [SHBG], luteinizing hormone [LH], follicle stimulating hormone [FSH], anti-Müllerian hormone [AMH], and prolactin), thyroid hormones (free thyroxine [FT4], total triiodothyronine [TT3], and thyroid stimulating hormone [TSH]), insulin growth factor 1 (IGF-1), adrenocorticotropic hormone (ACTH), and cortisol. CYP2C19 G681A and CYP2D6 G1846A polymorphisms were determined in blood from 117 participants. Multiple linear regression, interaction terms, and stratified analyses were performed.

RESULTS

Urinary ETU was detected in 74.6% of participants, 1N in 38.1%, and 3-PBA in 19.4%. Positive associations between detectable 3-PBA and TT3 and between detectable 1N and DHEAS were found, and marginally-significant associations of 1N with reduced E₂ and FSH were observed. Poor CYP2C19 and CYP2D6 metabolizers (GA and AA genotype carriers) showed a greater increase in DHEAS for detected versus undetected 1N compared with GG genotype carriers. Poor CYP2D6 metabolizers (1846 GA and AA genotypes) evidenced increased cortisol for detected versus undetected ETU.

CONCLUSIONS

The associations observed between urinary pesticide metabolites and altered thyroid and reproductive hormones are novel and should be verified in studies with larger sample size. Further research on gene-environment interactions is warranted to establish individual susceptibility to pesticides and the risk of adverse health effects.

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 1 year with three repeated measures of pesticide exposure. Generalized estimating equations examined associations between housing type (green vs. 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.

Variability of urinary pyrethroid biomarkers in Chinese young-aged men and women over one year

Pyrethroids are a class of the most commonly used insecticides. The urinary metabolites are usually used as biomarkers of pyrethroid exposures in humans. In this study, the temporal variability of urinary pyrethroid biomarkers was investigated among 114 Chinese young-aged adults who provided up to 4-11 urine samples over one year. The detection rates of four urinary pyrethroid biomarkers, 3-phenoxybenzoic acid (3PBA), 4-fluoro-3-phenoxybenzoic acid (4F-3PBA), trans-2,2-(dichloro)-2-dimethylvinylcyclopropane carboxylic acid (trans-DCCA) and cis-2,2-(dichloro)-2-dimethylvinylcyclopropane carboxylic acid (cis-DCCA) were 100%, 8%, 69% and 44%, respectively. The intraclass correlation coefficient (ICC) estimates for 3PBA indicated poor reproducibility (<0.15) in the spot urine samples of young-aged adults over a week, month and year. Log-transformed 3PBA used the least number of random spot urine samples (≥4) per person, which would provide a reliable biomarker estimate (ICC≥0.40) over a year. As the predictors of the top 33% yearly average 3PBA concentrations, the sensitivity and specificity of 3PBA ranged from 0.25 to 0.89, 0.58 to 0.96, respectively. Based on the results of this study, we recommend at least 4 urine samples collected 3 months apart for prospective assessment of pyrethroid exposure in the epidemiological studies to estimate exposure-response relationships between pyrethroids and health outcomes with relative long-term exposure periods.

Estimating human exposure to pyrethroids' mixtures from biomonitoring data using physiologically based pharmacokinetic modeling

Human biomonitoring data provide evidence to exposure of environmental chemicals. Physiologically based pharmacokinetic (PBPK) modelling together with an adequate exposure scenario allows to transpose measured concentrations of chemicals or their metabolites into exposure levels, as daily intakes. In France, high levels of urinary pyrethroids metabolites have been measured in populations. Our work aims at estimating the exposure of the French ENNS cohort to mixtures of four pyrethroids (deltamethrin, permethrin, cypermethrin, and cyfluthrin) from the urinary concentrations of five pyrethroids' metabolites commonly measured in biomonitoring studies. We developed a modelling approach based on a global toxicokinetic model that accounts for the cumulative exposure to pyrethroids as some of the metabolites can be shared by several parent compounds and for human inter-individual variability in metabolism. The median of the individual daily intakes was estimated to 8.1 ng/kg bw/day for permethrin, 17.7 ng/kg bw/day for cypermethrin, 20.4 ng/kg bw/day for cyfluthrin and 34.3 ng/kg bw/day for deltamethrin leading to similar weights for the pair permethrin and cypermethrin (36%), cyfluthrin (31%) and deltamethrin (33%) to the cumulative exposure. Accounting for human variability enabled to explain some of the variations in the metabolites' levels within the cohort. The cumulative exposure was then weighted by their toxicities towards three neurotoxic effects to calculate margins of exposure (MOE). Low MOE values were always associated with high measured concentrations of metabolites in urine and the lowest MOEs were observed for the autonomic division. No risks associated with reconstructed mixtures of pyrethroids were expected for the ENNS cohort. Our approach is an asset to analyse the biomarkers of exposure to pyrethroids simultaneously and could be easily adapted to any local or national specificities in pyrethroids' exposure or populations.

Predictors of Urinary Pyrethroid and Organophosphate Compound Concentrations among Healthy Pregnant Women in New York

Our study aimed to investigate dietary and non-dietary predictors of exposure to pyrethroids, organophosphates pesticides and 2,4-D herbicide in two cohorts of pregnant women in New York City: 153 women from the Thyroid Disruption and Infant Development (TDID) cohort and 121 from the Sibling/Hermanos Cohort(S/H). Baseline data on predictors were collected from the women at time of recruitment. We used three different modeling strategies to address missing data due to biomarker values below the limit of detection (<LOD): (1) logistic regression models with biomarkers categorized as (<median, ≥median); (2) linear regression models, imputing the <LOD values with (LOD/√2); (3) regression models, considering <LOD values as left-censored. Generally, all three models identified similar predictors of exposure. We found that ethnicity, higher income and education predicted higher concentrations of most of the biomarkers in both cohorts. Mothers who consumed processed meat in the TDID cohort, and broiled, barbequed food or burgers in the S/H cohort, tended to have lower concentrations of organophosphates and 2,4-D. The choice of modeling led to a few different predictors identified, and the selection of modeling strategy should be based on the study question.

Urinary levels of organophosphate pesticides and predictors of exposure in pre-school and school children living in agricultural and urban communities from south Spain

BACKGROUND

Despite the widespread use of organophosphate (OP) pesticides, information on predictors of children's exposure to such pesticides is scarce.

OBJECTIVE

To assess exposure to OP pesticides in children 3-11 year-old living in agricultural communities and urban areas from Andalusia (Southern Spain), and to identify the main determinants of exposure.

METHODS

A longitudinal study was conducted in children 3-11-year-old children living in agricultural communities and urban areas from the provinces of Almeria, Granada and Huelva (Andalusia, Spain) between 2010 and 2011. Urinary levels of six dialkylphosphate (DAP) metabolites were measured by UHPLC-QqQ-MS/MS at the periods of low and high pesticide use in the agriculture (LPU and HPU, respectively). Information on sociodemographic characteristics, parental occupation, residential history, lifestyle and diet, among other relevant factors, was obtained from questionnaires administered to the mothers.

RESULTS

A total of 559 and 597 children participated in LPU and HPU periods, respectively. The proportion of urine samples below LOD was 67.4% for ΣDMs (sum of dimethyl metabolites), 77% for ΣDEs (sum of diethyl metabolites) and 58.5% for ΣDAPs (sum of total dialkylphosphate metabolites) in LPU period, and 50.4% for ΣDMs, 65.3% for ΣDEs and 43.9% for ΣDAPs in HPU period. Significantly greater urinary ΣDAP, ΣDM and ΣDE levels were observed in HPU relative to LPU period. Maternal schooling years, proximity of the house to crops or greenhouses, use of insecticides at home, spraying the garden with pesticides, storage of pesticides at home, house cleaning frequency, as well as child's frequency of bath/shower, were found to be the major predictors of urinary levels of ΣDAP. Likewise, not washing fruit and vegetables before consumption and banana consumption were also identified as determinants of the exposure levels.

CONCLUSIONS

Urinary levels of metabolites of OP pesticides found in this study were relatively lower compared to similar studies. DAP levels were significantly increased in HPU period. Maternal schooling years and variables related to residential environment and home exposures were identified as the most relevant determinants of DAP metabolites. Regarding diet, banana consumption and not washing fruit before consumption were also identified as determinants of the exposure levels. This study contributes to improve our knowledge on the main sources and determinants of children exposure to OPS, and given that children are more vulnerable than adults this information is essential to reduce children exposure and protect their health.

Association between cholinesterase's inhibition and cognitive impairment: A basis for prevention policies of environmental pollution by organophosphate and carbamate pesticides in Chile

BACKGROUND

In Chile organophosphate pesticides are widely used in the production of fruits. Pesticides use is regulated for professional practice but there is no regulation regarding exposure to the general population.

OBJECTIVE

To relate exposure to cholinesterase's inhibitor pesticides during the spray season with neuropsychological impairment in occupationally exposed (OE) and environmentally exposed (EE) groups of people.

METHODS

Exposure was assessed through inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity and neuropsychological outcomes were evaluated through a large battery of tests covering general mental status, language, memory, attention, executive function, praxis and psychomotricity. Evaluations were carried out firstly in a period of no/low organophosphate pesticide use and subsequently during the spray season. All parameters were calculated as the relative change from baseline to spray season.

RESULTS

For this study in total 156 participants were recruited divided equally over participants with environmental exposures (EE) and participants with occupational exposure (OE). In the EE, BChE's enzyme activity inhibition ≥30% showed significant association with 10% or more decreased performance in several tests evaluating six of the eight cognitive areas (excepting psychomotricity and mood status); besides, for AChE inhibition in EE, the association was significant in three tests evaluating attention and one of executive function. Whereas, in OE, the inhibition of the BChE ≥30% was associated with a low performance of one attention test and for AChE the exceedance of the standard was associated with diminished performance in one test of memory and attention, respectively. The association between biomarkers of biological effect and cognitive impairment persisted among the EE group after removing confounders. No association was found between biomarkers of biological acute effect and decreased cognitive performance in the OE group.

CONCLUSIONS

Increased exposure to pesticides was confirmed by increased inhibition of cholinesterase's in both exposure groups; which was associated with a diminished neuropsychological performance, mainly in the environmentally exposed study group. [310 words].

Assessment of children's exposure to currently used pesticides in wallonia, Belgium

In spring 2016, a study was carried out to characterize currently used pesticide (CUP) exposure among children living in Wallonia (Belgium). Pesticides were measured in both first morning urine voids of 258 children aged from 9 to 12 years and in ambient air collected close to the children's schools. Out of the 46 pesticides measured in the air, 19 were detected with frequencies varying between 11 % and 100 %, and mean levels ranging from <0.04 to 2.37 ng/m³. Only 3 parent pesticides were found in 1-10% of the urine samples, while all the metabolites analyzed were positively detected at least once. The captan metabolite (THPI) was quantified in 23.5 % of the samples, while 3,5,6-trichloro-2-pyridinol (chlopryrifos metabolite) was detected in all urines with levels ranging from 0.36-38.96 μg/l. 3-phenoxybenzoic acid (3-PBA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (t-DCCA) and diethylphosphate were the most abundant pyrethroid metabolites and dialkylphosphate measured. The air inhalation was demonstrated to be a minor route of exposure for the selected CUPs. Statistical regressions highlighted predictors of exposure for some pesticides such like consumption of grey bread, presence of carpets at home or indoor use of pesticides, although no clear source was identified for most of them.

Application of a combined aggregate exposure pathway and adverse outcome pathway (AEP-AOP) approach to inform a cumulative risk assessment: A case study with phthalates

Advancements in measurement and modeling capabilities are providing unprecedented access to estimates of chemical exposure and bioactivity. With this influx of new data, there is a need for frameworks that help organize and disseminate information on chemical hazard and exposure in a manner that is accessible and transparent. A case study approach was used to demonstrate integration of the Adverse Outcome Pathway (AOP) and Aggregate Exposure Pathway (AEP) frameworks to support cumulative risk assessment of co-exposure to two phthalate esters that are ubiquitous in the environment and that are associated with disruption of male sexual development in the rat: di(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP). A putative AOP was developed to guide selection of an in vitro assay for derivation of bioactivity values for DEHP and DnBP and their metabolites. AEPs for DEHP and DnBP were used to extract key exposure data as inputs for a physiologically based pharmacokinetic (PBPK) model to predict internal metabolite concentrations. These metabolite concentrations were then combined using in vitro-based relative potency factors for comparison with an internal dose metric, resulting in an estimated margin of safety of ~13,000. This case study provides an adaptable workflow for integrating exposure and toxicity data by coupling AEP and AOP frameworks and using in vitro and in silico methodologies for cumulative risk assessment.

Organophosphate metabolite concentrations in maternal urine during pregnancy

The burden of organophosphate (OP) pesticides in pregnant women from Tarragona (n = 157), a Mediterranean area of intense agricultural activity, has been assessed from the study of hydroxylated organic metabolites in urine samples in the three trimesters of pregnancy. 2-Diethylamino-6-methylpyrimidin-4-ol (DEAMPY), a metabolite of pirimiphos, was the compound found in higher concentration, medians 0.66-2.8 μg/g creatinine. 4-Nitrophenol (PNP), a metabolite of parathion, medians 0.24-0.41 μg/g creatinine, was the second most abundant compound. 2-Isopropyl-6-methyl-4-pyrimidol (IMPY), a metabolite of diazinon, was also present but in lower concentrations. Except for DEAMPY, the concentrations found in this cohort were lower than those reported in studies from other countries. Intraclass correlation coefficients (ICCs) were calculated for the compounds found in more than the 35% of the samples, the reliability between trimesters was poor (<0.40) to fair (0.40-0.60). Statistically significant differences were observed for the creatinine adjusted concentrations of the most abundant OP metabolites in these trimesters when examined with the Wilcoxon signed rank test for paired data. In general, no association was found between urinary OP metabolites and most demographic and lifestyle predictors. However, a positive significant association was observed for women with vegetarian diet and for women of higher economic status and eventual consumption of organic food which showed higher PNP concentrations. These results suggest that higher fruit and vegetable consumption may involve higher OP pesticide ingestion but the overall association was weak.

Estimating the cumulative human exposures to pyrethroids by combined multi-route PBPK models: Application to the French population

Human biomarkers of exposure to pyrethroid insecticides are usually urinary concentrations of metabolites that can be specific to a pyrethroid or common to several compounds. We developed a global toxicokinetic model that links the external exposure to four widely-used pyrethroids and their isomers (deltamethrin and cis and trans isomers of permethrin, cypermethrin, and cyfluthrin) to the urinary concentrations of metabolites (cis- and trans-DCCA, 3-PBA, F-PBA and DBCA). This global model includes physiologically based pharmacokinetic models for each parent compound and one-compartment models for the metabolites. Existing in vivo, in vitro and in silico data were used for model calibration, and human toxicokinetic data for model evaluation. Overall, the global model reproduced the data accurately as about 90% of predictions were inside the 3-fold error interval. A sensitivity analysis showed that the most influent parameter for each urinary metabolite concentration was the fraction of parent compound that is transformed into that metabolite. The global model was then tested with realistic exposures for the French population: the predictions were consistent with biomonitoring data. The global model is a tool that will improve the interpretation of biomonitoring data for pyrethroids.

Assessing effects of germline exposure to environmental toxicants by high-throughput screening in C. elegans

Chemicals that are highly prevalent in our environment, such as phthalates and pesticides, have been linked to problems associated with reproductive health. However, rapid assessment of their impact on reproductive health and understanding how they cause such deleterious effects, remain challenging due to their fast-growing numbers and the limitations of various current toxicity assessment model systems. Here, we performed a high-throughput screen in C. elegans to identify chemicals inducing aneuploidy as a result of impaired germline function. We screened 46 chemicals that are widely present in our environment, but for which effects in the germline remain poorly understood. These included pesticides, phthalates, and chemicals used in hydraulic fracturing and crude oil processing. Of the 46 chemicals tested, 41% exhibited levels of aneuploidy higher than those detected for bisphenol A (BPA), an endocrine disruptor shown to affect meiosis, at concentrations correlating well with mammalian reproductive endpoints. We further examined three candidates eliciting aneuploidy: dibutyl phthalate (DBP), a likely endocrine disruptor and frequently used plasticizer, and the pesticides 2-(thiocyanomethylthio) benzothiazole (TCMTB) and permethrin. Exposure to these chemicals resulted in increased embryonic lethality, elevated DNA double-strand break (DSB) formation, activation of p53/CEP-1-dependent germ cell apoptosis, chromosomal abnormalities in oocytes at diakinesis, impaired chromosome segregation during early embryogenesis, and germline-specific alterations in gene expression. This study indicates that this high-throughput screening system is highly reliable for the identification of environmental chemicals inducing aneuploidy, and provides new insights into the impact of exposure to three widely used chemicals on meiosis and germline function.

The ever-increasing number of new chemicals introduced into our environment poses a significant problem for risk assessment. In addition, assessing the direct impact of toxicants on human meiosis remains challenging. We successfully utilized a high-throughput platform in the nematode C. elegans, a genetically tractable model organism which shares a high degree of gene conservation with humans, to identify chemicals that affect the germline leading to aneuploidy. We assessed chemicals that are highly prevalent in the environment in worms carrying a fluorescent reporter construct allowing for the identification of X chromosome nondisjunction combined with a mutation increasing cuticle permeability for analysis of low doses of exposure. Follow up analysis of three chemicals: DBP, permethrin and TCMTB, further validated the use of this strategy. Exposure to these chemicals resulted in elevated levels of DNA double-strand breaks, activation of a DNA damage checkpoint, chromosome morphology defects in late meiotic prophase I as well as impaired early embryogenesis and germline-specific changes in gene expression. Our results support the use of this high-throughput screening system to identify environmental chemicals inducing aneuploidy, and provide new insights into the effects of exposure to DBP, permethrin, and TCMTB on meiosis and germline function.

Analysis of metabolites of organophosphate and pyrethroid pesticides in human urine from urban and agricultural populations (Catalonia and Galicia)

Isotope dilution solid phase extraction UPLC-MS/MS has been used to develop a robust and rapid methodology for the determination of eight specific metabolites of organophosphate and pyrethroid pesticides in human urine. The use of methanol:acetone (25:75v/v) affords an improvement in extraction efficiency in comparison to these individual solvents. The use of synthetic urine improves selectivity and limits of detection for the calibration straight lines. The method provides detection limits of 14-69pg/ml and 18-19pg/ml for the organophosphate and pyrethroid metabolites, respectively. Urine analyses of these metabolites in urban non-occupationally exposed individuals and farm workers shows that ingestion of these pesticides occurred in both populations. The concentrations of organophosphate pesticide metabolites in the latter were twofold than those from non-exposed populations.

Exploring Associations Between Postural Balance and Levels of Urinary Organophosphorus Pesticide Metabolites

OBJECTIVE

Apply a data-driven approach to explore associations between postural balance and pesticide exposure among Latino farmworkers and non-farmworkers.

METHODS

Lasso-regularized, generalized linear models were used to examine associations between postural control measures in four experimental conditions (2 visual × 2 cognitive difficulty) and dialkylphosphate (DAP) urinary metabolite levels.

RESULTS

Obtained models generally performed poorly at explaining postural control measures. However, when both visual and cognitive conditions were altered-the most challenging balance condition-models for some postural balance measures contained several DAP metabolites and had relatively better fits.

CONCLUSIONS

The current results were equivocal regarding associations between postural control measures and DAP metabolite concentrations. However, farmworker status appears to be an important variable in understanding this association. Future work should use a posturally- and cognitively-challenging test condition to reveal any potential associations.

Exposure to organophosphorus pesticides in Norwegian mothers and their children: Diurnal variability in concentrations of their biomarkers and associations with food consumption

Several studies have suggested that exposure to organophosphorus (OP) pesticides is detrimental for health, and in particular for children where moderate doses may have a negative impact on the neurodevelopment. This study surveys levels of the 6 non-specific urinary metabolites (dialkyl phosphates (DAPs)) of OP pesticides in Norwegian mothers (n=48) and their children (n=54), and examines the diurnal variation in concentrations as well as associations with consumption of specific food products. The highest median concentration measured in urine was found for dimethyl thiophosphate (5.3 and 5.5ng/mL_SG; specific gravity corrected) for both children and mothers, respectively, followed by diethyl phosphate (3.8 and 5.3ng/mL_SG, respectively). The intra-class correlation coefficients of DAPs among mothers were moderate (0.49-0.68), and consumption of fruit explained between 8% and 55% of the variations in the mothers' and their children's urinary DAP concentrations.

"Exposure to the insecticides permethrin and malathion induces leukemia and lymphoma-associated gene aberrations in vitro"

Epidemiological studies have associated the exposure to permethrin and malathion with increased risk of leukemia and lymphoma. The aim of this study was to evaluate whether in vitro exposure to permethrin and malathion induces aberrations in genes involved in the etiology of these hematological malignancies. Genetic abnormalities in the IGH, KMT2A (MLL), ETV6 and RUNX1 genes, and aneuploidy induced by the in vitro exposure to permethrin and malathion (200μM, 24h), were analyzed by FISH in peripheral blood mononuclear cells (PBMCs). The gene fusions IGH-BCL2, KMT2A-AFF1 and ETV6-RUNX1 were further analyzed with nested RT-PCR in PBMCs, and in K562 cells exposed to acute and chronic treatments (0.1μM, 24h or every third day for two weeks) of insecticides. FISH analysis revealed that permethrin induces aneuploidy and structural alterations in IGH and KMT2A genes, and malathion induces breaks in KMT2A. RT-PCR detected ETV6-RUNX1 fusion in PBMCs acutely exposed to permethrin. Permethrin also induced ETV6-RUNX1 and IGH-BCL2 fusions in K562 cells, and malathion induced KMT2A-AFF1 and ETV6-RUNX1 fusions. Overall, we identified that both insecticides induce breaks and fusions in the studied genes, and permethrin induces aneuploidy. This study presents evidence of damage in cancer genes caused by these insecticides.

Sex-Specific Effects of Organophosphate Diazinon on the Gut Microbiome and Its Metabolic Functions

BACKGROUND

There is growing recognition of the significance of the gut microbiome to human health, and the association between a perturbed gut microbiome with human diseases has been established. Previous studies also show the role of environmental toxicants in perturbing the gut microbiome and its metabolic functions. The wide agricultural use of diazinon, an organophosphate insecticide, has raised serious environmental health concerns since it is a potent neurotoxicant. With studies demonstrating the presence of a microbiome-gut-brain axis, it is possible that gut microbiome perturbation may also contribute to diazinon toxicity.

OBJECTIVES

We investigated the impact of diazinon exposure on the gut microbiome composition and its metabolic functions in C57BL/6 mice.

METHODS

We used a combination of 16S rRNA gene sequencing, metagenomics sequencing, and mass spectrometry-based metabolomics profiling in a mouse model to examine the functional impact of diazinon on the gut microbiome.

RESULTS

16S rRNA gene sequencing revealed that diazinon exposure significantly perturbed the gut microbiome, and metagenomic sequencing found that diazinon exposure altered the functional metagenome. Moreover, metabolomics profiling revealed an altered metabolic profile arising from exposure. Of particular significance, these changes were more pronounced for male mice than for female mice.

CONCLUSIONS

Diazinon exposure perturbed the gut microbiome community structure, functional metagenome, and associated metabolic profiles in a sex-specific manner. These findings may provide novel insights regarding perturbations of the gut microbiome and its functions as a potential new mechanism contributing to diazinon neurotoxicity and, in particular, its sex-selective effects. Citation: Gao B, Bian X, Mahbub R, Lu K. 2017. Sex-specific effects of organophosphate diazinon on the gut microbiome and its metabolic functions. Environ Health Perspect 125:198-206; http://dx.doi.org/10.1289/EHP202.

Biodegradation of the Pyrethroid Pesticide Esfenvalerate by Marine-Derived Fungi

Esfenvalerate biodegradation by marine-derived fungi is reported here. Esfenvalerate (S,S-fenvalerate) and its main metabolites [3-phenoxybenzaldehyde (PBAld), 3-phenoxybenzoic acid (PBAc), 3-phenoxybenzyl alcohol (PBAlc), and 2-(4-chlorophenyl)-3-methylbutyric acid (CLAc)] were quantitatively analyzed by a validated method in triplicate experiments. All the strains (Penicillium raistrickii CBMAI 931, Aspergillus sydowii CBMAI 935, Cladosporium sp. CBMAI 1237, Microsphaeropsis sp. CBMAI 1675, Acremonium sp. CBMAI 1676, Westerdykella sp. CBMAI 1679, and Cladosporium sp. CBMAI 1678) were able to degrade esfenvalerate, however, with different efficiencies. Initially, 100 mg L(-1) esfenvalerate (Sumidan 150SC) was added to each culture in 3 % malt liquid medium. Residual esfenvalerate (64.8-95.2 mg L(-1)) and the concentrations of PBAc (0.5-7.4 mg L(-1)), ClAc (0.1-7.5 mg L(-1)), and PBAlc (0.2 mg L(-1)) were determined after 14 days. In experiments after 7, 14, 21, and 28 days of biodegradation with the three most efficient strains, increasing concentrations of the toxic compounds PBAc (2.7-16.6 mg L(-1), after 28 days) and CLAc (6.6-13.4 mg L(-1), after 28 days) were observed. A biodegradation pathway was proposed, based on HPLC-ToF results. The biodegradation pathway includes PBAld, PBAc, PBAlc, ClAc, 2-hydroxy-2-(3-phenoxyphenyl)acetonitrile, 3-(hydroxyphenoxy)benzoic acid, and methyl 3-phenoxy benzoate. Marine-derived fungi were able to biodegrade esfenvalerate in a commercial formulation and showed their potential for future bioremediation studies in contaminated soils and water bodies.

Exposure of Preschool-Age Greek Children (RHEA Cohort) to Bisphenol A, Parabens, Phthalates, and Organophosphates

Phthalate esters (PEs), bisphenol A (BPA), and parabens (PBs), which are used in numerous consumer products, are known for their endocrine disrupting properties. Organophosphate chemicals (OPs), which form the basis of the majority of pesticides, are known for their neurotoxic activity in humans. All of these chemicals are associated with health problems to which children are more susceptible. Once they enter the human body, PEs, BPA, PBs, and OPs are metabolized and/or conjugated and finally excreted via urine. Hence, human exposure to these substances is examined through a determination of the urinary concentrations of their metabolites. This study assessed the exposure of Greek preschool-age children to PEs, BPA, PBs, and OPs by investigating the urinary levels of seven PEs metabolites, six PBs, BPA, and six dialkyl phosphate metabolites in five-hundred samples collected from 4-year-old children, subjects of the "RHEA" mother-child cohort in Crete, Greece. Daily intake of endocrine disruptors, calculated for 4 year old children, was lower than the corresponding daily intake for 2.5 year old children, which were determined in an earlier study of the same cohort. In some cases the daily intake levels exceeded the U.S. Environmental Protection Agency Tolerable Daily Intake (TDI) values and the EFSA Reference Doses (RfD) (e.g., for di-2-ethyl-hexyl phthalate, 3.6% and 1% of the children exceeded RfD and TDi, respectively). Exposure was linked to three main sources: PEs-BPA to plastic, PBs-diethyl phthalate to personal hygiene products, and OPs to food.

Occurrence of biomarkers of pesticide exposure in non-invasive human specimens

Biomonitoring has been used in many types of investigations, including national programmes and epidemiological studies, to explore the occurrence of biomarkers of pesticide exposure in the general population or relevant groups. This review discusses recent studies that measure levels of biomarkers of pesticide exposure in non-invasive human specimens such as urine, breast milk, meconium and hair. Specific and non-specific metabolites of organophosphate and pyrethroid insecticides have been widely investigated in urine, where some of the suitable biomarkers present rates of detection higher than 80%, which stand for an ongoing chronic exposure to traces of these chemicals. Hair is a promising emerging matrix, but some issues on its suitability and the biological relevance needs further research. Breast milk was used in research investigations focused mainly on legacy pesticides, which provide useful information about time trends.

Urinary concentration of 3-phenoxybenzoic acid in elementary students in South Korea

OBJECTIVES

Pyrethroid pesticides are among the most commonly using insecticides in South Korean households and have been the subject of considerable interest among public health professionals for their potential health effects. The objective of this study is to examine the level of urinary 3-phenoxybenzoic acid (3-PBA) among elementary students in South Korea.

METHODS

We conducted a cross-sectional study to evaluate pyrethroid pesticide exposure levels by measuring the urinary metabolites of 3-PBA using a gas chromatography-mass spectrometry method in March 2011. Study participants were 70 Asan-area and Incheon-area elementary students.

RESULTS

All respondents had values above the detection limit, and the geometric means of 3-PBA in all children were 1.85 μg/L and 1.46 μg/g creatinine. Children with the top 10% urinary levels of 3-PBA were more likely to be girls, under nine years of age, living in a rural area, and living in a residential type apartment.

CONCLUSIONS

South Korean children have a higher concentration of urinary 3-PBA compared with those of other countries. Further research identifying exposure pathways and intervention efforts to reduce environmental pesticide use are needed in South Korea.

A Statistical Analysis of the Effects of Urease Pre-treatment on the Measurement of the Urinary Metabolome by Gas Chromatography-Mass Spectrometry

Urease pre-treatment of urine has been utilized since the early 1960s to remove high levels of urea from samples prior to further processing and analysis by gas chromatography-mass spectrometry (GC-MS). Aside from the obvious depletion or elimination of urea, the effect, if any, of urease pre-treatment on the urinary metabolome has not been studied in detail. Here, we report the results of three separate but related experiments that were designed to assess possible indirect effects of urease pre-treatment on the urinary metabolome as measured by GC-MS. In total, 235 GC-MS analyses were performed and over 106 identified and 200 unidentified metabolites were quantified across the three experiments. The results showed that data from urease pre-treated samples 1) had the same or lower coefficients of variance among reproducibly detected metabolites, 2) more accurately reflected quantitative differences and the expected ratios among different urine volumes, and 3) increased the number of metabolite identifications. Overall, we observed no negative consequences of urease pre-treatment. In contrast, urease pretreatment enhanced the ability to distinguish between volume-based and biological sample types compared to no treatment. Taken together, these results show that urease pretreatment of urine offers multiple beneficial effects that outweigh any artifacts that may be introduced to the data in urinary metabolomics analyses.

A test house study of pesticides and pesticide degradation products following an indoor application

Preexisting pesticide degradates are a concern for pesticide biomonitoring studies as exposure to them may result in overestimation of pesticide exposure. The purpose of this research was to determine whether there was significant formation and movement, of pesticide degradates over a 5-week period in a controlled indoor setting after insecticide application. Movement of the pesticides during the study was also evaluated. In a simulated crack and crevice application, commercially available formulations of fipronil, propoxur, cis/trans-permethrin, and cypermethrin were applied to a series of wooden slats affixed to the wall in one room of an unoccupied test house. Floor surface samples were collected through 35 days post-application. Concentrations of the pesticides and the following degradates were determined: 2-iso-propoxyphenol, cis/trans 3-(2,2-dichlorovinyl)-3-3-dimethyl-(1-cyclopropane) carboxylic acid, 3-phenoxybenzoic acid, fipronil sulfone, fipronil sulfide, and fipronil desulfinyl. Deltamethrin, which had never been applied, and chlorpyrifos, which had been applied several years earlier, and their degradation products, cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid, and, 3,5,6-trichloro-2-pyridinol, respectively, were also measured. Propoxur was the only insecticide with mass movement away from the application site. There was no measurable formation or movement of the degradates. However, all degradates were present at low levels in the formulated product. These results indicate longitudinal repetitive sampling of indoor degradate levels during short-term studies, is unnecessary.

PRACTICAL IMPLICATIONS

Exposure to preexisting pesticide degradates may inflate estimates of exposure in biomonitoring studies where these compounds are used as biomarkers. To date, there is no published information on formation of pesticide degradates following an indoor application. We found that the study pesticides have low rates of degradation and are unlikely to be a significant factor affecting results of short-term (weeks) biomonitoring studies. Therefore, relatively few indoor samples are needed to estimate background levels of degradation products resulting from a recent pesticide application.

Biomonitoring exposure assessment to contemporary pesticides in a school children population of Spain

The exposure to pesticides amongst school-aged children (6-11 years old) was assessed in this study. One hundred twenty-five volunteer children were selected from two public schools located in an agricultural and in an urban area of Valencia Region, Spain. Twenty pesticide metabolites were analyzed in children's urine as biomarkers of exposure to organophosphate (OP) insecticides, synthetic pyrethroid insecticides, and herbicides. These data were combined with a survey to evaluate the main predictors of pesticide exposure in the children's population. A total of 15 metabolites were present in the urine samples with detection frequencies (DF) ranging from 5% to 86%. The most frequently detected metabolites with DF>53%, were 3,5,6-trichloro-2-pyridinol (TCPy, metabolite of chlorpyrifos), diethyl phosphate (DEP, generic metabolite of OP insecticides), 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMPY, metabolite of diazinon) and para-nitrophenol (PNP, metabolite of parathion and methyl parathion). The calculated geometric means ranged from 0.47 to 3.36 µg/g creatinine, with TCPy and IMPY showing the higher mean concentrations. Statistical significant differences were found between exposure subgroups (Mann-Whitney test, p<0.05) for TCPy, DEP, and IMPY. Children living in the agricultural area had significantly higher concentrations of DEP than those living in the urban area. In contrast, children aged 6-8 years from the urban area, showed statistically higher IMPY levels than those from agricultural area. Higher levels of TCPy were also found in children with high consumption of vegetables and higher levels of DEP in children whose parents did not have university degree studies. The multivariable regression analysis showed that age, vegetable consumption, and residential use of pesticides were predictors of exposure for TCPy, and IMPY; whereas location and vegetable consumption were factors associated with DEP concentrations. Creatinine concentrations were the most important predictors of urinary TCPy and PNP metabolites.

Longitudinal assessment of chlorpyrifos exposure and self-reported neurological symptoms in adolescent pesticide applicators

OBJECTIVES

Occupational exposure of organophosphorus pesticides, such as chlorpyrifos (CPF), in adolescents is of particular concern because of the potential vulnerability of the developing neurological system. The objectives of this study were to examine how neurological symptoms reported over the application season vary across time, whether these effects are reversible postapplication and if there are associations between CPF biomarkers and neurological symptoms in an adolescent study population.

SETTING

The longitudinal study was conducted in two agricultural districts of Menoufia Governorate, Egypt between April 2010 and January 2011.

PARTICIPANTS

Male adolescent participants, including CPF applicators (n=57) and non-applicators (n=38), were recruited.

PRIMARY AND SECONDARY OUTCOME MEASURES

Self-reported data for 25 neurological symptoms were collected at 32 time points over the 8-month period before, during and after the application season. Additionally, urine and blood samples were collected to measure urine trichloro-2-pyridinol (TCPy), a CPF-specific biomarker and blood cholinesterase activity.

RESULTS

Applicators and non-applicators report the highest numbers of symptoms during the application season, followed by a reduction in symptoms after the application ended. Applicators reported a greater percentage of neurological symptoms, relative to baseline, than non-applicators after accounting for potential covariates. Among the applicators, cumulative TCPy was positively and significantly associated with the average percentage of symptoms (B=4.56, 95% CI 3.29 to 5.84; p<0.001). Significant associations (p=0.03-0.07) between the change in butyrylcholinesterase activity from the preapplication to the postapplication season and several domains of neurological symptoms were also found, even after adjusting for potential covariates.

CONCLUSIONS

These observations demonstrate changes in the reporting of symptoms across the application season, showing an increase in symptom reporting during application and recovery following the end of pesticide application. These findings reinforce the growing concern regarding the neurotoxic health effects of CPF in adolescent applicators in developing countries and the need for developing and implementing intervention programmes.