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Objective: The purpose of the investigation is to determine if a relationship exists between heart rate and urinary biomarkers of chronic, subacute chlorpyrifos pesticide exposure in youth. Methods: Using 2001-2002 NHANES data, a sample of 1233 children ages 6 - 18 was grouped based on detection status of 3,5,6-trichloropyridinol (TCPy) in urine. Radial pulse and brachial pulse were recorded as measures of heart rate by physicians. T-tests and linear regression analyses were performed to test for associations between TCPy concentrations and heart rate. Results: None of the associations between TCPy levels and heart rate outcomes were found to be significant. Nonsignificant effects in the TCPy-detected groups included a slightly reduced heart rate in girls, as well as a slightly elevated heart rate in boys when compared to the undetected controls. Neither was there any significant observable difference in heart rate due to detection status in the sample overall. Conclusions: At this time, an effect on heart rate attributable to chronic, low-level chlorpyrifos exposure in youth cannot be determined. Children and adolescents detected did not demonstrate a substantial change in pulse measures when compared to controls. It is recommended that subsequent studies examine chlorpyrifos biomarkers as they may relate to other indicators of cardiovascular health.

Chlorpyrifos (CPF), an organophosphate insecticide, has been linked to adverse neurodevelopmental effects in animal studies. However, little is known about long-term neurotoxicity of early-life CPF exposure in humans. We aimed to evaluate the associations of both prenatal and early childhood CPF exposure with neurodevelopment of children. In this observational study based on Sheyang Mini Birth Cohort, pregnant women were recruited from an agricultural region between June 2009 and January 2010, and their children were followed up from birth to age three. Urinary 3,5,6-Trichloro-2-pyridinol (TCPy), a specific metabolite of CPF, was quantified using large-volume-injection gas chromatography-tandem mass spectrometry. Developmental quotients (DQs) of children in motor, adaptive, language, and social areas were assessed by trained pediatricians. Data from 377 mother-child pairs were used in the current study. Associations between CPF exposure and neurodevelopmental indicators were estimated using generalized linear models with adjustment for potential confounders. The median concentrations of TCPy in maternal and children's urine were 5.39 μg/L and 5.34 μg/L, respectively. No statistically significant association was found between maternal urinary TCPy concentrations and children neurodevelopment. While for postnatal exposure, we found lower motor area DQ score 0.61 [95% confidence interval (CI): −1.13, −0.09; p = 0.02] and social area DQ score 0.55 (95% CI: −1.07, −0.03; p = 0.04) per one-unit increase in the ln-transformed childhood urinary TCPy concentrations. Further stratification by sex indicated that the inverse associations were only observed in boys, but not in girls. Our findings suggest that adverse neurodevelopmental effects were associated with early childhood CPF exposure, but not prenatal exposure. Additional longitudinal studies are needed to replicate these results and to further understand the toxicological mechanisms of CPF.

STUDY OBJECTIVES: The neurobiological processes involved in establishing sleep regulation are vulnerable to environmental exposures as early as seven weeks of gestation. Studies have linked in utero pesticide exposure to childhood sleep-disordered breathing. However, the impact of in utero pesticide exposure on the sleep health of adolescents remains unexplored. MATERIALS AND METHODS: Data from 137 mother-adolescent pairs from a Mexico City cohort were analyzed. We used maternal urinary 3-phenoxybenzoic acid (3-PBA, pyrethroid metabolite) and 3, 5, 6-trichloro-2-pyridinol (TCPy, chlorpyrifos metabolite) from trimester three to estimate in utero pesticide exposure. Among adolescents, we obtained repeated measures of objectively assessed sleep duration, midpoint, and fragmentation using wrist-actigraphy devices for 7 consecutive days in 2015 and 2017. Unstratified and sex-stratified associations between maternal urinary 3-PBA and TCPy and adolescent sleep measures were examined using linear mixed models. We also examined the interactive effects of maternal pesticide exposure and offspring sex on sleep outcomes. RESULTS: 3-PBA and TCPy were detected in 44.4% and 93% of urine samples, respectively. In adjusted models, we observed monotonic associations between TCPy with longer sleep duration and later sleep midpoint. Adjusted findings demonstrated that higher exposure to maternal TCPy was associated with longer sleep duration (p, trend = 0.01), and later sleep timing (p = 0.07). Findings from interaction tests between exposure and offspring sex were not statistically significant. Adjusted sex-stratified findings showed that the association between TCPy with duration and midpoint was evident only among female offspring; those in the highest tertile of exposure had a 59 minute (95% CI: 12.2, 104.8) (p, trend = 0.004) longer sleep duration and a 0.6 h (95% CI: −0.01, 1.3) (p, trend = 0.01) later sleep midpoint. We found no significant associations between 3-PBA and sleep outcomes. CONCLUSION: Although findings from interaction tests were not statistically significant, effect estimates demonstrated that associations between maternal pesticide exposure and longer sleep duration and later sleep timing were stronger in female offspring.

Pesticides are an important and high use group of chemicals as they increase crop yield in agricultural activities and help control disease spread in public areas. Globally, over 3 billion kilograms of active pesticide ingredients are used per year. The general population may be exposed to these pesticides through dietary ingestion, inhalation, ingestion of dust and soil, and dermal absorption. Pesticide exposure has been linked to numerous adverse health effects, particularly in children who may have additional exposure pathways and metabolise toxicants more slowly and thus are more sensitive to chemical toxicity. Assessing their pesticide exposure and relevant health impact is therefore particularly important. Human biomonitoring using human body fluids is seen as the “gold standard” approach to assess such exposure and risk. Urine is an ideal matrix to investigate recent exposures for currently used pesticides as the majority of them have short half-lives ( 60%) detected in urine samples from Australian and New Zealand children: dialkylphosphate metabolites (DAPs, except for diethyl dithiophosphate (DEDTP)), 3,5,6-trichloro-2-pyridinol (TCPY), para-nitrophenol (PNP), 3-phenoxybenzoic acid, and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid. Urine samples from Australian children also saw a high detection frequency of atrazine mercapturate (ATZ), metabolite of a chlorotriazine herbicide, atrazine. In contrast, detection of ATZ in urine samples from New Zealand children was rare (≤ 2%) but a phenoxyacetic herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), had a detection frequency of 86%, compared to the Australian study (< 45%). Although comparison between results based on pooled (the Australian study in Chapter 3) and individual (the New Zealand study in Chapter 5) samples should proceed with caution, the above results showed that Australian and New Zealand children share a common exposure of OPs and PYRs but may differ in certain herbicide exposure.Concentrations of DAPs were generally comparable between Australian (0-5 y) and New Zealand children (5-14 y), and were at the lower end compared to other countries. The exception was diethyl thiophosphate (DETP) for Australian pre-schoolers, who had 3 times higher concentration (geometric mean (GM) of 1.8 ng/mL) in urine compared to Japanese peers (~0.6 ng/mL). The other exception was dimethyl phosphate (DMP), for which New Zealand children had a median value of 11 μg/g creatinine, comparable with an existing Australian study on children of the same age but higher than results from other countries such as the US. The profile of DAPs, namely the concentration of ∑DMAP (sum of DMP, dimethyl thiophosphate (DMTP) and dimethyl dithiophosphate (DMDTP)) compared to the one for ∑DEAP (sum of diethyl phosphate (DEP), DETP and DEDTP), were similar between Australia and New Zealand and several other countries such as Canada and Israel. It was however different from some other countries such as Chile and Malaysia, which may reflect the difference in OP use patterns in different countries. The highest level was measured for TCPY, a metabolite for chlorpyrifos, chlorpyrifos-methyl and triclopyr, in both Australian (GM of 9.7 ng/mL urine) and New Zealand (GM of 13 μg/g creatinine) studies. They were generally higher than results from other countries, indicating a prevalent use of and exposure to pesticide products containing the above pesticides in Australia and New Zealand. Although overall exposure risk is low for these pesticides as assessed by calculated daily intake or against Biomonitoring Equivalents, compared to peers in the US, Australian and New Zealand children may have higher exposures to chlorpyrifos/triclopyr and pyrethroids. Biomarker association analysis suggested an important role of permethrin and cypermethrin as sources for pyrethroid exposure for both populations.Age is identified as an important predictor for pesticide exposure but from different directions for children in different ages. Exposure seems to increase following weaning or as a result of increased dietary intake and mobility/activity (0-5 y), and since then, starts decreasing when children are getting older (5-14 y). Girls appear to have elevated concentrations of PNP in urine compared to boys in the 5-14 y group, which may be related to the use of nitrobenzene or PNP itself associated with production of dyes and flavouring agents in cosmetics such as nail polish that girls generally tend to access more than boys.For lifestyle predictors, fruit and vegetable consumptions were found associated with pesticide exposure for children under 3 years but not in the school-age (5-14) group. However, for the school-aged children in New Zealand, urine samples from low spray season had significantly higher concentrations of several biomarkers, which might be associated with consumption of imported fruits and vegetables during this season. Washing fruits and vegetables and hands appear to decrease the exposure to certain pesticides (but not all). Living in rural areas is associated with increased exposure to pyrethroids via pest control practices, whereas children living in urban areas tend to have higher exposure to nitrobenzene or PNP. Having a dog in the home was associated with higher exposure risk to pyrethroids. The exposure risk is further increased for children with a low socioeconomic status.

The aim of this study was to obtain a longitudinal evaluation of the exposure to chlorpyrifos (CP) and chlorpyrifos-methyl (CPM) in agricultural workers in South Tyrol and in a residential group living in the same area. CP and CPM are widely used pesticides in agriculture. Biological monitoring of CP and CPM exposure in humans can be achieved by analyzing urinary levels of 3,5,6-trichloro-2-pyridinol (TCPy). TCPy a metabolite of CP and CPM which is produced by a two-step metabolic transformation. Between May 14th, 2014 and March 16th, 2015 we conducted a longitudinal study on 28 farmers actively working in spray pesticide treatment and 43 non-farmers living in the same agricultural area of South Tyrol (Italy). Urine samples were collected at two time points: during the pesticide treatment period and in a temporally distant season that should guarantee metabolite clearance. We developed and validated a liquid chromatography-tandem mass spectrometry (LC–MS/MS) method for the determination of urinary TCPy levels. During the treatment season, both farmers and residents showed higher TCPy levels (median = 6.8 and 6.73 ug/g creatinine, respectively) than during the non-treatment season (median = 2.54 and 3.22 ug/g creatinine, respectively), suggesting a similar effect of the pesticide spraying on both groups. However, the observed TCPy levels resulted in a daily CP and CPM intake well below the limits recommended by FAO/WHO. During the non-treatment season, non-farmers showed higher TCPy levels values than farmers, suggesting the existence of TCPy of other unmeasured sources of exposure not considered in this study. This suggests that, for a comprehensive evaluation of the risks associated with TCPy exposure, additional sources should be identified in addition to CP and CPM pesticides.

Background: 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. Objective: To investigate associations between biomarkers of maternal gestational exposure to organophosphate and pyrethroid insecticides and the child & rsquo;s language development at age 20 & ndash;36 months in the prospective Odense Child Cohort. Methods: 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 & ndash;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. Results: The generic pyrethroid metabolite 3-phenoxybenzoic acid (3-PBA) and the chlorpyrifos metabolite 3,5,6trichloro-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. Conclusion: 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.

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.

Chronic occupational exposure to organophosphorus pesticides (OPs) is consistently associated with deficits on behavioral tests when compared to unexposed comparison groups. However, a dose-response relationship has yet to be established, leading some to doubt an association between occupational OP exposure and behavioral deficits. Pesticide application teams in Egypt who are primarily exposed to one OP, chlorpyrifos (CPF), were recruited into a field assessment. Trail Making A and the more challenging Trail Making B tests were administered to 54 engineers (who supervise the pesticide application process, usually from the side of the field), 59 technicians (who guide the pesticide applicators in the field), 31 applicators (who mix and apply pesticides using knapsack sprayers), and 150 controls (who did not work in the fields) at two different times during the OP application season as well as immediately after applications had ended and 1.5 months later. All participants were males since only males work on pesticide application teams in Egypt. Urinary levels of 3,5,6-trichloro-2-pyridinol (TCPy), a specific metabolite of CPF, confirmed the pattern of lower to higher CPF exposures from engineers to technicians to applicators, and these were all greater than urinary metabolite levels in controls. A consistent relationship between job title and performance speed on the behavioral task was observed: Controls had the best (fastest) performance on Trail Making A and B tests throughout the application season, and applicators had significantly slower performance than engineers on Trail Making A (p = 0.015) and B (p = 0.003). However, individual urinary TCPy, blood acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) levels did not predict individual performance. This study identifies a dose-related effect based on job title, which serves as a surrogate for chronic exposure in that differing job titles exhibit varying group exposure levels. The results establish that chronic occupational exposure to chlorpyrifos is neurotoxic and suggest that the classic biomarkers of recent CPF exposure are not predictive of chronic exposure effects.

Although Spain does not have a regular national human biomonitoring program yet, different research groups are active in evaluating the exposure of children and adults to chemicals. In the last seven years, several studies in Spain have evaluated the internal exposure of the population to currently used pesticides. The present review analyzes the scope of these studies, the employed analytical methods and the main results of the exposure and risk, mainly for children and mothers. The frequency of exposure to biomarkers of exposure to organophosphate pesticides is high. Some non-specific dialkyl phosphate metabolites (DAPs), such as the diethyl phosphate (DEP), present Detection Frequencies (DFs) in the range of 65–92% in various studies. Also, the specific biomarker of the chlorpyrifos (3,5,6-trichloro-2-pyridinol, TCPy), achieves Detection Frequencies between 74% and 100% in many studies. For pyrethroids, the metabolite 3-phenoxybenzoic acid (PBA) is present, in general, in more than the 65% of the studied samples. Highly polar herbicides were only assessed in one study and both glyphosate and its metabolite aminomethylphosphonic acid showed Detection Frequencies around 60%. However, putting the biomonitoring data in a risk assessment context, the mean Hazard Quotient (HQ), used as a metric for the individual risk, ranges from 0.0006 (glyphosate) to 0.93 in farm workers (parathion), which means that is unlike that the exposure poses a health concern (HQ

Background Organophosphate insecticides and the herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D) are used to protect crops or control weeds. Pyrethroids are used to manage pests both in agriculture and in residences, and to reduce the transmission of insect-borne diseases. Several studies have reported inverse associations between exposure to organophosphates (as a larger class) and birth outcomes but these associations have not been conclusive for pyrethroids or 2,4-D, specifically. We aimed to investigate the association between birth outcomes and urinary biomarkers of pyrethroids, organophosphates and 2,4-D among healthy pregnant women living in New York City. Methods We quantified urinary biomarkers of 2,4-D and of organophosphate and pyrethroid insecticides from 269 women from two cohorts: a) Thyroid Disruption And Infant Development (TDID) and b) Sibling/Hermanos cohort (S/H). We used weighted quantile sum regression and multivariable linear regression models to evaluate the associations between a mixture of urinary creatinine-adjusted biomarker concentrations and birth outcomes of length, birthweight and head circumference, controlling for covariates. We also used linear regression models and further classified biomarkers concentrations into three categories (i: non-detectable; ii: between the limit of detection and median; and iii: above the median) to investigate single pesticides’ association with these birth outcomes. Covariates considered were delivery mode, ethnicity, marital status, education, income, employment status, gestational age, maternal age and pre-pregnancy BMI. Analyses were conducted separately for each cohort and stratified by child sex within each cohort. Results In TDID cohort, we found a significant inverse association between weighted quantile sum of mixture of pesticides and head circumference among boys. We found that the urinary biomarkers of organophosphate chlorpyrifos, TCPy, and 2,4-D had the largest contribution to the overall mixture effect in the TDID cohort among boys (b = −0.57, 95%CI: −0.92, −0.22) (weights = 0.81 and 0.16 respectively) but not among girls. In the multivariable linear regression models, we found that among boys, for each log unit increase in 3,5,6-trichloro-2-pyridinol (TCPy, metabolite of organophosphate chlorpyrifos) in maternal urine, there was a −0.56 cm decrease in head circumference (95%CI: −0.92, −0.19). Among boys in the TDID cohort, 2,4-D was associated with smaller head circumference in the second (b = −1.57; 95%CI: −2.74, −0.39) and third (b = −1.74, 95%CI: −2.98, −0.49) concentration categories compared to the first. No associations between pyrethroid and organophosphate biomarkers and birth outcomes were observed in girls analyzed in WQS regression or individually in linear regression models in TDID cohort. In the S/H cohort, head circumference increased with higher concentrations of 3-phenoxybenzoic acid (3-PBA, a biomarker of several pyrethroids) (b = 0.53, 95%CI: 0.03, 1.04) among boys and head circumference was lower among girls in the high compared to low category of 2,4-D (b = −2.27, 95%CI: − 3.98, −0.56). Birth length was also positively associated with the highest concentration of 2,4-D compared to the lowest among boys (b = 4.01, 95%CI: 0.02,8.00). Conclusions Weighted quantile sum of pesticides was negatively associated with head circumference among boys in one cohort. Nonetheless, due to directional homogeneity assumption in WQS no positive associations were detected. In linear regression models with individual pesticides, concentrations of TCPy were inversely associated with head circumference in boys and higher concentrations of 2,4-D was inversely associated with head circumference among girls; 2,4-D concentrations were also associated with higher birth length among boys. Concentrations of 3-PBA was positively associated with head circumference among boys.

We herein report a fatal intoxication case caused by the ingestion of the insecticides chlorpyrifos-methyl (CPFM) and fenitrothion (MEP). A 70-year-old man was found dead in his house and a cup containing a small amount of agricultural chemicals was on the table near his body. External and internal examinations revealed no injuries. In a gas chromatography-mass spectrometry (GC-MS) screening test, CPFM, MEP, and their metabolites, 3,5,6-trichloro-2-pyridinol (TCPY) and 3-methyl-4-nitrophenol (3MNP), respectively, were qualitatively detected in his stomach contents. The concentrations (µg/g) of CPFM, TCPY, MEP, and 3MNP in the extracts of each body fluid and organ tissue were assessed by GC-MS and were as follows: 27.8, 56.2, 17.2, and 2.82 (heart blood); 6.60, 42.9, 1.80, and 2.59 (peripheral blood); 0.0821, 45.9, 2,09, and 102 (urine); 21.4, 26.6, 76.2, and 3.83 (brain (frontal portion)); 16.1, 101, 9.67, and 1.26 (liver); 7.45, 101, 21.4, and 26.1 (right kidney); and 73,500, 9750, 232,000, and 1880 (stomach contents), respectively. Based on these results and autopsy findings, the cause of death was acute fatal intoxication by CPFM and MEP.

Pesticides offer many benefits for humanity and agriculture, but at the same time pose a potential risk to human health because of their widespread use and high biological activity. Human biomonitoring (HBM) studies are the main tool to investigate human exposure to pesticides and other chemicals, but face limitations such as sampling biases, long time to complete and high costs. Wastewater-based epidemiology (WBE) is an alternative approach that is centered on the chemical analysis of biomarkers of (pesticide) exposure in urban wastewater. The present study used WBE to assess human exposure to selected classes of pesticides, triazines, pyrethroids and organophosphates, in Norway. Untreated wastewater samples were collected from four cities, covering approximately 20% of the Norwegian population. The highest population weighted mass loads (mg/day/1000 inhabitants) were for alkyl phosphates and the lowest for triazines. Some differences were observed for the two metabolites, 2-isopropyl-6-methyl-4-pyrimidinol (IMPY) and 3-(2,2-dichlorovinyl)-2,2-dimethyl-(1-cyclopropane) carboxylic acid (DCCA), which were higher in the rural city of Hamar. WBE figures were comparable with HBM findings for the specific metabolite of chlorpyrifos and chlorpyrifos methyl (3,5,6-trichloro-2-pyridinol; TCPY) but were different for the alkyl phosphates. Pyrethroid intake was calculated and was lower than the acceptable daily intake in all the cities, indicating low risk for human health. This is the most extensive WBE study performed to date to assess national human exposure to pesticides. This study demonstrated that WBE has the potential to be a useful complementary biomonitoring tool for assessing population-wide exposure to pesticides, overcoming some of the limitations of HBM.

Background: Pyrethroids and chlorpyrifos are widely used insecticides, but the potential impact of prenatal exposure on child neurodevelopment has only been addressed in few longitudinal studies. Objectives: To investigate associations between prenatal exposure to pyrethroids and chlorpyrifos and traits of ADHD in 2-4-year-old children. Methods: Metabolites of chlorpyrifos and pyrethroids were measured in maternal urine collected at gestational week 28 among 1207 women from the Odense Child Cohort. Of these, 948 completed the Child Behavior Check List for ages 1.5–5 years (CBCL: 1½-5). Negative binomial and logistic regression models were used to estimate relative differences in ADHD problem scores (CBCL: 1½-5 subscale) expressed as the ratio of expected scores between exposure groups and the odds (OR) of scoring equal to or above the 90th percentile in relation to maternal urinary metabolite concentrations (continuous ln2-transformed or categorized into tertiles). The analyses were adjusted for maternal education level, parental psychiatric diagnosis, child age and sex. Results: The chlorpyrifos metabolite, 3,5,6-trichloro-2-pyridinol (TCPY), the generic pyrethroid metabolite, 3-phenoxybenzoic acid (3-PBA), and the metabolite of trans-isomers of permethrin, cypermethrin, and cyfluthrin, trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (trans-DCCA), were detected in 90%, 94%, and 11%, respectively, of the urine samples. Each doubling in maternel 3-PBA concentration was associated with a 3% increase in the ADHD score (Ratio: 1.03 (95% CI: 1.00,1.07)) and a 13% higher odds of having a ADHD score ≥ the 90th percentile (OR: 1.13 (1.04,1.38)). Similar associations were seen for 3-PBA as categorical variable (p-trend=0.052 in negative binimoal regression, p-trend=0.007 in logistic regression). Furthermore, concurrent concentrations of 3-PBA and TCPY above their medians were associated with higher ADHD score (Ratio: 1.20 (1.04, 1.38)) and higher odds of scoring ≥ the 90th percentile (OR: 1.98 (1.26, 3.11)). Maternal trans-DCCA above the detection level increased the odds of ADHD symptoms (OR: 1.76 (1.08, 2.86)). The associations were not modified by sex. Conclusions: Prenatal exposure to pyrethroids was associated with ADHD related traits at 2–4 years of age. Considering the widespread use of pyrethroids these results are of concern.

Background Exposure to environmental chemicals, including organophosphorus pesticides, is associated with behavioral disorders such as attention deficit hyperactivity disorder (ADHD). However, the impact of occupational pesticide exposure on ADHD development in adolescents has not been examined. Objective We examined the association between exposure to chlorpyrifos and ADHD symptoms among adolescents in Egypt. Methods Adolescent pesticide applicators and non-applicators, 12–21 years old, participated in a 10-month longitudinal study examining health effects from pesticide exposure. Repeated urine and blood samples were collected at various time points during the 10-months to assess biomarkers of chlorpyrifos exposure (urinary trichloro-2-pyridinol or TCPy) and effect (blood acetyl cholinesterase activity and butyryl cholinesterase activity). Parents from a subset of the cohort (N = 64) completed the Short Form of Conners’ Parent Rating Scale – Revised. Poisson regressions were used to examine the associations between the number of ADHD symptoms and occupation and biomarkers. Results Pesticide applicators had significantly more symptoms of ADHD than participants in the non-applicator group. Urinary TCPy levels were associated with increased symptoms, demonstrating a dose-response effect. Applicators with ADHD reported applying pesticides for more hours during the application season and had greater cumulative TCPy levels than participants without ADHD. One fourth of all applicators met the criteria for an ADHD diagnosis (having 6 or more reported symptoms). Conclusions This study provides preliminary evidence of an association between occupational exposure to chlorpyrifos and ADHD symptoms among adolescent pesticide applicators in spite of its limited small sample size. There is a critical need to investigate the susceptibility of children and adolescents to repeated occupational and environmental exposures to pesticides because the developing brain may be uniquely sensitive to the neurotoxic effects of these agents.

Human biomonitoring provides information about chemicals measured in biological matrices, but their interpretation remains uncertain because of pharmacokinetic (PK) interactions. This study examined the PKs in blood from Long–Evans rats after a single oral dose of 0.4 mg/kg bw of each pesticide via a mixture of the 17 pesticides most frequently measured in humans. These pesticides are β-endosulfan; β-hexachlorocyclohexane [β-HCH]; γ-hexachlorocyclohexane [γ-HCH]; carbofuran; chlorpyrifos; cyhalothrin; cypermethrin; diazinon; dieldrin; diflufenican; fipronil; oxadiazon; pentachlorophenol [PCP]; permethrin; 1,1-dichloro-2,2bis(4-chlorophenyl)ethylene [p,p′-DDE]; 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane [p,p′-DDT]; and trifluralin. We collected blood at 10 min to 48-h timepoints in addition to one sample before gavage (for a control). We used GS–MS/MS to measure the pesticide (parents and major metabolites) concentrations in plasma, determined the PK parameters from 20 sampling timepoints, and analyzed the food, litter, and cardboard in the rats’ environment for pesticides. We detected many parents and metabolites pesticides in plasma control (e.g., diethyl phosphate [DEP]; PCP; 3-phenoxybenzoic acid [3-PBA]; 3,5,6-trichloro-2-pyridinol [TCPy], suggesting pre-exposure contamination. The PK values post-exposure showed that the AUC0−∞ and Cmax were highest for TCPy and PCP; β-endosulfan, permethrin, and trifluralin presented the lowest values. Terminal T1/2 and MRT for γ-HCH and β-HCH ranged from 74.5 h to 117.1 h; carbofuran phenol presented the shortest values with 4.3 h and 4.8 h. These results present the first PK values obtained through a realistic pattern applied to a mixture of 17 pesticides to assess exposure. This study also highlights the issues of background exposure and the need to work with a relevant mixture found in human matrices.

Background: There is a paucity of research that tracks changes in liver and kidney function among pesticide applicators. The aim of the current study was to investigate the role of repeated seasonal exposure to the organophosphorus pesticide, chlorpyrifos, on serum measures of liver and kidney function. Methods: Pesticide exposure was assessed by measuring the urinary concentrations of 3,5,6-trichloro-2 pyridinol (TCPy), a specific biomarker for chlorpyrifos. Chlorpyrifos exposure and 8 serum markers of liver and kidney function were measured at 15 timepoints over 3 years prior to, during, and following the end of seasonal pesticide application among adolescent applicators and non-applicators from 4 field stations in Menoufia, Egypt. Results: Urinary TCPy levels showed increases during the application cycles and recovery at the end of each application season. Altered serum markers of liver and kidney function were associated with chlorpyrifos exposure, with some markers recovering 3 months after the end of exposure each year, while other measures demonstrated progressive increase up to 300% the baseline levels at the end of 3 years. Conclusion: The study demonstrated that frequent assessment of liver and kidney function is a sound practice to evaluate cellular injury following chronic repeated occupational and environmental exposure to chlorpyrifos.

Background Chronic low-level exposure to organophosphorus pesticides is associated with adverse health effects, including a decline in neurological functioning and long-term impairment. These negative effects may be more detrimental in children and adolescents due to their critical stage in development. Little work has investigated the effects of chronic exposure to pesticides, specifically chlorpyrifos (CPF) during the adolescent period. Objectives To examine effects of CPF exposure over a year-long period within a group of male adolescents in Egypt (N = 242, mean age = 17.36), including both pesticide applicators and non-applicators. Methods Associations between average CPF exposure (measured via urinary metabolite levels of 3,5,6-trichloro-2-pyridinol [TCPy]) and neurobehavioral functioning were examined in a 1-year longitudinal study. Given previous literature, higher levels of TCPy were expected to be associated with worse neurobehavioral functioning. Results Using mixed effects linear regression, average TCPy exposure predicted deficits in more complex neurobehavioral tasks (Benton visual retention, digit span reverse, match to sample, serial digit learning, and alternating tapping) with estimates of effects ranging from −0.049 to 0.031. Age (effects ranging from 0.033 to 0.090) and field station (effects ranging from −1.266 to −0.278) were significantly predictive of neurobehavioral functioning over time. An interaction effect was found for field station and TCPy across several neurobehavioral domains. Discussion Results show that occupational exposure to pesticides may have particularly deleterious effects on complex neurobehavioral domains. Additionally, differences across field stations and the age at which individuals are exposed may be important factors to investigate in future research.

Certain pesticides may affect children's neurodevelopment. We assessed whether pesticide exposure was associated with impaired neurobehavioral outcomes in children aged 6–9 years. We conducted a cross-sectional study in 140 children living near banana plantations and plantain farms in the Talamanca County, Costa Rica and assessed their neurobehavioral performance. Exposure was determined by analyzing urinary metabolites of chlorpyrifos (3,5,6-trichloro-2-pyridinol, TCPy), mancozeb (ethylenethiourea, ETU), and pyrethroids (3-phenoxybenzoic acid, 3-PBA). Repeated urine samples were obtained for 36 children. We estimated associations of pesticide concentrations with neurobehavioral outcomes using multivariable linear and logistic regression models. Median (25th–75th percentiles) TCPy, ETU, and 3-PBA concentrations were 1.4 (.7–3.1), 1.2 (.7–3.0), and. 8 (.5–1.5) μg/L, respectively. Intraclass correlation coefficients (ICC) ranged between. 32 and. 67. After adjustment for potential confounders, higher urinary TCPy concentrations were associated with poorer working memory in boys (n = 59) (β per 10-fold increase in TCPy concentrations = −7.5, 95% CI: −14.4, −.7); poorer visual motor coordination (β = −1.4, 95% CI: −2.7, −.1); increased prevalence of parent-reported cognitive problems/inattention (adjusted OR per 10-fold increase in urinary concentrations = 5.8, 95% CI: 1.6, 22.9), oppositional disorders (aOR = 3.9, 95% CI: 1.0, 16.0), and ADHD (aOR = 6.8, 95% CI: 1.8, 28.6), and; decreased ability to discriminate colors (aOR = 6.6, 95% CI: 1.6, 30.3; the higher the score the worse). Higher ETU concentrations were associated with poorer verbal learning outcomes (β = −7.0, 95% CI: −12.7, −1.3). Higher 3-PBA concentrations were associated with poorer processing speed scores, particularly in girls (β = −8.8, 95% CI: −16.1, −1.4). Our findings indicate that children living near banana and plantain plantations are exposed to pesticides that may affect their neurodevelopment, which for certain domains may differ between boys and girls. We recommend the implementation of measures to reduce pesticide exposure in children living nearby banana plantations. (Less)

Chlorpyrifos is a widely used organophosphorus pesticide that efficiently protects crops against pests. However, recent studies suggest that severe exposure to chlorpyrifos may present adverse health effects in human. To analyze the exposure level and metabolic characteristics of chlorpyrifos pesticide in urban adults and farmers with/without occupation pesticide contact, the occurrence of urinary chlorpyrifos and methyl chlorpyrifos (CP-me), as well as their metabolite, 3,5,6-trichloro-2-pyridinol (TCPy), was determined in farmers of an agricultural village in China, and in urban adults of a nearby town. The geometric mean (GM) concentrations of TCPy, which is the major marker of chlorpyrifos exposure, were 4.29 and 7.57μg/g-creatinine in urban adults and farmers before pesticide application, respectively. Chlorpyrifos spraying significantly increased the concentrations of urinary TCPy. In the first day after spraying, a GM concentration of 43.7μg/g-creatinine was detected in the urine specimens from farmers, which decreased to 38.1 and 22.8μg/g-creatinine in the second and third day after chlorpyrifos spraying. The ratio of TCPy and its parent compounds, i.e. chlorpyrifos and CP-me, was positively associated with the sum concentration of urinary chlorpyrifos, CP-me, and TCPy, suggesting the increasing metabolic efficiency of chlorpyrifos to TCPy at higher chlorpyrifos exposure levels. To estimate the farmers' occupational exposure to chlorpyrifos pesticide, a new model based on the fitted first-order elimination kinetics of TCPy was established. Occupational chlorpyrifos exposure in a farmer was estimated to be 3.70μg/kg-bw/day (GM), which is an exposure level that is higher than the recommended guideline levels. Significant increase of urinary 8-hydroxydeoxyguanosine (8-OHdG) was observed on the first day after chlorpyrifos spraying, which indicates a potential oxidative damage in farmers. However, urinary 8-OHdG returned to its baseline level within two days.

Background Chlorpyrifos (CPF) is an organophosphate insecticide, acaricide, and miticide used primarily to control foliage and soilborne insect pests on a variety of food and feed crops. Since trace amounts of these compounds are found in water and food products, they easily enter into the organ system unnoticed. In the same way, the compound or its metabolite gets transmitted from the parent to the embryo mainly through blood vessels. Since blood vessels form the major route of transport, it is pertinent to study the effect of these compounds during angiogenesis. The effect of CPF and 3,5,6-trichloro-2-pyridinol (TCPy) on the angiogenesis of chick embryo was evaluated in the chorioallantoic membrane (CAM) using an ex vivo model. Methods Nine-day-old incubated eggs where inoculated with various doses of CPF and TCPy. After 48 h of incubation, the CAM layers were retrieved and analyzed using angiogenesis software to obtain the density of blood vessels. Histomorphometric studies were performed to measure the thickness of vessel walls. The expression of VEGF, VEGFR2, and N-cadherin genes responsible for angiogenesis were analyzed. Results The exposure to the parent compound CPF and its metabolite TCPy promoted angiogenesis in groups administered with lower concentration of the pesticide and its metabolite, whereas a decline in angiogenesis was observed at higher concentrations. These observations were made by analyzing the density, histomorphometry results, and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) results. The density, thickness, and lumen size of blood vessels in the groups with low concentration of CPF and TCPy were 28.34, 9 μm, and 30 μm, respectively, whereas in the groups with higher CPF and TCPy concentrations, they were 12, 3 μm, and 9 μm, respectively. Conclusions Hence, CPF and its metabolites interfere with angiogenesis in the CAM of chick embryos. Because of their estrogen-mimicking ability, pesticides are the prime etiological suspects of increasing alteration in blood vessel formation. These results may be of help in future studies on the effect of CPF in embryonic growth, wound healing, diabetes, and tumors.

The aim of the study was to evaluate the association between environmental exposure to nonpersistent insecticides and semen quality (concentration, motility, morphology, computer-aided semen analysis [CASA] parameters, and sperm DNA damage). Urine samples ( n = 315) collected from men who attended the infertility clinic with normal semen concentration of 15 to 300 mln/ml and age under 45 years were analyzed for two metabolites (1-naphthol [1N] and 3,5,6-trichloro-2-pyridinol [TCPY]) of nonpersistent insecticides. Participants provided semen, blood, and saliva samples; additionally, men filled a detailed questionnaire. The results identified that urinary TCPY concentration was significantly associated with a decrease in motility; also there was a positive association between TCPY and DNA fragmentation index (DFI). 1N concentration was negatively associated with a percentage of sperm with normal morphology and positively with one of the CASA parameters (curvilinear velocity [VCL]). The results suggest that environmental exposure to nonpersistent insecticides may have an impact on semen quality parameters and sperm DNA damage.

Introduction Chlorpyrifos (CPF) and profenofos (PFF) are organophosphorus (OP) pesticides that are applied seasonally in Egypt to cotton fields. Urine trichloro-2-pyridinol (TCPy), a specific CPF metabolite, and 4-bromo-2-chlorophenol (BCP), a specific PFF metabolite, are biomarkers of exposure, while inhibition of blood butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) activities are effect biomarkers which may be associated with neurotoxicity. Methods Urine TCPy and BCP and blood BChE and AChE activities were measured in 37 adult Egyptian Ministry of Agriculture workers during and after 9–17 consecutive days of CPF application followed by PFF (8–10 days), and a second CPF application (5 days) in 2008. In a separate longitudinal study, 57 adolescent applicators and 38 age-matched non-applicators were studied over 10 months in 2010. Results During the OP applications, mean TCPy and BCP levels were significantly higher than baseline levels and remained elevated following the application periods. Peak urinary BCP and peak TCPy levels for individuals (ranging from 13.4 to 8052 and 16.4 to 30,107 ug/g creatinine, respectively) were also highly correlated (r=0.77, p Conclusion Biomarker data in the adolescent non-applicators, which mirrored that of the applicators, indicated that the non-applicators received environmental CPF exposures. The variability in environmental and occupational exposures suggest that job title and work location should not be used as the sole basis for categorising OP exposures. Together, these results can serve to guide future investigations in assessing health risks of OPs and guide efforts to reduce exposures.

Introduction Chlopyrifos organophosphorous pesticides (OPs) are regularly applied for protection of the cotton crop in Egypt. OP absorption subsequent to dermal exposure has been estimated to be 94%–96% of the total dose. Legs and lower body parts are the most affected during cotton pesticide applications. Pesticides residues on the cotton plants also contaminate clothing and uncovered arms or legs of the applicators as they pass. Protective equipment is not readily available in Egypt. This pilot study was conducted to determine if wearing plastic coverings over pants or changing work practices could reduce pesticide exposure among Egyptian pesticide workers. Methods A controlled intervention study included: protective clothing (plastic pants modelled by the workers and staff who participated in 4 educational focus groups); spray away (instructions were provided to spray away form the workers’ path); control (followed routine work practices). Exposure was assessed measuring pre- and post-application urinary TCPy levels (3,5,6-trichloro-2-pyridinol), the primary chlorpyrifos metabolite used as a biomarker of absorbed dose. Work activities were recorded throughout the three-day study period. Results Twenty-four adult workers (n=8 per group) participated in the study. Time spent applying (range 15–36 min) and mixing (range 10–12 min) pesticides varied between groups and job categories. Other than the pants group, none of the workers had protective clothing. Spraying away did not produce consistent results. Average TCPy levels of the protective clothing group were lower compared to the other two groups, though the differences were not statistically significant (p>0.05). Conclusion Work habits, time spent applying or mixing pesticides and environmental conditions (e.g., wind direction) are important exposure determinants of urinary TCPy levels. However, use of protective clothing covering legs and lower parts of the body would reduce skin contamination, a major route of pesticide exposure. Work was supported by NIEHS grants ES017223 and ES016308.

Introduction While the impact of acute high exposures (i.e., poisoning) to organophosphorus insecticides is well understood, the impact of low level exposures, particularly on neurobehavioral functioning, is still under debate. Even less information is available regarding cumulative exposure, particularly among adolescents who may be working in agriculture. The goal was to examine the impact of chlorpyrifos exposure on biomarkers of exposure and neurobehavioral performance in adolescents across an application season. Methods Male Egyptian adolescents (applicators and non-applicators) were assessed 35 times before, during and after the pesticide application season. At each session, participants (n=89) completed a neurobehavioral test battery and urine was collected for analysis of the chlorpyrifos metabolite 3,5,6-trichloro-2 pyridinol (TCPy) (biomarker of exposure). Cumulative urinary TCPy over the study period was used to classify participants into low ( Results Urinary TCPy increased during application with recovery following the end of application. High exposed participants had significantly elevated metabolite levels throughout the 10 month study period. Deficits in motor skills and slower reaction times, along with deficits in executive function and short-term memory were found between the high and low exposure groups. Changes in neurobehavioral performance across the application season indicate a pattern of impaired performance among the high exposed compared to the low exposed. Deficits increased during the application season and remained for months after application ended. Conclusion The findings indicate that neurobehavioral deficits increase during the application season, as exposure also increases, and remain after the application ends, even when the biomarkers of exposure are reduced. This is particularly important when considering the developmental changes that occur during adolescence. An intervention to reduce pesticide exposure has been implemented in this population. (Supported by NIEHS and the Fogarty Institute R21 ES017223 and R01 ES022163, Rohlman).

Background/aim Organophosphate (OP) and pyrethroid (PYR) pesticides have a strong potential to disrupt the brain and nervous system of insects. This neurotoxic effect is not highly selective and therefore the compounds are also toxic to other non-target species, including humans. Once in the human body, OP and PYR pesticides are typically metabolised and excreted in urine within 4–48 hours after exposure. Methods A new analytical methodology for the quantification of OP and PYR urinary metabolites has been developed taking into account the wide range of concentrations of these compounds in humans from general and highly exposed populations (e.g. rural or agricultural areas). Six biomarkers of OP pesticides and two biomarkers of PYR compounds have been quantified by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). This methodology has been externally checked-out by participation in rounds of the G-Equas programme. A total of 125 urine samples from two adult Spanish populations have been analysed: farmworkers (n=45) and individuals living in urban and rural areas (n=80) from Catalonia and Galicia. Results The most abundant OP metabolites were PNP (metabolite of parathion and methyl paration, found in all samples analysed), followed by TCPY (metabolite of chlorpyrifos, found in 95% of the samples) and DEAMPY (metabolite of pirimiphos, 77% of detection), with median concentrations of 1.8 ng/ml, 1.1 ng/ml and 3.2 ng/ml, respectively. None of the samples had MDA (metabolite of malathion), and a few of them ( Concerning PYR metabolites, 3-PBA (metabolite of several commercial pyrethroids) was found in 81% of the samples (median concentration of 1.5 ng/ml) and 4-F-3-PBA (metabolite of cyfluthrin) was found in half of the cohort, with a median concentration of 0.076 ng/ml. Conclusion Metabolites of OP and PYR pesticides were observed in both farmworkers and general populations living in rural and urban areas, the former showing twofold average concentrations of OP metabolites than the second. These differences are consistent with occupational activity. The results show that both populations are generally exposed to pesticides such as chlorpyriphos, pirimiphos and parathion.

There are few studies documenting the dust loaded with pesticides as a potential non-dietary exposure source for occupational worker and populations living near agricultural farms and pesticides formulation plants. In present study we have evaluated the pesticide concentration in dust from potential sites and relevant health risk from dust ingestion. Furthermore, the effect of currently used pesticides was investigated on blood and urine parameters of subjects: farmer, factory worker, urban resident and rural resident and controlled subjects with presumably different levels of exposure. The urinary metabolites (TCPY and IMPY) were quantified as biomarkers of exposure to chlorpyrifos and diazinon in relation with biomarkers of effect including BuChE, LH, FSH, testosterone and oxidative stress. Results showed that chlorpyrifos and diazinon were present in higher concentration in dust and posed a high health risk to exposed subjects. The mean SOD value was high among the farmer (3048 U/g Hb) followed by factory worker (1677.6U/g Hb). The urinary biomarkers – TCPY and IMPY- were found higher in exposed subjects as compared to control. Furthermore, testosterone was found in higher concentration in factory worker than control (12.63 ng/ml vs 4.61 ng/ml respectively). A decreased BuChE activity was noticed in occupational group and significant differences were observed in control verses exposed subjects. The PCA analysis evidenced the impact of pesticides on exposure biomarkers and male reproductive hormones. The study suggests that dust contaminated with pesticides engenders significant health risk particularly related to the nervous and endocrine system, not only for occupational workers exposed to direct ingestion but also for nearby residential community. Succinctly putting: Pesticides loaded dust in the city of Lahore, being a high priority concern for the government of Pakistan, demands to be addressed.

Chlorpyrifos (CPF) is an organophosphourus insecticide applied to cotton fields by adolescents employed by the Egyptian Ministry of Agriculture. Urinary 3,5,6-trichloro-2-pyridinol (TCPy) is a biomarker of CPF exposure that has substantial variability among these applicators. In order to identify predictors of CPF exposure, we conducted a longitudinal study of 43 adolescent pesticide applicators in Egypt from April 2010 to January 2011 in Egypt. Urinary TCPy was quantified at 25 time-points, prior to, during, and following application. We used log-linear regression and a best subset selection approach to identify the exposure determinants that were most predictive of cumulative TCPy and participants’ highest TCPy values (peak exposure). Applicators had cumulative urinary TCPy levels ranging from 167 to 49,8208 µg/g creatinine. Total hours applying CPF (semi-partial r2 = 0.32), and total hours in the field applying other pesticides (semi-partial r2=0.08) were the strongest predictors of cumulative TCPy. Applicators had peak urinary TCPy levels ranging from 4 to 5,715 µg/g creatinine. The amount of time applying pesticides prior to blood draw was the strongest predictor of peak TCPy (semipartial r2=0.30). We also observed evidence that wearing clean clothes to work was associated with lower longitudinal TCPy. Our results suggest there is an opportunity for targeted interventions, particularly related to hygiene or implementation of personal protective equipment usage to reduce CPF exposure among adolescent pesticide workers.

A combination experimental and computational approach was developed to predict chemical transport into saliva. A serous-acinar chemical transport assay was established to measure chemical transport with nonphysiological (standard cell culture medium) and physiological (using surrogate plasma and saliva medium) conditions using 3,5,6-trichloro-2-pyridinol (TCPy) a metabolite of the pesticide chlorpyrifos. High levels of TCPy protein binding were observed in cell culture medium and rat plasma resulting in different TCPy transport behaviors in the 2 experimental conditions. In the nonphysiological transport experiment, TCPy reached equilibrium at equivalent concentrations in apical and basolateral chambers. At higher TCPy doses, increased unbound TCPy was observed, and TCPy concentrations in apical and basolateral chambers reached equilibrium faster than lower doses, suggesting only unbound TCPy is able to cross the cellular monolayer. In the physiological experiment, TCPy transport was slower than nonphysiological conditions, and equilibrium was achieved at different concentrations in apical and basolateral chambers at a comparable ratio (0.034) to what was previously measured in rats dosed with TCPy (saliva:blood ratio: 0.049). A cellular transport computational model was developed based on TCPy protein binding kinetics and simulated all transport experiments reasonably well using different permeability coefficients for the 2 experimental conditions (1.14 vs 0.4 cm/h for nonphysiological and physiological experiments, respectively). The computational model was integrated into a physiologically based pharmacokinetic model and accurately predicted TCPy concentrations in saliva of rats dosed with TCPy. Overall, this study demonstrates an approach to predict chemical transport in saliva, potentially increasing the utility of salivary biomonitoring in the future.

Chlorpyrifos (CPF) is a commonly used organophosphate insecticide (OP). In adults, exposure to OPs has been inconsistently associated with reduced lung function. OP exposure and lung function has not been assessed in adolescents. The objective of this study was to assess CPF exposure and lung function among Egyptian adolescents. We conducted a 10-month study of male adolescent pesticide applicators (n = 38) and non-applicators of similar age (n = 24). Urinary 3,5,6-trichloro-2-pyridinol (TPCy), a CPF-specific metabolite, was analyzed in specimens collected throughout the study. Spirometry was performed twice after pesticide application: day 146, when TCPy levels were elevated and day 269, when TCPy levels were near baseline. Applicators had higher levels of TCPy (mean cumulative TCPy day 146 = 33,217.6, standard deviation (SD) = 49,179.3) than non-applicators (mean cumulative TCPy day 146 = 3290.8, SD = 3994.9). Compared with non-applicators, applicators had higher odds of reporting wheeze, odds ratio = 3.41 (95% CI: 0.70, 17.41). Cumulative urinary TCPy was inversely associated with spirometric measurements at day 146, but not at day 269. Although generally non-significant, results were consistent with an inverse association between exposure to CPF and lung function.

Sensitivity to some chemicals in animals and humans are known to vary with age. Age-related changes in sensitivity to chlorpyrifos have been reported in animal models. A life-stage physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model was developed to predict disposition of chlorpyrifos and its metabolites, chlorpyrifos-oxon (the ultimate toxicant) and 3,5,6-trichloro-2-pyridinol (TCPy), as well as B-esterase inhibition by chlorpyrifos-oxon in humans. In this model, previously measured age-dependent metabolism of chlorpyrifos and chlorpyrifos-oxon were integrated into age-related descriptions of human anatomy and physiology. The life-stage PBPK/PD model was calibrated and tested against controlled adult human exposure studies. Simulations suggest age-dependent pharmacokinetics and response may exist. At oral doses ⩾0.6 mg/kg of chlorpyrifos (100- to 1000-fold higher than environmental exposure levels), 6 months old children are predicted to have higher levels of chlorpyrifos-oxon in blood and higher levels of red blood cell cholinesterase inhibition compared to adults from equivalent doses. At lower doses more relevant to environmental exposures, simulations predict that adults will have slightly higher levels of chlorpyrifos-oxon in blood and greater cholinesterase inhibition. This model provides a computational framework for age-comparative simulations that can be utilized to predict chlorpyrifos disposition and biological response over various postnatal life stages.

A solid phase extraction method was developed to isolate four insecticide degradates from baby food that were measured subsequently using high-performance liquid chromatography–tandem mass spectrometry. The degradates [parent insecticide] measured were malathion dicarboxylic acid [malathion], 3,5,6-trichloro-2-pyridinol [chlorpyrifos, chlorpyrifos methyl] (TCPy), cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid [permethrin, cypermethrin, cyfluthrin], and 3-phenoxybenzoic acid [general pyrethroid]. All degradates produced recoveries between 80 and 120% except TCPy in fruit (122% recovery), and all relative standard deviations were

Children and adolescents may have occupational exposure to pesticides. Although previous studies examining prenatal pesticide exposure have identified neurobehavioral deficits in children, there are limited studies examining the impact of occupational exposure in children. The objectives of this study are to estimate exposures to the organophosphorus pesticide, chlorpyrifos (CPF), by measuring urinary levels of 3,5,6-trichloro-2-pyridinol (TCPy), a specific CPF metabolite, and blood cholinesterase (ChE) activities and to characterize neurobehavioral performance in adolescents working as seasonal pesticide applicators and non-applicator controls. A neurobehavioral test battery, consisting of 14 tests, was used to assess a broad range of functions. Applicators performed worse than controls on the majority of tests. Principal component analysis was used to reduce the number of outcome variables and two components, focused on reasoning-short-term memory and attention-executive functioning, showed significant deficits in applicators compared to non-applicators. Elevated metabolite levels were found in the applicators compared to the non-applicators, confirming CPF exposure in the applicators. Although this study is limited by a small sample size, it provides preliminary evidence of moderate CPF exposures, decreased blood ChE in some applicators and decreased neurobehavioral performance in an adolescent working population.

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

Background: Pesticide exposure during pregnancy is thought to adversely affect fetal growth, which in turn may impact child growth, but results have been inconsistent across studies and few have explored these effects in developing countries. Objectives: To quantify urinary concentrations of pesticide biomarkers in early pregnancy (

Background Organophosphate (OP) pesticides can be hazardous to human health if not applied with appropriate precautions. There is evidence in the Maule region of Chile that rural schoolchildren are exposed to OP pesticides. Objective To evaluate the effectiveness of an educational intervention on OP exposure and understanding of pesticides and their hazards (risk perception) in two school communities in the Maule Region of Chile during 2016. Method We conducted a quasi-experimental study about the effects on OP pesticide exposure of a community outreach and education program (COEP) administered in four 2-h sessions that's included hands-on activities among 48 schoolchildren from two rural schools. The intervention was directed to groups of parents and school-children separately, and aimed to educate them about the risks of exposure to pesticides and their effects on health. We measured 3,5,6-trichloro-2-pyridinol (TCPy), 2-isopropyl-4-methyl-6-hydroxypyrimidine (IMPY), malathion dicarboxylic acid (MDA), p-nitrophenol (PNP), specific urinary metabolites of the OP pesticides chlorpyrifos, diazinon, malathion and parathion, respectively, as well as the non-specific diethylakylphosphates (DEAPs) and dimethylalkylphosphates (DMAPs) in 192 urine samples of schoolchildren collected before and after the intervention. The risk perception of school children and their parents was also assessed through a questionnaire before and after the intervention. Generalized Estimated Equations were used to account for each child’s repeated measures during four sessions, two in September 2016 (pre-intervention) and two in November 2016 (post-intervention). Results The intervention level had significant effect on the risk perception of adults and children, which increased after the intervention. However, the intervention was not associated with reduced of urinary metabolites levels, with no significant differences between the pre and post measures. The detection frequencies were 1.1% (MDA), 71.4% (TCPy), 43.3% (IMPY), 98.96% (PNP), and 100% (DEAPs and DMAPs). Higher DEAPs urine concentrations were associated with eating more fruit at school (p = 0.03), a younger age (p = 0.03), and being male (p = 0.01). DMAPs showed no associations with potential predictor variables (e.g. OPs applied at home, fruit consumption at school, among others). Higher TCPy was associated with attending a school closer to farms (p = 0.04) and living in a home closer to farm fields (p = 0.01); higher PNP was marginally associated with children younger age (p = 0.035). Conclusion Environmental exposure to OP pesticides was unchanged even after behavior changes. It is possible that a longer time period is needed to observe changes in both behavior and urinary metabolites. The levels of DEP and DMP metabolites found here are above the reference population of the US, and our findings indicate exposure to a wide variety of OP pesticides. Given that individual-level interventions were not associated with lower exposures, efforts to reduce exposure must occur upstream and require stricter regulation and control of pesticide use by government agencies.

Analysis of the interaction of pesticides and their metabolites with the cellular proteins has drawn considerable attention in past several years to understand the effect of pesticides on environment and mankind. In this study, we have investigated the binding interaction of Bovine Serum Albumin (BSA) with a widely used organophosphorous insecticide chlorpyrifos (CPF), and its stable metabolite, 3,5,6-trichloro-2-pyridinol (TCPy) to provide a comparative analysis of the two molecules by employing various spectroscopic techniques viz., UV-vis absorption, Circular Dichroism (CD), and Fluorescence spectroscopy. The fluorescence quenching studies of BSA emission in two different solvents viz., water and methanol in presence of CPF and TCPy have led to the revelation of several interesting facts about the pesticide-protein interaction. It has been found that both the molecules cause static quenching of BSA emission as seen from the Stern-Volmer constant (Ksv) irrespective of the solvent used for the analysis. While TCPy is a stronger quencher in water, it exhibits comparable quenching capacity with CPF in methanol. The solvent dependent differential binding interaction of the two molecules finally indicates possibility of diverse bio-distribution of the pesticides within human body. The UV-vis and CD spectra of BSA in presence of the test molecules have unravelled that the molecules formed ground state complex that are highly reversible in nature and have minimal effect on the protein secondary structure. Furthermore it is also understood that structural changes of BSA in presence of CPF is significantly higher compared to that in presence of TCPY.

Egyptian adolescents are hired as seasonal workers to apply pesticides to the cotton crop and may perform this occupation for several years. However, few studies examined the effects of repeated pesticide exposure on health outcomes The goal of this study was to determine the impact of repeated pesticide exposure on neurobehavioral (NB) performance and biomarkers of exposure (urinary metabolite) and effect (cholinesterase activity). Eighty-four adolescents from two field stations in Menoufia, Egypt, were examined four times: before and during pesticide application season in 2010 and again before and during application season in 2011. At each of the four time points, participants completed a questionnaire, performed an NB test battery, and were assessed for urinary levels of the chlorpyrifos metabolite TCPy (3,5,6-trichloro-2-pyridinol) and blood cholinesterase activity. Following the study cohort over two consecutive pesticide application seasons revealed that TCPy levels significantly increased following exposure, and returned to baseline levels following the end of the application season. Blood butyryl cholinesterase activity exhibited a similar pattern. Although NB outcomes displayed learning and practice effects over time, deficits in performance were significantly associated with increased TCPy levels with reduction in the number of NB measures showing improvement over time. Biomarkers of exposure and effect demonstrated changes associated with pesticide application and recovery after application ended. Deficits in NB performance were correlated with elevated pesticide exposure. Data demonstrated that repeated pesticide exposure may exert a long-term adverse impact on human health.

Few population studies have measured urinary levels of pesticides in individuals with vegan, vegetarian, or organic diets. The objectives of this study were to evaluate whether a vegan/vegetarian diet was associated with increased exposure to organophosphate and carbamate pesticides, and to evaluate the impact of organic consumption on pesticide exposure in vegans and vegetarians. In the current pilot study conducted in 2013–2014, we collected spot urine samples and detailed 24 h recall dietary data in 42 adult residents of Amirim, a vegetarian community in Northern Israel. We measured urinary levels of non-specific organophosphate pesticide metabolites (dialkylphosphates, (DAPs)) and specific metabolites of the current-use pesticides chlorpyrifos (3,5,6-trichloro-2-pyridinol (TCPy)), propoxur (-isopropoxyphenol (IPPX)), and carbaryl (1-naphthol). Six DAP metabolites were detected in between 67 and 100% of urine samples, with highest geometric mean concentrations for dimethylphosphate (19.2 μg/g). Creatinine-adjusted median concentrations of total DAPs and of TCPy were significantly higher in Amirim residents compared to the general Jewish population in Israel (0.29 μmol/g compared to 0.16, p 25% of the produce they consume is organic (0.065 μmol/L compared to 0.22, p

This study was designed to observe the production of degradates of two organophosphorus insecticides and one pyrethroid insecticide in beverages. Purified water, white grape juice, apple juice, and red grape juice were fortified with 500 ng/g malathion, chlorpyrifos, and permethrin, and aliquots were extracted for malathion dicarboxylic acid (MDA), 3,5,6-trichloro-2-pyridinol (TCPy), and 3-phenoxybenzoic acid (3-PBA) several times over a 15 day period of being stored in the dark at 2.5 °C. Overall, first-order kinetics were observed for production of MDA, and statistically significant production of TCPy was also observed. Statistically significant production of 3-phenoxybenzoic acid was not observed. Results indicate that insecticides degrade in food and beverages, and this degradation may lead to preexisting insecticide metabolites in the beverages. Therefore, it is suggested that caution should be exercised when using urinary insecticide metabolites to assess exposure and risk.

Organophosphorus (OP) and pyrethroid (PYR) compounds are the most widely used insecticides. OPs and PYRs are developmental neurotoxicants. Understanding the extent of exposure in the general population and especially in young children is important for the development of public health policy on regulation and use of these chemicals. Presented here are the results of the first investigation into the extent of environmental exposure to neurotoxic insecticides in preschool children in South Australia (SA).Children were enrolled from different areas of SA and assigned into urban, periurban and rural groups according to their residential address. Residential proximity to agricultural activity, parental occupational contact to insecticides and use of insecticides within the household were investigated as potential indirect measures of exposure. We used liquid chromatography/tandem mass spectrometry to measure the following metabolites of OPs and PYRs in urine samples as direct indicators of exposure: dialkylphosphates, p-nitrophenol, 3-methyl-4-nitrophenol, 3,5,6-trichloro-2-pyridinol, cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane-1-carboxylic acid, cis-3-(2,2-dibromovinyl)-2,2-dimethyl-cyclopropane-1-carboxylic acid, 2-methyl-3phenylbenzoic acid and 3-phenoxybenzoic acid. Results were analysed to assess factors affecting the risk and level of exposure. Results were also compared to the published data in similar age groups from US and German studies.The results of this study demonstrate that there was widespread chronic exposure to OPs and and PYRs in SA children. OP metabolites were detected more commonly than PYR. Exposure to more than one chemical and contemporaneous exposure to chemicals from both OP and PYR groups was common in the study population. There were some differences in risks and levels of exposure between the study groups. Exposure to some restricted use of chemicals, for example, fenitrothion, was higher in periurban and rural children. There was no difference among the study groups in exposure to chlorpyrifos, used commonly in agriculture and in domestic settings and most frequently found OP pesticide in food in Australia. South Australian children appear to have higher levels of exposure compared their peers in US and Germany. Keywords: Environmental exposure, Organophosphate, Pyrethroid, Neurotoxic insecticides, Children, South Australia

Chlorpyrifos (CPF) is a widely used organophosphorus (OP) pesticide. CPF is bioactivated by cytochrome P450s (CYPs) to the potent cholinesterase inhibitor chlorpyrifos oxon (CPF-O) or detoxified to 3,5,6-trichloro-2-pyridinol (TCPy). Human CYP2B6 has the highest reported Vmax)/Km (intrinsic clearance--CL(int)) for bioactivation while CYP2C19 has the highest reported CL(int) for detoxification of CPF. In this study, 22 human liver microsomes (HLMs) genotyped for common variants of these enzymes (CYP2B6*6 and CYP2C19*2) were incubated with 10 μM and 0.5 μM CPF and assayed for metabolite production. While no differences in metabolite production were observed in homozygous CYP2C19*2 HLMs, homozygous CYP2B6*6 specimens produced significantly less CPF-O than wild-type specimens at 10 μM (mean 144 and 446 pmol/min/mg, respectively). This correlated with reduced expression of CYP2B6 protein (mean 4.86 and 30.1 pmol/mg, for CYP2B6*6 and *1, respectively). Additionally, CYP2B6*1 and CYP2B6*6 were over-expressed in mammalian COS-1 cells to assess for the first time the impact of the CYP2B6*6 variant on the kinetic parameters of CPF bioactivation. The Vmax for CYP2B6*6 (1.05×10⁵ pmol/min/nmol CYP2B6) was significantly higher than that of CYP2B6*1 (4.13×10⁴ pmol/min/nmol CYP2B6) but the K(m) values did not differ (1.97 μM for CYP2B6*6 and 1.84 μM for CYP2B6*1) resulting in CL(int) rates of 53.5 and 22.5 nL/min/nmol CYP2B6 for *6 and *1, respectively. These data suggest that CYP2B6*6 has increased specific activity but reduced capacity to bioactivate CPF in HLMs compared to wild-type due to reduced hepatic protein expression, indicating that individuals with this genotype may be less susceptible to CPF toxicity.

Chlorpyrifos exposures were assessed in 12 Egyptian cotton field workers.3,5,6-trichloro-2-pyridinol (TCPy) was measured in 24-hour urine samples to estimate absorbed dose. Workshift air samples were used to calculate chlorpyrifos inhalation dose.Patches on legs had the highest chlorpyrifos loading rates among body regions sampled. Geometric mean chlorpyrifos air concentrations were 5·1, 8·2, and 45·0 μg/m(3) for engineers, technicians, and applicators, respectively; peak TCPy urinary concentrations were 75-129, 78-261, and 487-1659 μg/l, respectively; geometric mean doses were 5·2-5·4, 8·6-9·7, and 50-57 μg/kg, respectively, considering TCPy excretion half-life values of 27 and 41 hours. All worker doses exceeded the acceptable operator exposure level of 1·5 μg/kg/day. An estimated 94-96% of the dose was attributed to dermal exposure, calculated as the difference between total dose and inhalation dose.Interventions to reduce dermal exposure are warranted in this population, particularly for the hands, feet, and legs.

The paper presents a case study of the application of a “source-to-outcome” model for the evaluation of the health outcomes from dietary exposures to an insecticide, chlorpyrifos, in populations of adults (age 30) and children (age 3). The model is based on publically-available software programs that characterize the longitudinal dietary exposure and anthropometry of exposed individuals. These predictions are applied to a validated PBPK/PD model to estimate interindividual and longitudinal variation in brain and RBC AChE inhibition (key events) and chlorpyrifos concentrations in blood and TCPy in urine (biomarkers of exposure). The predicted levels of chlorpyrifos and TCPy are compared to published measurements of the biomarkers. Predictions of RBC AChE are compared to levels of inhibition associated with reported exposure-related effects in humans to determine the potential for the occurrence of adverse cholinergic effects. The predicted distributions of chlorpyrifos in blood and TCPy in urine were found to be reasonably consistent with published values, supporting the predictive value of the exposure and PBPK portions of the source-to-outcome model. Key sources of uncertainty in predictions of dietary exposures were investigated and found to have a modest impact on the model predictions. Future versions of this source-to-outcome model can be developed that consider advances in our understanding of metabolism, to extend the approach to other age groups (infants), and address intakes from other routes of exposure.