Search

Since the exposure of organophosphate pesticides are known to cause severe health consequences, it is important to understand the molecular interaction of these pesticides metabolites with vital biomolecules, especially with the proteins. Here, considering bovine serum albumin (BSA) as a model protein, we have examined its interaction with two selected organophosphate metabolites, 3,5,6-trichloro-2-pyridinol (TCPy) and paraoxon methyl (PM). TCPy and PM are resultant metabolites of two most widely used organophosphate pesticides chlorpyrifos and parathion respectively. 1H NMR line broadening, selective spin-lattice relaxation rate measurements, saturation transfer difference (STD) NMR of both TCPy and PM were carried out in the presence and absence of BSA. The obtained values of the affinity index (A), binding constants (Ka) and thermodynamic parameters indicated strong organophosphates-BSA interaction. Further, fluorescence quenching data on TCPy-BSA and PM-BSA interactions strongly supported the NMR results, besides providing the stoichiometry of these complexes. Molecular docking analysis unraveled viable, strong hydrogen bonds and electrostatic interactions in TCPy-BSA and PM-BSA complexes. This study also revealed substantial time-dependent changes in the 1H NMR intensity of PM in the presence of BSA, which suggests faster degradation of PM with increasing protein concentration during protein-metabolite interactions. The hydrolysis is attributed to the esterase-like action of BSA. The result provides key insights into the direct interaction of the organophosphate metabolites with a biologically important carrier protein, serum albumin.

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.

International audience; Background - A growing body of studies now suggests that the general population is continuously and ubiquitously exposed to numerous pesticides. However, studies investigating the possible role of environmental exposure to pesticides on fetal growth have focused on a limited set of substances, despite the hundreds of modern pesticides currently available. Aim - To explore the relation between maternal hair concentrations of 64 pesticides and metabolites and their newborns' measurements at birth, with data from the ELFE French nationwide birth cohort. Methods - We measured 64 compounds (10-100% detection) in bundles of hair 9 cm long collected at birth from 311 women who gave birth in France in 2011. We assessed their associations with birth weight, length, and head circumference, adjusted for potential confounders, and used elastic net regularization to simultaneously select the strongest predictors of measurements at birth. Selected variables were multiply imputed for missing values, and unpenalized estimators were assessed by standard linear regression. Results - We observed statistically significant associations between maternal hair concentrations of seven pesticides or pesticide metabolites and birth measurements (weight: fipronil sulfone; length: TCPy, bitertanol, DEP, and isoproturon; head circumference: tebuconazole and prochloraz). Analyses restricted to boys identified 12 additional compounds: 8 independently associated with birth weight (3Me4NP, DCPMU, DMST, fipronil, mecoprop, propoxur, fenhexamid, and thiabendazole), 2 with birth length (dieldrin and β-endosulfan), and 6 with head circumference (β-endosulfan, β-HCH, fenuron, DCPMU, propoxur, and thiabendazole). Conclusion - Our results suggest that prenatal exposure to 19 pesticides or metabolites from various chemical families may influence measurements at birth. As with any exploratory research findings, results should be interpreted cautiously, until they are replicated or verified by further epidemiological or mechanistic studies.

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

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.

The compound 3,5,6-trichloro-2-pyridinol (TCPy), a metabolite of the broad-spectrum organophosphorus insecticide chlorpyrifos, is both more persistent and more water soluble than its parent compound. This difference, which allows TCPy to more readily leach into surface water and groundwater, has led to widespread contamination of TCPy in soils and aquatic environments. In this study, the degradation of TCPy by sulfate radicals was evaluated using zero valent iron activated persulfate in aqueous media. Response surface methodology coupled with Box-Behnken design was applied to evaluate the effects of the independent variables (concentration of zero valent iron, concentration of persulfate, and pH) on the mineralization of TCPy by zero valent iron activated persulfate system. The interactions, coefficients, and residuals of these variables were statically evaluated by analysis of variance. Based on the model, the optimum conditions for maximum TCPy mineralization were determined as 10.4mM of persulfate, 1.2 g/L of zero valent iron and an initial pH of 3.2. The reaction kinetics of the degradation process were examined as functions of persulfate concentration, zero valent iron concentration, and pH. Results show that zero valent iron activated persulfate can effectively remove TCPy in water with a high mineralization rate of up to 81.1%. The degradation pathways of TCPy were proposed based on the products identified by GC-MS. Calculated ΔG values using density functional theory agreed with the proposed experimental pathway.

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.

Background Organophosphates are insecticides that inhibit the enzymatic activity of acetylcholinesterase (AChE). Because of this, AChE is considered a physiological marker of organophosphate exposure in agricultural settings. However, limited research exists on the associations between urinary organophosphate metabolites and AChE activity in children. Methods This study included 526 participants from 2 exams (April and July–October 2016) of ages 12–17 years living in agricultural communities in Ecuador. AChE activity was measured at both examinations, and organophosphate metabolites, including para-nitrophenol (PNP), 3,5,6-trichloro-2-pyridinol (TCPy), and malathion dicarboxylic acid (MDA) were measured in urine collected in July–October. We used generalized estimating equation generalized linear model (GEEGLM), adjusting for hemoglobin, creatinine, and other demographic and anthropometric covariates, to estimate associations of urinary metabolite concentrations with AChE activity (July–October) and AChE% change between April and July–October. Results The mean (SD) of AChE and AChE% change (April vs July–October) were 3.67 U/mL (0.54) and −2.5% (15.4%), respectively. AChE activity was inversely associated with PNP concentration, whereas AChE% change was inversely associated with PNP and MDA. There was evidence of a threshold: difference was only significant above the 80th percentile of PNP concentration (AChE difference per SD increase of metabolite = −0.12 U/mL [95%CI: 0.20, −0.04]). Likewise, associations with AChE% change were significant only above the 80th percentile of TCPy (AChE % change per SD increase of metabolite = −1.38% [95%CI: 2.43%, −0.32%]) and PNP -2.47% [95%CI: 4.45%, −0.50%]). PNP concentration at ≥80th percentile was associated with elevated ORs for low AChE activity of 2.9 (95% CI: 1.5, 5.7) and for AChE inhibition of ≤ -10% of 3.7 (95% CI: 1.4, 9.8). Conclusions Urinary organophosphate metabolites, including PNP, TCPy and MDA, particularly at concentrations above the 80th percentile, were associated with lower AChE activity among adolescents. These findings bring attention to the value of using multiple constructs of pesticide exposure in epidemiologic studies.

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.

In malaria-endemic areas in South Africa, traditional huts are sprayed with 1,1,1-trichloro-2,2-bis(chlorodiphenyl)ethane (DDT) while modern structures are sprayed with pyrethroid insecticides. With modernization of housing and DDT sourcing costs, spray programs have changed. Coupled with this is an increase in agricultural pesticide use, creating another source of exposure. However, DDT and pyrethroids are considered endocrine disrupting chemicals (EDCs). Exposure to complex mixtures of EDCs is associated with adverse male reproductive health including a decline in sperm and semen quality. Thus, the aim of the study was to investigate the impact of exposure to a complex mixture of EDCs, DDT pyrethroids and other agricultural pesticides, on seminal parameters, hormonal regulation and sperm chromatin integrity. In a cross-sectional study conducted between 2003 and 2008 (n = 544, from three DDT-sprayed villages—n = 310, three non-DDT sprayed villages—n = 234) and 2012–2017 (n = 431 young males from three DDT-exposed—n = 236; three non-DDT exposed—n = 195); young males were recruited from a malaria endemic area in Limpopo Province, South Africa where DDT was used in indoor residual spraying. Exposure levels of DDT (measured in blood plasma) pyrethroids and other pesticides (measured in urine) were determined and a semen analysis was conducted according to WHO standards. Linear regression models were examined to evaluate DDT/DDE effects on different reproductive outcomes. In sprayed villages p,p′-DDE exposure levels were significantly lower between 2012 and 2017 (mean ± SD: 5.80 ± 6.6 μg/g) compared to the 2003–2008 (216.9 ± 210.6 μg/g) period (P < 0.001). In the non-sprayed villages p,p′-DDE exposure levels were significantly lower between 2012 and 2017 (mean ± SD: 1.47 ± 3.68 μg/g) compared to the 2003–2008 (2.81 ± 4.26 μg/g) period (P < 0.001). Sperm counts were significantly lower (P = 0.04) in the 2012–2017 period (45.30 ± 49.20 mil/ml) compared to 2003–2008 (51.91 ± 48.25 mil/ml). Analysis showed that 3,5,6-trichloro-2-pyridinol (TCPY), 1,2,3-benzotriazine-4-one (BTA) a herbicide and 3-(2,2-dichlororvinyl)-2,2-dimethyl-cyclopropane-1-carboxylic acid (Trans/DCCA) were the most common metabolites. Despite the decline in exposure levels over time, seminal parameters and chromatin integrity were still affected. While still dependent on DDT and pyrethroids for malaria vector control, a more sustainable approach is needed towards malaria elimination, involving transdisciplinary approaches.

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.

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

Four new salts of the 3,4-dicyano-2-(dicyanomethylene)-5-methyl-6-phenyl-2H-pyridin-1-ide anion (TCPy−) with mono-, di-, tri- and tetraethylammonium cations were synthesized and structurally characterized by the single-crystal X-ray diffraction method. Solid state photoluminescence characteristics of the prepared salts were studied. Crystallographic features of the crystal packing which are responsible for the position of an emission band were characterized. A novel method of fluorescence determination of gaseous amines using TCPy was developed.

Human exposure to pesticides is widespread and has received much attention in recent years because of its link to adverse health outcomes. Measurement of urinary concentrations of pesticides and their metabolites is often used in the assessment of body burdens of these chemicals. However, pesticides and their metabolites can be present in blood circulatory system, although little is known on serum levels of pesticides. In this study, we aimed to examine the occurrence and profile of four organophosphate (OP), five pyrethroid (PYR) insecticides, two phenoxy acid (PA) herbicides, 14 neonicotinoid (neonic) insecticides and six dialkylphosphate metabolites in serum from 25 individuals diagnosed with osteoarthritis in Jeddah, Saudi Arabia. 2-Isopropyl-4-methyl-6-hydroxypyrimidine (IMPY), 3,5,6-trichloro-2-pyridinol (TCPY), 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, 3-phenoxybenzoic acid, N-desmethyl acetamiprid, dimethylphosphate (DMP) and dimethylthiophosphate (DMTP) were detected in ≥80% of the serum samples analyzed. Metabolites of OPs, DMTP (median concentration: 2.14 ng/mL), DMP (1.04 ng/mL) and TCPY (0.84 ng/mL), collectively accounted for 67–83% of the total serum pesticide concentrations. Serum concentrations of pesticides were similar to or lower than those reported in urine. Our preliminary evidence suggests that serum can be used as a matrix for the assessment of exposure to OPs, PYRs, PAs and neonics.

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.

Endometriosis is a hormone-responsive gynecologic disease, signifying its connotations across a woman’s life span. Previous studies suggested that endocrine disrupting chemicals were risk factors for endometriosis. Nevertheless, little is known on exposure to organophosphate, pyrethroid and phenoxy acid pesticides on endometriosis diagnosis. In this study, we determined the concentrations of 11 pesticides, metabolites of organophosphate and pyrethroid insecticides, and phenoxy herbicides, in urine collected from 619 reproductive-age women in Utah and California, using liquid chromatography-tandem mass spectrometry. The association of urinary concentrations of pesticides with an increase in the odds of endometriosis diagnosis was examined in 594 women who underwent laparoscopy/laparotomy (operative cohort: n = 471) or pelvic magnetic resonance imaging (population cohort: n = 123), during 2007–2009. 2-Isopropyl-4-methyl-6-hydroxypyrimidine (IMPY), malathion dicarboxylic acid (MDA), para-nitrophenol (PNP), 3,5,6-trichloro-2-pyridinol (TCPY), 3-phenoxybenzoic acid (3-PBA), and 2,4-dichlorophenoxyacetic acid (2,4-D) were detected in ≥95% of the urine samples analyzed. Urinary concentrations of IMPY, MDA, PNP, 3-PBA and 2,4-D tended to be higher in younger, non-Hispanic black, nulliparous and less affluent women. IMPY was the most dominant compound in urine followed by PNP and TCPY. When women in the 4th quartile of IMPY and the 2nd quartile of TCPY concentrations (μg/g creatinine) were compared with women in the 1st quartile, the odds ratios (ORs) for diagnosis of endometriosis increased significantly in unadjusted models (IMPY OR = 1.89, 95% confidence interval (Cl) = 1.12–3.20; TCPY OR = 1.65, 95% Cl = 1.02–2.69) for the operative (n = 471) and entire data set (n = 594), respectively. Our results suggest that exposure to elevated concentrations of diazinon (the parent compound of IMPY) and chlorpyrifos and chlorpyrifos-methyl (parent compounds of TCPY) may be associated with endometriosis. Keywords: Endometriosis, Organophosphate, Pyrethroid, Phenoxyacid, Pesticide, Urine

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 Variability of short-lived urinary pesticide metabolites during pregnancy raises challenges for exposure assessment. Objectives For urinary metabolite concentrations 3-phenoxybenzoic acid (3-PBA) and 3,5,6-trichloro-2-pyridinol (TCPy), we assessed: (1) temporal variability; (2) variation of two urine specimens within a trimester; (3) reliability for pesticide concentrations from a single urine specimen to classify participants into exposure tertiles; and (4) seasonal or year variations. Methods Pregnant mothers (N = 166) in the MARBLES (Markers of Autism Risk in Babies-Learning Early Signs) Study provided urine specimens (n = 528). First morning void (FMV), pooled, and 24-h specimens were analyzed for 3-PBA and TCPy. For 9 mothers (n = 88 specimens), each urine specimen was analyzed separately (not pooled) to estimate within- and between-person variance components expressed as intraclass correlation coefficients (ICC). Pesticide concentrations from two specimens within a trimester were also assessed using ICC's. Agreement for exposure classifications was assessed with weighted Cohen's kappa statistics. Longitudinal mixed effect models were used to assess seasonal or year variations. Results Urinary pesticide metabolites were detected in ≥ 93% of specimens analyzed. The highest ICC from repeated individual specimens was from specific gravity-corrected FMV specimens for 3-PBA (ICC=0.13). Despite high within-person variability, the median concentrations did not differ across trimesters. Concentrations from pooled specimens had substantial agreement predicting exposure categories for TCPy (K = 0.67, 95% CI (0.59, 0.76)) and moderate agreement for 3-PBA (K = 0.59, 95% CI (0.49, 0.69)). TCPy concentrations significantly decreased from 2007 to 2014. Conclusions Pooled specimens may improve exposure classification and reduce laboratory costs for compounds with short biological half-lives in epidemiological studies.

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 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.

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.

Objective To examine the association between urinary metabolites of organophosphate (OP) pesticides and serum concentrations of thyroid and reproductive hormones in male adolescents and to assess the potential effect of interactions between OP pesticides and paraoxonase 1 (PON1) polymorphisms on hormone levels. Methods Study subjects (N = 117) were male 16- to 17-year-olds from the Environment and Childhood (INMA)-Granada cohort in Spain. Concentrations of 3,5,6-trichloro-2-pyridinol (TCPy), a metabolite of chlorpyrifos/chlorpyrifos-methyl, 2-isopropyl-6-methyl-4-pyrimidinol (IMPy), a metabolite of diazinon, and diethylthiophosphate (DETP) and diethyldithiophosphate (DEDTP), non-specific metabolites of OP pesticides, were measured in a spot urine sample from each subject and adjusted for creatinine. Levels of reproductive hormones (total testosterone [TT], estradiol [E2], dehydroepiandrosterone sulfate [DHEAS], sex hormone binding globulin [SHBG], luteinizing hormone [LH], follicle stimulating hormone [FSH], anti-Mullerian hormone [AMH], insulin growth factor 1 [IGF-1], and prolactin), thyroid hormones (free thyroxine [FT4], total triiodothyronine [TT3], and thyroid stimulating hormone [TSH]), and PON1 Q192R and L55M polymorphisms were determined in blood drawn during the same clinical visit. Results Multiple linear regression models showed that detectable levels of TCPy were associated with an increase in DHEAS and decreases in E2, FSH, and AMH; detectable IMPy with increases in E2, DHEAS, FSH, AMH, and prolactin and decreases in SHBG and LH; and detectable DETP with marginally-significant increases in TT and TT3 and decreases in FSH, AMH, and prolactin. The effect of IMPy and DETP on DHEAS and TT levels, respectively, was higher in subjects that carried the PON1 55MM genotype, while the effect of TCPy, IMPy, and DETP on thyroid hormone levels was higher in PON1 192QR/RR or 55MM genotype carriers. Conclusions In male adolescents, non-occupational exposure to OP pesticides was associated with several changes in reproductive and thyroid hormone levels, and the magnitude of some associations was greater in adolescents genetically more susceptible to OP pesticide exposure who carry the PON1 55MM genotype.

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.

Urinary metabolites of organophosphate (OP) and pyrethroid (PYR) pesticides from seven years old children of a birth cohort study (n=199; PHIME cohort of Trieste, Italy) have been measured. Six OP and two PYR metabolites have been investigated, 2-diethylamino-6-methylpyrimidin-4-ol (DEAMPY, pirimiphos metabolite) was the one found at higher concentrations, median 3.4 ng/mL specific gravity adjusted (SG adjusted), followed by 4-nitrophenol (PNP, median 1.4 ng/mL SG adjusted) and 3,5,6-trichloro-2-pyridinol (TCPY, median 0.36 ng/mL SG adjusted), parathion and chlorpyriphos metabolites, respectively. TCPY concentrations were low in comparison to other distributions of OP metabolites in children from other studies. Accordingly, the PHIME cohort showed a distinct OP metabolite distribution with high concentrations of pirimiphos and parathion. Another specific characteristic of this cohort was the high concentration of 3-phenoxybenzoic acid (3-BPA, median 0.36 ng/mL SG adjusted), a general metabolite of PYR pesticides. Evaluation of anthropometric and socio-demographic characteristics of children and families only showed a positive association between family educational level and urinary concentrations of DEAMPY metabolite (p, Authors are grateful to the women who participated in our study as well as the people who helped in the recruitment in the different countries. This work was supported by the EU through its Sixth Framework Programme for RTD project PHIME (contract no FOOD-CT-2006- 016253), by GRANT LIFE 2012 ENV/GR/001040 "Crome Life - Cross Mediterranean Environment and Health Network”, by European Union projects HEALS (FP7-ENV-2013- 603946) and Neurosome (H2020-MSCA-ITN-2017 SEP-210411486), by RC 12/12 of Institute for Maternal and Child Health -IRCCS “Burlo Garofolo” – Trieste – Italy funded by the Italian Ministry of Health.

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 Organophosphorus pesticide (OP)-induced neurotoxicity remains a significant occupational health concern, management of which is complicated by the lack of biomarkers that reliably identify at-risk individuals. To address this issue, we used a preclinical model of occupational OP exposure to evaluate the relationship between OP-induced cognitive deficits and expression of conventional and novel biomarkers of exposure and effect. Methods Adult male Long Evans rats were exposed to CPF (3 or 10 mg/kg/d, s.c.) or an equal volume of vehicle for up to 21 days. Previous PBPK modelling studies confirmed that this exposure paradigm resulted in urinary TCPy levels and blood cholinesterase activity within the range of those observed in exposed Egyptian pesticide applicators. Learning and memory were assessed using appetitive Pavlovian discrimination between two tones and by Pavlovian fear conditioning. Tissues were collected for quantification of peripheral and central biomarkers of CPF exposure, inflammation and oxidative stress. Results Subchronic CPF exposure for 21 d interfered with the maintenance and reversal of appetitive behaviour, but these effects were not reliable. In contrast, CPF caused robust and reproducible dose-dependent deficits in Pavlovian fear conditioning at 21 but not 4, 10 or 15 days of exposure. CPF also increased urinary TCPy levels, caused a delayed decrease in blood and brain cholinesterase activity, increased urinary and brain F2-isoprostanes and upregulated expression of multiple oxidative stress biomarkers in brain and in the periphery. Of these biomarkers, only oxidative stress biomarkers correlated with cognitive deficits. Moreover, CPF-induced cognitive deficits were prevented by co-administration of the antioxidant Trolox (1 mg/kg, i.p.). Conclusion These findings demonstrate that subchronic exposures to CPF at levels that do not cause systemic cholinergic toxicity impair learning and memory via effects on the amygdala and hippocampus. Biomarker analyses suggest that oxidative stress, but not cholinesterase inhibition, contribute to CPF-induced cognitive deficits. Funding: R01 ES016308

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.