Use of biomarkers to indicate exposure of children to organophosphate pesticides: implications for a longitudinal study of children's environmental health

Identifying critical windows of prenatal phenol, paraben, and pesticide exposure and child neurodevelopment: Findings from a prospective cohort study

BACKGROUND

This study aimed to investigate how exposure to a mixture of endocrine disrupting chemicals (EDCs) during two points in pregnancy affects early childhood neurodevelopment.

METHODS

We analyzed publicly-available data from a high-risk cohort of mothers and their children (2007-2014) that measured six EDCs including methyl-, ethyl- and propyl parabens (MEPB, ETPB, PRPB), Bisphenol-A (BPA), 3,5,6-trichloro-2-pyridinol (TCPy), 3-phenoxybenzoic acid (3-PBA) in prenatal urine samples during the second and third trimesters. Neurodevelopmental scores were assessed using Mullen Scales of Early Learning (MSEL) at age 3. We used mean field variational Bayes for lagged kernel machine regression (MFVB-LKMR) to investigate the association between trimester-specific co-exposure to the six EDCs and MSEL scores at age 3, stratified by sex.

RESULTS

The analysis included 130 children. For females, the relationship between BPA and 3PBA with MSEL score varied between the two trimesters. In the second trimester, effect estimates for BPA were null but inversely correlated with MSEL score in the third trimester. 3PBA had a negative relationship with MSEL in the second trimester and positive correlation in the third trimester. For males, effect estimates for all EDCs were in opposing directions across trimesters. MFVB-LKMR analysis identified significant two-way interaction between EDCs for MSEL scores in both trimesters. For example, in females, the MSEL scores associated with increased exposure to TCPy were 1.75 units (95%credible interval -0.04, -3.47) lower in the 2nd trimester and 4.61 (95%CI -3.39, -5.84) lower in the third trimester when PRPB was fixed at the 75th percentile compared to when PRPB was fixed at the 25th percentile.

CONCLUSION

Our study provides evidence that timing of EDC exposure within the prenatal period may impact neurodevelopmental outcomes in children. More of these varying effects were identified among females. Future research is needed to explore EDC mixtures and the timing of exposure during pregnancy to enhance our understanding of how these chemicals impact child health.

A state-of-the-science review of analytical methods for urinary dialkylphosphate metabolites in the assessment of exposure to organophosphate pesticides: From 2000 to 2022

The general population and workers are exposed to organophosphate insecticides, one of the leading chemical classes of pesticides used in rural and urban areas. This paper aims to conduct an integrative review of the most used analytical methods for identifying and quantifying dialkylphosphate-which are metabolites of organophosphate insecticides-in the urine of exposed workers, discussing their advantages, limitations and applicability. Searches utilized the PubMed, the Scientific Electronic Library Online and the Brazilian Digital Library of Theses and Dissertations databases between 2000 and 2021. Twenty-five studies were selected. The extraction methods most used were liquid-liquid extraction (LLE) (36%) and solid-phase extraction (SPE) (36%), with the SPE being more economical in terms of time and amount of solvents needed, and presenting the best percentage of recovery of analytes, when compared with LLE. Nineteen studies (76%) used the gas chromatography method of separation, and among these, 12 records (63%) indicated mass spectrometry used as a detection technology (analyzer). Studies demonstrate that dialkylphosphates are sensitive and representative exposure biomarkers for environmental and occupational organophosphate exposure.

Unraveling the contemporary use of microbial fuel cell in pesticide degradation and simultaneous electricity generation: a review

Pesticide is an inevitable substance used worldwide to kill pests, but their indiscriminate use has posed serious complications to health and the environment. Various physical, chemical, and biological methods are employed for pesticide treatment, but this paper deals with microbial fuel cell (MFC) as a futuristic technology for pesticide degradation with electricity production. In MFC, organic compounds are utilized as the carbon source for electricity production and the generation of electrons which can be replaced with pollutants such as dyes, antibiotics, and pesticides as carbon sources. However, MFC is been widely studied for a decade for electricity production, but its implementation in pesticide degradation is less known. We fill this void by depicting a real picture of the global pesticide scenario with an eagle eye view of the bioremediation techniques implemented for pesticide treatment with phytoremediation and rhizoremediation as effective techniques for efficient pesticide removal. The enormous literature survey has revealed that not many researchers have ventured into this new arena of MFC employed for pesticide degradation. Based on the Scopus database, an increase in annual trend from 2014 to 2023 is observed for MFC-implemented pesticide remediation. However, a novel MFC to date for effective remediation of pesticides with simultaneous electricity generation is discussed for the first time. Furthermore, the limitation of MFC technology and the implementation of MFC and rhizoremediation as a clubbed system which is the least applied can be seen as promising and futuristic approaches to enhance pesticide degradation by bacteria and electricity as a by-product.

Urinary dialkylphosphate metabolites in the assessment of exposure to organophosphate pesticides: from 2000 to 2022

The general population and workers are exposed to organophosphate insecticides, one of the leading chemical classes of pesticides used in rural and urban areas, in the control of arboviruses and agriculture. These pesticides cause environmental/occupational exposure and associated risks to human and environmental health. The objective of this study was to carry out an integrative review of epidemiological studies that identified and quantified dialkylphosphate metabolites in the urine of exposed populations, focusing on the vector control workers, discussing the application and the results found. Searches utilized the Pubmed, Scielo, and the Brazilian Digital Library of Theses and Dissertations (BDTD) databases between 2000 and 2021. From the 194 selected studies, 75 (39%) were with children/adolescents, 48 (24%) with rural workers, 36 (19%) with the general population, 27 (14%) with pregnant women, and 9 (4%) with vector control workers. The total dialkylphosphate concentrations found in the occupationally exposed population were higher than in the general population. Studies demonstrate that dialkylphosphates are sensitive and representative exposure biomarkers for environmental and occupational organophosphate exposure. The work revealed a lack of studies with vector control workers and a lack of studies in developing countries.

Childhood exposure to pyrethroids and neurodevelopment in Canadian preschoolers

BACKGROUND

Pyrethroid insecticides are used both residentially and agriculturally and their toxicity targets the nervous system of insects. They might also interfere with development and function of the human brain. A few epidemiological studies suggest that exposure to pyrethroids may be associated with neurobehavioral problems in children but there is little data on potential associations with cognitive outcomes. Furthermore, many studies showed that the neurotoxic effects of several pesticides are modified by sex, hence, considerations of potential sex-differences are important to investigate.

OBJECTIVE

To study the cross-sectional association between urinary levels of pyrethroid metabolites and neurodevelopment, including neurobehavioral and cognitive outcomes, in preschool-age children, and to examine whether sex might modify these associations.

METHODS

We used data from a follow-up examination of the Maternal-Infant Research on Environmental Chemicals (MIREC), the MIREC Child Development study (MIREC-CD Plus) on children at age 3-4 years living in 6 Canadian cities. For each participant, we collected a urine sample for measurements of pyrethroids metabolites (cis-DBCA, cis-DCCA, trans-DCCA, 3-PBA, 4-F-3-PBA). We assessed neurodevelopment with the Wechsler Primary and Preschool Scale of Intelligence-III (WPPSI-III) and two scales of the Behavior Rating Inventory of Executive Function-Preschool (BRIEF-P). Parents reported children's behavior using the Behavior Assessment System for Children-2 (BASC-2) and the Social Responsiveness Scale-2 (SRS-2). We examined associations between children's urinary pyrethroid metabolite concentrations and neurodevelopmental scores with multiple linear regression models, adjusting for confounders, in boys and girls separately.

RESULTS

The study included 179 children (mean age: 3.2 y, range 2.8-4.0). The detection frequencies were high for most pyrethroid metabolites (83-100%), but lower for 4-F-3-PBA (36%). Higher concentrations of cis-DBCA were significantly associated with lower verbal, performance and full-scale IQ scores in boys (e.g., for a 2-fold increase in cis-DBCA, β = -2.0; 95% CI: -3.4, -0.6 for full-scale IQ). In girls, the only metabolite associated with cognitive scores was 3-PBA, which was associated with lower verbal IQ scores (β = -1.3, 95% CI: -2.6, -0.1). For neurobehavioral outcomes in boys, there were associations between poorer BASC-2 Adaptive Skills scores with higher concentrations of cis-DCCA (β = -1.6, 95% CI: -2.3, -0.9), trans-DCCA (β = -1.5, 95% CI: -2.2, -0.8), 3-PBA (β = -1.7, 95% CI: -2.5, -0.9), and sum of pyrethroid metabolites (β = -1.8, 95% CI: -2.6, -0.9). In girls, we observed a significant association between higher concentration of cis-DCCA and better BASC-2 Adaptive Skills score (β = 1.0; 95% CI, 0.2, 1.8), but not with other urinary pyrethroids metabolites. Scores on the SRS-2 and BRIEF-P were not associated with pyrethroid metabolites.

CONCLUSION

There were associations between some pyrethroid pesticide metabolites and indicators of neurodevelopmental disorder, especially among boys. These associations are in agreement with previous studies and could suggest that exposure to pyrethroid pesticides represents a risk of potential toxicity for the cognitive development of children, and a risk for behavioral development. However, the cross-sectional nature of this study limits causal inferences.

Neuroanatomical differences in Latinx children from rural farmworker families and urban non-farmworker families and related associations with pesticide exposure

Exposure to pesticides in humans may lead to changes in brain structure and function and increase the likelihood of experiencing neurodevelopmental disorders. Despite the potential risks, there is limited neuroimaging research on the effects of pesticide exposure on children, particularly during the critical period of brain development. Here we used voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) from magnetic resonance images (MRI) to investigate neuroanatomical differences between Latinx children (n = 71) from rural, farmworker families (FW; n = 48) and urban, non-farmworker families (NFW; n = 23). Data presented here serves as a baseline for our ongoing study examining the longitudinal effects of living in a rural environment on neurodevelopment and cognition in children. The VBM analysis revealed that NFW children had higher volume in several distinct regions of white matter compared to FW children. Tract-based spatial statistics (TBSS) of DTI data also indicated NFW children had higher fractional anisotropy (FA) in several key white matter tracts. Although the difference was not as pronounced as white matter, the VBM analysis also found higher gray matter volume in selected regions of the frontal lobe in NFW children. Notably, white matter and gray matter findings demonstrated a high degree of overlap in the medial frontal lobe, a brain region predominantly linked to decision-making, error processing, and attention functions. To gain further insights into the underlying causes of the observed differences in brain structure between the two groups, we examined the association of organochlorine (OC) and organophosphate (OP) exposure collected from passive dosimeter wristbands with brain structure. Based on our previous findings within this data set, demonstrating higher OC exposure in children from non-farmworker families, we hypothesized OC might play a critical role in structural differences between NFW and FW children. We discovered a significant positive correlation between the number of types of OC exposure and the structure of white matter. The regions with significant association with OC exposure were in agreement with the findings from the FW-NFW groups comparison analysis. In contrast, OPs did not have a statistically significant association with brain structure. This study is among the first multimodal neuroimaging studies examining the brain structure of children exposed to agricultural pesticides, specifically OC. These findings suggest OC pesticide exposure may disrupt normal brain development in children, highlighting the need for further neuroimaging studies within this vulnerable population.

Silica quantum dots; an optical nanosensing approach for trace detection of pesticides in environmental and biological samples

Both the environment and human health have suffered as a result of excessive and irrational pesticide use. The human body is vulnerable to a wide range of illnesses brought on by prolonged exposure to or intake of food contaminated with pesticide residues, including immunological and hormonal abnormalities and the development of certain tumors. Sensors based on nanoparticles stand out from more conventional spectrophotometry analytical methods due to their low detection limits, high sensitivity, and ease of use; that is why the demand for simple, fast, and less expensive sensing methods increases daily and presents myriad uses. Such demands are fulfilled by employing paper-based analytical devices having intrinsic properties. The presented work reports an on-site, easy-to-handle, and disposable paper-based sensing device for performing fast screening along with readout from a smartphone. The fabricated device utilizes luminescent silica quantum dots, immobilized into a paper cellulose matrix, and the resonance energy transfer phenomenon is employed. The silica quantum dots probes were fabricated from citric acid and, by undergoing physical adsorption, were confined on the nitrocellulose substrate in small wax-traced spots. The silica quantum dots were excited by smartphone ultraviolet LED, acting as an energy source and for capturing the image. The obtained LOD is 0.054 μM, and the coefficient of variation is less than 6.1%, comparable to the result obtained by UV-Visible and fluorometric analysis under similar experimental conditions. In addition, high reproducibility (≥9.8%) and high recovery ≥90% were obtained in spiked blood samples. The fabricated sensor sensitively detected pesticides giving a LOD of 2.5 ppm along with the development of yellow color within a short period of 5 min. The sensor functions well when sophisticated instrumentation is not accessible. The presented work shows the potential of the paper strip for the on-site detection of pesticides in biological and environmental samples.

Fetal Organophosphate Pesticide Exposure and Child Adiposity Measures at 10 Years of Age in the General Dutch Population

BACKGROUND

Fetal exposure to organophosphate (OP) pesticides might lead to fetal metabolic adaptations, predisposing individuals to adverse metabolic profiles in later life.

OBJECTIVE

We examined the association of maternal urinary OP pesticide metabolite concentrations in pregnancy with offspring body mass index (BMI) and fat measures at 10 years of age.

METHODS

Between 2002 and 2006, we included 642 mother-child pairs from the Generation R Study, a population-based prospective cohort study in Rotterdam, the Netherlands. We measured maternal urinary concentrations of OP pesticide metabolites, namely, dialkyl phosphates, including three dimethyl and three diethyl phosphates in early-, mid- and late-pregnancy. At 10 years of age, child total and regional body fat and lean mass were measured through dual energy X-ray absorptiometry, and abdominal and organ fat through magnetic resonance imaging.

RESULTS

Higher maternal urinary pregnancy-average or trimester-specific dialkyl, dimethyl, or diethyl phosphate concentrations were not associated with childhood BMI and the risk of overweight. In addition, we did not observe any association of dialkyl, dimethyl, or diethyl phosphate concentrations with total and regional body fat, abdominal visceral fat, liver fat, or pericardial fat at child age of 10 y.

CONCLUSION

We observed no associations of maternal urinary dialkyl concentrations during pregnancy with childhood adiposity measures at 10 years of age. Whether these associations develop at older ages should be further studied. https://doi.org/10.1289/EHP12267.

Prediction of in vivo prenatal chlorpyrifos exposure leading to developmental neurotoxicity in humans based on in vitro toxicity data by quantitative in vitro-in vivo extrapolation

Introduction: Epidemiological studies in children suggested that in utero exposure to chlorpyrifos (CPF), an organophosphate insecticide, may cause developmental neurotoxicity (DNT). We applied quantitative in vitro-in vivo extrapolation (QIVIVE) based on in vitro concentration and non-choline esterase-dependent effects data combined with Benchmark dose (BMD) modelling to predict oral maternal CPF exposure during pregnancy leading to fetal brain effect concentration. By comparing the results with data from epidemiological studies, we evaluated the contribution of the in vitro endpoints to the mode of action (MoA) for CPF-induced DNT. Methods: A maternal-fetal PBK model built in PK-Sim^® was used to perform QIVIVE predicting CPF concentrations in a pregnant women population at 15 weeks of gestation from cell lysate concentrations obtained in human induced pluripotent stem cell-derived neural stem cells undergoing differentiation towards neurons and glia exposed to CPF for 14 days. The in vitro concentration and effect data were used to perform BMD modelling. Results: The upper BMD was converted into maternal doses which ranged from 3.21 to 271 mg/kg bw/day. Maternal CPF blood levels from epidemiological studies reporting DNT findings in their children were used to estimate oral CPF exposure during pregnancy using the PBK model. It ranged from 0.11 to 140 μg/kg bw/day. Discussion: The effective daily intake doses predicted from the in vitro model were several orders of magnitude higher than exposures estimated from epidemiological studies to induce developmental non-cholinergic neurotoxic responses, which were captured by the analyzed in vitro test battery. These were also higher than the in vivo LOEC for cholinergic effects. Therefore, the quantitative predictive value of the investigated non-choline esterase-dependent effects, although possibly relevant for other chemicals, may not adequately represent potential key events in the MoA for CPF-associated DNT.

Organophosphorus Pesticide Exposure at 17 Weeks' Gestation and Odds of Offspring Attention-Deficit/Hyperactivity Disorder Diagnosis in the Norwegian Mother, Father, and Child Cohort Study

Prenatal organophosphorus pesticides (OPs) are ubiquitous and have been linked to adverse neurodevelopmental outcomes. However, few studies have examined prenatal OPs in relation to diagnosed attention-deficit/hyperactivity disorder (ADHD), with only two studies exploring this relationship in a population primarily exposed through diet. In this study, we used a nested case-control study to evaluate prenatal OP exposure and ADHD diagnosis in the Norwegian Mother, Father, and Child Cohort Study (MoBa). For births that occurred between 2003 and 2008, ADHD diagnoses were obtained from linkage of MoBa participants with the Norwegian Patient Registry (N = 297), and a reference population was randomly selected from the eligible population (N = 552). Maternal urine samples were collected at 17 weeks' gestation and molar sums of diethyl phosphates (ΣDEP) and dimethyl phosphates metabolites (ΣDMP) were calculated. Multivariable adjusted logistic regression models were used to estimate the association between prenatal OP metabolite exposure and child ADHD diagnosis. Additionally, multiplicative effect measure modification (EMM) by child sex was assessed. In most cases, mothers in the second and third tertiles of ΣDMP and ΣDEP exposure had slightly lower odds of having a child with ADHD, although confidence intervals were wide and included the null. EMM by child sex was not observed for either ΣDMP or ΣDEP. In summary, we did not find evidence that OPs at 17 weeks' gestation increased the odds of ADHD in this nested case-control study of ADHD in MoBa, a population primarily experiencing dietary exposure.

Organophosphorus insecticides exposure and sex hormones in general U.S. population: A cross-sectional study

BACKGROUND

Evidence showed organophosphorus (OPs) insecticide exposure is common in general population with endocrine-disrupting effects. However, the association between OPs metabolites and sex hormones remains unclear.

OBJECTIVE

To investigate the association between OPs metabolites and sex hormones.

METHODS

Data of 1438 participants from NHANES 2015-2016 was applied. Urinary OPs metabolites, dialkyl phosphates (DAPs), and serum sex hormones (total testosterone (TT), estradiol (E₂), and sex hormone-binding globulin (SHBG)) were measured. Free androgen index (FAI) and TT/E₂ ratio were also calculated. The generalized linear regression model and restricted cubic spline (RCS) model were employed to evaluate the association and exposure-response curve of DAPs and sex hormones in males and females. The modulation effect of age on their associations in female participants was also explored.

RESULTS

After adjusting for confounding factors, DETP was negatively associated with E₂ (β = -0.03; 95% CI: -0.05, -0.01) and FAI (β = -0.03; 95% CI: -0.06, -0.001) in males. In females, all the four DAP metabolites (DMP, DEP, DMTP, and DETP) were negatively associated with FAI (DMP: β = -0.06, 95% CI: -0.11, -0.01; DEP: β = -0.06, 95% CI: -0.12, -0.01; DMTP: -0.05, 95% CI: -0.09, -0.02; DETP: -0.09, 95% CI: -0.14, -0.04). DETP was also found negatively associated with TT and TT/E₂ ratio in females. The associations between DETP and TT, FAI, and TT/E₂ ratio were modified by gender (P_interaction<0.05). RCS analysis found these associations were in linear decreased exposure-response curves. For females of different age groups, the inverse associations of DETP with TT and FAI remained stable. Decreased FAI with DMP and DMTP was also found in females ≤50 years old.

CONCLUSIONS

Our study indicates OPs metabolites had negative associations with androgen indicators, which was characterized as decreased FAI and E₂ in males and decreased TT, FAI, and TT/E₂ ratio in females, particularly among females ≤50 years old. Further studies are warranted in larger-scale populations.

Organophosphate Insecticide Toxicity in Neural Development, Cognition, Behaviour and Degeneration: Insights from Zebrafish

Organophosphate (OP) insecticides are used to eliminate agricultural threats posed by insects, through inhibition of the neurotransmitter acetylcholinesterase (AChE). These potent neurotoxins are extremely efficacious in insect elimination, and as such, are the preferred agricultural insecticides worldwide. Despite their efficacy, however, estimates indicate that only 0.1% of organophosphates reach their desired target. Moreover, multiple studies have shown that OP exposure in both humans and animals can lead to aberrations in embryonic development, defects in childhood neurocognition, and substantial contribution to neurodegenerative diseases such as Alzheimer's and Motor Neurone Disease. Here, we review the current state of knowledge pertaining to organophosphate exposure on both embryonic development and/or subsequent neurological consequences on behaviour, paying particular attention to data gleaned using an excellent animal model, the zebrafish (Danio rerio).

Oxidative stress of glyphosate, AMPA and metabolites of pyrethroids and chlorpyrifos pesticides among primary school children in Cyprus

BACKGROUND

Exposure to various pesticides, such as pyrethroids and chlorpyrifos, has been previously associated with adverse effects on children's health. Scientific evidence on the human toxicity of glyphosate (GLY) and its primary metabolite, aminomethylphosphonic acid (AMPA) is limited, particularly for children. This study aimed to i) assess the exposure determinants of the studied pesticides measured in children in Cyprus, and ii) determine the association between the urinary pesticides and the biomarkers of DNA and lipid oxidative damage.

METHODS

A children's health study was set up in Cyprus (ORGANIKO study) by aligning it with the methodology and tools used in the European Human Biomonitoring Initiative (HBM4EU). Urinary GLY and AMPA, pyrethroid metabolites and the chlorpyrifos metabolite TCPy were measured in 177 children aged 10-11 years old, using mass spectrometry. Oxidative stress was assessed with 8-iso-prostaglandin F2a (8-iso-PGF2α) as a marker of lipid damage and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a DNA oxidative damage marker, both measured with immunoassays. Questionnaires about demographic characteristics, pesticide usage, and dietary habits were filled out by the parents. Μultivariable regression models examined associations between pesticides and biomarkers of effect using two creatinine adjustments (cr1: adding it as covariate and cr2: biomarkers of exposure and effect were creatinine-adjusted).

RESULTS

Parental educational level was a significant predictor of urinary pyrethroids but not for GLY/AMPA. Median [interquartile range, IQR] values for GLY and AMPA were  0.05). Similar significant associations with 8-OHdG were shown for a pyrethroid metabolite (3-PBA) and the chlorpyrifos metabolite (TCPy). No associations were observed between the aforementioned pesticides and 8-iso-PGF2α (p > 0.05).

CONCLUSIONS

This is the first children's health dataset demonstrating the association between AMPA and DNA oxidative damage, globally. More data is needed to replicate the observed trends in other children's populations around the globe.

Association between exposure to organophosphorus pesticides and the risk of diabetes among US Adults: Cross-sectional findings from the National Health and Nutrition Examination Survey

OBJECTIVE

Organophosphorus pesticides (OPPs) are commonly used pesticides across the world, however there is little epidemiological evidence linking their exposure to diabetes. Hence, this study aimed at investigating the effect of OPP exposure on the prevalence of diabetes in American adults.

METHODS

Adults (≥20 years old) were eligible for this study from the National Health and Nutrition Examination Survey (NHANES). Multivariate logistic regression model was employed to explore the associations of six main urinary OPPs metabolites with diabetes. Subgroup analyses were performed by age and gender. Combined effect of OPPs metabolites on the overall association with diabetes was evaluated by weighted quantile sum regression (WQS). Furthermore, Bayesian kernel machine regression (BKMR) model was implemented to explore joint effect of multiple OPPs metabolites on diabetes.

RESULTS

Ultimately, 6,593 adults were included in our analysis. Of them, 1,044 participants were determined as diabetes patients. The results of logistic regression shown that urinary OPPs metabolites concentrations, whether taken as continuous variables or quantiles, were in positive correlation with diabetes. Notably, the p for trend of diethylphosphate (DEP), a kind of OPPs metabolites, was less than 0.05 indicated that a linear trend may exist between levels of DEP and prevalence of diabetes among adults while this trend was not obversed in other OPPs metabolites. In the WQS model, combined exposure of OPPs metabolites had a significantly positive association with diabetes (OR: 1.057; 95% CI: 1.002, 1.114) and diethylphosphate (36.84%) made the largest contributor to the WQS index. The result of BKMR also suggested a positive trend of association between mixed OPPs metabolites and diabetes.

CONCLUSION

Our results add credibility to the argument that OPP exposure might trigger diabetes. Certainly, prospective data are required to corroborate our findings.

An Overview of Diabetes Mellitus in Egypt and the Significance of Integrating Preventive Cardiology in Diabetes Management

In Egypt, diabetes mellitus (DM) is a significant public health concern, and the disease is considered a modern pandemic throughout the world. The incidence of diabetes is steadily climbing, which is causing grave concern. As a result, it is essential to take into consideration the risk factors that are pervasive in Egyptian society and have led to the worsening of this problem. These risk factors include sedentary lifestyles, obesity, hepatitis C infections, pesticides, smoking, and bad cultural habits. In this review, we aim to demonstrate the possible solutions to fight diabetes mellitus and overcome its serious health and socioeconomic burdens in Egypt. A multidisciplinary, team-based approach is highly recommended in diabetes management. Primary care physicians, endocrinologists, nephrologists, and preventive cardiologists all play a crucial role in providing the highest possible level of care to diabetic patients by collaborating closely with one another. The assessment of cardiovascular risk and the prevention of life-threatening cardiovascular events, common among diabetic patients, warrant the introduction of preventive cardiology, a new and significant concept in diabetes care that demands adoption. The integration of preventive cardiology into the treatment of diabetic patients is expected to significantly cut down the morbidity and mortality rates associated with diabetes mellitus and provide them with a better quality of life.

The growing concern of chlorpyrifos exposures on human and environmental health

Chlorpyrifos (CP) and its highly electrophilic intermediates are principal toxic metabolites. The active form of CP i.e. chlorpyrifos oxon (CP-oxon) is responsible for both the insecticidal activity and is also of greater risk when present in the atmosphere. Thus, the combined effects of both CP, CP-oxan, and other metabolites enhance our understanding of the safety and risk of the insecticide CP. They cause major toxicities such as AChE inhibition, oxidative stress, and endocrine disruption. Further, it can have adverse hematological, musculoskeletal, renal, ocular, and dermal effects. Excessive use of this compound results in poisoning and potentially kills a non-target species upon exposure including humans. Several examples of reactive metabolites toxicities on plants, aquatic life, and soil are presented herein. The review covers the general overview on reactive metabolites of CP, chemistry and their mechanism through toxic effects on humans as well as on the environment. Considerable progress has been made in the replacement or alternative to CP. The different strategies including antidote mechanisms for the prevention and treatment of CP poisoning are discussed in this review. The approach analyses also the active metabolites for the pesticide activity and thus it becomes more important to know the pesticide and toxicity dose of CP as much as possible.

Concurrent urinary organophosphate metabolites and acetylcholinesterase activity in Ecuadorian adolescents

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.

Pesticide exposure in New Zealand school-aged children: Urinary concentrations of biomarkers and assessment of determinants

This study aimed to assess pesticide exposure and its determinants in children aged 5-14 years. Urine samples (n = 953) were collected from 501 participating children living in urban areas (participant n = 300), rural areas but not on a farm (n = 76), and living on a farm (n = 125). The majority provided two samples, one in the high and one in the low spraying season. Information on diet, lifestyle, and demographic factors was collected by questionnaire. Urine was analysed for 20 pesticide biomarkers by GC-MS/MS and LC-MS/MS. Nine analytes were detected in > 80% of samples, including six organophosphate insecticide metabolites (DMP, DMTP, DEP, DETP, TCPy, PNP), two pyrethroid insecticide metabolites (3-PBA, trans-DCCA), and one herbicide (2,4-D). The highest concentration was measured for TCPy (median 13 μg/g creatinine), a metabolite of chlorpyrifos and triclopyr, followed by DMP (11 μg/g) and DMTP (3.7 μg/g). Urine metabolite levels were generally similar or low compared to those reported for other countries, while relatively high for TCPy and pyrethroid metabolites. Living on a farm was associated with higher TCPy levels during the high spray season. Living in rural areas, dog ownership and in-home pest control were associated with higher levels of pyrethroid metabolites. Urinary concentrations of several pesticide metabolites were higher during the low spraying season, possibly due to consumption of imported fruits and vegetables. Organic fruit consumption was not associated with lower urine concentrations, but consumption of organic food other than fruit or vegetables was associated with lower concentrations of TCPy in the high spray season. In conclusion, compared to other countries such as the U.S., New Zealand children had relatively high exposures to chlorpyrifos/triclopyr and pyrethroids. Factors associated with exposure included age, season, area of residence, diet, in-home pest control, and pets.

Electrochemical detection of methyl-paraoxon based on bifunctional cerium oxide nanozyme with catalytic activity and signal amplification effect

A new electrochemical sensor for organophosphate pesticide (methyl-paraoxon) detection based on bifunctional cerium oxide (CeO₂) nanozyme is here reported for the first time. Methyl-paraoxon was degraded into p-nitrophenol by using CeO₂ with phosphatase mimicking activity. The CeO₂ nanozyme-modified electrode was then synthesized to detect p-nitrophenol. Cyclic voltammetry was applied to investigate the electrochemical behavior of the modified electrode, which indicates that the signal enhancement effect may attribute to the coating of CeO₂ nanozyme. The current research also studied and discussed the main parameters affecting the analytical signal, including accumulation potential, accumulation time, and pH. Under the optimum conditions, the present method provided a wider linear range from 0.1 to 100 μmol/L for methyl-paraoxon with a detection limit of 0.06 μmol/L. To validate the proof of concept, the electrochemical sensor was then successfully applied for the determination of methyl-paraoxon in three herb samples, i.e., Coix lacryma-jobi, Adenophora stricta and Semen nelumbinis. Our findings may provide new insights into the application of bifunctional nanozyme in electrochemical detection of organophosphorus pesticide.

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A new electrochemical method for methyl-paraoxon detection by using bifunctional nanozyme was presented.

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The cerium oxide nanozyme modified glassy carbon electrode was prepared to improve the sensitivity.

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The developed method has been successfully applied in three herbal plant samples.

Wastewater-based epidemiology as a novel tool to evaluate human exposure to pesticides: Triazines and organophosphates as case studies

Production and application of pesticides have risen remarkably in the last few decades. Even if they provide many benefits, they can be hazardous for humans and ecosystems when they are not used cautiously. Human exposure to pesticides is well documented, but new approaches are needed to boost the available information. This work proposes a new application of wastewater-based epidemiology (WBE) to assess the exposure of the general population to organophosphate and triazine pesticides (pyrethroid pesticides have already been validated). Several human urinary metabolites tested as WBE biomarkers, were suitable. Untreated wastewater samples from different European countries were analyzed by liquid chromatography-tandem mass spectrometry. Biomarker concentrations were converted to mass loads and used to back-calculate the local population's exposure to the parent pesticides, using specific correction factors developed in this study. Exposure to organophosphates and pyrethroids showed spatial and seasonal variations. Finally, pesticide exposure was estimated in twenty cities of ten European countries and compared with the acceptable daily intake, concluding that some populations might face health risks. The study confirms WBE as a suitable approach for assessing the average community exposure to pesticides and is a valuable complementary biomonitoring tool. WBE can provide valuable data for public health.

Using primary teeth and archived dried spots for exposomic studies in children: Exploring new paths in the environmental epidemiology of pediatric cancer

It is estimated that 300,000 children 0-14 years of age are diagnosed with cancer worldwide each year. While the absolute risk of cancer in children is low, it is the leading cause of death due to disease in children in high-income countries. In spite of this, the etiologies of pediatric cancer are largely unknown. Environmental exposures have long been thought to play an etiologic role. However, to date, there are few well-established environmental risk factors for pediatric malignancies, likely due to technical barriers in collecting biological samples prospectively in pediatric populations for direct measurements. In this review, we propose the use of novel or underutilized biospecimens (dried blood spots and teeth) and molecular approaches for exposure assessment (epigenetics, metabolomics, and somatic mutational profiles). Future epidemiologic studies of pediatric cancer should incorporate novel exposure assessment methodologies, data on molecular features of tumors, and a more complete assessment of gene-environment interactions.

Organophosphate Pesticide Exposures in Early and Late Pregnancy Influence Different Aspects of Infant Developmental Performance

Organophosphate (OP) pesticides can transfer from mother to fetus via the placenta and amniotic fluid and may affect the development of infants. This study aims to evaluate the associations between maternal OP concentrations collected in the 1st-2nd trimester and the 3rd trimester of pregnancy and the infant developmental performance. The Screening Test of the Bayley Scales of Infants and Toddler Development, Third Edition (BSID-III screening test) was used to assess development performance at 2 and 6 months of age. Multiple regression analysis showed a negative correlation between cognitive performance at 2 months and maternal diethylthiophosphate (DETP) levels in the 1st-2nd trimester (β ± SE = -0.012 ± 0.004, p < 0.05). We also found that expressive communication and fine motor performance at 6 months were negatively associated with maternal diethyldithiophosphate (DEDTP) levels in the 3rd trimester (β ± SE = -0.047 ± 0.016, p < 0.05, and β ± SE = -0.044 ± 0.017, p < 0.05, respectively). These results suggest that maternal ethylated OP concentrations at different timing of exposure during pregnancy may influence different aspects of infant developmental performance.

Non-linear model analysis of the relationship between cholinesterase activity in rats exposed to 2, 2-dichlorovinyl dimethylphosphate (dichlorvos) and its metabolite concentrations in urine

Urinary dialkylphosphates (DAPs) are measured to assess exposure to organophosphorus pesticides (OPs), but they are common metabolites of OPs and not specific indices for individual agents. Biomonitoring (BM) of urinary DAPs has been widely adopted as an assessment of individual exposure in general environments, however, guidance values for DAPs based on health effects have yet to be established. The present study aimed to clarify the relationship between the amount of urinary dimethylphosphate (DMP), a metabolite of dichlorvos (DDVP), and the inhibition of cholinesterase (ChE) activity in rats exposed to DDVP. The relationship was analyzed using a nonlinear model analysis, and the excretion level of urinary DMP equivalent to ChE 20 % inhibition (EL20) and the lower limit of the 95 % confidence interval of EL20 (ELL20) were estimated. EL20 and ELL20 (mg/24 h urine) of brain, erythrocyte, and plasma ChE activities after 10-day administration of DDVP were 0.21 and 0.15, 0.11 and 0.06, and 0.23 and 0.09, respectively. Extrapolating ELL20 of the brain ChE to humans, the range of 24 h urinary DMP concentration according to the 20 % inhibition of cholinesterase activity was estimated to be 20.5-30.8 mg/l. In conclusion, the amount of urinary DMP as ELL20 for DDVP exposure was identified and could probably be used as a novel index for the assessment of risk from OP exposure. Further studies are needed to clarify the ELL20 s derived from OPs other than DDVP, for informing efforts to establish guidance values of urinary OP metabolites that should prevent neurotoxicity.

A Method for Diagnosing Organophosphate Pesticide Exposure in Humans using Liquid Chromatography Coupled Tandem Mass Spectrometry

Organophosphate (OP) pesticides are commonly utilized worldwide for agricultural purposes and pose a health threat through air, ground, and water contamination. Here, we present a convenient method for diagnosing exposure to OP pesticides in humans. This immunoprecipitation method relies on extraction of butyrylcholinesterase (BChE), a biomarker of OP poisoning that adducts OP compounds, from human serum using agarose beads conjugated to anti-BChE antibodies. Extracted BChE was then digested with pepsin and analyzed for unadducted and OP-adducted peptides by high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). To characterize and validate this method, pooled human plasma was exposed to parathion and dichlorvos to form diethoxyphospho, aged ethoxyphospho and dimethoxyphospho adducts with BChE. Untreated plasma was also analyzed for unadducted peptides. Additionally, samples were analyzed using Ellman's assay to measure BChE functional activity. The percent inhibition of BChE was 53.5±5.76 and 95.2±0.37%, respectively, for plasma treated with parathion for 1 hour and 24 hours. The percent inhibition was 97.2±0.98 for plasma treated with dichlorvos for 1 hour. The percent inhibition was 97.9±0.41% when the plasma treated with parathion for 1 hour, parathion for 24 hour and dichlorvos for 1 hour were mixed. Individual adducts were quantified in a single chromatographic run. Untreated plasma contained 26.4±1.87 ng/mL of unadducted BChE and no adducted peptides. In contrast, the plasma sample treated with both pesticides contained no unadducted BChE, but did contain 9.46±1.10, 10.9±0.98 and 14.1±1.10 ng/mL of diethoxyphospho, aged-ethoxy, and dimethoxyphospho peptides, respectively. The ability to identify and measure BChE and BChE adducts to parathion and dichlorvos is expected to be useful for diagnosing human exposure to multiple OP pesticides.

Prenatal exposure to organophosphate pesticides and brain morphology and white matter microstructure in preadolescents

BACKGROUND

Prenatal exposure to organophosphate (OP) pesticides associate with impaired neurodevelopment in humans and animal models. However, much uncertainty exists about the brain structural alterations underlying these associations. The objective of this study was to determine whether maternal OP pesticide metabolite concentrations in urine repeatedly measured during gestation are associated with brain morphology and white matter microstructure in 518 preadolescents aged 9-12 years.

METHOD

Data came from 518 mother-child pairs participating in the Generation R Study, a population-based birth cohort from Rotterdam, the Netherlands. Maternal urine concentrations were determined for 6 dialkylphosphates (DAPs) including 3 dimethyl (DM) and 3 diethyl (DE) alkyl phosphate metabolites, collected at early, mid, and late pregnancy. At child's age 9-12 years, magnetic resonance imaging was performed to obtain T1-weighted images for brain volumes and surface-based cortical thickness and cortical surface area, and diffusion tensor imaging was used to measure white matter microstructure through fractional anisotropy (FA) and mean diffusivity (MD). Linear regression models were fit for the averaged prenatal exposure across pregnancy.

RESULTS

DM and DE metabolite concentrations were not associated with brain volumes, cortical thickness, and cortical surface area. However, a 10-fold increase in averaged DM metabolite concentrations across pregnancy was associated with lower FA (B = -1.00, 95%CI = -1.80, -0.20) and higher MD (B = 0.13, 95%CI = 0.04, 0.21). Similar associations were observed for DE concentrations.

CONCLUSIONS

This study provides the first evidence that OP pesticides may alter normal white matter microstructure in children, which could have consequences for normal neurodevelopment. No associations were observed with structural brain morphology, including brain volumes, cortical thickness, and cortical surface area.

Organophosphate pesticides exposure during fetal development and IQ scores in 3 and 4-year old Canadian children

BACKGROUND

Organophosphate pesticides are widely used in agriculture and for other purposes, leading to ubiquitous exposure in human populations. Some studies reported cognitive deficits in children exposed prenatally to organophosphate pesticides, but findings from recent studies were inconsistent. Furthermore, recent biomonitoring studies suggest exposure levels have decreased. Hence, the risks from current prenatal exposure to organophosphate pesticides for child neurodevelopment are uncertain. Furthermore, sex-differences also remain to be better documented in relation to potential neurodevelopmental effects.

OBJECTIVE

To examine the association between prenatal exposure to organophosphate pesticides and IQ scores among boys and girls living in several major Canadian cities.

METHODS

We used data from the MIREC cohort (Maternal-Infant Research on Environmental Chemicals). Women were recruited in 2008-2011 from 10 Canadian cities during their first trimester of pregnancy, and urine spot samples were collected for measurement of three dimethyl alkyl phosphate (DMAP) and three diethyl alkyl phosphate (DEAP) metabolites. When children were 3-4 years of age, we used the Wechsler Preschool and Primary Scales of Intelligence-III (WPPSI-III) to assess cognitive ability of children from 6 out of the 10 cities (Halifax, Hamilton, Kingston, Montreal, Toronto, and Vancouver). We analysed the association between maternal exposure to organophosphate pesticides (DMAP and DEAP urinary metabolites) and children's IQ scores with generalized estimating equations (GEEs) to take into account the clustered-data resulting from the six study sites. All analyses were sex-stratified (n = 296 boys and 311 girls).

RESULTS

The participants were predominantly well-educated, white women, with a relatively high household income. Children had a mean age of 3.4 years at the moment of IQ assessment (range, 3.0-4.1 years). In girls, there was no association between IQ scores and DEAPs or DMAPs. Higher concentrations of DEAPs were significantly associated with poorer Verbal IQ scores (for a 10-fold increase in concentrations, -6.28; 95% CIs, -12.13, -0.43) in boys. The association for Performance IQ in boys also indicated poorer scores with higher DEAP concentrations, but the confidence intervals included the null value (-4.05; 95% CIs, -10.19, 2.10). The relation between DMAPs and IQ scores in boys was also negative, but association estimates were small and not significant.

CONCLUSION

Urinary metabolites of organophosphate pesticides were not associated with IQ in girls, but we observed that higher maternal urinary DEAPs were associated with poorer Verbal IQ in boys. However, exposure misclassification may be an issue as only one urine sample per woman was analysed. The present study contributes to the accumulating evidence linking exposure to organophosphate pesticides during fetal development with poorer cognitive function in children, bringing data on the risks in a context of low exposure levels encountered in primarily urban populations from Canada.

Urinary Organophosphate Metabolite Concentrations and Pregnancy Outcomes among Women Conceiving through in Vitro Fertilization in Shanghai, China

BACKGROUND

Animal studies suggest that pesticide exposure elicits endocrine changes, increases embryo implantation failure, and decreases litter size. However, only a few epidemiological studies have evaluated the effects of pesticides on the outcomes of in vitro fertilization (IVF) pregnancies.

OBJECTIVES

This study examined the associations between preconception organophosphate pesticides (OP) exposure and pregnancy outcomes among women undergoing IVF in a Chinese population.

METHODS

This study included 522 women with infertility who underwent IVF. Women were recruited from a prospective study, the China National Birth Cohort (CNBC), from Shanghai, China, between July 2017 and December 2018. Demographic and clinical information were collected from medical records and through questionnaires. Preconception exposure to OP was assessed by measuring six nonspecific dialkylphosphate (DAP) metabolites [diethylthiophosphate (DETP), diethylphosphate (DEP), diethyldithiophosphate (DEDTP), dimethylthiophosphate (DMTP), dimethylphosphate (DMP), dimethyldithiophosphate (DMDTP)] in urine samples collected at recruitment. Generalized estimating equation (GEE) models were used to evaluate the associations between OP and pregnancy outcomes.

RESULTS

Compared with women in the lowest quartile (Q1) of individual DEP and Σ4DAP (the sum of DMP, DMTP, DEP, and DETP), women in the highest quartile (Q4) had lower odds of successful implantation, clinical pregnancy, and live birth, and most of the negative trends were significant (p-trends<0.05). There were no significant associations between urinary DAP concentrations and early IVF outcomes, including total and mature oocyte counts, best embryo quality, fertilization, E2 trigger levels, and endometrial wall thickness.

CONCLUSION

Preconception OP exposure was inversely associated with successful implantation, clinical pregnancy, and live birth in women who underwent IVF. https://doi.org/10.1289/EHP7076.

Toxicity evaluation of pesticide chlorpyrifos in male Japanese quails (Coturnix japonica)

In the current study, chlorpyrifos was used as a test chemical to evaluate its possible toxicological effect on birds. A total of 45 adult male Japanese quails were divided into five groups (A to E). Each group, containing 9 birds was further divided into 3 sub-groups (containing 3 birds each). Group A served as control, while all other groups and sub-groups were exposed to selected pesticide for different trial periods. Chlorpyrifos sub-lethal doses were orally administered daily at the rate of 3, 6, 9, and 12 mg/kg body weight per day to group B, C, D, and E, respectively. Birds were kept under observation for behavioral changes throughout the trial periods. Clinical signs, histological alterations, genotoxicity, and blood biochemical alterations were recorded after each 15-day trial. Mild to moderate clinical signs like staggering gait, tremors, diarrhea, dullness, less frequency of crowing, and decrease foam production were observed in group D and E throughout the study. The changes in the body weight gain and blood biochemical parameters among different groups at a given trial period were insignificant. The appearance of micronuclei in group E birds was more significant, indicating that nucleus damage was dose-dependent while to lesser extent duration-dependent. The comet assay showed significant dose- and duration-dependent DNA damage among various groups. In comparison with control group, extensive histological degenerative alterations in the liver, testes, and kidneys were observed in birds of group D and E, where mild to severe alteration like congestion, vacuolation, necrosis, apoptosis, karyopyknosis, extensive degeneration, and alteration in many cellular structures were noticeable.

Assessment of genetic effects and pesticide exposure of farmers in NW Greece

The present study aims at evaluating potential genotoxic and cytotoxic effects caused by the occupational exposure of farmers to pesticide mixtures in the Aitoloakarnania Prefecture (Greece). The aforementioned assessment was conducted through in vivo Cytokinesis Block Micronucleus assay (CBMN assay) in peripheral blood lymphocytes, in relation to chemical analysis of pesticide residues in blood samples. The exposure of the farmers' population studied to different combinations of pesticides induced significant differences in the frequencies of micronuclei (MN) compared to those of the control group. Furthermore, our results indicated a possible clastogenic and aneugenic effect of pesticides on the genetic material of the farmers exposed. Five pesticides (trifluralin, chlorpyriphos methyl, metolachlor, fenthion and dimethoate) and three metabolites (fenthion sulfone, fenthion sulfoxide and 4,4' DDE) were detected in the 62.5% of blood samples, with mean concentrations ranging from 0.4 ng/ml to 48 ng/ml. Since the farmers studied probably exhibit detectable levels of systematic exposure to the pesticides applied, continuous educational programs focused on the rational and safe use of pesticides, together with implementation of risk communication strategies among farmers are highly recommended.

Assessment of human exposure to selected pesticides in Norway by wastewater analysis

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.

Exposure to Organophosphate Pesticides and Menstrual Cycle Characteristics in Chinese Preconceptional Women

Organophosphates (OPs) are the most heavily used pesticides in China. The Chinese population, including preconceptional women, is highly exposed, yet little is known regarding the associations between OP exposure and menstruation in humans. We conducted a cross-sectional analysis in women preparing for pregnancy to investigate the relationship between biomarkers of OP exposure and menstrual cycle characteristics. From 2013 to 2015, 627 women visiting free preconception-care clinics at 2 maternity hospitals in Shanghai, China, were included. Information on menstrual cycle characteristics was obtained through questionnaires. OP exposure was assessed by measuring urine concentrations of 6 dialkylphosphate metabolites (dimethylphosphate, dimethylthiophosphate, dimethyldithiophosphate, diethylphosphate, diethylthiophosphate, and diethyldithiophosphate). The relationship between concentrations of dialkylphosphate metabolites and menstrual cycle characteristics was analyzed using multiple linear regression models and logistic regression models. Log-transformed levels of diethyl phosphate metabolites (the sum of diethylphosphate and diethylthiophosphate levels) were related to a higher risk of irregularity of menstrual cycles (adjusted odds ratio = 2.36, 95% confidence interval: 1.28, 4.34). Subjects with a higher concentration of diethyl phosphate metabolites (log-transformed) had a shorter duration of menstrual bleeding (adjusted β = -0.33, 95% confidence interval: -0.64, -0.02). The findings suggest that OP exposure may be associated with alterations in menstrual function in preconceptional women.

Review of Biomarkers and Analytical Methods for Organophosphate Pesticides and Applicability to Nerve Agents

Introduction

Recent malicious use of chemical warfare agents (CWAs) is a reminder of their severity and ongoing threat. One of the main categories of CWAs is the organophosphate (OP) nerve agents. Presently, there is an urgent need to identify and evaluate OP nerve agent biomarkers that can facilitate identification of exposed individuals post-CWA incident. While exposures to OP nerve agents may be scenario-specific, the public is commonly exposed to OP compounds through the ubiquitous use of OP pesticides, which are chemically related to nerve agents. Therefore, a systematic literature review and methodological quality assessment were conducted for OP pesticide biomarker studies to serve as a baseline to assess if these approaches may be adapted to OP nerve agent exposures.

Materials and Methods

We conducted a systematic literature review to identify biomarkers of OP pesticide exposures. English language studies of any design that reported primary data on biomarkers for exposures in nonhuman primates or adult human study participants were eligible for inclusion. Using standard criteria for assessing the completeness of reported analytical methods, the quality of study methods was critically evaluated.

Results

A total of 1,044 studies of biomarkers of OP pesticide exposure were identified, of which 75 articles satisfied the inclusion and exclusion criteria. These studies described 143 different analyte/sample matrix combinations: 99 host-based biomarkers, 28 metabolites, 12 pesticides, and 4 adducts. The most commonly reported biomarkers were dialkyl phosphate urinary metabolites (22 studies), blood acetylcholinesterase, and plasma butyrylcholinesterase (26 studies each). None of the assessed quality review criteria were fully addressed by all identified studies, with almost all criteria scoring less than 50%.

Conclusion

Cholinesterase activity may have utility for identifying individuals with exposures surpassing a given threshold of OP nerve agent, but further investigation of how acetylcholinesterase and butyrylcholinesterase levels correlate with observed patient symptoms may be required to ensure accuracy of results. As CWAs and nerve agents are more readily used, more standardized reporting of biomarker measurements are needed to develop new approaches for OP nerve agent biomarkers.

Urinary Dialkylphosphate Metabolite Levels in US Adults-National Health and Nutrition Examination Survey 1999-2008

Background: Urinary dialkylphosphate metabolites are considered to be a proxy of the cumulative exposure to organophosphorus pesticides. We analyzed the urinary levels of six dialkylphosphate (DAP) metabolites in US adults, to assess the factors associated with levels of urinary metabolites, and observe the time trends. Methods: We analyzed the combined urinary levels of Dimethylphosphate (DMP), Diethylphosphate (DEP), Dimethylthiophosphate (DMTP), Diethylthiophosphate (DETP), Dimethyldithiophosphate (DMDTP), and Diethyldithiophosphate (DEDTP) in the National Health and Nutrition Examination Survey (NHANES) from 1999 and 2008. Results: Increased age and female gender were positively associated with combined levels of urinary DAP metabolites; BMI < 18.5 kg/m2, BMI > 25 kg/m2, current smoking, and later survey year were inversely associated with combined levels of DAP metabolites. Among those with at least one detectable DAP in their urine, the mean levels decreased starting in 2001, but stayed relatively stable through 2008. Although the maximum combined urinary DAP level was highest in 1999-2000, throughout all years, we observed extremely high levels of exposure for subgroups of individuals. Conclusion: Despite the fact that organophosphorus pesticides were banned for residential use in the US in 2006, there are still opportunities for exposure in the general population. The average urinary DAP levels have decreased over time; however, the decline appears to have plateaued in recent years, and there remains highly exposed individuals.

Organophosphate pesticide metabolite concentrations in urine during pregnancy and offspring attention-deficit hyperactivity disorder and autistic traits

BACKGROUND

Prenatal exposure to organophosphate (OP) pesticides has been associated with altered neuronal cell development and behavioral changes in animal offspring. However, the few studies investigating the association between prenatal OP pesticide exposure and neurodevelopmental outcomes such as Attention-Deficit Hyperactivity Disorder (ADHD) and autistic traits in children produced mixed findings.

OBJECTIVE

The objective of the present study was to examine whether maternal urinary concentrations of OP pesticide metabolites are associated with ADHD and autistic traits in children participating in the Generation R Study, a population-based birth cohort from Rotterdam, the Netherlands.

METHOD

Maternal concentrations of 6 dialkylphosphates (DAPs) were measured using gas chromatography coupled with tandem mass spectrometry in urine samples collected at <18 weeks, 18-25 weeks, and > 25 weeks of gestation in 784 mother-child pairs. DAP metabolite concentrations were expressed as molar concentrations divided by creatinine levels and log₁₀ transformed. ADHD traits were measured at ages 3, 6, and 10 years using the Child Behavior Checklist (CBCL) (n = 781) and autistic traits were measured at age 6 years using the Social Responsiveness Scale (SRS) (n = 622). First, regression models were fit for the averaged prenatal exposure across pregnancy. Second, we investigated associations for each collection phase separately, and applied a mutually adjusted model in which the effect of prenatal DAP concentrations from each time period on ADHD and autistic traits were jointly estimated. All associations were adjusted for relevant confounders.

RESULTS

Median DAP metabolite concentration was 309 nmol/g creatinine at <18 weeks, 316 nmol/g creatinine at 18-25 weeks, and 308 nmol/g creatinine at >25 weeks of gestation. Overall, DAP metabolite concentrations were not associated with ADHD traits. For instance, a log10 increase in averaged total DAP concentrations across gestation was not associated with a lower ADHD score (-0.03 per SD 95 CI: -0.28 to 0.23). Similarly, no associations between maternal DAP concentrations and autistic traits were detected.

CONCLUSIONS

In this study of maternal urinary DAP metabolite concentrations during pregnancy, we did not observe associations with ADHD and autistic traits in children. These are important null observations because of the relatively high background DAP concentrations across pregnancy, the relatively large sample size, and the 10-year follow-up of the offspring. Given the measurement error inherent in our OP pesticide exposure biomarkers, future studies using more urine samples are needed to accurately measure OP pesticide exposure over pregnancy in relation to ADHD and autistic traits.

Reliability and factorial validity of a questionnaire to assess organophosphate pesticide exposure to agricultural workers in Maule, Chile

The aim was to evaluate the reliability and validity of a questionnaire to assess organophosphate pesticide (OP) exposure in agricultural workers. We then enrolled a random sample of 114 agricultural workers from the region of Maule, Chile (mean age = 50 years [SD = 12]). An internal consistency analysis (Cronbach's alpha> 0.70) and a Varimax rotational factorial analysis were applied. The instrument had a high reliability to predict likely occupational pesticide exposures: Cronbach's alpha = 0.95, the Kaiser-Meyer-Olkin (KMO) measure was 0.90 and the Bartell sphericity test = p < 0.001. Four factors explaining 68% of the variance were extracted. The factors identified were as follows: (1) labor conditions during application of OPs; (2) use of personal protective equipment; (3) workplace conditions related to OP exposure and (4) home conditions related to OP exposure. The questionnaire has adequate metric properties to characterize likely OP exposure of agricultural workers and to explore associated working and home conditions.

Effect of pesticide exposure on the cholinesterase activity of the occupationally exposed tea garden workers of northern part of West Bengal, India

Context: Pesticide poisoning and related deaths are a global concern, but there is little information about its effect on the occupationally exposed tea garden workers of North Bengal. Objective: This study investigates the level of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in the blood of the tea garden workers at risk of exposure to a mixture of pesticides. Materials and methods: The study sample consisted of pesticide exposed workers, non-exposed (control), smokers and alcoholics. AChE and BuChE activity was measured and tested for significance. Results: Results showed that AChE activity was half in the pesticide exposed individuals than controls (p≤ 0.001). BuChE activity was also significantly decreased in the pesticide exposed individuals than controls (p≤ 0.001), while AChE and BuChE activity in smokers and alcoholics were not different from that of controls. However, significantly decreased AChE and BuChE activities were recorded in pesticide exposed workers compared to smokers and alcoholics. Conclusions: The results indicated that the decrease in enzyme activities in tea garden workers was due to mixed pesticides (containing organophosphates) exposure. Age was not found to influence the enzyme activities. However, the gender had little effect on the enzyme activities but the effect was not so prominent.

Simultaneous assessment of phenolic metabolites in human urine for a specific biomonitoring of exposure to organophosphate and carbamate pesticides

Organophosphate pesticides (OPP) and carbamates are still counted among the most prominent agents used for crops protection. Up to date the determination of dialkylphosphates and their thio derivatives in urine is established for the OPP biomonitoring. However, this approach does not provide information on the exposure to specific OPP agents. A lot of OPP as well as some carbamates also provide specific urinary biomarkers indeed. Analytical methods for the determination of phenolic metabolites of OPP and carbamates have already been established by different working groups. However, these approaches only acquire one or few analytes. Therefore, we developed an analytical procedure which enables the simultaneous assessment of a wide spectrum of phenolic metabolites of OPP, carbamates and other pesticides in human urine using GC-MS/MS. The method includes enzymatic hydrolysis, solid phase extraction, derivatization, and subsequent GC-MS/MS analysis. The method showed detection limits between 0.1 and 0.4 μg/l. Variation coefficients ranged from 1 to 9 % for precision in series and 1 % to 13 % for inter-day precision. Furthermore, recovery rates between 87 and 117 % were determined. Compared with other published analytical procedures, the present method enables the simultaneous monitoring of a much broader spectrum of pesticides and biocides whose structures contain aryl moieties with competitive or improved analytical reliability. Furthermore, the suitability of the developed procedure was verified through the successful application to urine samples of pesticide exposed humans.

Determination of insecticide residues and their adverse effects on blood profile of occupationally exposed individuals

Insecticides, essential for crop protection measures, leave behind several toxic residues that can result in a series of human health disorders. Therefore, this study was planned for the determination of residues and adverse effects of insecticides in blood samples of sprayers, pesticide-industry workers and controls by using blood parameters of these individuals as biomarkers. Optimized analytical methods using GC-MS and HPLC for the simultaneous detection of 22 currently used insecticides were adopted. Eight of twenty-seven (22.22%) sprayers' blood samples were found positive for five different insecticides. Eleven of twenty-seven (40.74%) pesticide-industry workers were found positive for eight different insecticides. The blood samples of both the exposed groups, sprayers and industry workers had significantly (P < 0.001; Mann-Whitney U-tests) low hemoglobin-Hb concentrations (12.17 ± 2.13 and 12.22 ± 2.37 g/dl respectively) than the average value of the control group with 14.23 ± 2.37 g/dl. The erythrocyte sedimentation rates (ESRs) in sprayers and insecticide industry workers (28.78 ± 20.72 and 28.17 ± 25.14 mm/1st h respectively) were greater significantly (P < 0.001; Mann-Whitney U test) than the control blood samples (9.53 ± 3.34 mm/1st h). These results indicate that the exposed individuals have experienced significant hemotoxic effects during insecticide exposure. The study also predicts the risk to exposed individuals in developing countries like Pakistan and demands realization of safety measures to prevent such dangerous effects of pesticide exposures.

Investigation of associations between exposures to pesticides and testosterone levels in Thai farmers

We conducted a cross-sectional study to assess the relationship between pesticide exposures and testosterone levels in 133 male Thai farmers. Urine and serum samples were collected concurrently from participants. Urine was analyzed for levels of specific and nonspecific metabolites of organophosphates (OPs), pyrethroids, select herbicides, and fungicides. Serum was analyzed for total and free testosterone. Linear regression analyses revealed significant negative relationships between total testosterone and the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) after controlling for covariates (eg, age, BMI, smoking status). Positive significant associations were found between some OP pesticides and total testosterone. Due to the small sample size and the observational nature of the study, future investigation is needed to confirm our results and to elucidate the biological mechanisms.

Occupational predictors of urinary dialkyl phosphate concentrations in Mexican flower growers

Background Flower growers have high potential for exposures to pesticides. Occupational factors, such as tasks performed, the production method (organic or conventional), the use of personal protective equipment (PPE), and workplace characteristics influence the intensity of pesticide exposure. Objective To evaluate occupational characteristics affecting urinary concentration of dialkylphosphate (DAP) metabolites of organophosphate pesticides among a group of Mexican floricultural workers. Methods A questionnaire was administered to 117 workers who also provided a first morning urine sample. According to tasks performed and the production methods, pesticide contact was defined as low, medium, or high. PPE use was categorized as acceptable, fairly acceptable, and unacceptable. Urinary concentration of DAP metabolites were determined using gas-liquid chromatography. Association between occupational characteristics and DAP urinary concentrations was assessed by means of linear regression models. Results After adjusting for potential confounders, the workers in the medium and high contact categories had significantly higher DAP concentrations than those in the low contact category (β: 0.3, CI 95%: 0.1-0.5). Greenhouse workers had greater DAP concentrations than outdoors workers (β: 0.3, CI 95%: 0.1-0.5). Compared with non-acceptable use of PPE, acceptable use of PPE was associated with lower DAP concentrations (β: -0.4, CI 95% -0.6 to -0.1). Conclusion Improved safety training is needed for correct PPE usage, especially among flower growers who use conventional pest control methods and who work in a greenhouse environment.

Epidemiology of and Risk Factors for Type 2 Diabetes in Egypt

BACKGROUND

Diabetes is a fast-growing health problem in Egypt with a significant impact on morbidity, mortality, and health care resources. Currently, the prevalence of type 2 diabetes (T2D) in Egypt is around 15.6% of all adults aged 20 to 79.

OBJECTIVE

To describe the epidemiology, principal causes, associated risk factors, cultural aspects, and challenges that may contribute to the rapid rise in T2D in Egypt.

METHODS

Review of papers in PubMed and relevant gray literature.

FINDINGS

The International Diabetes Federation (IDF) has identified Egypt as the ninth leading country in the world for the number of patients with T2D. The prevalence of T2D in Egypt was almost tripled over the last 2 decades. This sharp rise could be attributed to either an increased pattern of the traditional risk factors for T2D such as obesity and physical inactivity and change in eating pattern or other risk factors unique to Egypt. These include increased exposure to environmental risk factors like pesticides and increased prevalence of chronic hepatitis C.

CONCLUSIONS

Prevention, early identification, and effective intervention are integral components of effective T2D care in Egypt. These strategies may reduce the expanding economic burden associated with T2D care.

Wastewater-based epidemiology to assess pan-European pesticide exposure

Human biomonitoring, i.e. the determination of chemicals and/or their metabolites in human specimens, is the most common and potent tool for assessing human exposure to pesticides, but it suffers from limitations such as high costs and biases in sampling. Wastewater-based epidemiology (WBE) is an innovative approach based on the chemical analysis of specific human metabolic excretion products (biomarkers) in wastewater, and provides objective and real-time information on xenobiotics directly or indirectly ingested by a population. This study applied the WBE approach for the first time to evaluate human exposure to pesticides in eight cities across Europe. 24 h-composite wastewater samples were collected from the main wastewater treatment plants and analyzed for urinary metabolites of three classes of pesticides, namely triazines, organophosphates and pyrethroids, by liquid chromatography-tandem mass spectrometry. The mass loads (mg/day/1000 inhabitants) were highest for organophosphates and lowest for triazines. Different patterns were observed among the cities and for the various classes of pesticides. Population weighted loads of specific biomarkers indicated higher exposure in Castellon, Milan, Copenhagen and Bristol for pyrethroids, and in Castellon, Bristol and Zurich for organophosphates. The lowest mass loads (mg/day/1000 inhabitants) were found in Utrecht and Oslo. These results were in agreement with several national statistics related to pesticides exposure such as pesticides sales. The daily intake of pyrethroids was estimated in each city and it was found to exceed the acceptable daily intake (ADI) only in one city (Castellon, Spain). This was the first large-scale application of WBE to monitor population exposure to pesticides. The results indicated that WBE can give new information about the "average exposure" of the population to pesticides, and is a useful complementary biomonitoring tool to study population-wide exposure to pesticides.

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

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

Monitoring population exposure to pesticides based on liquid chromatography-tandem mass spectrometry measurement of their urinary metabolites in urban wastewater: A novel biomonitoring approach

Biomonitoring studies have documented the high exposure of the population to pesticides which are widely used for crop protection, industrial and household purposes. This is the first study which has measured human urinary metabolites of pesticides in urban wastewater as biomarkers of population exposure. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to measure fifteen urinary metabolites selected from the major classes of pesticides. Raw wastewater samples were processed by solid phase extraction (SPE) or direct injection into the LC-MS/MS system. Recoveries ranged from 75 to 115% and the limits of quantification were 1-15ng/L for the SPE method and 40-800ng/L for direct injection. The method was employed for the analysis of 44 composite 24-h wastewater samples collected in seven Italian cities. Most of the target substances were detected at concentrations ranging from 1.1ng/L to 1.6μg/L. The highest concentrations were for some common metabolites of alkyl phosphates and pyrethroids and the specific metabolite of chlorpyrifos and chlorpyrifos-methyl (3,5,6-trichloro-2-pyridinol). The frequency of detection and abundance of most of the measured metabolites were in line with the profiles reported in urine biomonitoring studies. This method is therefore proposed as a novel "biomonitoring approach" for obtaining objective, direct information on the levels of exposure of a specific population to pesticides, and current research is addressed to validate the method identifying the most reliable biomarkers.