Pre- and postnatal exposures to pesticides and neurodevelopmental effects in children living in agricultural communities from South-Eastern Spain

Oxime-functionalized anti-insecticide fabric reduces insecticide exposure through dermal and nasal routes, and prevents insecticide-induced neuromuscular-dysfunction and mortality

Farmers from South Asian countries spray insecticides without protective gear, which leads to insecticide exposure through dermal and nasal routes. Acetylcholinesterase plays a crucial role in controlling neuromuscular function. Organophosphate and carbamate insecticides inhibit acetylcholinesterase, which leads to severe neuronal/cognitive dysfunction, breathing disorders, loss of endurance, and death. To address this issue, an Oxime-fabric is developed by covalently attaching silyl-pralidoxime to the cellulose of the fabric. The Oxime-fabric, when stitched as a bodysuit and facemask, efficiently deactivates insecticides (organophosphates and carbamates) upon contact, preventing exposure. The Oxime-fabric prevents insecticide-induced neuronal damage, neuro-muscular dysfunction, and loss of endurance. Furthermore, we observe a 100% survival rate in rats when repeatedly exposed to organophosphate-insecticide through the Oxime-fabric, while no survival is seen when organophosphate-insecticide applied directly or through normal fabric. The Oxime-fabric is washable and reusable for at least 50 cycles, providing an affordable solution to prevent insecticide-induced toxicity and lethality among farmers.

Prenatal exposure to pyrethroids and chlorpyrifos and IQ in 7-year-old children from the Odense Child Cohort

BACKGROUND

Organophosphates and pyrethroids are two major groups of insecticides used for crop protection worldwide. They are neurotoxicants and exposure during vulnerable windows of brain development may have long-term impact on human neurodevelopment. Only few longitudinal studies have investigated associations between prenatal exposure to these substances and intelligence quotient (IQ) at school age in populations with low, mainly dietary, exposure.

OBJECTIVE

To investigate associations between maternal urinary concentrations of insecticide metabolites at gestational week 28 and IQ in offspring at 7-years of age.

MATERIALS AND METHODS

Data was derived from the Odense Child Cohort (OCC). Metabolites of chlorpyrifos (TCPy) and pyrethroids (3-PBA, cis- and trans-DCCA, 4-F-3PBA, cis-DBCA) were measured in maternal urine collected at gestational week (GW) 28. An abbreviated version of the Danish Wechsler Intelligence Scale for Children fifth edition (WISC-V) consisting of four subtests to estimate full scale IQ (FSIQ) was administered by trained psychologists. Data were analyzed by use of multiple linear regression and adjusted for confounders.

RESULTS

812 mother/child-pairs were included. Median concentrations were 0.21 μg/L for 3-PBA, 1.67 μg/L for TCPy and the mean IQ for children were 99.4. Null association between maternal 3-PBA and child IQ at 7 years was seen, but with trends suggesting an inverse association. There was a significant association for maternal TCPy and child IQ at mid-level exposure. Trans-DCCA above the level of detection (LOD) was also associated with slightly lower child IQ, but the association was also not statistically significant.

CONCLUSIONS

We found no significant associations between maternal 3-PBA metabolites and child IQ at 7 years, but with trends suggesting an inverse association. A non-significant trend between maternal TCPy exposure and child IQ in 7-year-children was seen even in this low exposed population. Given the widespread exposure and increasing use of insecticides, this should be elaborated in future studies.

The research landscape concerning environmental factors in neurodevelopmental disorders: Endocrine disrupters and pesticides-A review

In recent years, environmental epidemiology and toxicology have seen a growing interest in the environmental factors that contribute to the increased prevalence of neurodevelopmental disorders, with the purpose of establishing appropriate prevention strategies. A literature review was performed, and 192 articles covering the topic of endocrine disruptors and neurodevelopmental disorders were found, focusing on polychlorinated biphenyls, polybrominated diphenyl ethers, bisphenol A, and pesticides. This study contributes to analyzing their effect on the molecular mechanism in maternal and infant thyroid function, essential for infant neurodevelopment, and whose alteration has been associated with various neurodevelopmental disorders. The results provide scientific evidence of the association that exists between the environmental neurotoxins and various neurodevelopmental disorders. In addition, other possible molecular mechanisms by which pesticides and endocrine disruptors may be associated with neurodevelopmental disorders are being discussed.

Frequency of urinary pesticides in children: a scoping review

Pesticides are any mix of ingredients and substances used to eliminate or control unwanted vegetable or animal species recognized as plagues. Its use has been discussed in research due to the scarcity of strong scientific evidence about its health effects. International literature is still insufficient to establish a global recommendation through public policy. This study aims to explore international evidence of the presence of pesticides in urine samples from children and their effects on health through a scoping review based on the methodology described by Arksey and O'Malley. The number of articles resulting from the keyword combination was 454, and a total of 93 manuscripts were included in the results and 22 were complementary. Keywords included in the search were: urinary, pesticide, children, and childhood. Children are exposed to pesticide residues through a fruit and vegetable intake environment and household insecticide use. Behavioral effects of neural damage, diabetes, obesity, and pulmonary function are health outcomes for children that are commonly studied. Gas and liquid chromatography-tandem mass spectrometry methods are used predominantly for metabolite-pesticide detection in urine samples. Dialkylphosphates (DAP) are common in organophosphate (OP) metabolite studies. First-morning spot samples are recommended to most accurately characterize OP dose in children. International evidence in PubMed supports that organic diets in children are successful interventions that decrease the urinary levels of pesticides. Several urinary pesticide studies were found throughout the world's population. However, there is a knowledge gap that is important to address (public policy), due to farming activities that are predominant in these territories.

Neurobehavioral Effects of Low-Dose Chronic Exposure to Insecticides: A Review

The modes of action of insecticides frequently involve a neurotoxic effect; therefore, the study of neurotoxic effects caused by long-term and low-dose insecticide exposure is of particular interest. This study looks at whether or not new studies conducted after 2009 and up to 2021 have provided new evidence for a better understanding of the actual neurobehavioral risk associated with long-term insecticide exposure. We selected and reviewed studies carried out on the neurobehavioral effects of neurotoxic insecticides (organophosphates and/or carbamates, pyrethroids, multiple or undefined insecticides, and organochlorines) considering occupational and non-occupational exposures. The articles were also scored and ranked based on seven parameters. Eighty-six studies were chosen for a final review process from among the 950 scientific papers identified. Twenty-six addressed occupational exposure and six environmental exposure. Among the latter group of studies, 17 focused on rural residents, to be assumed exposed because of living in rural areas, and 43 on the general population. Pending doubts have not been resolved in the last ten years due to the presence of contradictory and hardly comparable results and the fact that in most of the studies showing an evident neurobehavioral impairment the frequent presence of a previous episode of poisoning and hospitalization, with severe brain hypoxia, impaired the possibility of confirming the presence of a causal association with insecticide exposure. Interestingly, the most severely exposed groups, such as applicators who did not wear personal protective equipment, performed worse on neurobehavioral tests. As for residential exposure, there is sufficient evidence to suggest that prenatal OP exposure may increase the risk of ADHD in children.

Cytotoxicity Mechanisms of Eight Major Herbicide Active Ingredients in Comparison to Their Commercial Formulations

Commercial pesticide formulations contain co-formulants, which are generally considered as having no toxic effects in mammals. This study aims to compare the toxicity of 8 major herbicide active ingredients-namely glyphosate, dicamba, 2,4-D, fluroxypyr, quizalofop-p-ethyl, pendimethalin, propyzamide and metazachlor-with a typical commercial formulation of each active ingredient. Cytotoxicity and oxidative stress capability was assessed in human hepatoma HepG2 cells. Using an MTT assay, formulations of glyphosate (Roundup Probio), fluroxypyr (Hurler), quizalofop-p-ethyl (Targa Super) and dicamba (Hunter) were more toxic than the active ingredient alone. Metazachlor and its formulation Sultan had similar cytotoxicity profiles. Cytotoxicity profiles were comparable in immortalised human fibroblasts. Toxilight necrosis assays showed the formulation of metazachlor (Sultan50C) resulted in significant membrane disruption compared to the active ingredient. Generation of reactive oxygen species was detected for glyphosate, fluroxypyr, pendimethalin, quizalofop-p-ethyl, the formulation of 2,4-D (Anti-Liserons), and dicamba and its formulation Hunter. Further testing of quizalofop-p-ethyl and its formulation Targa Super in the ToxTracker assay system revealed that both products induced oxidative stress and an unfolded protein response. In conclusion, these results show that most herbicide formulations tested in this study are more toxic than their active ingredients in human tissue culture cell model systems. The results add to a growing body of evidence, which implies that commercial herbicide formulations and not just their active ingredients should be evaluated in regulatory risk assessment of pesticides.

Urinary para-nitrophenol levels of pregnant women and cognitive and motor function of their children aged 2 years: Evidence from the SMBCS (China)

BACKGROUND

Urinary para-nitrophenol (PNP), an exposure biomarker of ethyl parathion (EP) and methyl parathion (MP) pesticides, was still pervasively detected in the general population even after global restriction for years. And the concern whether there is an association of PNP level with child development of the nervous system is increasing. The current study aimed to evaluate the maternal urinary PNP concentrations during late pregnancy and the associations of PNP levels with cognitive and motor function of their children at the age of 2 years.

METHODS

323 mother-child pairs from the Sheyang Mini Birth Cohort Study were included in the current study. Gas chromatography-tandem mass spectrometry was used to measure concentrations of PNP, the specific metabolite of EP and MP, in maternal urine samples during pregnancy. Developmental quotients (DQs) scores measured with Gesell Developmental Scales were employed to evaluate cognitive and motor function of children aged 2 years. Generalized linear models were performed to analyze the associations of PNP concentrations in pregnant women's urine samples with cognitive and motor function of their children.

RESULTS

Maternal PNP was detected in all urine samples with a median of 4.11 μg/L and a range from 0.57 μg/L to 109.13 μg/L, respectively. Maternal urinary PNP concentrations showed a negative trend with DQ of motor area [regression coefficient (β) = - 1.35; 95 % confidence interval (95 %CI): - 2.37, - 0.33; P < 0.01], and the children whose mothers were in the fourth quartile exposure group performed significantly worse compared to the reference group (β = - 1.11; 95 %CI: - 1.80, - 0.42; P < 0.01). As for average DQ score, children with their mothers' urinary PNP concentrations in the third quartile group had higher scores than those in the first quartile group (β = 0.39; 95 %CI: 0.03, 0.75; P = 0.04). In sex-stratified analyses, a negative trend between maternal urinary PNP concentrations and DQ scores in motor area of children was only observed in boys (β = - 1.62; 95 %CI: - 2.80, - 0.43; P < 0.01). Boys in the third quartile group had higher DQ average scores than those in the lowest quartile as reference (β = 0.53; 95 %CI: 0.02, 1.04; P = 0.04).

CONCLUSIONS

The mothers from SMBCS may be widely exposed to EP and/or MP, which were associated with the cognitive and motor function of their children aged 2 years in a sex-specific manner. Our results might provide epidemiology evidence on the potential effects of prenatal exposure to EP and/or MP on children's cognitive and motor function.

Impacts of dietary exposure to pesticides on faecal microbiome metabolism in adult twins

BACKGROUND

Dietary habits have a profound influence on the metabolic activity of gut microorganisms and their influence on health. Concerns have been raised as to whether the consumption of foodstuffs contaminated with pesticides can contribute to the development of chronic disease by affecting the gut microbiome. We performed the first pesticide biomonitoring survey of the British population, and subsequently used the results to perform the first pesticide association study on gut microbiome composition and function from the TwinsUK registry.

METHODS

Dietary exposure of 186 common insecticide, herbicide, or fungicide residues and the faecal microbiome in 65 twin pairs in the UK was investigated. We evaluated if dietary habits, geographic location, or the rural/urban environment, are associated with the excretion of pesticide residues. The composition and metabolic activity of faecal microbiota was evaluated using shotgun metagenomics and metabolomics respectively. We performed a targeted urine metabolomics analysis in order to evaluate whether pesticide urinary excretion was also associated with physiological changes.

RESULTS

Pyrethroid and/or organophosphorus insecticide residues were found in all urine samples, while the herbicide glyphosate was found in 53% of individuals. Food frequency questionnaires showed that residues from organophosphates were higher with increased consumption of fruit and vegetables. A total of 34 associations between pesticide residue concentrations and faecal metabolite concentrations were detected. Glyphosate excretion was positively associated with an overall increased bacterial species richness, as well as to fatty acid metabolites and phosphate levels. The insecticide metabolite Br2CA, reflecting deltamethrin exposure, was positively associated with the phytoestrogens enterodiol and enterolactone, and negatively associated with some N-methyl amino acids. Urine metabolomics performed on a subset of samples did not reveal associations with the excretion of pesticide residues.

CONCLUSIONS

The consumption of conventionally grown fruit and vegetables leads to higher ingestion of pesticides with unknown long-term health consequences. Our results highlight the need for future dietary intervention studies to understand effects of pesticide exposure on the gut microbiome and possible health consequences.

Hair, serum and urine chromium levels in children with cognitive defects: A systematic review and meta-analysis of case control studies

Environmental chromium exposure may cause impaired development of children. We conducted a systematic review and meta-analysis. Electronic databases including PubMed, Embase, Web of Science and CINAHL were searched to identify case-control studies that reported childhood Cr exposure and cognitive development. The Newcastle-Ottawa Scale (NOS) was used to ensure the quality of the included studies. Cr levels were compared in cases and controls, and a random effect meta-analysis was performed using Stata version 16. Twelve of 61 studies identified in the literature search were eligible for this analysis. Hair, serum and urine Cr measurements were reported by seven, two and one studies, respectively. In addition, one study reported both serum and hair Cr exposure and another reported urine and hair Cr exposure. The pooled standard mean differences (SMD) showed that hair Cr levels were non-significantly lower among children with cognitive defects (-0.01 μg/g, 95% CI: -0.04, 00, p = 0.27). In serum and urine, the pooled SMD was higher in children with cognitive deficits compared with healthy control children (0.32 μg/g, 95% CI: -0.78, 1.42, p = 0.56 and 0.64 μg/g, CI: -0.07,1.36, p = 0.08; respectively). In summary, this systematic review found no significant differences in hair, serum and urine Cr levels between children with cognitive deficits and healthy control children when all study data were pooled in the meta-analysis. Larger studies using standardized criteria and longitudinal assessment of cognitive development are needed to determine whether there is a dose response effect of childhood Cr exposure on cognitive development of children.

Role of endocrine disrupting chemicals in children's neurodevelopment

Environmental stressors, like endocrine disrupting chemicals (EDC), are considered important contributors to the increased rates of neurodevelopmental dysfunctions. Considering the cumulative research on adverse neurodevelopmental effects associated with prenatal exposure to EDC, the purpose of this study was to review the available limited literature about the effects of postnatal exposure to EDC on child neurodevelopment and behaviour. Despite widespread children's exposure to EDC, there are a limited number of epidemiological studies on the association of this exposure with neurodevelopmental disorders, in particular in the postnatal period. The available research suggests that postnatal EDC exposure is related to adverse neurobehavioral outcomes in children; however the underlying mechanisms of action remain unclear. Timing of exposure is a key factor determining potential neurodevelopmental consequences, hence studying the impact of multiple EDC co-exposure in different vulnerable life periods could guide the identification of sensitive subpopulations. Most of the reviewed studies did not take into account sex differences in the EDC effects on children neurodevelopment. We believe that the inclusion of sex in the study design should be considered as the role of EDC on children neurodevelopment are likely sex-specific and should be taken into consideration when determining susceptibility and potential mechanisms of action.

Alterations in small RNA profiles in liver following a subchronic exposure to a low-dose pesticide mixture in Sprague-Dawley rats

Small RNAs have emerged as a promising new type of biomarker to monitor health status and track the development of diseases. Here we report changes in the levels of small RNAs in the liver of rats exposed to a mixture of six pesticides frequently detected in foodstuffs (azoxystrobin, boscalid, chlorpyrifos, glyphosate, imidacloprid and thiabendazole). Multivariate analysis with OPLS-DA methods showed that small RNA profiles can discriminate samples from pesticide treated rats from their concurrent controls. A total of 9 miRNAs were found to have their levels altered in the liver of the pesticide-treated rats in comparison to the controls, which included 7 that were downregulated (miR-22-5p, miR-193a-3p, miR-32-5p, miR-33-5p, miR-122-5p, miR-22-3p, miR-130a-3p) and 2 that were upregulated (miR-486-5p, miR-146a-5p). These miRNAs were predicted to regulate genes, which were found to have their expression altered by the pesticide mixture and have known health implications in the regulation of hepatic metabolism. This supports and extends our recent conclusions that high- throughput 'omics' analyses can reveal molecular perturbations, which can potentially act as sensitive and accurate markers of health risks arising from exposure to environmental pollutants such as pesticides.

Personal exposure assessment of pesticides in residents: The association between hand wipes and urinary biomarkers

BACKGROUND

Residential exposure to pesticides may occur via inhalation of airborne pesticides, direct skin contacts with pesticide-contaminated surfaces, and consumption of food containing pesticide residues. The aim was to study the association of dermal exposure to pesticides between the use and non-use periods, between farmer and non-farmer families and between dermal exposure and the excretion of metabolites from urine in residents living close to treated agricultural fields.

METHODS

In total, 112 hand wipes and 206 spot urine samples were collected from 16 farmer and 38 non-farmer participants living within 50 m from an agricultural field in the Netherlands. The study took place from May 2016 to December 2017 during the use as well as the non-use periods of pesticides. Hand wipes were analysed for the parent compound and urines samples for the corresponding urinary metabolite of five applied pesticides: asulam, carbendazim (applied as thiophanate-methyl), chlorpropham, prochloraz and tebuconazole. Questionnaire data was used to study potential determinants of occurrence and levels of pesticides in hand wipes according to univariate and multivariate analysis.

RESULTS

Carbendazim and tebuconazole concentrations in hand wipes were statistically significantly higher in the pesticide-use period compared to the non-use period. In addition, especially during the use periods, concentrations were statistically significantly higher in farmer families compared to non-farmer families. For asulam, chlorpropham and prochloraz, the frequency of non-detects was too high (57-85%) to be included in this analysis. The carbendazim contents in urine samples and hand wipes were correlated on the first and second day after taking the hand wipe, whereas chlorpropham was only observed to be related on the second day following the spray event.

CONCLUSIONS

Concentrations in hand wipes were overall higher in pesticide use periods compared to non-use periods and higher in farmer families compared to non-farmer families. Only for carbendazim a strong correlation between concentrations in hand wipes and its main metabolite in urine was observed, indicating dermal exposure via contaminated indoor surfaces. We expect this to be related to the lower vapour pressure and longer environmental lifetime of carbendazim compared to the other pesticides studies.

The protective function of taurine on pesticide-induced permanent neurodevelopmental toxicity in juvenile rats

Numerous studies have confirmed that prenatal or early postnatal exposure to pesticides can lead to functional deficits in the developing brain. This study aimed to investigate whether combined exposure to paraquat (PQ) and maneb (MB) during puberty could cause permanent toxic effects in the neural system of rats. In addition, the neuroprotective function of taurine (T) and its possible mechanism were investigated. Rats were administered PQ + MB intragastrically for 12 continuous weeks, while taurine dissolved in water was fed to the rats for 24 continuous weeks. In the behavioral tests, the rats' trajectories became complex, and the reaction latencies and mistake frequencies increased. Significant changes were found in the hippocampal neurons of the PQ + MB groups but not in the taurine treatment groups. PQ + MB stimulated cAMP to reduce the production of protein kinase A (PKA) and inhibited the activation of other elements, such as brain-derived neurotrophic factor (BDNF), cAMP response element binding protein (CREB), phospho-CREB (p-CREB), immediate-early genes (IEGs)Arc, and c-Fos. Importantly, taurine regulated the level of cAMP and the expression of the abovementioned proteins. Together, our findings implied that adolescent exposure to PQ + MB may impact the behavior and cognitive function of rats via the cAMP-PKA-CREB signaling pathway, while taurine may in turn exert neuroprotection by diminishing these impacts.

Relationship between Autism Spectrum Disorder and Pesticides: A Systematic Review of Human and Preclinical Models

Autism spectrum disorder (ASD) is a complex set of neurodevelopmental pathologies characterized by impoverished social and communicative abilities and stereotyped behaviors. Although its genetic basis is unquestionable, the involvement of environmental factors such as exposure to pesticides has also been proposed. Despite the systematic analyses of this relationship in humans, there are no specific reviews including both human and preclinical models. The present systematic review summarizes, analyzes, and discusses recent advances in preclinical and epidemiological studies. We included 45 human and 16 preclinical studies. These studies focused on Organophosphates (OP), Organochlorine (OC), Pyrethroid (PT), Neonicotinoid (NN), Carbamate (CM), and mixed exposures. Preclinical studies, where the OP Chlorpyrifos (CPF) compound is the one most studied, pointed to an association between gestational exposure and increased ASD-like behaviors, although the data are inconclusive with regard to other ages or pesticides. Studies in humans focused on prenatal exposure to OP and OC agents, and report cognitive and behavioral alterations related to ASD symptomatology. The results of both suggest that gestational exposure to certain OP agents could be linked to the clinical signs of ASD. Future experimental studies should focus on extending the analysis of ASD-like behaviors in preclinical models and include exposure patterns similar to those observed in human studies.

Multi-omics phenotyping of the gut-liver axis reveals metabolic perturbations from a low-dose pesticide mixture in rats

Health effects of pesticides are not always accurately detected using the current battery of regulatory toxicity tests. We compared standard histopathology and serum biochemistry measures and multi-omics analyses in a subchronic toxicity test of a mixture of six pesticides frequently detected in foodstuffs (azoxystrobin, boscalid, chlorpyrifos, glyphosate, imidacloprid and thiabendazole) in Sprague-Dawley rats. Analysis of water and feed consumption, body weight, histopathology and serum biochemistry showed little effect. Contrastingly, serum and caecum metabolomics revealed that nicotinamide and tryptophan metabolism were affected, which suggested activation of an oxidative stress response. This was not reflected by gut microbial community composition changes evaluated by shotgun metagenomics. Transcriptomics of the liver showed that 257 genes had their expression changed. Gene functions affected included the regulation of response to steroid hormones and the activation of stress response pathways. Genome-wide DNA methylation analysis of the same liver samples showed that 4,255 CpG sites were differentially methylated. Overall, we demonstrated that in-depth molecular profiling in laboratory animals exposed to low concentrations of pesticides allows the detection of metabolic perturbations that would remain undetected by standard regulatory biochemical measures and which could thus improve the predictability of health risks from exposure to chemical pollutants.

Early-life carbamate exposure and intelligence quotient of seven-year-old children

BACKGROUND

Early-life carbamate exposure during developmental period has been linked with adverse health effects and attracted attention.

METHODS

Three hundred and three children at age of seven were included in the current study. Urinary carbofuranphenol concentrations were measured using gas chromatography-tandem mass spectrometry. Verbal, performance and full-scale intelligence quotients (IQ_V, IQ_P, and IQ_FS) were assessed using Wechsler Intelligence Scale for Children-Chinese Revised. Generalized linear models were used to explore the associations between carbofuranphenol levels and IQs. Generalized estimating equations were used to explore long-term health effect and sensitive time window.

RESULTS

Carbofuranphenol was detected in 96.6% of the seven-year-old urinary samples, the geometric mean, median, and inter quartile range of the carbofuranphenol concentrations were 0.67 μg/L, 0.30 μg/L, and 0.09-3.72 μg/L, respectively, which were similar with the level of three-year-old children from the SMBCS cohort. Seven-year-old carbofuranphenol level was negatively associated with IQ_P [β = -0.044; 95% confidence interval (CI): -0.087, -0.001; p = 0.045]. Three-year-old carbofuranphenol level was negatively associated with IQ_P (β = -0.100; 95% CI: -0.186, -0.014; p = 0.022) and IQ_FS (β = -0.087; 95% CI: -0.173, -0.001; p = 0.047). Carbamate exposure of maternal and children at both three and seven years old had negative associations with IQ_P (β = -0.089; 95% CI: -0.171, -0.007; p = 0.034), and IQ_FS (β = -0.064; 95% CI: -0.127, -0.000; p = 0.049) of children at age of seven.

CONCLUSION

Results of the present study verify that children in an agricultural region of China were widely exposed to carbamate pesticides. Carbamate exposure in utero and at three and seven years may adversely impact children's neurodevelopment.

Exposure and cumulative risk assessment to non-persistent pesticides in Spanish children using biomonitoring

The main objective of the present research is to evaluate the exposure to pesticides in children (n = 568) from the Valencian Region (Spain). Six non-specific and 20 specific metabolites of organophosphate pesticides (OPs), herbicides (Herb), and pyrethroids (Pyr) were analyzed in urine samples. The biomarkers with the highest detection frequencies (>70%) were diethyl phosphate, p-nitrophenol, 3-phenoxybenzoic acid, and 3,5,6-trichloro-2-pyridinol, whose geometric mean concentrations (ng·ml-n1) were 1.53, 1.03, 1.51 and 1.19, respectively. Robust regression models showed that the province of residence and the recent consumption of vegetables, legumes and cereals were some of the most important predictors of pesticide exposure. Pesticide risk assessment is estimated using two different strategies: one based on the pesticides' mode of action (MoA); and the other based on cumulative assessment groups (CAGs), proposed by EFSA. The estimated daily intakes (EDIs) ranged from 0.08 (chlorpyrifos) to 1.62 μg·kg bw-1 (λ-cyhalothrin). The MoA approach resulted in hazard quotients ranging from 0.01 (chlorpyrifos) to 0.65 (λ-cyhalothrin), and a hazard index for OPs lower than 1. Similarly, the risk assessment based on CAGs led to total margins of exposure (MOETs) far from 100. In conclusion, both risk assessment strategies does not reveal any evidence of a potential health risk due to pesticide exposure in Spanish children.

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.

Endocrine-disrupting chemicals: implications for human health

Since reports published in 2015 and 2016 identified 15 probable exposure-outcome associations, there has been an increase in studies in humans of exposure to endocrine-disrupting chemicals (EDCs) and a deepened understanding of their effects on human health. In this Series paper, we have reviewed subsequent additions to the literature and identified new exposure-outcome associations with substantial human evidence. Evidence is particularly strong for relations between perfluoroalkyl substances and child and adult obesity, impaired glucose tolerance, gestational diabetes, reduced birthweight, reduced semen quality, polycystic ovarian syndrome, endometriosis, and breast cancer. Evidence also exists for relations between bisphenols and adult diabetes, reduced semen quality, and polycystic ovarian syndrome; phthalates and prematurity, reduced anogenital distance in boys, childhood obesity, and impaired glucose tolerance; organophosphate pesticides and reduced semen quality; and occupational exposure to pesticides and prostate cancer. Greater evidence has accumulated than was previously identified for cognitive deficits and attention-deficit disorder in children following prenatal exposure to bisphenol A, organophosphate pesticides, and polybrominated flame retardants. Although systematic evaluation is needed of the probability and strength of these exposure-outcome relations, the growing evidence supports urgent action to reduce exposure to EDCs.

Crop proximity index for monitoring of peri-urban land use in agro-industrial crop regions

The agro-industrial production of genetically modified organisms uses great amounts of pesticides, close to cities, which generates growing concern due to the numerous evidence of their negative effects on health and the environment. In a context of the lack, or inaccessibility, of official data on crop dynamics and pesticide use, environmental indicators using satellite data are needed for the proper monitoring of peri-urban areas. The objective of this research is to make a crop proximity index using satellite information to assess and monitor peri-urban agro-industrial activity. Twenty cities in Argentina and ten in the United States were selected. The CPI index is designed to evaluate a city and its peri-urban areas as a whole by taking account of the land uses and factors that can potentially influence the proximity to agro-industrial activity to the population living in those cities. Agriculture factor was weighted by proximity or remoteness using perimeter rings from the urban edge. All the necessary data for the calculation of the CPI index were obtained through the classification and processing of Sentinel 2 satellite images with software and the Google Earth Engine platform. The results show a worrying situation, 90% of cities in Argentina and 80% in the United States have a negative CPI. Most of the cities examined are extremely close to extensive areas of crops, that use a high amount of pesticides and which do not have the protection of trees or buffer zones.

Urinary organophosphate metabolites and oxidative stress in children living in agricultural and urban communities

Exposure to organophosphate (OP) pesticides in children may increase oxidative stress, resulting in the development of chronic diseases. This study aims to compare urinary OP metabolites and oxidative stress between children in agricultural and urban communities. The study also investigated the factors associated with urinary OP metabolites among children. Urine samples were collected from children for measuring levels of OP metabolites, glutathione (GSH), and malondialdehyde (MDA). The remarkable findings were that total dialkylphosphate (DAP) levels detected among children in this agricultural community were significantly higher than those from the urban community (P = 0.001). Multiple linear regression showed that total diethylphosphate (DEP) levels among children in the agricultural community were negatively associated with distances from children's residence to the agricultural fields (β ± SE. = - 1.535 ± 0.334, 95%CI = - 2.202, - 0.863) and positively associated with playing on farms (β ± SE. = 0.720 ± 0.342, 95%CI = 0.036, 1.405). In addition, total dimethylphosphate (DMP) levels were positively associated with children working on farms (β ± SE. = 0.619 ± 0.264, 95%CI = 0.091, 1.147). Importantly, GSH levels among children in the agricultural community were significantly lower than those in the urban community (P < 0.001), but MDA levels did not differ. These results therefore suggest that children can be exposed to OPs both outdoors and indoors. Our results also provide supporting evidence that OP exposure can cause oxidative stress in children. As oxidative stress contributes to several chronic diseases, a good proposed strategy for the future would include measurement of oxidative stress biomarkers among children exposed to OPs as an early warning of chronic diseases.

An analysis of the versatility and effectiveness of composts for sequestering heavy metal ions, dyes and xenobiotics from soils and aqueous milieus

The persistence and bioaccumulation of environmental pollutants in water bodies, soils and living tissues remain alarmingly related to environmental protection and ecosystem restoration. Adsorption-based techniques appear highly competent in sequestering several environmental pollutants. In this review, the recent research findings reported on the assessments of composts and compost-amended soils as adsorbents of heavy metal ions, dye molecules and xenobiotics have been appraised. This review demonstrates clearly the high adsorption capacities of composts for umpteen environmental pollutants at the lab-scale. The main inferences from this review are that utilization of composts for the removal of heavy metal ions, dye molecules and xenobiotics from aqueous environments and soils is particularly worthwhile and efficient at the laboratory scale, and the adsorption behaviors and effectiveness of compost-type adsorbents for agrochemicals (e.g. herbicides and insecticides) vary considerably because of variabilities in structure, topology, bond connectivity, distribution of functional groups and interactions of xenobiotics with the active humic substances in composts. Compost-based field-scale remediation of environmental pollutants is still sparse and arguably much challenging to implement if, furthermore, real-world soil and water contamination issues are to be addressed effectively. Hence, significant research and process development efforts should be promptly geared and intensified in this direction by extrapolating the lab-scale findings in a cost-effective manner.

Prenatal β-Hexachlorocyclohexane (β-HCH) Exposure and 7-Year Child IQ in the CHAMACOS Birth Cohort

Fetal and infant exposures to β-hexachlorocyclohexane (β-HCH) occur through placental and breastmilk transfers. No studies have examined the relationship between β-HCH and child intelligence quotient (IQ). This study examined associations between in utero β-HCH exposure and cognitive development in 7-year-old children. Data from women and children (n = 256) participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) birth cohort study were evaluated. We assessed exposure to β-HCH by measuring maternal serum concentration during pregnancy. We administered the Wechsler Intelligence Scale for Children (WISC), Fourth Edition, to children at age 7. Analyses were adjusted for maternal age, country of birth, work status, parity, and other pesticide exposures, language used for child cognitive assessment, and duration of breastfeeding. Higher serum β-HCH concentrations were associated with higher cognitive scores across all unadjusted models for the full-scale and sub-scale cognitive tests. In the adjusted models, a 10-fold increase in serum β-HCH concentration was associated with a 4.5-point increase in Working Memory IQ score (95% CI, 0.6 to 8.3; p = 0.02). We observed no significant interaction by length of breastfeeding or sex on associations. Our findings suggest that prenatal exposure to β-HCH is not adversely related to IQ at age 7 in a cohort of Mexican American children with fairly high exposure in utero as measured by maternal serum levels. Future research must replicate these findings in other study cohorts of women and children.

Maternal and Neonatal Hair Cortisol Levels Are Associated with Infant Neurodevelopment at Six Months of Age

Background: Maternal stress during pregnancy can affect fetal development during certain sensitive periods. Objective: To longitudinally assess maternal hair cortisol levels during pregnancy, and the postpartum along with neonatal hair cortisol levels that could be associated with infant neurodevelopment at six months of age. Methods: A sample of 41 pregnant women longitudinally assessed during the first, second, and third trimester and the postpartum, along with their 41 full-term neonates participated in this study. Hair cortisol levels were assessed from participants. Infant neurodevelopment was assessed by means of the Bayley Scale of Infants Development, Third Edition at age six months. Results: Maternal hair cortisol levels in the first and second trimester accounted for 24% and 23%, respectively, of variance of infant gross motor development (p < 0.05). Maternal hair cortisol levels during the postpartum accounted for 31% of variance of infant cognitive development (p < 0.05), and 25% of variance of infant gross motor development (p < 0.05). Neonatal hair cortisol levels accounted for 28% of variance of infant gross motor development (p < 0.05). Conclusions: The preconception and prenatal time are sensitive periods related to infant neurodevelopment along with the cortisol levels surrounding the fetus while in the womb. Pregnant women could be assessed for hair cortisol levels while attending a prenatal appointment.

Residential proximity to greenhouse agriculture and neurobehavioral performance in Ecuadorian children

BACKGROUND

Children living near greenhouse agriculture may have an increased risk of pesticide exposure due to drift or direct contact with pesticide-treated areas. However, little is known about whether this increased potential for chronic exposure may impair their neurodevelopment.

METHODS

We examined 307 children aged 4-9 years, living in agricultural communities in Ecuador (ESPINA study). The two exposures calculated were residential distance from the nearest flower plantation perimeter and flower plantation surface area within 100 m of homes. Five neurobehavioral domains were assessed: Attention/Inhibitory Control, Memory/Learning, Visuospatial processing and Sensorimotor (higher values reflect better performance). Low scores were defined according to the test's cut-offs. Models were adjusted for demographic, socio-economic and growth variables.

RESULTS

The mean (SD) residential distance to the nearest flower plantation was 446 m (344). Living 100 m closer to crops was associated with increased odds (OR [95% CI]) of low scores in the domains of Memory/Learning (1.24 [1.05, 1.46]) and Language (1.09 [1.00, 1.19]). Associations were strongest among children living within 50 m, having significantly lower scores in Language (-1.28 which is ~50% of a SD [-2.50, -0.06]), Attention/Inhibitory Control (-1.24 units, [-2.45, -0.04]), and Memory/Learning (-0.91, [-1.99, 0.17]), compared to children living farther than 500 m. Analyses of areas of flower crops near homes concurred with these findings.

CONCLUSIONS

Close residential proximity to greenhouse floricultural crops was associated with adverse neurobehavioral performance in Attention/Inhibitory Control, Language and Memory/Learning among children. This highlights the importance of reducing pesticide drift from plantations to nearby homes.

Exposure to carbamate and neurodevelopment in children: Evidence from the SMBCS cohort in China

BACKGROUND

Carbamate pesticides exposure have been linked with adverse health effects during developmental period. Based on 377 mother-child pairs from Sheyang Mini Birth Cohort Study, the present study aimed to assess carbofuranphenol exposure of three-year-old children and explore the associations between prenatal or postnatal carbofuranphenol exposures and neurodevelopmental indicators.

METHODS

Urinary carbofuranphenol concentrations were measured by gas chromatography-tandem mass spectrometry. Neural developmental quotient (DQ) of children was evaluated using Gesell Developmental Schedules. Generalized linear models were used to examine the associations between carbofuranphenol concentrations and neurodevelopment.

RESULTS

Geometric mean, geometric standard deviation, median, inter quartile range of postnatal urinary carbofuranphenol concentrations were 0.653 μg/L, 9.345 μg/L, 0.413 μg/L, 0.150-1.675 μg/L, respectively. Postnatal carbofuranphenol level showed negatively significant trend in language DQ [beta (β) = -0.121; 95% confidence interval (95% CI): 0.212, -0.031; p value (p) = 0.008] and total average DQ (β = -0.059, 95% CI: 0.115, -0.003; p = 0.035). Prenatal carbofuranphenol level showed negative correlations with children's adaptive DQ (β = -0.755; 95% CI: 1.257, -0.254; p = 0.003), social DQ (β = -0.341; 95% CI: 0.656, -0.027; p = 0.032) and total average DQ (β = -0.349; 95% CI: 0.693, -0.005; p = 0.047).

CONCLUSION

The results of the present study supposed children in agricultural region of China are widely exposed to carbamate pesticides, and both prenatal and postnatal exposure to carbamate pesticides may lead to neurodevelopmental effect.

Urinary metabolites of organophosphate and pyrethroid pesticides in children from an Italian cohort (PHIME, Trieste)

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<0.05), which could reflect distinct dietary habits depending on the educational level. Estimated daily intakes were evaluated, all studied metabolites were found within safe levels.

Childhood chromium exposure and neuropsychological development in children living in two polluted areas in southern Spain

This study aimed to assess the association between exposure to chromium and neuropsychological development among children. A cross-sectional study was conducted with 393 children aged 6-11 years old randomly selected from State-funded schools in two provinces in Southern Spain (Almeria and Huelva), in 2010 and 2012. Chromium levels in urine and hair samples were analyzed by inductively coupled plasma mass spectrometry with an octopole reaction system. Neuropsychological development was evaluated using the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) and three computerized tests from the Behavioural Assessment and Research System (BARS): Reaction Time Test (RTT), Continuous Performance Test (CPT) and Selective Attention Test (SAT). Multivariable linear regression models adjusted for potential confounders, including heavy metals, were applied to examine the association between chromium levels and neuropsychological outcomes. A 10-fold increase in urine chromium levels was associated with a decrease of 5.99 points on the WISC-IV Full-Scale IQ (95% CI: 11.98 to -0.02). Likewise, a 10-fold increase in urine chromium levels in boys was associated with a decrease of 0.03 points in the percentage of omissions (95% CI: 0.0 to 0.05) in the SAT, with an increase of 68.35 points in latency (95% CI: 6.60 to 130.12) in the RTT, and with an increase in the number of trials with latencies > 1000 ms (β = 37.92; 95% CI: 2.73 to 73.12) in the RTT. An inverse significant association was detected between chromium levels in hair and latency in the SAT in boys (β = -50.53; 95% CI: 86.86 to -14.22) and girls (β = -55.95; 95% CI: 78.93 to -32.97). Excluding trials with latencies >1000 ms in the RTT increased latency scores by 29.36 points in boys (95% CI: 0.17 to 58.57), and 39.91 points in girls (95% CI: 21.25 to 58.59). This study is the first to show the detrimental effects of postnatal chromium exposure on neuropsychological development in school-aged children.

Effects of prenatal and postnatal exposure to organophosphate pesticides on child neurodevelopment in different age groups: a systematic review

Exposure to pesticides is a major factor in the cause of dysfunction in the nervous system and neurodevelopment disorders in children at critical periods of great vulnerability. The aim of this study was to review scientific evidence published on neurodevelopmental effects of prenatal and postnatal exposure to organophosphate pesticides (OPs) in different stages, including neonates, infants, toddlers, preschool children, and school-age children. Full-text articles published in PubMed, Scopus, and ISI databases between 1973 and 2019 were reviewed and the scientific evidence was evaluated. Results: Fifty studies were eligible for inclusion in this quantitative synthesis. Fifteen of these papers evaluated the effects on neonates and infants, 18 on the effects on toddlers and preschool children, and 24 the effects on school-age children. Considerable evidence suggests that prenatal exposure to OPs contributes to child neurodevelopment disorders in all stages, whereas data about the effects of postnatal exposure are limited. Therefore, the available evidence supports the theory that sensitive time-windows occur prenatally rather than postnatally. Although 45 out of the total 50 selected articles found an association between OP exposure and child neurodevelopment, some of the evidence is controversial. A standardized methodology is needed to enable the comparison of the results in several studies, and further research studies are needed to warrant firmer conclusions. A systematic review of this evidence should be performed continuously to update the state of knowledge regarding neurodevelopmental effects associated with OP exposure.

Optimization of Resolving Power, Fragmentation, and Mass Calibration in an Orbitrap Spectrometer for Analysis of 24 Pesticide Metabolites in Urine

Mass spectrometer parameters such as Resolving Power, type of fragmentation, and mass calibration mode were optimized in the analysis of 24 pesticide metabolites in human urine using Ultra-High Pressure Liquid Chromatography coupled to Orbitrap High-Resolution Mass Spectrometer (UHPLC-HRMS). The best results were achieved with a Resolving Power of 25,000 FWHM and by applying Collision Induced Dissociation fragmentation mode (40 eV).

Exposure to environmental toxicants and young children's cognitive and social development

Background Understanding the role of environmental toxicant exposure on children's development is an important area of inquiry in order to better understand contextual factors that shape development and ultimately school readiness among young children. There is evidence suggesting negative links between exposure to environmental toxicants and negative physical health outcomes (i.e. asthma, allergies) in children. However, research on children's exposure to environmental toxicants and other developmental outcomes (cognitive, socioemotional) is limited. Objectives The goal of the current review was to assess the existing literature on the links between environmental toxicants (excluding heavy metals) and children's cognitive, socioemotional, and behavioral development among young children. Methods This literature review highlights research on environmental toxicants (i.e. pesticide exposure, bisphenol A, polycyclic aromatic hydrocarbons, tobacco smoke, polychlorinated biphenyls, flame retardants, phthalates and gas pollutions) and children's development across multiple domains. Results The results highlight the potential risk of exposure to multiple environmental toxicants for young children's cognitive and socioemotional development. Discussion Discussion will focus on the role of environmental toxicants in the cognitive and socioemotional development of young children, while highlighting gaps in the existing literature.

Longitudinal, Seasonal, and Occupational Trends of Multiple Pesticides in House Dust

BACKGROUND

Children are especially vulnerable to pesticide exposure and can suffer lasting health effects. Because children of farmworkers are exposed to a variety of pesticides throughout development, it is important to explore temporal patterns of coexposures.

OBJECTIVES

The objectives of this study were to characterize the pesticide co-exposures, determine how they change over time, and assess differences between farmworker and nonfarmworker households.

METHODS

Dust collected from 40 farmworker and 35 nonfarmworker households in the Yakima Valley of the State of Washington in 2005 and then again in 2011 was analyzed for 99 pesticides. Eighty-seven pesticides representing over 28 classes were detected. Pesticides were grouped into classes using U.S. EPA pesticide chemical classifications, and trends in concentrations were analyzed at the class level.

RESULTS

Levels of organophosphates, pyridazinones, and phenols significantly decreased between 2005 and 2011 in both farmworker and nonfarmworker households. Levels of anilides, 2,6-dinitroanilines, chlorophenols, triclosan, and guanidines significantly increased in both farmworker and nonfarmworker households in 2011 vs. 2005. Among farmworkers alone, there were significantly lower levels of N-methyl carbamates and neonicotinoids in 2011.

CONCLUSIONS

We observed significant reductions in the concentrations of many pesticides over time in both farmworker and nonfarmworker households. Although nonfarmworker households generally had lower concentrations of pesticides, it is important to note that in comparison with NHANES participants, nonfarmworkers and their families still had significantly higher concentrations of urinary pesticide metabolites. This finding highlights the importance of detailed longitudinal exposure monitoring to capture changes in agricultural and residential pesticide use over time. This foundation provides an avenue to track longitudinal pesticide exposures in an intervention or regulatory context. https://doi.org/10.1289/EHP3644.

Bayesian varying coefficient kernel machine regression to assess neurodevelopmental trajectories associated with exposure to complex mixtures

Exposure to environmental mixtures can exert wide-ranging effects on child neurodevelopment. However, there is a lack of statistical methods that can accommodate the complex exposure-response relationship between mixtures and neurodevelopment while simultaneously estimating neurodevelopmental trajectories. We introduce Bayesian varying coefficient kernel machine regression (BVCKMR), a hierarchical model that estimates how mixture exposures at a given time point are associated with health outcome trajectories. The BVCKMR flexibly captures the exposure-response relationship, incorporates prior knowledge, and accounts for potentially nonlinear and nonadditive effects of individual exposures. This model assesses the directionality and relative importance of a mixture component on health outcome trajectories and predicts health effects for unobserved exposure profiles. Using contour plots and cross-sectional plots, BVCKMR also provides information about interactions between complex mixture components. The BVCKMR is applied to a subset of data from PROGRESS, a prospective birth cohort study in Mexico city on exposure to metal mixtures and temporal changes in neurodevelopment. The mixture include metals such as manganese, arsenic, cobalt, chromium, cesium, copper, lead, cadmium, and antimony. Results from a subset of Programming Research in Obesity, Growth, Environment and Social Stressors data provide evidence of significant positive associations between second trimester exposure to copper and Bayley Scales of Infant and Toddler Development cognition score at 24 months, and cognitive trajectories across 6-24 months. We also detect an interaction effect between second trimester copper and lead exposures for cognition at 24 months. In summary, BVCKMR provides a framework for estimating neurodevelopmental trajectories associated with exposure to complex mixtures.

Metabolomics of Pregnancy Complications: Emerging Application of Maternal Hair

In recent years, the study of metabolomics has begun to receive increasing international attention, especially as it pertains to medical research. This is due in part to the potential for discovery of new biomarkers in the metabolome and to a new understanding of the "exposome", which refers to the endogenous and exogenous compounds that reflect external exposures. Consequently, metabolomics research into pregnancy-related issues has increased. Biomarkers discovered through metabolomics may shed some light on the etiology of certain pregnancy-related complications and their adverse effects on future maternal health and infant development and improve current clinical management. The discoveries and methods used in these studies will be compiled and summarized within the following paper. A further focus of this paper is the use of hair as a biological sample, which is gaining increasing attention across diverse fields due to its noninvasive sampling method and the metabolome stability. Its significance in exposome studies will be considered in this review, as well as the potential to associate exposures with adverse pregnancy outcomes. Currently, hair has been used in only two metabolomics studies relating to fetal growth restriction (FGR) and gestational diabetes mellitus (GDM).

Organophosphorus pesticide residue levels in homes located near orchards

Organophosphorus pesticides (OPs) are commonly applied to agricultural crops. Families living in these communities may have higher exposure to OPs due to take home exposures and close proximity to agricultural fields. The objectives of this study were to measure OP concentrations in home carpet dust in agricultural and non-agricultural households and examine factors that may impact OP concentrations such as occupation, housing characteristics, and resident behaviors. Agricultural households had at least one parent who worked in agriculture during the previous 5 years. Carpet dust samples were collected at two time points from 278 households in an agricultural community located in the Pacific Northwest from 2008-2011. Samples were analyzed for four types of OPs: azinphos-methyl, phosmet, malathion, and chlorpyrifos. Overall, OP detection frequencies and concentrations were higher in agricultural households compared to non-agricultural households. Factors associated with higher OP concentrations in home carpet dust were identified and included: (1) homes with two or more agricultural workers living in the home, (2) homes located in close proximity to an agricultural field or orchard, (3) having an entry floor mat, and (4) frequently vacuuming the house. Having air conditioning in the home had a protective effect with OP concentrations. While the use of these four OPs is restricted or limited for residential use in the United States, results show that they were still found in the indoor environment. The understanding of the impact of agricultural work and other factors that elevate levels of OPs in the home is crucial to mitigating pesticide exposure in agricultural communities.

Urine collection methods for non-toilet-trained children in biological monitoring studies: Validation of a disposable diaper for characterization of tebuconazole exposure

Young children differ from adults in their exposure and susceptibility to environmental chemicals (e.g. pesticides) because of various factors such as behavior, diet and physiology. Their heightened vulnerability to environmental stressors makes it important to obtain appropriate urine samples for exposure characterization. However, collecting urine from non-toilet-trained children has been shown to be methodologically and practically challenging. Four urine collection approaches were tested: a disposable diaper, a urine bag, a collection pad and the clean catch. The success rate and the user rating of each method was evaluated. The success rates were 67%, 21%, 17% and 4% for the disposable diaper, urine bag, collection pad and clean catch, respectively. The average user ratings on a 0-10 (0 = inconvenient, 10 = convenient) scale were 9.0, 4.7, 7.3 and 2.5, respectively. Subsequently, the best rated method, the disposable polyacrylate diaper was tested with hydroxy-tebuconazole as an exposure biomarker for the fungicide tebuconazole and creatinine for urine density adjustment. After LC-MS/MS analysis, the recoveries of hydroxy-tebuconazole in the range of 0.05-25 ng/mL were on average 106%, and for creatinine 87%. Precisions (relative standard deviation) were for both 3%. The overall procedure including collection and extraction was assessed, resulting in three out of seven positive samples. Based on this study, the disposable diaper is a suitable method for urine collection of non-toilet-trained children for biomonitoring of tebuconazole. This method can serve as a basis for extension to other substances of interest.

Prevention of pesticide-induced neuronal dysfunction and mortality with nucleophilic poly-Oxime topical gel

Organophosphate-based pesticides inhibit acetylcholinesterase (AChE), which plays a pivotal role in neuromuscular function. While spraying in the field, farmworkers get exposed to pesticides through the dermal route. Internalized pesticide inhibits AChE, which leads to neurotoxicity, cardiotoxicity, cognitive dysfunction, loss of endurance, and death in severe cases. Here, we present a nucleophilic pyridine-2-aldoxime-functionalized chitosan-based topical gel (poly-Oxime gel) that rapidly deactivates organophosphates, methyl parathion (MPT), on the skin of rats, which leads to reduced AChE inhibition in the blood and tissues. Testing the robustness of poly-Oxime gel, we report reduction in AChE inhibition following repeated dermal administration of MPT in the presence of poly-Oxime gel. Furthermore, poly-Oxime gel prevented MPT-induced neuromuscular dysfunction, loss of endurance, and locomotor coordination. We observe a 100% survival in rats following topical MPT administration in the presence of poly-Oxime gel. This prophylactic gel may therefore help farmworkers by limiting pesticide-induced toxicity and mortality.

Pyrethroid bifenthrin induces oxidative stress, neuroinflammation, and neuronal damage, associated with cognitive and memory impairment in murine hippocampus

Exposure to synthetic pyrethroid (SPs) pesticides such as bifenthrin (BF) has been associated with adverse neurodevelopmental outcomes and cognitive impairments, but the underlying neurobiological mechanism is poorly understood so far. The present study has been designed to evaluate changes in behavior and in biomarkers of oxidative stress and neuroinflammation in the hippocampus of rats subchronically treated with BF. Rats exposed daily to BF at doses of 0.6 and 2.1 mg/kg b. w. for 60 days exhibited spatial and cognitive impairments as well as memory dysfunction after 60 days. This repeated BF treatment also significantly increased mRNA expression of pro-inflammatory cytokines tumor necrosis factor (TNF-α), interleukin (IL-1β), (IL-6), nuclear factor erythroid-2 (Nrf2), cyclooxygenase-2 (COX-2), nuclear factor-kappaB pathway (NF-kappaB), and prostaglandin E₂ (PGE₂) in the hippocampus. It further resulted in a significant increase in protein levels of Nrf2, COX-2, microsomal prostaglandin synthase-1 (mPGES-1) and NF-kappaB. This was accompanied by oxidative/nitrosative stress in the hippocampus of treated rats, as shown by increased levels of malondialdehyde (MDA), protein carbonyls (PCO), and nitric oxide (NO), and reduced levels of enzymatic (catalase, superoxide dismutase, and glutathione peroxidase) and non-enzymatic (reduced glutathione) antioxidants. The data are in line with those obtained in organotypic hippocampal slice cultures (OHSCs) isolated from mouse brain and exposed to BF for 72 h, showing neuronal death only at the high dose of 20 μM when compared to controls. These findings suggest that exposure to BF induces neuronal damage, alters redox state, and causes neuroinflammation in the hippocampus, which might lead to cognitive and memory impairment.

Paraquat and Maneb Exposure Alters Rat Neural Stem Cell Proliferation by Inducing Oxidative Stress: New Insights on Pesticide-Induced Neurodevelopmental Toxicity

Pesticide exposure has been linked to the pathogenesis of neurodevelopmental and neurodegenerative disorders including autism spectrum disorders, attention deficit/hyperactivity, and Parkinson's disease (PD). Developmental exposure to pesticides, even at low concentrations not harmful for the adult brain, can lead to neuronal loss and functional deficits. It has been shown that prenatal or early postnatal exposure to the herbicide paraquat (PQ) and the fungicide maneb (MB), alone or in combination, causes permanent toxicity in the nigrostriatal dopamine system, supporting the idea that early exposure to these pesticides may contribute to the pathophysiology of PD. However, the mechanisms mediating PQ and MB developmental neurotoxicity are not yet understood. Therefore, we investigated the neurotoxic effect of low concentrations of PQ and MB in primary cultures of rat embryonic neural stem cells (NSCs), with particular focus on cell proliferation and oxidative stress. Exposure to PQ alone or in combination with MB (PQ + MB) led to a significant decrease in cell proliferation, while the cell death rate was not affected. Consistently, PQ + MB exposure altered the expression of major genes regulating the cell cycle, namely cyclin D1, cyclin D2, Rb1, and p19. Moreover, PQ and PQ + MB exposures increased the reactive oxygen species (ROS) production that could be neutralized upon N-acetylcysteine (NAC) treatment. Notably, in the presence of NAC, Rb1 expression was normalized and a normal cell proliferation pattern could be restored. These findings suggest that exposure to PQ + MB impairs NSCs proliferation by mechanisms involving alterations in the redox state.

Serum concentrations of organochlorine compounds and predictors of exposure in children living in agricultural communities from South-Eastern Spain

BACKGROUND

Information on exposure levels to organochlorine compounds (OCs) in child population is limited, despite their greater vulnerability to the adverse health effects of these chemicals.

OBJECTIVE

To determine serum concentrations of 10 OCs (including organochlorine pesticides and polychlorinated biphenyls -PCBs-) in children living in agricultural communities from Almería (South-Eastern Spain), and to identify the main predictors of exposure related to socio-economic characteristics, diet and lifestyle.

METHODS

A cross-sectional study was conducted on 133 children aged 6-11 years selected from public schools of the study area. OCs compounds were determined in serum samples by GC/ECD. Anthropometric measures were obtained during sample collection. Information on sociodemographic characteristics, parental occupation, residential history, lifestyle and frequency of food consumption, among other relevant factors, was obtained by questionnaires administered to the mothers.

RESULTS

Geometric means of serum concentrations (ng/ml) were 0.11 for β-hexachloro-cyclohexane (β-HCH), 0.09 for endosulfan, 0.20 for endosulfan-ether, 0.51 for hexachorobenzene (HCB), 0.08 for mirex, 0.06 for oxychlordane, 0.36 for p,p'-DDE, 0.20 for PCB 138, 0.36 for PCB 153, and 0.45 for PCB 180. Percentage of samples above the limit of detection (0.05 ppb) ranged from 32 (β-HCH) to 100 (HCB). A high variability in OC levels depending on the compound was observed between our results and others found in similar studies carried out in children. Variables related to fish consumption were found to be the major dietary determinant of PCB 138, p,p´-DDE, endosulfan-α, β-HCH, mirex and oxychlordane levels.

CONCLUSIONS

Children participating in this study showed detectable levels of many OC, despite these compounds are no longer used. Their presence in children serum can be explained by their high lipophilicity and environmental persistence, leading to contamination of fatty food. In this line, fish consumption seemed to be the most relevant determinant of OC levels found in our study.

Interactions of organophosphorus pesticides with solute carrier (SLC) drug transporters

1. Organophosphorus pesticides (OPs) are known to interact with human ATP-binding cassette drug efflux pumps. The present study was designed to determine whether they can also target activities of human solute carrier (SLC) drug transporters. 2. The interactions of 13 OPs with SLC transporters involved in drug disposition, such as organic cation transporters (OCTs), multidrug and toxin extrusion proteins (MATEs), organic anion transporters (OATs) and organic anion transporting polypeptides (OATPs), were mainly investigated using transporter-overexpressing cell clones and fluorescent or radiolabeled reference substrates. 3. With a cut-off value of at least 50% modulation of transporter activity by 100 µM OPs, OAT1 and MATE2-K were not impacted, whereas OATP1B1 and MATE1 were inhibited by two and three OPs, respectively. OAT3 activity was similarly blocked by three OPs, and was additionally stimulated by one OP. Five OPs cis-stimulated OATP2B1 activity. Both OCT1 and OCT2 were inhibited by the same eight OPs, including fenamiphos and phosmet, with IC₅₀ values however in the 3-30 µM range, likely not relevant to environmental exposure. 4. These data demonstrated that various OPs inhibit SLC drug transporter activities, especially those of OCT1 and OCT2, but only when used at high concentrations not expected to occur in environmentally-exposed humans.

Sex-Specific Neurotoxic Effects of Organophosphate Pesticides Across the Life Course

PURPOSE OF REVIEW

This review discusses the sex-specific effects of exposure to various organophosphate (OP) pesticides throughout the life course and potential reasons for the differential vulnerabilities observed across sexes.

RECENT FINDINGS

Sex is a crucial factor in the response to toxicants, yet the sex-specific effects of OP exposure, particularly in juveniles and adults, remain unresolved. This is largely due to study design and inconsistencies in exposure and outcome assessments. Exposure to OPs results in multiple adverse outcomes influenced by many factors including sex. Reported sex-specific effects suggest that males are more susceptible to OPs, which reflects the sex-dependent prevalence of various neurodevelopmental and neurodegenerative disorders such as autism and amyotrophic lateral sclerosis (ALS), in which males are at greater risk. Thus, this review proposes that the biological sex-specific effects elicited by OP exposure may in part underlie the dimorphic susceptibilities observed in neurological disorders. Understanding the immediate and long-term effects of OP exposure across sexes will be critical in advancing our understanding of OP-induced neurotoxicity and disease.

How does exposure to pesticides vary in space and time for residents living near to treated orchards?

This study investigated changes over 25 years (1987-2012) in pesticide usage in orchards in England and Wales and associated changes to exposure and risk for resident pregnant women living 100 and 1000 m downwind of treated areas. A model was developed to estimate aggregated daily exposure to pesticides via inhaled vapour and indirect dermal contact with contaminated ground, whilst risk was expressed as a hazard quotient (HQ) based on estimated exposure and the no observed (adverse) effect level for reproductive and developmental effects. Results show the largest changes occurred between 1987 and 1996 with total pesticide usage reduced by ca. 25%, exposure per unit of pesticide applied slightly increased, and a reduction in risk per unit exposure by factors of 1.3 to 3. Thereafter, there were no consistent changes in use between 1996 and 2012, with an increase in number of applications to each crop balanced by a decrease in average application rate. Exposure per unit of pesticide applied decreased consistently over this period such that values in 2012 for this metric were 48-65% of those in 1987, and there were further smaller decreases in risk per unit exposure. All aggregated hazard quotients were two to three orders of magnitude smaller than one, despite the inherent simplifications of assuming co-occurrence of exposure to all pesticides and additivity of effects. Hazard quotients at 1000 m were 5 to 16 times smaller than those at 100 m. There were clear signals of the impact of regulatory intervention in improving the fate and hazard profiles of pesticides used in orchards in England and Wales over the period investigated.

Residential proximity to agricultural land and risk of brain tumor in the general population

The effect of pesticides on human health is still controversial, particularly as regards long-term health effects like cancer. The literature does suggest, however, that they could be involved in the occurrence of brain tumors, although the results concerning residential exposure are scarce. Our objective was to investigate the association between residential proximity to agricultural pesticides and brain tumors among adults in France by using a geographical information system. CERENAT is a population-based case-control study carried out in France in 2004-2006. We used two geographical data sources on agricultural land use to create exposure scores based on crop surface areas near the residence, for open field crops, vineyards and orchards. Conditional logistic regression for matched sets was used to estimate Odds Ratios (ORs) and 95% confidence intervals (95%CI). We found a significant association between meningioma and proximity to open field crops above the 75th percentile (OR 2.30 95%CI 1.04-5.10). Non-significant associations were also found with proximity of vineyards above the 95th percentile (OR 1.90 95%CI 0.41-8.69) and orchards above the 95th percentile (OR 5.50, 95%CI 0.49-61.94). No significant association was found between glioma and proximity to agricultural land. Further investigations are needed, particularly to improve the quality and availability of geographical data on agricultural land use.

Scientific Opinion of the PPR Panel on the follow-up of the findings of the External Scientific Report 'Literature review of epidemiological studies linking exposure to pesticides and health effects'

In 2013, EFSA published a comprehensive systematic review of epidemiological studies published from 2006 to 2012 investigating the association between pesticide exposure and many health outcomes. Despite the considerable amount of epidemiological information available, the quality of much of this evidence was rather low and many limitations likely affect the results so firm conclusions cannot be drawn. Studies that do not meet the 'recognised standards' mentioned in the Regulation (EU) No 1107/2009 are thus not suited for risk assessment. In this Scientific Opinion, the EFSA Panel on Plant Protection Products and their residues (PPR Panel) was requested to assess the methodological limitations of pesticide epidemiology studies and found that poor exposure characterisation primarily defined the major limitation. Frequent use of case-control studies as opposed to prospective studies was considered another limitation. Inadequate definition or deficiencies in health outcomes need to be avoided and reporting of findings could be improved in some cases. The PPR Panel proposed recommendations on how to improve the quality and reliability of pesticide epidemiology studies to overcome these limitations and to facilitate an appropriate use for risk assessment. The Panel recommended the conduct of systematic reviews and meta-analysis, where appropriate, of pesticide observational studies as useful methodology to understand the potential hazards of pesticides, exposure scenarios and methods for assessing exposure, exposure-response characterisation and risk characterisation. Finally, the PPR Panel proposed a methodological approach to integrate and weight multiple lines of evidence, including epidemiological data, for pesticide risk assessment. Biological plausibility can contribute to establishing causation.

Prenatal Residential Proximity to Agricultural Pesticide Use and IQ in 7-Year-Old Children

BACKGROUND

Residential proximity to agricultural pesticide use has been associated with neural tube defects and autism, but more subtle outcomes such as cognition have not been studied.

OBJECTIVES

We evaluated the relationship between prenatal residential proximity to agricultural use of potentially neurotoxic pesticides and neurodevelopment in 7-year-old children.

METHODS

Participants included mothers and children (n=283) living in the agricultural Salinas Valley of California enrolled in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study. We estimated agricultural pesticide use within 1 km of maternal residences during pregnancy using a geographic information system, residential location, and California’s comprehensive agricultural Pesticide Use Report data. We used regression models to evaluate prenatal residential proximity to agricultural use of five potentially neurotoxic pesticide groups (organophosphates, carbamates, pyrethroids, neonicotinoids, and manganese fungicides) and five individual organophosphates (acephate, chlorpyrifos, diazinon, malathion, and oxydemeton-methyl) and cognition in 7-year-old children. All models included prenatal urinary dialkyl phosphate metabolite concentrations.

RESULTS

We observed a decrease of 2.2 points [95% confidence interval (CI): −3.9, −0.5] in Full-Scale IQ and 2.9 points (95% CI: −4.4, −1.3) in Verbal Comprehension for each standard deviation increase in toxicity-weighted use of organophosphate pesticides. In separate models, we observed similar decrements in Full-Scale IQ with each standard deviation increase of use for two organophosphates (acephate and oxydemeton-methyl) and three neurotoxic pesticide groups (pyrethroids, neonicotinoids, and manganese fungicides).

CONCLUSIONS

This study identified potential relationships between maternal residential proximity to agricultural use of neurotoxic pesticides and poorer neurodevelopment in children. https://doi.org/10.1289/EHP504.

Distributions and determinants of urinary biomarkers of organophosphate pesticide exposure in a prospective Spanish birth cohort study

BACKGROUND

Prenatal exposure to organophosphate pesticides (OPs) has been associated with impaired child development. Pesticide exposure determinants need to be studied in order to identify sources and pathways of pesticide exposure. The aim of this paper is to describe prenatal exposure to OPs and evaluate the associated factors in pregnant women.

METHODS

The study population consisted of pregnant women (n = 573) who participated in the INMA birth cohort study in Valencia (Spain, 2003-2006). OP metabolites were analyzed in maternal urine at the 32nd week of gestation using a liquid chromatography-high resolution mass spectrometry method. The analysis included non-specific (diethyl phosphate [DEP], diethyl thiophosphate [DETP], dimethyl thiophosphate [DMTP], dimethyl dithiophosphate [DMDTP]) and specific metabolites (2-diethylamino-6-methyl-4-pyrimidinol [DEAMPY], 2-isopropyl-4-methyl-6-hydroxypyrimidine [IMPY], para-nitrophenol [PNP], and 3,5,6-trichloro-2-pyridinol [TCPY]). Information about the sociodemographic, environmental, and dietary characteristics was obtained by questionnaire. The association between log-transformed OPs and covariates was analyzed using multivariable interval censored regression.

RESULTS

The detection frequencies were low, DMTP and TCPY being the most frequently detected metabolites (53.8% and 39.1%, respectively). All the OP metabolites were positively associated with maternal intake of fruits and vegetables. Other maternal characteristics related to the OPs were body mass index (BMI) before pregnancy and smoking habit during pregnancy. Women with lower BMI and those who did not smoke presented higher OP concentrations. Moreover, mothers who had a yard or garden with plants at home or who lived in an urban area were also more exposed to OPs.

CONCLUSIONS

The OP detection frequencies and the concentrations observed in our study population were low, compared with most of the previously published studies. Given the high vulnerability of the fetus to neurotoxicant exposure, further research on the determinants of the body burden of OPs during pregnancy would be necessary. The knowledge gained from such studies would enhance the effectiveness of public health control and future recommendations in order to reduce the risk to both the health of pregnant women and the health and development of their children.