Associations between pesticide mixtures applied near home during pregnancy and early childhood with adolescent behavioral and emotional problems in the CHAMACOS study

Prenatal and childhood neonicotinoid exposure and neurodevelopment: A study in a young Taiwanese cohort

Neonicotinoid insecticides (NEOs) dominate the global pesticide market because of their low cost and effectiveness. However, epidemiological studies regarding the potential adverse health effects of exposure to NEOs before birth and in early childhood are limited. Therefore, this study investigated the associations between NEO exposure before birth and during early childhood and neurodevelopment. A total of 273 mother-child pairs were enrolled in this study. Mothers provided urine samples in the third trimester and breast milk during the first and third months of lactation. Their children provided urine samples and were evaluated for neurodevelopment by using the Bayley Scales of Infant and Toddler Development, Third Edition at 2-3 years (N = 96) and the Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV) at 4-6 years (N = 63). The sum of the concentrations of seven NEOs (ΣNEOs) and the relative potency factor of NEOs, based on comparison with imidacloprid (IMIRPF), were used to assess total exposure to NEOs. Multivariate linear regression analyses were conducted to assess the associations between prenatal and childhood exposure to NEOs and neurodevelopment. The results of the analysis revealed that clothianidin (CLO) and thiamethoxam were the most common NEOs to which children in the Taipei metropolitan area were exposed and that exposure concentrations were high in the Taipei metropolitan area. Imidacloprid was the most frequently detected NEO during the postnatal period. Additionally, exposure to NEOs through breast milk was low. Exposure to CLO, ΣNEOs, and IMIRPF in boys aged 4-6 years was negatively correlated with WPPSI-IV Fluid Reasoning Index. The results of this study indicate that exposure during the third trimester to NEOs does not affect neurodevelopment but that childhood exposure to NEOs may, especially for boys. Further studies with larger sample sizes are required to confirm the sex-specific associations between NEO exposure and neurodevelopment.

Organophosphate pesticide exposure and risk of SARS-CoV-2 infection

Several studies have reported immune modulation by organophosphate (OP) pesticides, but the relationship between OP exposure and SARS-CoV-2 infection is yet to be studied. We used two different measures of OP pesticide exposure (urinary biomarkers (N = 154) and residential proximity to OP applications (N = 292)) to examine the association of early-childhood and lifetime exposure to OPs and risk of infection of SARS-CoV-2 using antibody data. Our study population consisted of young adults (ages 18-21 years) from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) Study, a longitudinal cohort of families from a California agricultural region. Urinary biomarkers reflected exposure from in utero to age 5 years. Residential proximity reflected exposures between in utero and age 16 years. SARS-CoV-2 antibodies in blood samples collected between June 2022 and January 2023 were detected via two enzyme linked immunosorbent assays, each designed to bind to different SARS-CoV-2 antigens. We performed logistic regression for each measure of pesticide exposure, adjusting for covariates from demographic data and self-reported questionnaire data. We found increased odds of SARS-CoV-2 infection among participants with higher urinary biomarkers of OPs in utero (OR = 1.94, 95% CI: 0.71, 5,58) and from age 0-5 (OR = 1.90, 95% CI: 0.54, 6.95).

Organophosphorus pesticide exposure from house dust and parent-reported child behavior in Latino children from an orchard community

BACKGROUND

Organophosphorus pesticide (OP) exposure is known to have adverse effects on the nervous system. Children from agricultural communities are at risk of exposure to these chemicals from their indoor environments that can lead to neurological and developmental problems, including changes in behavior.

OBJECTIVE

The aim of this study is to evaluate whether the take-home pathway exposure is associated with behavioral and emotional problems in Latino Orchid Community children.

METHOD

The study was implemented over a period of two years (2008-2010) in an orchard farming community with a total of 324 parents who had children between the ages of 5-12 years old. Mothers of the children were asked to complete the Child Behavior Checklist (CBCL) and dust from their carpets was collected. Emotional and behavioral deficits were assessed based on the CBCL and house dust was assessed for OP concentrations. In this study, correlations between OPs in house dust and CBCL subscales were estimated using linear regression models with total OP concentrations classified by tertiles. This study also facilitated the comparison between the agricultural and non-agricultural families in terms of behavioral deficits and house dust concentrations of pesticides.

RESULTS

The data from the study shows that there was a positive association between the concentration of OP residues in house dust and internalizing behavior (β=2.06, p=0.05) whereas the association with externalizing behavior was not significant after accounting for sociocultural covariates. Significant positive associations of OP residues with somatic problems (p=0.02) and thought problems (p=0.05) were also found.

CONCLUSION

The data support a potential role of OP exposure in childhood development, with a specific focus on internalizing behavior. Future work focused on longitudinal studies may uncover the long-term consequences of OP exposure and behavior.

Gestational glyphosate exposure and early childhood neurodevelopment in a Puerto Rico birth cohort

INTRODUCTION

N-(phosphonomethyl)glycine, or glyphosate, is a non-selective systemic herbicide widely used in agricultural, industrial, and residential settings since 1974. Glyphosate exposure has been inconsistently linked to neurotoxicity in animals, and studies of effects of gestational exposure among humans are scarce. In this study we investigated relationships between prenatal urinary glyphosate analytes and early childhood neurodevelopment.

METHODS

Mother-child pairs from the PROTECT-CRECE birth cohort in Puerto Rico with measures for both maternal urinary glyphosate analytes and child neurodevelopment were included for analysis (n = 143). Spot urine samples were collected 1-3 times throughout pregnancy and analyzed for glyphosate and aminomethylphosphonic acid (AMPA), an environmental degradant of glyphosate. Child neurodevelopment was assessed at 6, 12, and 24 months using the Battelle Developmental Inventory, 2nd edition Spanish (BDI-2), which provides scores for adaptive, personal-social, communication, motor, and cognitive domains. We used multivariable linear regression to examine associations between the geometric mean of maternal urinary glyphosate analytes across pregnancy and BDI-2 scores at each follow-up. Results were expressed as percent change in BDI-2 score per interquartile range increase in exposure.

RESULTS

Prenatal AMPA concentrations were negatively associated with communication domain at 12 months (%change = -5.32; 95%CI: 9.04, -1.61; p = 0.007), and communication subdomain scores at 12 and 24 months. At 24 months, four BDI-2 domains were associated with AMPA: adaptive (%change = -3.15; 95%CI: 6.05, -0.25; p = 0.038), personal-social (%change = -4.37; 95%CI: 7.48, -1.26; p = 0.008), communication (%change = -7.00; 95%CI: 11.75, -2.26; p = 0.005), and cognitive (%change = -4.02; 95%CI: 6.72, -1.32; p = 0.005). Similar trends were observed with GLY concentrations, but most confidence intervals include zero. We found no significant associations at 6 months.

CONCLUSIONS

Our results suggest that gestational exposure to glyphosate is associated with adverse early neurodevelopment, with more pronounced delays at 24 months. Given glyphosate's wide usage, further investigation into the impact of gestational glyphosate exposure on neurodevelopment is warranted.

Evaluating the accuracy of satellite-based methods to estimate residential proximity to agricultural crops

BACKGROUND

Epidemiologic investigations increasingly employ remote sensing data to estimate residential proximity to agriculture as a means of approximating individual-level pesticide exposure. Few studies have examined the accuracy of these methods and the implications for exposure misclassification.

OBJECTIVES

Compare metrics of residential proximity to agricultural land between a groundtruth approach and commonly-used satellite-based estimates.

METHODS

We inspected 349 fields and identified crops in current production within a 0.5 km radius of 40 residences in Idaho. We calculated the distance from each home to the nearest agricultural field and the total acreage of agricultural fields within a 0.5 km buffer. We compared these groundtruth estimates to satellite-derived estimates from three widely used datasets: CropScape, the National Land Cover Database (NLCD), and Landsat imagery (using Normalized Difference Vegetation Index thresholds).

RESULTS

We found poor to moderate agreement between the classification of individuals living within 0.5 km of an agricultural field between the groundtruth method and the comparison datasets (53.1-77.6%). All satellite-derived estimates overestimated the acreage of agricultural land within 0.5 km of each home (average = 82.8-148.9%). Using two satellite-derived datasets in conjunction resulted in substantial improvements; specifically, combining CropScape or NLCD with Landsat imagery had the highest percent agreement with the groundtruth data (92.8-93.8% agreement).

SIGNIFICANCE

Residential proximity to agriculture is frequently used as a proxy for pesticide exposure in epidemiologic investigations, and remote sensing-derived datasets are often the only practical means of identifying cultivated land. We found that estimates of agricultural proximity obtained from commonly-used satellite-based datasets are likely to result in exposure misclassification. We propose a novel approach that capitalizes on the complementary strengths of different sources of satellite imagery, and suggest the combined use of one dataset with high temporal resolution (e.g., Landsat imagery) in conjunction with a second dataset that delineates agricultural land use (e.g., CropScape or NLCD).

Molecular Docking Analysis at the Human α7-nAChR and Proliferative and Evoked-Calcium Changes in SH-SY5Y Cells by Imidacloprid and Acetamiprid Insecticides

Acetamiprid (ACE) and Imidacloprid (IMI) are widely-used neonicotinoid insecticides (NNIs) with functional activity at human acetylcholine nicotinic receptors and, therefore, with putative toxic effects. The objective of this study was the evaluation of the interactions between NNIs and α7-nAChR, as this receptor keeps intracellular Ca2+ ([Ca2+]i) to an optimum for an adequate neuronal functioning. Possible interactions between NNIs and the cryo-EM structure of the human α-7 nAChR were identified by molecular docking. Additionally, NNI effects were analyzed in neuroblastoma SH-SY5Y cells, as they naturally express α-7 nAChRs. Functional studies included proliferative/cytotoxic effects (MTT test) in undifferentiated SH-SY-5Y cells and indirect measurements of [Ca2+]i transients in retinoic acid-differentiated SH-SY-5Y cells loaded with Fluo-4 AM. Docking analysis showed that the binding of IMI and ACE occurred at the same aromatic cage that the specific α-7 nAChR agonist EVP-6124. IMI showed a better docking strength than ACE. According to the MTT assays, low doses (10-50 µM) of IMI better than ACE stimulated neuroblastoma cell proliferation. At higher doses (250-500 µM), IMI also prevailed over ACE and dose-dependently triggered more abrupt fluorescence changes due to [Ca2+]i mobilization in differentiated SH-SY5Y neurons. Indeed, only IMI blunted nicotine-evoked intracellular fluorescence stimulation (i.e., nicotine cross-desensitization). Summarizing, IMI demonstrated a superior docking strength and more robust cellular responses compared to ACE, which were likely associated with a stronger activity at α-7nAChRs. Through the interaction with α-7nAChRs, IMI would demonstrate its high neurotoxic potential for humans. More research is needed for investigating the proliferative effects of IMI in neuroblastoma cells.

Maternal exposure of mice to glyphosate induces depression- and anxiety-like behavior in the offspring via alterations of the gut-brain axis

The past decade has been characterized by increased awareness and de-stigmatization of mental health issues, in particular the most common neuropsychiatric disorders depression and anxiety. Further, with growing understanding of neurodevelopmental disorders such as attention deficit and hyperactivity disorder and autism spectrum disorder, the number of diagnosed patients has increased. The pathogenesis of these behavioral disorders is multifactorial and early-life exposure to environmental chemicals has been proposed to be a relevant risk factor that might mediate these effects by disturbances on the gut-brain-axis. However, for glyphosate, the most widely used pesticide worldwide, there are only limited and inconsistent findings that link chronic low-dose exposure in particular during early life to neurobehavioral disorders. Here, we explored the impact of maternal oral glyphosate exposure (0.5 and 50 mg/kg body weight/day) during pregnancy and the lactational period on offspring's behavior, brain gene expression and gut microbiota using a cross-generational mouse model. Behavioral analyses revealed a depression- and anxiety-like behavior as well as social deficits most notably in adult female offspring of glyphosate-exposed dams. Furthermore, the expression of tryptophan hydroxylase 2, an enzyme discussed to be linked to behavioral problems, was reduced in the hippocampus of female offspring and correlated to a glyphosate-induced DNA hypermethylation of the gene. Moreover, maternal glyphosate exposure significantly altered the gut microbiota in the female offspring including a decreased abundance of Akkermansia and increased abundance of Alistipes and Blautia, bacteria involved in tryptophan metabolism and associated with depression- and anxiety-like disorders. Our results suggest that glyphosate might influence the gut-brain axis crosstalk following in-utero and lactational exposure. This study underlines the importance of understanding the impact of exposure to pesticides on the gut-brain axis and further emphasizes the need for microbiome analyses to be compulsorily included in health risk assessments of pesticides.

Association between maternal urinary neonicotinoid concentrations and child development in the Japan Environment and Children's Study

BACKGROUND

Recent studies have reported the effect of neonicotinoid (NEO) exposures on development in human. However, information about the risk of childhood development delays due to NEO exposures is limited.

OBJECTIVES

The study aimed to examine the association between NEO exposure and child development up to 4 years of age using data of the Japan Environment and Children's Study.

METHODS

The study employed urinary NEO and metabolite concentrations in the first and second or third trimesters; the Japanese translation of the Ages and Stages Questionnaire (third edition; J-ASQ-3) scores on developmental delay in five domains, namely communication, gross motor skills, fine motor skills, problem solving, and personal-social characteristics from 6 months to 4 years of age; and self-reported questionnaire data. The associations between urinary NEO concentrations and J-ASQ-3 results were analysed using the treed distributed lag mixture model. A total of 8538 participants were included in statistical analyses.

RESULTS

The determination rates of urinary acetamiprid-N-desmethyl (dm-ACE), clothianidin (CLO), dinotefuran (DIN) and thiamethoxam (THX) were greater than 50%. Median urinary dm-ACE, CLO, DIN and THX concentrations were 0.34, 0.14, 0.22 and 0.05 ng/ml, respectively, in samples collected during gestational weeks < 23, and 0.28, 0.12, 0.18 and 0.04 ng/ml, respectively, in those collected during gestational weeks ≥ 23. The binomial scores divided by the cut-off values of the J-ASQ were used in the treed distributed lag mixture model. The highest percentage for a domain with a value less than the cut-off value was 'problem solving' at 6 months of age among all the J-ASQ-3 scores (10.5%). There was no statistically significant association between maternal urinary dm-ACE, CLO, DIN and THX concentrations during pregnancy and the J-ASQ-3 results up to 4 years of age. Objective assessment of child development in different populations may be warranted to confirm our findings.

Methods in Public Health Environmental Justice Research: a Scoping Review from 2018 to 2021

PURPOSE OF REVIEW

The volume of public health environmental justice (EJ) research produced by academic institutions increased through 2022. However, the methods used for evaluating EJ in exposure science and epidemiologic studies have not been catalogued. Here, we completed a scoping review of EJ studies published in 19 environmental science and epidemiologic journals from 2018 to 2021 to summarize research types, frameworks, and methods.

RECENT FINDINGS

We identified 402 articles that included populations with health disparities as a part of EJ research question and met other inclusion criteria. Most studies (60%) evaluated EJ questions related to socioeconomic status (SES) or race/ethnicity. EJ studies took place in 69 countries, led by the US (n = 246 [61%]). Only 50% of studies explicitly described a theoretical EJ framework in the background, methods, or discussion and just 10% explicitly stated a framework in all three sections. Among exposure studies, the most common area-level exposure was air pollution (40%), whereas chemicals predominated personal exposure studies (35%). Overall, the most common method used for exposure-only EJ analyses was main effect regression modeling (50%); for epidemiologic studies the most common method was effect modification (58%), where an analysis evaluated a health disparity variable as an effect modifier. Based on the results of this scoping review, current methods in public health EJ studies could be bolstered by integrating expertise from other fields (e.g., sociology), conducting community-based participatory research and intervention studies, and using more rigorous, theory-based, and solution-oriented statistical research methods.

Disparities in Toxic Chemical Exposures and Associated Neurodevelopmental Outcomes: A Scoping Review and Systematic Evidence Map of the Epidemiological Literature

BACKGROUND

Children are routinely exposed to chemicals known or suspected of harming brain development. Targeting Environmental Neuro-Development Risks (Project TENDR), an alliance of > 50 leading scientists, health professionals, and advocates, is working to protect children from these toxic chemicals and pollutants, especially the disproportionate exposures experienced by children from families with low incomes and families of color.

OBJECTIVE

This scoping review was initiated to map existing literature on disparities in neurodevelopmental outcomes for U.S. children from population groups who have been historically economically/socially marginalized and exposed to seven exemplar neurotoxicants: combustion-related air pollution (AP), lead (Pb), mercury (Hg), organophosphate pesticides (OPs), phthalates (Phth), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs).

METHODS

Systematic literature searches for the seven exemplar chemicals, informed by the Population, Exposure, Comparator, Outcome (PECO) framework, were conducted through 18 November 2022, using PubMed, CINAHL Plus (EBSCO), GreenFILE (EBSCO), and Web of Science sources. We examined these studies regarding authors' conceptualization and operationalization of race, ethnicity, and other indicators of sociodemographic and socioeconomic disadvantage; whether studies presented data on exposure and outcome disparities and the patterns of those disparities; and the evidence of effect modification by or interaction with race and ethnicity.

RESULTS

Two hundred twelve individual studies met the search criteria and were reviewed, resulting in 218 studies or investigations being included in this review. AP and Pb were the most commonly studied exposures. The most frequently identified neurodevelopmental outcomes were cognitive and behavioral/psychological. Approximately a third (74 studies) reported investigations of interactions or effect modification with 69% (51 of 74 studies) reporting the presence of interactions or effect modification. However, less than half of the studies presented data on disparities in the outcome or the exposure, and fewer conducted formal tests of heterogeneity. Ninety-two percent of the 165 articles that examined race and ethnicity did not provide an explanation of their constructs for these variables, creating an incomplete picture.

DISCUSSION

As a whole, the studies we reviewed indicated a complex story about how racial and ethnic minority and low-income children may be disproportionately harmed by exposures to neurotoxicants, and this has implications for targeting interventions, policy change, and other necessary investments to eliminate these health disparities. We provide recommendations on improving environmental epidemiological studies on environmental health disparities. To achieve environmental justice and health equity, we recommend concomitant strategies to eradicate both neurotoxic chemical exposures and systems that perpetuate social inequities. https://doi.org/10.1289/EHP11750.

Prenatal and Childhood Exposure to Organophosphate Pesticides and Behavior Problems in Adolescents and Young Adults in the CHAMACOS Study

BACKGROUND

We previously reported associations of prenatal exposure to organophosphate (OP) pesticides with poorer neurodevelopment in early childhood and at school age, including poorer cognitive function and more behavioral problems, in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a birth cohort study in an agriculture community.

OBJECTIVE

We investigated the extent to which early-life exposure to OP pesticides is associated with behavioral problems, including mental health, in youth during adolescence and early adulthood.

METHODS

We measured urinary dialkylphosphates (DAPs), nonspecific OP metabolites, in urine samples collected from mothers twice during pregnancy (13 and 26 wk) and at five different times in their children (ages 6 months to 5 y). We assessed maternal report and youth report of externalizing and internalizing behavior problems using the Behavior Assessment System for Children, 2nd edition (BASC-2), when the youth were ages 14, 16, and 18 y. Because there was evidence of nonlinearity, we estimated associations across quartiles of DAPs and modeled repeated outcome measures using generalized estimating equations.

RESULTS

There were 335 youths with prenatal maternal DAP measures and 14-. 16-, or 18-y BASC-2 scores. Prenatal maternal DAP concentrations (specific gravity-adjusted median, Q 1 - Q 3 = 159.4 , 78.7 - 350.4  nmol / L ) were associated with higher T-scores (more behavior problems) from maternal report, including more hyperactivity [fourth vs. first quartile of exposure β = 2.32 ; 95% confidence interval (CI): 0.18, 4.45], aggression (β = 1.90 ; 95% CI: 0.15, 3.66), attention problems (β = 2.78 ; 95% CI: 0.26, 5.30), and depression (β = 2.66 ; 95% CI: 0.08, 5.24). Associations with youth report of externalizing problems were null, and associations with depression were suggestive (fourth vs. first quartile of exposure β = 2.15 ; 95% CI: - 0.36 , 4.67). Childhood DAP metabolites were not associated with behavioral problems.

DISCUSSION

We found associations of prenatal, but not childhood, urinary DAP concentrations with adolescent/young adult externalizing and internalizing behavior problems. These findings are consistent with prior associations we have reported with neurodevelopmental outcomes measured earlier in childhood in CHAMACOS participants and suggests that prenatal exposure to OP pesticides may have lasting effects on the behavioral health of youth as they mature into adulthood, including their mental health. https://doi.org/10.1289/EHP11380.

Neurocytotoxicity of imidacloprid- and acetamiprid-based comercial insecticides over the differentiation of SH-SY5Y neuroblastoma cells

Neonicotinoids are effective insecticides with specificity for invertebrate nicotinic acetylcholine receptors. Neonicotinoids are chemically stable and tend to remain in the environment for long so concerns about their neurotoxicity in humans do nothing but increase. Herein, we evaluated the chronic toxic effects of acetamiprid- and imidacloprid-based insecticides over the differentiation of human neuroblastoma SH-SY5Y cells, which were exposed to these insecticides at a concentration range similar to that applied to crop fields (0.01-0.5 mM). Both insecticides did not have acute cytotoxic effects in both non-differentiated and in staurosporine-differentiated SH-SY5Y cells cytotoxicity as measured by the MTT and vital-dye exclusion tests. However, after a chronic (7-day) treatment, only imidacloprid dose-dependently decreased the viability of SH-SY5Y cells (F(4,39) = 43.05, P < 0.001), largely when administered-during cell differentiation (F(4,39) = 51.86, P < 0.001). A well-defined dose-response curve was constructed for imidacloprid on day 4 (R² = 0.945, EC₅₀ = 0.14 mM). During differentiation, either imidacloprid or acetamiprid dose-dependently caused neurite branch retraction on day 3, likely because of oxidative stress, to the extent that cells turned into spheres without neurites after 7-day treatment. Despite their apparent safety, the neurodevelopmental vulnerability of SH-SY5Y neurons to the chronic exposure to imidacloprid and to a lesser extent to acetamiprid points to a neurotoxic risk for humans.

Contributions of nearby agricultural insecticide applications to indoor residential exposures

BACKGROUND

Pesticide exposure has been associated with adverse health effects. We evaluated relationships between proximity to agricultural insecticide applications and insecticides in household dust, accounting for land use and wind direction.

METHODS

We measured concentrations (ng/g) of nine insecticides in carpet-dust samples collected from 598 California homes. Using a geographic information system (GIS), we integrated the California Pesticide Use Reporting (CPUR) database to estimate agricultural use within residential buffers with radii of 0.5 to 4 km. We calculated the density of use (kg/km2) during 30-, 60-, 180-, and 365-day periods prior to dust collection and evaluated relationships between three density metrics (CPUR unit-based, agricultural land area adjusted, and average daily wind direction adjusted) and dust concentrations. We modeled natural-log transformed concentrations using Tobit regression for carbaryl, chlorpyrifos, cypermethrin, diazinon, and permethrin. Odds of detection were modeled with logistic regression for azinphos-methyl, cyfluthrin, malathion, and phosmet. We adjusted for season, year, occupation, and home/garden uses.

RESULTS

Chlorpyrifos use within 1-4 km was associated with 1 to 2-times higher dust concentrations in both the 60- and 365-day periods. Carbaryl applications within 2-4 km of homes 60-days prior to dust collection were associated with 3 to 7-times higher concentrations and the 4 km trend was strongest using the wind-adjusted metric (p-trend = 0.04). For diazinon, there were 2-times higher concentrations for the 60-day metrics in the 2 km buffer and for the CPUR and wind-adjusted metrics within 4 km. Cyfluthrin, phosmet, and azinphos-methyl applications within 4 km in the prior 365-days were associated with 2-, 6-, and 3-fold higher odds of detection, respectively.

CONCLUSIONS

Agricultural use of six of the nine insecticides within 4 km is an important determinant of indoor contamination. Our findings demonstrated that GIS-based metrics for quantifying potential exposure to fugitive emissions from agriculture should incorporate tailored distances and time periods and support wind-adjustment for some, but not all insecticides.

Racial and social disparities in Ventura County, California related to agricultural pesticide applications and toxicity

Application of agricultural pesticides poses health concerns for farmworkers and for local communities due to pesticide drift from spraying or fumigation, pesticide volatilization into the air, contamination of household dust, as well as direct exposure for people who work in agriculture and their families. In this analysis of pesticide use records for Ventura County, California (USA) from 2016 to 2018, we identified the most prevalent toxicological effects of the pesticides applied. We also developed a cumulative toxicity index that incorporates specific toxicity endpoints for individual pesticides, the severity and strength of association for each endpoint, and the reliability of the data sources. Combining the toxicity index for each pesticide with the pounds applied within each square mile section in Ventura County, we calculated the total toxicity-weighted pesticide use and identified pesticides associated with higher potential risk to health. Analysis of U.S. Census data for Ventura County found a greater percentage of Hispanic/Latino, African American and Asian community members in township sections with a greater volume of pesticides applied and higher toxicity-weighted pesticide use. Similarly, areas with limited economic and social resources had elevated pesticide application overall and elevated toxicity-weighted pesticide use. The combination of toxicological and demographic analyses presented in this study provides information that can support the development of policies to protect public health from excessive exposure to pesticides and better environmental health protection for socially vulnerable populations.

Residential proximity to agricultural pesticide use and risk-taking behaviors in young adults from the CHAMACOS study

BACKGROUND

Prenatal pesticide exposure has been associated with poorer neurodevelopment during childhood, which could lead to greater risk-taking behaviors and delinquency in adolescence. This association may be augmented by adversity exposure.

OBJECTIVES

Evaluate the relationship between prenatal pesticide exposure and risk-taking behavior in young adults at 18-years of age. Assess whether adversity exposure modifies these associations.

METHODS

Participants included mother-child dyads (n = 467) enrolled in the Center for the Health Assessment of Mothers and Children Of Salinas (CHAMACOS) study, a longitudinal birth cohort set in the agricultural Salinas Valley of California. We estimated agricultural pesticide use within one km of maternal residences during pregnancy using a geographic information system, residential addresses, and California's Pesticide Use Reporting data. We used Bayesian hierarchical regression to evaluate associations of prenatal exposure to a mixture of 11 neurotoxic pesticides with self-reported police encounters, risk-taking behaviors, and unique types and frequency of delinquent acts. We also evaluated effect modification of these relationships by adversity exposure.

RESULTS

We observed generally null associations of neurotoxic pesticide use with risk-taking behaviors. Prenatal residential proximity to chlorpyrifos use was associated with higher risk of a police encounter, a delinquent act, and higher incidence of both unique types of acts committed and total frequency of delinquent acts. Prenatal residential proximity to dimethoate use was associated with a higher incidence of police encounters and methomyl with a higher risk of committing a delinquent act. There were no consistent differences when stratified by the number of adverse childhood experiences.

CONCLUSIONS

We observed mostly null associations between prenatal residential proximity to agricultural pesticide use and risk-taking behaviors at age 18, with little evidence of effect modification by childhood adversity. There were suggestive associations for chlorpyrifos use with having any police encounter and with all measures of delinquent acts that warrant confirmation in other studies.

Interactions of agricultural pesticide use near home during pregnancy and adverse childhood experiences on adolescent neurobehavioral development in the CHAMACOS study

BACKGROUND

Studies have documented independent adverse associations between prenatal and early-life exposure to environmental chemicals and social adversity with child neurodevelopment; however, few have considered these exposures jointly. The objective of this analysis is to examine whether associations of pesticide mixtures and adolescent neurobehavioral development are modified by early-life adversity in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort.

METHODS

We used linear mixed effects Bayesian Hierarchical Models (BHM) to examine the joint effect of applications of 11 agricultural pesticides within 1 km of maternal homes during pregnancy and youth-reported Adverse Childhood Experiences (ACEs) with maternal and youth-reported internalizing behaviors, hyperactivity, and attention problems assessed via the Behavior Assessment for Children (BASC) (mean = 50, standard deviation = 10) at ages 16 and 18 years (n = 458).

RESULTS

The median (25th-75th percentiles) of ACEs was 1 (0-3); 72.3% of participants had low ACEs (0-2 events) and 27.7% had ACEs (3+ events). Overall, there was little evidence of modification of exposure-outcome associations by ACEs. A two-fold increase in malathion use was associated with increased internalizing behaviors among those with high ACEs from both maternal- (β = 1.9; 95% Credible Interval (CrI): 0.2, 3.7 for high ACEs vs. β = -0.1; 95% CrI: 1.2, 0.9 for low ACEs) and youth-report (β = 2.1; 95% CrI: 0.4, 3.8 for high ACEs vs. β = 0.2; 95% CrI: 0.8, 1.2 for low ACEs). Applications of malathion and dimethoate were also associated with higher youth-reported hyperactivity and/or inattention among those with high ACEs.

CONCLUSION

We observed little evidence of effect modification of agricultural pesticide use near the home during pregnancy and adolescent behavioral problems by child ACEs. Future studies should examine critical windows of susceptibility of exposure to chemical and non-chemical stressors and should consider biomarker-based exposure assessment methods.