Mixed-Methods Assessment of Farmworkers' Perceptions of Workplace Compliance with Worker Protection Standards and Implications for Risk Perceptions and Protective Behaviors.

INTRODUCTION: The Environmental Protection Agency (EPA)'s Worker Protection Standards is the primary set of legislation aimed at protecting farmworkers from occupational pesticide exposure in the United States. Previous studies suggest that worker adoption of Pesticide Protective Behaviors (PPBs) promoted by WPS is associated with lower urinary pesticide concentrations. However, adoption of PPBs is often outside of the control of individual farmworkers and dependent on workplace factors such as employer provisioning of Personal Protective Equipment (PPE) and access to trainings/resources. METHODS: We conducted a mixed-method study including urinary pesticide biomonitoring, surveys, and interviews with 62 Latinx farmworkers in southwestern Idaho from April to July 2022. We integrated findings across the various data sources to identify emergent themes relating to farmworkers' perceptions of workplace compliance with WPS and potential implications for their pesticide risk perceptions, protective behaviors, and urinary pesticide concentrations. RESULTS: Participants reported some indications of poor workplace compliance with WPS regulations, notably inconsistent access to clean handwashing stations and notification of pesticide applications. Some farmworkers, particularly pesticide applicators, viewed herbicides to be categorically safer than other classes of pesticides such as insecticides; these perceptions appeared to influence protective behaviors, such as the relatively low use of PPE while applying herbicides. These findings are underscored by the higher concentrations of biomarkers of herbicides, but not insecticides, among pesticide applicators compared with non-applicators (e.g. median 2,4-D concentrations = 1.40 µg/L among applicators and 0.69 µg/L among non-applicators). Participants further reported concerns regarding the inadequacy of pesticide safety training, pesticide drift, and the lack of communication regarding pesticide applications on and near fields where they are working. DISCUSSION: Participants' perceptions that herbicides are categorically safer than other pesticide classes is in direct conflict with WPS training, raising concerns about discrepancies between WPS instruction and other on-the-job training, as well as the inadequate provisioning of PPE during the application of certain pesticides. Our findings also suggest that current WPS regulations may not sufficiently address farmworkers' concerns, particularly in regard to pesticide drift.

Dietary Predictors of Urinary Biomarkers of Pyrethroids in the General Population - A Scoping Review.

BACKGROUND: Pyrethroid pesticides are ubiquitous environmental contaminants, contributing to chronic and potentially harmful exposure among the general population. Although studies have measured pesticide residues on agricultural products, the link between food intake and concentrations of pyrethroid biomarkers in urine remains unclear. OBJECTIVE: This scoping review aims to analyze peer-reviewed publications investigating dietary predictors of pyrethroid exposure through urinary biomarkers. We assess existing evidence, identify research gaps, and highlight current limitations. METHODS: We conducted a comprehensive search using PubMed and Google Scholar. Eligible studies examined associations between diets, food items or dietary components, and measured urinary pyrethroid biomarkers. No geographical restriction was applied to our search. Results were summarized in themes referring to study characteristics, relevant outcomes, biomarker measurement, dietary assessment and statistical analyses. RESULTS: We identified 20 relevant articles. Most studies presented evidence on associations between the consumption of organic diets or food items and reduced concentrations of 3-phenobenzoic acid metabolites in urine. There was less evidence for diet affecting other pyrethroid-specific biomarkers. Dietary assessment methodologies and recall periods varied, as did the number and timing of urine collections. Many studies did not control for potential alternative pyrethroid sources, exposure to other pesticides, or demographic and socioeconomic characteristics. CONCLUSION: Researchers should consider standardized dietary assessment, chemical analyses of foods consumed, adequate recall time, and food preparation methods. Consistency in biomarker measurement, including urine collection time and corrections for specific gravity or creatinine, is needed. Ensuring the validity of such studies also requires larger samples and appropriate control for confounders.

The Effect of Pesticide Spray Season and Residential Proximity to Agriculture on Glyphosate Exposure among Pregnant People in Southern Idaho, 2021.

BACKGROUND: Glyphosate is one of the most heavily used pesticides in the world, but little is known about sources of glyphosate exposure in pregnant people living in agricultural regions. OBJECTIVE: Our objective was to evaluate glyphosate exposure during pregnancy in relation to residential proximity to agriculture as well as agricultural spray season. METHODS: We quantified glyphosate concentrations in 453 urine samples collected biweekly from a cohort of 40 pregnant people in southern Idaho from February through December 2021. We estimated each participant's glyphosate exposure as the geometric mean (GM) of glyphosate concentrations measured in all samples (average n=11 samples/participant), as well as the GM of samples collected during the pesticide "spray season" (defined as those collected 1 May-15 August; average n=5 samples/participant) and the "nonspray season" (defined as those collected before 1 May or after 15 August; average n=6 samples/participant). We defined participants who resided <0.5km from an actively cultivated agriculture field to live "near fields" and those residing ≥0.5km from an agricultural field to live "far from fields" (n=22 and 18, respectively). RESULTS: Among participants living near fields, urinary glyphosate was detected more frequently and at significantly increased GM concentrations during the spray season in comparison with the nonspray season (81% vs. 55%; 0.228µg/L vs. 0.150µg/L, p<0.001). In contrast, among participants who lived far from fields, neither glyphosate detection frequency nor GMs differed in the spray vs nonspray season (66% vs. 64%; 0.154µg/L vs. 0.165µg/L, p=0.45). Concentrations did not differ by residential proximity to fields during the nonspray season (0.154µg/L vs. 0.165µg/L, for near vs. far, p=0.53). DISCUSSION: Pregnant people living near agriculture fields had significantly increased urinary glyphosate concentrations during the agricultural spray season than during the nonspray season. They also had significantly higher urinary glyphosate concentrations during the spray season than those who lived far from agricultural fields at any time of year, but concentrations did not differ during the nonspray season. These findings suggest that agricultural glyphosate spray is a source of exposure for people living near fields. https://doi.org/10.1289/EHP12768.

Urinary Glyphosate Concentrations among Pregnant Participants in a Randomized, Crossover Trial of Organic and Conventional Diets.

BACKGROUND: Consumption of an organic diet reduces exposure to a range of agricultural pesticides. Only three studies have examined the effect of an organic diet intervention on exposure to the herbicide glyphosate, the most heavily used agricultural chemical in the world. Despite its widespread use, the primary sources of glyphosate exposure in humans are poorly understood. OBJECTIVE: Our objective was to examine the effect of an organic diet intervention on urinary glyphosate concentrations among pregnant individuals. METHODS: We conducted a 2-wk randomized crossover trial in which 39 pregnant participants living near (≤0.5km) and far (>0.5km) from agricultural fields received a 1-wk supply of conventional groceries and 1 wk of organic groceries, randomized to order. We collected daily first morning void urine samples and analyzed composite samples from each week for glyphosate. We examined differences in urinary glyphosate concentrations between the conventional week and the organic week among all participants and stratified by residential proximity to an agricultural field. RESULTS: Median specific gravity-adjusted glyphosate concentrations were 0.19µg/L and 0.16µg/L during the conventional and organic weeks, respectively. We observed modest decreases in urinary glyphosate concentrations from the conventional to organic week among far-field participants, but no difference among near-field participants. In secondary analyses excluding participants who did not meet a priori criteria of compliance with the intervention, we observed significant decreases in urinary glyphosate concentrations, particularly among far-field participants (p<0.01-0.02, depending on exclusion criteria). DISCUSSION: This trial is the first to examine the effect of an organic diet intervention on glyphosate among people living near and far from agricultural fields. Our results suggest that diet is an important contributor to glyphosate exposure in people living >0.5km from agricultural fields; for people living near crops, agriculture may be a dominant exposure source during the pesticide spray season. https://doi.org/10.1289/EHP12155.

Perspective: Organic food consumption during pregnancy and the potential effects on maternal and offspring health.

Pregnancy represents a critical window for both maternal and child health. Previous studies have shown that the consumption of an organic diet during pregnancy can reduce pesticide exposure compared with the consumption of a conventional diet. It is possible that this could, in turn, improve pregnancy outcomes, because maternal pesticide exposure during pregnancy has been associated with increased risk of pregnancy complications. Organic foods are produced by methods that comply with organic standards, generally restricting the use of agrochemicals, such as synthetic pesticides. In the past few decades, the global demand for organic foods has increased drastically, driven in large part by consumer beliefs that organic foods provide benefits to human health. However, the effects of organic food consumption during pregnancy on maternal and child health have not been established. This narrative review aims to summarize current evidence regarding the consumption of organic foods during pregnancy and the potential effects on short- and long-term health outcomes in mothers and offspring. We performed a comprehensive literature search and identified studies investigating the association between organic food consumption during pregnancy and health outcomes in mothers and their offspring. The outcomes identified from the literature search included pre-eclampsia, gestational diabetes mellitus, hypospadias, cryptorchidism, and otitis media. Although existing studies suggest that consumption of organic foods (overall or a specific kind) during pregnancy may have health benefits, further investigation to replicate the findings in other populations is needed. Moreover, because these previous studies have all been observational and thus may be limited by the potential for residual confounding and reverse causation, causal inference cannot be established. We argue that the next necessary step in this research is a randomized trial to test the efficacy of organic diet intervention in pregnancy on maternal and offspring health.

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).

Measurement of urinary pesticide biomarkers among Latina farmworkers in southwestern Idaho.

BACKGROUND: Women who work in agriculture may have greater risk of pesticide exposure than men who share this occupation. Despite an increase in the fraction of the agricultural workforce comprised by women, few studies have characterized pesticide exposure in the USA with a focus on among these workers. OBJECTIVE: This pilot study aimed to describe pesticide exposure in a cohort of Latina farmworkers in farming communities in southwestern Idaho. METHODS: We collected urine samples from 29 Latina farmworkers, which were analyzed for 11 pesticide biomarkers. We evaluated the effect of pesticide spray season on urinary biomarker levels, and explored the effect of self-reported status as a pesticide handler on measured exposures. RESULTS: No significant differences were found between biomarker levels in samples collected during the nonspray and spray seasons. We observed 11 extreme outlying values in samples collected during the pesticide spray season. The most extreme outlying values (MDA: 51.7 ng/mL; 3-PBA: 11.8 ng/mL; trans-DCCA: 23.4 ng/mL; and 2,4-D: 31.1 ng/mL) were all provided during the spray season by women who reported loading, mixing or applying pesticides. CONCLUSIONS: These results provide suggestive evidence that Latina farmworkers who handle pesticides during the spray season may be at an increased risk of exposure to organophosphate and pyrethroid insecticides, as well as the herbicide 2,4-D. We recommend that future research into pesticide exposures among farmworkers should include particular focus on this group.

Synthetic Pesticides and Health in Vulnerable Populations: Agricultural Workers.

PURPOSE OF REVIEW: This review aims to summarize epidemiological literature published between May 15, 2018, and May 14, 2019, that examines the relationship between exposure to synthetic pesticides and health of agricultural workers. RECENT FINDINGS: Current research suggests that exposure to synthetic pesticides may be associated with adverse health outcomes. Agricultural workers represent a potentially vulnerable population, due to a combination of unique social and cultural risk factors as well as exposure to hazards inherent in agricultural work. Pesticide exposure among agricultural workers has been linked to certain cancers, DNA damage, oxidative stress, neurological disorders, and respiratory, metabolic, and thyroid effects. This review describes literature suggesting that agricultural workers exposed to synthetic pesticides are at an increased risk of certain cancers and neurological disorders. Recent research on respiratory effects is sparse, and more research is warranted regarding DNA damage, oxidative stress, metabolic outcomes, and thyroid effects.

Understanding Challenges to Well-Being among Latina FarmWorkers in Rural Idaho Using in an Interdisciplinary, Mixed-Methods Approach.

The aim of this study was to identify social, cultural and workplace-related risk factors affecting well-being among Latina farmworkers in rural Idaho. We recruited 70 Latina farmworkers from southwestern Idaho in 2019. We employed an inter-disciplinary, mixed-methods approach-including surveys, focus groups, interviews, and pesticide biomonitoring-to characterize multiple domains that influence well-being, including food security and access, housing conditions, social supports, access to medical care, and workplace safety. Six major themes emerged as primary challenges to Latina farmworkers' well-being. In the public sphere, study participants identified these challenges as long working hours, concerns regarding pesticide exposure, and lack of enforcement of regulatory protections. Participants' concerns regarding pesticide exposure were underscored by biological sampling results; multiple biomarkers of pesticide exposure were detected in all samples, with the highest concentrations measured in samples collected from women who reported mixing, loading or applying pesticides. Within the private sphere, food security and provisioning, childcare responsibilities, and social isolation were identified as significant challenges to well-being. Gender, ethnicity, and geography emerged as important, intersecting statuses that shaped the life experiences of these agricultural workers. Our findings suggest that gender may play a particularly critical role in the unique challenges facing Latina farmworkers. As a result, the services and regulations needed to support well-being in this population may be highly specific, and almost certainly include attention to work-family dynamics, pesticide exposure, and social connections.

Effect of a 24-week randomized trial of an organic produce intervention on pyrethroid and organophosphate pesticide exposure among pregnant women.

BACKGROUND: Introduction of an organic diet can significantly reduce exposure to some classes of pesticides in children and adults, but no long-term trials have been conducted. OBJECTIVES: To assess the effect of a long-term (24-week) organic produce intervention on pesticide exposure among pregnant women. METHODS: We recruited 20 women from the Idaho Women, Infants, and Children (WIC) program during their first trimester of pregnancy. Eligible women were nonsmokers aged 18-35 years who reported eating exclusively conventionally grown food. We randomly assigned participants to receive weekly deliveries of either organic or conventional fruits and vegetables throughout their second or third trimesters and collected weekly spot urine samples. Urine samples, which were pooled to represent monthly exposures, were analyzed for biomarkers of organophosphate (OP) and pyrethroid insecticides. RESULTS: Food diary data demonstrated that 66% of all servings of fruits and vegetables consumed by participants in the "organic produce" group were organic, compared to <3% in the "conventional produce" group. We collected an average of 23 spot samples per participant (461 samples total), which were combined to yield 116 monthly composites. 3-Phenoxybenzoic acid (3-PBA, a non-specific biomarker of several pyrethroids) was detected in 75% of the composite samples, and 3-PBA concentrations were significantly higher in samples collected from women in the conventional produce group compared to the organic produce group (0.95 vs 0.27 µg/L, p = 0.03). Another pyrethroid biomarker, trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid, was detected more frequently in women in the conventional compared to the organic produce groups (16% vs 4%, p = 0.05). In contrast, we observed no statistically significant differences in detection frequency or concentrations for any of the four biomarkers of OP exposure quantified in this trial. DISCUSSION: To our knowledge, this is the first long-term organic diet intervention study, and the first to include pregnant women. These results suggest that addition of organic produce to an individual's diet, as compared to conventional produce, significantly reduces exposure to pyrethroid insecticides.

Environmental Health Sciences in a Translational Research Framework: More than Benches and Bedsides.

BACKGROUND: Environmental health scientists may find it challenging to fit the structure of the questions addressed in their discipline into the prevailing paradigm for translational research. OBJECTIVE: We aim to frame the translational science paradigm to address the stages of scientific discovery, knowledge acquisition, policy development, and evaluation in a manner relevant to the environmental health sciences. Our intention is to characterize differences between environmental health sciences and clinical medicine, and to orient this effort towards public health goals. DISCUSSION: Translational research is usually understood to have evolved from the bench-to-bedside framework by which basic science transitions to clinical treatment. Although many health-related fields have incorporated the terminology and context of translational science, environmental health research has not always found a clear fit into this paradigm. We describe a translational research framework applicable to environmental health sciences that retains the basic structure that underlies the original bench-to-bedside paradigm. We propose that scientific discovery (T1) in environmental health research frequently occurs through epidemiological or clinical observations. This discovery often involves understanding the potential for human health effects of exposure to a given environmental chemical or chemicals. The practical applications of this discovery evolve through an understanding of exposure-response relationships (T2) and identification of potential interventions to reduce exposure and improve health (T3). These stages of translation require an interdisciplinary partnership between exposure sciences, exposure biology, toxicology, epidemiology, biostatistics, risk assessment, and clinical sciences. Implementation science then plays a crucial role in the development of environmental and public health practice and policy interventions (T4). Outcome evaluation (T5) often takes the form of accountability research, as environmental health scientists work to quantify the costs and benefits of these interventions. CONCLUSION: We propose an easily visualized framework for translation of environmental health science knowledge-from discovery to public health practice-that reflects the crucial interactions between multiple disciplines in our field. https://doi.org/10.1289/EHP4067.

Author Correction: Integrating data from multiple time-location measurement methods for use in exposure assessment: the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air).

In addition to the acknowledgments that were included, the authors wish to add the following: MESA was supported by contracts HHSN268201500003I, N01-HC-95159, N01-HC-95160, N01-HC-95161, N01-HC-95162, N01-HC-95163, N01-HC-95164, N01-HC-95165, N01-HC-95166, N01-HC-95167, N01-HC-95168, and N01-HC-95169 from the National Heart, Lung, and Blood Institute.

Estimating ambient-origin PM2.5 exposure for epidemiology: observations, prediction, and validation using personal sampling in the Multi-Ethnic Study of Atherosclerosis.

OBJECTIVES: We aim to characterize the qualities of estimation approaches for individual exposure to ambient-origin fine particulate matter (PM2.5), for use in epidemiological studies. METHODS: The analysis incorporates personal, home indoor, and home outdoor air monitoring data and spatio-temporal model predictions for 60 participants from the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air). We compared measurement-based personal PM2.5 exposure with several measured or predicted estimates of outdoor, indoor, and personal exposures. RESULTS: The mean personal 2-week exposure was 7.6 (standard deviation 3.7) µg/m3. Outdoor model predictions performed far better than outdoor concentrations estimated using a nearest-monitor approach (R = 0.63 versus R = 0.43). Incorporating infiltration indoors of ambient-derived PM2.5 provided better estimates of the measurement-based personal exposures than outdoor concentration predictions (R = 0.81 versus R = 0.63) and better scaling of estimated exposure (mean difference 0.4 versus 5.4 µg/m3 higher than measurements), suggesting there is value to collecting data regarding home infiltration. Incorporating individual-level time-location information into exposure predictions did not increase correlations with measurement-based personal exposures (R = 0.80) in our sample consisting primarily of retired persons. CONCLUSIONS: This analysis demonstrates the importance of incorporating infiltration when estimating individual exposure to ambient air pollution. Spatio-temporal models provide substantial improvement in exposure estimation over a nearest monitor approach.

Contribution of the in-vehicle microenvironment to individual ambient-source nitrogen dioxide exposure: the Multi-Ethnic Study of Atherosclerosis and Air Pollution.

Exposure estimates that do not account for time in-transit may underestimate exposure to traffic-related air pollution, but exact contributions have not been studied directly. We conducted a 2-week monitoring, including novel in-vehicle sampling, in a subset of the Multi-Ethnic Study of Atherosclerosis and Air Pollution cohort in two cities. Participants spent the majority of their time indoors and only 4.4% of their time (63 min/day) in-vehicle, on average. The mean ambient-source NO2 concentration was 5.1 ppb indoors and 32.3 ppb in-vehicle during drives. On average, indoor exposure contributed 69% and in-vehicle exposure contributed 24% of participants' ambient-source NO2 exposure. For participants in the highest quartile of time in-vehicle (≥1.3 h/day), indoor and in-vehicle contributions were 60 and 31%, respectively. Incorporating infiltrated indoor and measured in-vehicle NO2 produced exposure estimates 5.6 ppb lower, on average, than using only outdoor concentrations. The indoor microenvironment accounted for the largest proportion of ambient-source exposure in this older population, despite higher concentrations of NO2 outdoors and in vehicles than indoors. In-vehicle exposure was more influential among participants who drove the most and for participants residing in areas with lower outdoor air pollution. Failure to characterize exposures in these microenvironments may contribute to exposure misclassification in epidemiologic studies.

Integrating data from multiple time-location measurement methods for use in exposure assessment: the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air).

Tools to assess time-location patterns related to environmental exposures have expanded from reliance on time-location diaries (TLDs) and questionnaires to use of geospatial location devices such as data-logging Global Positioning System (GPS) equipment. The Multi-Ethnic Study of Atherosclerosis and Air Pollution obtained typical time-location patterns via questionnaire for 6424 adults in six US cities. At a later time (mean 4.6 years after questionnaire), a subset (n=128) participated in high-resolution data collection for specific 2-week periods resulting in concurrent GPS and detailed TLD data, which were aggregated to estimate time spent in various microenvironments. During these 2-week periods, participants were observed to spend the most time at home indoors (mean of 78%) and a small proportion of time in-vehicle (mean of 4%). Similar overall patterns were reported by these participants on the prior questionnaire (mean home indoors: 75%; mean in-vehicle: 4%). However, individual micro-environmental time estimates measured over specific 2-week periods were not highly correlated with an individual's questionnaire report of typical behavior (Spearman's ρ of 0.43 for home indoors and 0.39 for in-vehicle). Although questionnaire data about typical time-location patterns can inform interpretation of long-term epidemiological analyses and risk assessment, they may not reliably represent an individual's short-term experience.

Advances in Understanding Air Pollution and CVD.

The MESA Air (Multi-Ethnic Study of Atherosclerosis and Air Pollution) leveraged the platform of the MESA cohort into a prospective longitudinal study of relationships between air pollution and cardiovascular health. MESA Air researchers developed fine-scale, state-of-the-art air pollution exposure models for the MESA Air communities, creating individual exposure estimates for each participant. These models combine cohort-specific exposure monitoring, existing monitoring systems, and an extensive database of geographic and meteorological information. Together with extensive phenotyping in MESA-and adding participants and health measurements to the cohort-MESA Air investigated environmental exposures on a wide range of outcomes. Advances by the MESA Air team included not only a new approach to exposure modeling, but also biostatistical advances in addressing exposure measurement error and temporal confounding. The MESA Air study advanced our understanding of the impact of air pollutants on cardiovascular disease and provided a research platform for advances in environmental epidemiology.