Alteration of oral microbiome composition in children living with pesticide-exposed farm workers.

Our prior work shows that azinphos-methyl pesticide exposure is associated with altered oral microbiomes in exposed farmworkers. Here we extend this analysis to show the same association pattern is also evident in their children. Oral buccal swab samples were analyzed at two time points, the apple thinning season in spring-summer 2005 for 78 children and 101 adults and the non-spray season in winter 2006 for 62 children and 82 adults. The pesticide exposure for the children were defined by the farmworker occupation of the cohabitating household adult and the blood azinphos-methyl detection of the cohabitating adult. Oral buccal swab 16S rRNA sequencing determined taxonomic microbiota proportional composition from concurrent samples from both adults and children. Analysis of the identified bacteria showed significant proportional changes for 12 of 23 common oral microbiome genera in association with azinphos-methyl detection and farmworker occupation. The most common significantly altered genera had reductions in the abundance of Streptococcus, suggesting an anti-microbial effect of the pesticide. Principal component analysis of the microbiome identified two primary clusters, with association of principal component 1 to azinphos-methyl blood detection and farmworker occupational status of the household. The children's buccal microbiota composition clustered with their household adult in ∼95% of the households. Household adult farmworker occupation and household pesticide exposure is associated with significant alterations in their children's oral microbiome composition. This suggests that parental occupational exposure and pesticide take-home exposure pathways elicit alteration of their children's microbiomes.

Application of improved approach to evaluate a community intervention to reduce exposure of young children living in farmworker households to organophosphate pesticides.

The take-home pathway is a significant source of organophosphate pesticide exposure for young children (3-5 years old) living with an adult farmworker. This avoidable exposure pathway is an important target for intervention. We selected 24 agricultural communities in the Yakima Valley of Washington State and randomly assigned them to receive an educational intervention (n = 12) to reduce children's pesticide exposure or usual care (n = 12). We assessed exposure to pesticides in nearly 200 adults and children during the pre and post-intervention periods by measuring metabolites in urine. We compared pre- and post-intervention exposures by expressing the child's pesticide metabolite concentration as a fraction of the adult's concentration living in the same household, because the amount of pesticides applied during the collection periods varied. Exposures in our community were consistently higher, sometimes above the 95th percentile of the exposures reported by the National Health and Nutrition Examination Survey (NHANES). While intervention and control communities demonstrated a reduction in the ratio of child to adult exposure, this reduction was more pronounced in intervention communities (2.7-fold, p < 0.001 compared to 1.7-fold, p = 0.052 for intervention and control, respectively). By examining the child/adult biomarker ratio, we demonstrated that our community-based intervention was effective in reducing pesticide exposure to children in agricultural communities.

Evaluation of the relationship between residential orchard density and dimethyl organophosphate pesticide residues in house dust.

Reducing residential pesticide exposure requires identification of exposure pathways. Compared to the agriculture worker 'take-home' and residential use pathways, evidence of the 'drift' pathway to pesticide exposure has been inconsistent. Questionnaire data from individuals (n = 99) and dust samples (n = 418) from households across three growing seasons in 2011 were from the For Healthy Kids! study. Summed dimethyl organophosphate pesticide (OP) (Azinphos-Methyl, Phosmet, and Malathion) concentrations were quantified from house dust samples. Spatially-weighted orchard densities surrounding households were calculated based on various distances from homes. Regression models tested associations between orchard density, residential pesticide use, agriculture worker residents, and summed dimethyl OP house dust concentrations. Estimated relationships between orchard density and dimethyl OP in house dust were mixed: a 5% increase in orchard density resulted in 0.3 and 0.5% decreases in dimethyl OP house dust concentrations when considering land-cover 750 m or 1250 m away from households, respectively, but null associations with land-cover 60 m or 200 m away. Dimethyl OP house dust concentrations were 400% higher within homes where at least two residents were agriculture workers. Despite inconclusive evidence for the drift pathway due to potential for bias, relationships between number of agriculture workers and dimethyl OP house dust concentration underscores the take-home pathway.

Seasonal and occupational trends of five organophosphate pesticides in house dust.

Since 1998, the University of Washington's Center for Child Environmental Health Risks Research has followed a community-based participatory research strategy in the Lower Yakima Valley of Washington State to assess pesticide exposure among families of Hispanic farmworkers. As a part of this longitudinal study, house dust samples were collected from both farmworker and non-farmworker households, across three agricultural seasons (thinning, harvest and non-spray). The household dust samples were analyzed for five organophosphate pesticides: azinphos-methyl, phosmet, malathion, diazinon, and chlorpyrifos. Organophosphate pesticide levels in house dust were generally reflective of annual use rates and varied by occupational status and agricultural season. Overall, organophosphate pesticide concentrations were higher in the thinning and harvest seasons than in the non-spray season. Azinphos-methyl was found in the highest concentrations across all seasons and occupations. Farmworker house dust had between 5- and 9-fold higher concentrations of azinphos-methyl than non-farmworker house dust. Phosmet was found in 5-7-fold higher concentrations in farmworker house dust relative to non-farmworker house dust. Malathion and chlorpyriphos concentrations in farmworker house dust ranged between 1.8- and 9.8-fold higher than non-farmworker house dust. Diazinon showed a defined seasonal pattern that peaked in the harvest season and did not significantly differ between farmworker and non-farmworker house dust. The observed occupational differences in four out of five of the pesticide residues measured provides evidence supporting an occupational take home pathway, in which workers may bring pesticides home on their skin or clothing. Further, these results demonstrate the ability of dust samples to inform the episodic nature of organophosphate pesticide exposures and the need to collect multiple samples for complete characterization of exposure potential.

Human Oral Buccal Microbiomes Are Associated with Farmworker Status and Azinphos-Methyl Agricultural Pesticide Exposure.

In a longitudinal agricultural community cohort sampling of 65 adult farmworkers and 52 adult nonfarmworkers, we investigated agricultural pesticide exposure-associated changes in the oral buccal microbiota. We found a seasonally persistent association between the detected blood concentration of the insecticide azinphos-methyl and the taxonomic composition of the buccal swab oral microbiome. Blood and buccal samples were collected concurrently from individual subjects in two seasons, spring/summer 2005 and winter 2006. Mass spectrometry quantified blood concentrations of the organophosphate insecticide azinphos-methyl. Buccal oral microbiome samples were 16S rRNA gene DNA sequenced, assigned to the bacterial taxonomy, and analyzed after "centered-log-ratio" transformation to handle the compositional nature of the proportional abundances of bacteria per sample. Nonparametric analysis of the transformed microbiome data for individuals with and without azinphos-methyl blood detection showed significant perturbations in seven common bacterial taxa (>0.5% of sample mean read depth), including significant reductions in members of the common oral bacterial genus Streptococcus Diversity in centered-log-ratio composition between individuals' microbiomes was also investigated using principal-component analysis (PCA) to reveal two primary PCA clusters of microbiome types. The spring/summer "exposed" microbiome cluster with significantly less bacterial diversity was enriched for farmworkers and contained 27 of the 30 individuals who also had azinphos-methyl agricultural pesticide exposure detected in the blood. IMPORTANCE: In this study, we show in human subjects that organophosphate pesticide exposure is associated with large-scale significant alterations of the oral buccal microbiota composition, with extinctions of whole taxa suggested in some individuals. The persistence of this association from the spring/summer to the winter also suggests that long-lasting effects on the commensal microbiota have occurred. The important health-related outcomes of these agricultural community individuals' pesticide-associated microbiome perturbations are not understood at this time. Future investigations should index medical and dental records for common and chronic diseases that may be interactively caused by this association between pesticide exposure and microbiome alteration.

The role of diet in children's exposure to organophosphate pesticides.

BACKGROUND: Studies suggest that some of the greatest exposure to OPs in children occurs in agricultural communities and various pathways of exposure including the take-home pathway, proximity to orchards, and diet have been explored. However, the importance of the dietary pathway of exposure for children in agricultural communities is not well understood. OBJECTIVES: Our goal was to ascertain whether there were associations between measures of OP exposure and apple juice, fruit, and vegetable consumption across growing seasons by children of farmworkers and non-farmworkers in a rural agricultural setting. METHODS: Study participants were children of farmworker (N=100) or non-farmworker (N=100) households from a longitudinal cohort study. Dietary intake of fruits and vegetables was assessed using a "5-A-Day" abbreviated food frequency questionnaire, and exposure to OPs was characterized using three urinary di-methyl and three di-ethyl metabolite measurements per child for each of three growing seasons. We used generalized estimating equations to examine data. RESULTS: Consumption frequency of fruits and vegetables was similar between children of farmworkers and non-farmworkers and across seasons. There were a few significant trends between dimethyl metabolites (DMAP) and fruit, vegetable or apple juice consumption; however, no clear pattern held across seasons or occupation. One difference was found in vegetable consumption during the harvest season, where the farmworker families showed a significant relationship between vegetable consumption and dimethyl metabolite levels (p=0.002). We also found a significant difference in this relationship between farmworkers and non-farmworkers (p=0.001). No significant trends between fruit and vegetable consumption and diethyl (DEAP) metabolites were found. CONCLUSIONS: Our study shows the importance of considering season and parents' occupation in understanding OP exposure routes among children in an agricultural community. The impact of these factors on dietary OP exposure requires a more thorough analysis of the availability and consumption of produce from different sources including farms using pesticides where parents worked.

Seasonal variation in cortisol biomarkers in Hispanic mothers living in an agricultural region.

CONTEXT: Characterization of stress exposure requires understanding seasonal variability in stress biomarkers. OBJECTIVE: To compare acute and chronic stress biomarkers between two seasons in a cohort of rural, Hispanic mothers. METHODS: Stress questionnaires and cortisol measurements (hair, blood and saliva) were collected in the summer and fall. RESULTS: Cortisol biomarkers were significantly different and stress questionnaires were significantly correlated between seasons. DISCUSSION: The variability in cortisol and relative stability of questionnaires between seasons may indicate that cortisol responds to subtle stressors not addressed in questionnaires. CONCLUSIONS: There are significant differences in stress biomarkers in our cohort between seasons.

Exposure to free and conjugated forms of bisphenol A and triclosan among pregnant women in the MIREC cohort.

BACKGROUND: Bisphenol A (BPA) and triclosan (TCS) are two nonpersistent chemicals that have been frequently measured in spot urine samples from the general population but less so in pregnant women; however, data are limited on the free (bioactive) and conjugated forms of these phenols. OBJECTIVES: The Maternal-Infant Research on Environmental Chemicals (MIREC) Study addressed these data gaps by utilizing stored maternal urine samples from a large multicenter cohort study of Canadian pregnant women. METHODS: Concentrations of free and conjugated forms of BPA and TCS were measured in about 1,890 first-trimester urine samples by ultra performance liquid chromatography-tandem mass spectrometry using isotope dilution. RESULTS: The glucuronides of BPA and TCS were the predominant forms of these chemicals measured (detected in 95% and 99% of samples, respectively), whereas the free forms were detected in 43% and 80% of samples, respectively. The geometric mean urinary concentrations for glucuronides of BPA and TCS were 0.80 µg/L (95% CI: 0.75, 0.85) and 12.30 µg/L (95% CI: 11.08, 13.65), respectively. Significant predictors of BPA included maternal age < 25 vs. ≥ 35 years, current smoking, low vs. high household income, and low vs. high education. For TCS, urinary concentrations were significantly higher in women ≥ 25 years of age, never vs. current smokers, and women with high household income and high education. CONCLUSIONS: The results from this study represent the largest national-level data on urinary concentrations of free and conjugated forms of BPA and TCS in pregnant women and suggest that maternal characteristics predicting elevated urinary concentrations of these phenols largely act in opposite directions.

Variability in the take-home pathway: farmworkers and non-farmworkers and their children.

Organophosphate pesticides (OPs) are related to ill health among adults, including farmworkers who are exposed to OPs as part of their regular work. Children of both farmworkers and non-farmworkers in agricultural communities may also be affected by pesticide exposure. Study groups of 100 farmworkers with a referent child (aged 2-6 years) and 100 non-farmworkers with a referent child were recruited to participate in three data collection periods over the course of a year. At each collection, participants provided three urine samples within 5 days, and homes and vehicles were vacuumed to collect pesticide residues in dust. In thinning and harvest seasons, farmworkers and their children had higher dimethyl urinary metabolites than non-farmworkers and their children. During the non-spray season, the urinary metabolites levels decreased among farmworkers to a level comparable to that of non-farmworkers. Farmworkers consistently had higher pesticide residues in their home and vehicle dust. Differences exist between farmworkers and non-farmworkers in urinary metabolites, and the differences extended throughout the agricultural seasons.OP metabolites are seen at much higher levels for farmworkers and their children than for non-farmworkers and their children during agricultural seasons when OPs are in use. These metabolite levels were significantly higher than the nationwide NHANES IV survey and up to 10-fold higher than other rural agricultural studies.

Using a biokinetic model to quantify and optimize cortisol measurements for acute and chronic environmental stress exposure during pregnancy.

To fully understand the potentially harmful effects of prenatal stress exposure impacts, it is necessary to quantify long-term and episodic stress exposure during pregnancy. There is a strong body of research relating psychological stress to elevated cortisol levels in biomarkers. Recently, maternal hair has been used to measure cortisol levels, and provides the unique opportunity to assess stress exposure throughout gestation. Understanding how cortisol in the hair is related to more common biomarkers, such as, blood, saliva and urine is currently lacking. Therefore, we developed a biokinetic model to quantify the relationships between hair, blood, saliva and urine cortisol concentrations using published literature values. Hair concentrations were used to retrospectively predict peaks in blood and saliva concentrations over days and months. Simulations showed realistic values in all compartments when results were compared with published literature. We also showed that the significant variability of cortisol in blood leads to a weak relationship between long-term and episodic measurements of stress. To our knowledge, this is the first integrative biokinetic cortisol model for blood, urine, hair and saliva. As such, it makes an important contribution to our understanding of cortisol as a biomarker and will be useful for future epidemiological studies.

Do workplace and home protective practices protect farm workers? Findings from the "For Healthy Kids" study.

OBJECTIVE: To assess associations of protective workplace and home practices with pesticide exposure levels. METHODS: Using data from orchard workers in the Yakima Valley, Washington, we examined associations of workplace and home protective practices with (1) urinary metabolite concentrations of dimethylthiophosphate (DMTP) in adults and children aged 2 to 6 years and (2) azinphos-methyl levels in house and vehicle dust. RESULTS: Data were collected from 95 orchard workers and 94 children. Contrary to expectation, adult farm workers who wore boots or washed hands using hand sanitizer had higher concentrations of DMTP than those who did not. Children who attended daycare had higher DMTP concentrations than children who did not. CONCLUSIONS: Few workplace or home practices were associated with pesticide exposure levels; workers who used hand sanitizer had higher concentrations of DMTP, as did children who attended daycare.

Organophosphate pesticide exposure and residential proximity to nearby fields: evidence for the drift pathway.

OBJECTIVES: Residential proximity to pesticide-treated farmland is an important pesticide exposure pathway. METHODS: In-person interviews and biological samples were collected from 100 farmworker and 100 non-farmworker adults and children living in Eastern Washington State. We examined the relationship of residential proximity to farmland to urinary metabolite concentrations of dimethylphosphate (DMTP) and levels of pesticide residues in house dust. RESULTS: DMTP concentrations were higher in farmworkers than non-farmworkers (71 µg/L vs 6 µg/L) and in farmworker children than non-farmworker children (17 µg/L vs 8 µg/L). Compared to non-farmworker households, farmworker households had higher levels of azinphos-methyl (643 ng/g vs 121 ng/g) and phosmet (153 ng/g vs 50 ng/g). Overall, a 20% reduction in DMTP concentration was observed per mile increase in distance from farmland. CONCLUSIONS: Lower OP metabolite concentrations correlated with increasing distance from farmland.

Where's the dust? Characterizing locations of azinphos-methyl residues in house and vehicle dust among farmworkers with young children.

Organophosphate pesticides are commonly used in the United States, and farmworkers are at risk for chronic exposure. Using data from a community randomized trial to interrupt the take-home pathway of pesticide exposure, we examined the association between floor surface type (smooth floor, thin carpet, and thick carpet) and rooms in which dust samples were collected (living room vs. non-living room) and concentrations of azinphos-methyl residues in home environments. We also examined the association between vehicle type (truck, auto, or other) and footwell floor surfaces (carpeted, smooth surface, or no mat) and concentrations of azinphos-methyl in vehicle dust samples. Dust samples were collected from 203 and 179 households and vehicles, respectively. All households had at least one child aged 2-6. Vehicle dust samples were collected from footwells of the vehicle used for commuting to and from work. A total of 183 samples were collected from living rooms, and 20 were collected from other rooms in the home. Forty-two samples were collected from thick carpets, 130 from thin carpets, and 27 from smooth floor surfaces. Thick and thin carpets had a significantly greater dust mass than smooth floor surfaces (6.0 g/m(2) for thick carpets, 7.8 g/m(2) for thin carpets, and 1.5 g/m(2) for smooth surfaces). Of the 179 vehicle samples, 113 were from cars, 34 from trucks, and 32 from other vehicles. Vehicles with no mats had a significantly higher mass of dust (21.3 g) than those with hard mats (9.3 g) but did not differ from vehicles with plush mats (12.0 g). Further research is needed to characterize the environment in which children may be exposed to pesticides.

Organophosphate Pesticide Exposure Among Pome and Non-Pome Farmworkers: A Subgroup Analysis of a Community Randomized Trial.

OBJECTIVE: We examined the effectiveness of a community randomized intervention among farmworkers who did and did not work in pome fruit (apples and pears). METHODS: Urine samples were collected from two cross-sectional groups of farmworkers and analyzed for the presence of dimethylthiophosphate. RESULTS: There was no significant time by crop interaction for changes in urinary metabolite concentrations among adult farmworkers (P = 0.79 pome fruit workers; P = 0.83 non-pome fruit workers) or their children (P = 0.25 children of pome fruit workers; P = 0.91 children of non-pome fruit workers). We found greater urinary metabolite concentrations of dimethylthiophosphate among pome fruit workers (compared with non-pome fruit workers) and among workers at final data collection (compared with baseline). CONCLUSION: Further research is needed to identify effective interventions to reduce pesticide exposure in farmworkers and their children.

Para niños saludables: a community intervention trial to reduce organophosphate pesticide exposure in children of farmworkers.

BACKGROUND: Exposure to organophosphate (OP) pesticides is an occupational hazard for farmworkers and affects their children through the take-home pathway. OBJECTIVES: We examined the effectiveness of a randomized community intervention to reduce pesticide exposure among farmworkers and their children. METHODS: We conducted a baseline survey of a cross-sectional sample of farmworkers (year 1) in 24 participating communities. Communities were randomized to intervention or control. After 2 years of intervention, a new cross-sectional survey of farmworkers was conducted (year 4). Farmworkers with a child 2-6 years of age were asked to participate in a substudy in which urine was collected from the farmworker and child, and dust was collected from the home and the vehicle driven to work. RESULTS: The median concentration of urinary metabolites was higher in year 4 than in year 1 for dimethylthiophosphate (DMTP) and dimethyldithiophosphate in adults and for DMTP for children. There were significant increases within both the intervention and control communities between year 1 and year 4 (p < 0.005); however, the differences were not significant between study communities after adjusting for year (p = 0.21). The dust residue data showed azinphos-methyl having the highest percentage of detects in vehicles (86% and 84% in years 1 and 4, respectively) and in house dust (85% and 83% in years 1 and 4, respectively). There were no significant differences between intervention and control communities after adjusting for year (p = 0.49). CONCLUSIONS: We found no significant decreases in urinary pesticide metabolite concentrations or in pesticide residue concentrations in house and vehicle dust from intervention community households compared with control community households after adjusting for baseline. These negative findings may have implications for future community-wide interventions.

Organophosphate pesticide exposure and work in pome fruit: evidence for the take-home pesticide pathway.

Organophosphate (OP) pesticides are commonly used in the United States, and farmworkers are at risk for chronic exposure. Using a sample of 218 farmworkers in 24 communities and labor camps in eastern Washington State, we examined the association between agricultural crop and OP pesticide metabolite concentrations in urine samples of adult farmworkers and their children and OP pesticide residues in house and vehicle dust samples. Commonly reported crops were apples (71.6%), cherries (59.6%), pears (37.2%), grapes (27.1%), hops (22.9%), and peaches (12.4%). Crops were grouped into two main categories: pome fruits (apples and pears) and non-pome fruits. Farmworkers who worked in the pome fruits had significantly higher concentrations of dimethyl pesticide metabolites in their urine and elevated azinphos-methyl concentrations in their homes and vehicles than workers who did not work in these crops. Among pome-fruit workers, those who worked in both apples and pears had higher urinary metabolites concentrations and pesticide residue concentrations in dust than did those who worked in a single pome fruit. Children living in households with pome-fruit workers were found to have higher concentrations of urinary dimethyl metabolites than did children of non-pome-fruit workers. Adult urinary concentrations showed significant correlations with both the vehicle and house-dust azinphos-methyl concentrations, and child urinary concentrations were correlated significantly with adult urinary concentrations and with the house-dust azinphos-methyl concentration. The results provide support for the take-home pathway of pesticide exposure and show an association between measures of pesticide exposure and the number of pome-fruit crops worked by farmworkers.

Health symptoms and exposure to organophosphate pesticides in farmworkers.

BACKGROUND: Few studies have examined the relationship between reported health symptoms and exposure to organophosphate (OP) pesticides. METHODS: Fisher's exact test was used to assess the relationship between self-reported health symptoms and indicators of exposure to OP pesticides in 211 farmworkers in Eastern Washington. RESULTS: The health symptoms most commonly reported included headaches (50%), burning eyes (39%), pain in muscles, joints, or bones (35%), a rash or itchy skin (25%), and blurred vision (23%). Exposure to pesticides was prevalent. The proportion of detectable samples of various pesticide residues in house and vehicle dust was weakly associated with reporting certain health symptoms, particularly burning eyes and shortness of breath. No significant associations were found between reporting health symptoms and the proportion of detectable urinary pesticide metabolites. CONCLUSIONS: Certain self-reported health symptoms in farmworkers may be associated with indicators of exposure to pesticides. Longitudinal studies with more precise health symptom data are needed to explore this relationship further.