Air, Dermal, and Urinary Metabolite Levels of Backpack and Tractor Sprayers Using the Herbicide Acetochlor in Thailand.

Acetochlor is a chloroacetanilide selective pre-emergent herbicide used for controlling grass and broadleaf weeds in crops. This study compared the acetochlor exposures of backpack and tractor sprayers and assessed whether dermal or air exposures were more important contributors to the overall body burden as measured by urinary metabolites. Sixty sugarcane farmers in Nakhonsawan province, Thailand participated in the study, and breathing zone air and dermal patch samples were collected during spraying. Urine samples were collected before spraying, at the end of the spraying task, and on the day after spraying. For backpack and tractor sprayers, there was no significant difference in their breathing zone air concentrations, total body dermal samples, or urinary 2-methy-6-methyaniline (EMA) concentrations on the day after spraying. In addition, although most backpack and tractor sprayers wore long pants and long sleeve shirts, they were still exposed to acetochlor, as evidenced by a significant increase in the urinary EMA from before spraying (GM = 11.5 µg/g creatinine) to after spraying (GM = 88.5 µg/g creatinine) to the next day (GM = 111.0 µg/g creatinine). Breathing zone air samples were significantly correlated with those of total body dermal patch samples and with urinary EMA concentrations after spraying. This suggests that both air and dermal exposure contribute to urinary EMA levels.

Pesticide residues on children's hands, home indoor surfaces, and drinking water among conventional and organic farmers in Thailand.

This study measured pesticide levels on children's hands, home indoor surfaces, and drinking water among Thai conventional and organic farm families in three provinces. Farm families in Nakhonsawan and Phitsanulok provinces were the conventional farmers and those in Yasothon province were the organic farmers. Samples were collected in the dry and wet seasons over 2 years (2017 and 2018). All samples were analyzed for organophosphates (OPs), carbamate, pyrethroid, triazines, glyphosate, and aminomethylphosphonic acid (AMPA). On children's hands, the highest concentrations for the 2 palmar surfaces were found for cypermethrin (7.46 µg) and fipronil (2.88 µg). On home surfaces of approximately 1000 cm2, the highest concentrations were found for cypermethrin (27.94 µg) and fipronil 49.76 µg)/1000 cm2. For the conventional farmers, the most common pesticides on children's hand wipes were cypermethrin and fipronil, which are used as in-home pesticides as well as agricultural pesticides. However, home surface wipes showed other pesticides associated with agriculture were presented in the home during the seasons when they were used, suggesting spray drift or carry home sources for these pesticides. During the wet season, pesticides were found in the drinking water of all provinces. Most common were fenitrothion, profenofos, fenthion, atrazine, and AMPA. Profenofos was found at levels above the health guidelines. During 2017, there was extensive flooding in Thailand which may have contributed to the drinking water contamination, even though most farmers report using tap water or bottled drinking water. Future work is needed to assess the risk of all sources of pesticide exposures in children and to repeat the drinking water pesticide contamination analysis.

Cross-shift change of acute kidney injury biomarkers in sugarcane farmers and cutters.

Sugarcane farmers and cutters have been reported to be at high risk of acute kidney injury. This cross-sectional study aimed to assess acute kidney injury biomarkers, and cross-shift change among 150 sugarcane cutters and 98 sugarcane farmers in Thailand. Physical health examination, environmental measurements, and measured urinary neutrophil gelatinase-associated lipocalin (NGAL) were assessed. Cross-shift change of urine creatinine (uCr), albumin creatinine ratio (ACR), and NGAL between sugarcane farmers and cutters was compared. Factors influencing abnormal post-shift ACR and NGAL were analyzed by binary logistic regression adjusted with covariates. Sugarcane cutters were significantly more likely to take nonsteroidal anti-inflammatory drugs (NSAID) and herbs to relieve pain than sugarcane farmers. Males were more likely to be current smokers and drinkers although 62% of cutters and 56% of farmers were female. Sugarcane farmers and cutters had similar post-shift estimated glomerular filtration rate (eGFR) and ACR levels. Cross-shift measurements showed that both sugarcane cutters and sugarcane farmers had significantly higher post-shift geometric mean (GM) urinary NGAL, but that the cross-shift changes of NGAL were significantly higher for sugarcane cutters (182%) vs. sugarcane farmers (112%). Water intake less than recommendation of subjects was a significant predictor of a higher risk for an abnormal post-shift ACR after controlling for covariates, while being a sugarcane cutter was a predictor of a lower risk of an abnormal risk of a post-shift NGAL after controlling for covariates. Measurements of heat stress (WBGT plus workload) found that sugarcane cutters exceeded recommended exposures while sugarcane farmers were compliance to the TLV. These findings suggest that to protect sugarcane farmers and cutters, preventative measures are needed.

Disruption of the Diurnal Cortisol Hormone Pattern by Pesticide Use in a Longitudinal Study of Farmers in Thailand.

Alteration of the hypothalamic-pituitary-adrenal (HPA) axis hormones has been associated with a range of chronic metabolic and cardiovascular health conditions. This study evaluated whether type of farming (organic versus conventional) or the number of self-reported days of spraying pesticides in the past 8 months was associated with diurnal cortisol levels. Salivary cortisol levels were measured four times a day (waking, 30 min after waking, 6 h after waking and bedtime) longitudinally, 8 months apart during three rounds of data collection. Pesticide using (conventional) and organic farmers were recruited to participate. Pesticide use in the previous 8 months was determined as the number of spray days for each type of pesticide used (herbicide, insecticide, fungicide) from self-reported questionnaires. Estimates of cortisol levels at four time points, the cortisol awakening response (CAR), and the diurnal cortisol slope (DCS) were estimated with a longitudinal mixed model that accounted for the non-linearity of cortisol levels across the day. Conventional farmers had significantly lower cortisol levels at waking than organic farmers (3.39 versus 3.86 ng ml-1), 30 min after waking (5.87 versus 6.96 ng ml-1), 6 h after waking (1.62 versus 1.88 ng ml-1), and lower diurnal cortisol slope (-2.26 versus -2.51 ng ml-1). Farmers who frequently applied herbicides (90th percentile of the number of spray days in the past 8 months) had significantly lower waking, 30 min after waking, 6 h after waking, bedtime and diurnal cortisol slopes compared with those with no spray days of herbicide in the past 8 months (organic and some of the conventional farmers). Those who frequently applied insecticides in the past 8 months had significantly lower bedtime levels and diurnal cortisol slopes, compared with those with no spray days of insecticide in the past 8 months. There were no significant differences in cortisol hormones between those who frequently applied fungicides and those who did not spray fungicides. Repeated pesticide use appears to be disrupting the HPA axis and depressing the normal diurnal cortisol rhythm among conventional Thai farmers.

Acute Changes in Thyroid Hormone Levels among Thai Pesticide Sprayers.

The objective of this study was to investigate the relationship of acute pesticide exposures and acute changes in thyroid hormones among Thai farmers. We recruited 78 farmers, who were scheduled to spray insecticides (chlorpyrifos and/or cypermethrin) or herbicides (paraquat and/or glyphosate). On the day before spraying, farmers collected their first morning void urine and went for blood collection. On the spray day, urine samples were collected at end of the spraying event and they were interviewed with questionnaires. The next morning, the first morning void urine and blood samples were collected. Blood samples were analyzed for thyroid hormones. Urine samples were analyzed for the metabolites of the pesticide sprayed. The results showed that the thyroid hormones, free triiodothyronine (FT3) and total triiodothyronine (T3) were significantly reduced as urinary chlorpyrifos metabolite increased the day after spraying. Total thyroxine (T4) significantly increased as cypermethrin metabolites increased the day after spraying. T4 significantly increased as urinary glyphosate levels increased; however, FT3 and T3 decreased significantly as urinary paraquat levels increased the day after spraying. These findings suggest that acute exposures to the pesticides chlorpyrifos, cypermethrin, paraquat and glyphosate can produce acute effects on the hypothalamic-pituitary-thyroid (HPT) axis, acutely altering thyroid hormone levels.

Longitudinal Study of Thyroid Hormones between Conventional and Organic Farmers in Thailand.

Many pesticides are endocrine-disrupting chemicals that can interfere with hormone levels. This study aimed to assess the longitudinal impact of exposure to pesticides on thyroid hormone levels, including Thyroid Stimulating Hormone (TSH), Free Triiodothyronine (FT3), Free Thyroxine (FT4), Triiodothyronine (T3), and Thyroxine (T4). Both conventional (i.e., pesticide using) and organic farmers were interviewed using questionnaires, and blood samples were collected at 7-9 a.m. to determine thyroid hormone levels for four rounds, with a duration of eight months between each round. A linear mixed model of the natural log of the individual hormone levels used random intercepts for subjects while controlling gender, baseline age, and body mass index (BMI) was used to compare between conventional and organic farmers or the impact of cumulative days of spraying insecticides, herbicides or fungicides. The estimated marginal means of the thyroid hormone levels (TSH, FT3, T3, and T4) estimated from the linear mixed models were significantly higher among the conventional farmers than organic farmers. As cumulative spray days of insecticide, herbicide or fungicide increased, TSH and FT3 increased significantly. FT4 decreased significantly as cumulative spray days of insecticide or fungicide increased. These findings suggest that the insecticides, herbicides, and fungicides sprayed by conventional farmers exert endocrine-disrupting activities, altering the hypothalamic-pituitary-thyroid (HPT) axis homeostasis.

Longitudinal Study of Metabolic Biomarkers among Conventional and Organic Farmers in Thailand.

The aim of this longitudinal study is to assess how pesticide use may impact metabolic biomarkers by collecting and comparing data from conventional (n = 13) and organic farmers (n = 225) every eight months for four rounds. Farmers were interviewed about family health history, food consumption behaviors, self-reported health problems, agricultural activities, and history of pesticide use. Systolic and diastolic blood pressure and body mass index (BMI) were measured. Blood samples were collected for total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), blood glucose, and triglycerides. A linear mixed model with random intercepts for subjects was used to compare the metabolic biomarkers between conventional and organic farmers and to examine the impact of the number of pesticide spray days for all four rounds after controlling for covariates. The conventional farmers reported using insecticides, herbicides, and fungicides. The marginal means for chemical farmers were significantly higher than organic farmers for total cholesterol, LDL, HDL, glucose, systolic and diastolic blood pressure, BMI, and waist circumference. Increasing the number of days of spraying either insecticides or fungicides was associated with an increase in HDL, LDL, and cholesterol levels. Increasing the number of herbicide spray days was associated with an increase in systolic and diastolic blood pressure and a decrease in BMI. These findings suggest that pesticide-using conventional farmers may be at higher risk of metabolic disease in the future.

Thyroid Hormones in Conventional and Organic Farmers in Thailand.

Pesticides can act as endocrine disruptors by different mechanisms including inhibition of iodine absorption, increases in thyroid hormone clearance, decreased cellular uptake of thyroid hormones, or changes in expression of thyroid hormone regulated genes. This study examined how exposure to pesticides impacts thyroid hormone levels, thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), free T3 (FT3), and free T4 (FT4) by comparing conventional (n = 195) and organic farmers (n = 222), and by evaluating which types of pesticides might be associated with changes in thyroid hormone levels. Questionnaires were used to collect information about farmer characteristics, self-reported stress, agricultural activities, and history of pesticide use. Conventional farmers were asked to report the type and quantity of pesticides used each day. The TSH, FT3, T3, and T4 levels of conventional farmers were 1.6, 1.2, 1.3, and 1.1 times higher than those of organic farmers, respectively, after adjusting for covariates. Several specific herbicides had a significant relationship between the amount applied and an increase in thyroid hormone levels, after covariate adjustment. They included: paraquat (TSH, FT3 and T3); acetochlor (FT4); atrazine (TSH, FT3 and T3); glyphosate (T4); diuron (TSH) and the "other" herbicides including alachlor, propanil, and butachlor (FT4 and T3). The most commonly used herbicide among conventional farmers was glyphosate, followed by paraquat, 2,4-dichlorophenoxyacetic acid (2,4-D). These findings suggest that exposure to pesticides could impact the development of metabolic diseases and other health outcomes by altering the endocrine system (the thyroid hormone levels) through the hypothalamic-pituitary-thyroid (HPT) axis. This work is a part of a longitudinal study which will evaluate the sub-chronic effects of repeated exposure to different types of pesticides on thyroid hormone levels.