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.

Hydrogeogenic fluoride in groundwater and dental fluorosis in Thai agrarian communities: a prevalence survey and case-control study.

BACKGROUND: Dental fluorosis can be a disease of social inequity in access to safe drinking water. This dental public health issue becomes prominent in socially disadvantaged agrarian communities in fluoride endemic areas where the standard irrigation system is unavailable and groundwater containing natural fluoride is the major drinking water source. This study aimed to determine the prevalence and severity of dental fluorosis in children and to evaluate its association with fluoride in groundwater in the aforementioned setting in Thailand. METHODS: A cross-sectional survey of 289 children in Nakhon Pathom Province was conducted in 2015. Children with very mild to severe fluorosis were regarded as 'cases' while their counterparts were 'controls' for a subsequent case-control study. Records of fluoride concentrations in groundwater used for household supply corresponding to resident and number of years by age of each child during 2008-2015 were retrieved. Other exposure variables were measured using a questionnaire. Prevalence ratio (PR), a measure indicating the relative effect of different levels of fluoride on dental fluorosis, was obtained from Poisson regression with robust standard error. RESULT: There were 157 children with very mild to moderate dental fluorosis (54.3% prevalence). The univariable analysis revealed that the prevalence of dental fluorosis among children with fluoride concentrations in water sources of 0.7-1.49 (index category 1) and ≥ 1.5 ppm (index category 2) was 1.62 (95% CI; 0.78, 3.34) and 2.75 (95% CI; 1.42, 5.31) times the prevalence among those with fluoride < 0.7 ppm (referent category). After adjusting for all covariates, the adjusted prevalence ratios in both index categories were 1.64 (95% CI; 0.24, 11.24) and 2.85 (95% CI; 0.44, 18.52) which were close to their corresponding crude estimates. Since the magnitude of confounding, measured by (PRcrude-PRadjusted)/PRadjusted, were less than 10% for both index categories; this indicated the limited confounding effect of all covariates. CONCLUSIONS: In fluoride endemic areas, groundwater containing natural fluoride utilized for household consumption resulted in high dental fluorosis prevalence, particularly in the groundwater with fluoride concentrations of ≥ 1.5 ppm.

A Microfluidic Paper-Based Analytical Device for Type-II Pyrethroid Targets in an Environmental Water Sample.

A detection method for type-II pyrethroids in an environmental water sample using a microfluidic paper-based analytical device (µPAD) is reported here. The detection approach is based on the formation of cyanide from the hydrolysis of type-II pyrethroids and the colorimetric detection of cyanide on a layer-based µPAD. Parafilm and inexpensive laminating pouches were used to create a hydrophobic barrier for the assay on the µPAD. This detection approach was selective to type-II pyrethroids in water for which an environmental water sample was tested. The calibration curves for cypermethrin, deltamethrin, cyhalothrin, and fenvalerate ranged from 2 to 40 µg/mL without sample preconcentration. The lower concentrations of type-II pyrethroids can be assessed by including a preconcentration step prior to the detection on a µPAD. This detection system provides an alternative platform for fast, semiquantitative testing for pesticide contamination in environmental surface water by allowing for portability, low reagent/sample consumption, and low-cost testing.

ORGANOPHOSPHATES IN MECONIUM OF NEWBORN BABIES WHOSE MOTHERS RESIDED IN AGRICULTURAL AREAS OF THAILAND.

Organophosphates (OPs) are widely used for pest and weed control in many countries including Thailand. In addition to causing environmental pollution, OPs affect human health by overstimulating neurotoxicants, and OP exposure during pregnancy can lead to adverse health effects of mothers and their fetuses. Using gas chromatography-mass spectrometry with a dedicated extraction protocol to identify OPs in meconium of newborn babies (n = 68) from hospitals in Amnat Charoen, Kanchanaburi and Nakhon Sawan provinces, agricultural regions of Thailand, among ten OP types analyzed, eight were detected in 98% of meconium samples (chlorpyrifos (median ± interquartile range (IQR) 0.08 ± 0.03-0.16 µg/g) in 32% of samples, demeton-s-methyl (0.35 ± 0.26-0.49 µg/g) in 73%, dichlorvos (0.67 ± 0.58-0.71 µg/g) in 38%, dimethoate (0.43 ± 0.09-1.56 µg/g) in 50%, ethion (0.21 ± 0.19-0.26 µg/g) in 12%, malathion (0.28 ± 0.15-0.52 µg/g) in 50%, omethoate (5.63 ± 4.85-8.57 µg/g) in 34%, and tolclofos-methyl (0.08 ± 0.03-0.10 µg/g) in 41%). There are no significant differences in these parameters from babies whose mothers did and did not work in the agricultural or who lived near (within one km) and distant from farmland. The findings should be of benefit in developing programs to protect pregnant women and newborn babies from exposure to OP pesticides.

Mental Health Disorders among Thai Farmers: Occupational and Non-Occupational Stressors.

This cross-sectional study aimed to identify occupational and non-occupational factors that impact levels of stress, depression, and anxiety among farmers located in the northern part of Thailand, including the potential psychological impacts of pesticide use. The participants (N=270) were interviewed with a survey adopted and modified from peer-reviewed articles and questionnaires. The survey consists of four parts, including demographic information and pesticide exposure; perceived farm stressors employing Farm Stressor Survey (FSS); mental health disorder utilizing Srithanya Stress Scale (ST5), Nine-Questions Depression- Rating Scale (9Q), and Depression Anxiety Stress Scale 21 (DASS21); in addition to COVID-related stress utilizing COVID Stress Scale (CSS). The participants were categorized into two groups i.e., Spray and No Spray based on their self-reported occupational use of pesticide spraying within the past year. No significant associations were observed between occupational pesticide exposures and mental health disorder scores. Being female, having a second job besides a farmer, having applied pesticides for greater than 20 years, and having a higher farm stressor perception showed a significant positive association with self-reported mental health disorders; while having a good agricultural practice and PPE use showed a significant negative association with those outcomes. This pilot study scrutinized expanded sources of stress in farm work and provided information for the development of more effective mental disorder intervention programs for Thai farmers.

Exposure of Young Children to Permethrin and Cypermethrin Insecticides in the Residential Environment.

The aims of this study were to evaluate the exposure to permethrin and cypermethrin of young children aged between 2 and 5 years in Nakhon Pathom and Sing Buri provinces, Thailand. A questionnaire that included general demographic information, household characteristics, insecticide usage and exposure-related behavior in children was used to interview parents or family caregivers. Permethrin and cypermethrin concentrations on floor surfaces and children's hands, as well as their urinary metabolites, were analyzed by gas chromatography coupled with mass spectrometry. The results showed that permethrin and cypermethrin were detected in 62% and 83% of the children's hand wipe samples, with geometric mean (GM) levels of 0.02 µg and 0.04 µg, respectively. Permethrin and cypermethrin were detected in 79% and 93% of floor surface wipe samples, with GM levels of 0.90 µg/m2, and 1.49 µg/m2, respectively. For children's urine, the GM concentrations of cis- and trans-DCCA, 3-PBA, and total pyrethroid metabolites were 0.84, 0.31 and 1.23 nmol/g creatinine, respectively. This study found that household insecticide product usage and having a tile floor were associated with increased permethrin concentrations on the children's hands and floor surfaces. However, cypermethrin concentrations on floor surfaces were significantly higher in families using aerosol insecticide sprays and insecticide products in the living room and bedroom. The predictors of the total pyrethroid, DCCA and 3-PBA metabolites are permethrin on children's hands or floor surfaces and cypermethrin on floor surfaces.

Health risk assessment of volatile organic compounds in a high risk group surrounding Map Ta Phut industrial estate, Rayong Province.

OBJECTIVE: The health risks of a high-risk group, surrounding Map Ta Phut industrial estate, Rayong, which may be exposed to VOCs through inhalation of contaminated air and dermal contact of contaminated water were assessed. MATERIAL AND METHOD: The health risk was assessed for 19 subjects categorized as children, adult and elderly from Ban plong and Nongfab communities following the US Environmental Protection Agency (EPA) method. The VOC concentrations in ambient air and ground water were monitored by Pollution Control Department (PCD), Ministry of Natural Resources and Environment to represent average VOC exposure of subjects. RESULTS: The lifetime cancer risk of VOCs exposure from inhalation and dermal contact with ground water were 1.32 x 10(-7)-5.21 x 10(6) for elderly 1.18 x 10(-7)-6.20 x 10(-6)for adult and 8.93 x 10(-7)-5.93 x 10(-6) for children. For non-cancer risk, the hazard index was 0.44 for elderly, 0.38-0.42 for adult and 0.55 for children. CONCLUSION: The lifetime cancer risk of the high-risk group living near Map Ta Phut industrial estate was in acceptable range for elderly, adult and children. For non-cancer risk, it is also acceptable.

Health effects of people living close to a petrochemical industrial estate in Thailand.

OBJECTIVE: An acute health effect of people living near the petrochemical industrial estate in Thailand was assessed using a panel study design. MATERIAL AND METHOD: The populations in communities near the petrochemical industrial estates were recruited. The daily air pollutant concentrations, daily percentage of respiratory and other health symptoms reported were collected for 63 days. The effect of air pollutants to reported symptoms of people were estimated by adjusted odds ratios and 95% confidence interval using binary logistic regression. RESULTS: The significant associations were found with the adjusted odds ratios of 38.01 for wheezing, 18.63 for shortness of breath, 4.30 for eye irritation and 3.58 for dizziness for total volatile organic compounds (Total VOCs). The adjusted odds ratio for carbon monoxide (CO2) was 7.71 for cough, 4.55 for eye irritation and 3.53 for weakness and the adjusted odds ratio for ozone (O3) was 1.02 for nose congestion, sore throat and 1.05 for phlegm. CONCLUSION: The results showed that the people living near petrochemical industrial estate had acute adverse health effects, shortness of breath, eye irritation, dizziness, cough, nose congestion, sore throat, phlegm and weakness from exposure to industrial air pollutants.

Assessment of occupational exposure to malathion and bifenthrin in mosquito control sprayers through dermal contact.

OBJECTIVE: To assess occupational exposure of malathion and bifenthrin concentrations by dermal contact and urinary 3-(2-chloro-3, 3, 3-trifluoro-1-propenyl)-2, 2-dimethyl-cyclopropanecarboxylic (TFP) acid, health symptoms developed and the relationship between bifenthrin concentrations and TFP acid in urine of the mosquito control sprayers. MATERIAL AND METHOD: The aerosols of these two pesticides were collected using 100 cm2 cotton patches attached on the skin of upper legs of 54 volunteer of mosquito control sprayers. Their urine samples were also collected before and after application. RESULTS: These subjects exposed to average malathion and bifenthrin concentrations of 0.18 and 0.32 microg/cm2, respectively After application, the average concentration of urinary TFP acid in the sprayers was 39.22 +/- 0.77 mg/g creatinine ranging from 0.58 to 261.19 mg/g creatinine. A significant difference was found between urinary TFP acid levels before and after application (p < 0.001) but the bifenthrin concentrations through dermal contact and urinary TFP acid levels were not significantly correlated (p > 0.05). CONCLUSION: The mosquito control sprayers had dermal contact with smoke of malathion and bifenthrin and some sprayers developed health symptoms after exposure. They should use protective clothing made ofplastic, nylon or polyester to protect sprayers from skin contact.

Urinary Cypermethrin Metabolites among Conventional and Organic Farmers in Thailand.

Cypermethrin, a pyrethroid insecticide, is frequently spread on agricultural farmlands and is also used in households in Thailand. Conventional pesticide-using farmers (n = 209) were recruited from the Phitsanulok and Nakornsawan provinces. Certified organic farmers (n = 224) were also recruited in the Yasothorn province. The farmers were interviewed via a questionnaire and the urine from their first morning void was collected. The urine samples were analyzed for 3-phenoxybenzoic acid (3-PBA), cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DCCA), and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (trans-DCCA). The results showed no significant difference in the urinary cypermethrin metabolites between the conventional farmers and the organic farmers, for whom the usage of cypermethrin was not accounted for. However, when conventional farmers who used cypermethrin on the farm and in the home were compared with conventional farmers who did not use any cypermethrin or with organic farmers, a significant difference was noted for all metabolites except for trans-DCCA. These findings show that the most significant exposures to cypermethrin are among conventional farmers who use the insecticide on their farms or in their homes. However, measurable levels of all metabolites were found among both conventional and organic farmers who only used cypermethrin in the home or not at all, suggesting that the at-home use of pyrethroids and other possible exposures from pyrethroid residues on market-bought food may contribute to urinary levels of pyrethroids that exceed those of the general population in the US and Canada.

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.

Exposure to trinitrotoluene and health effects among workers in an artillery and ammunition plant.

OBJECTIVE: To determine urinary trinitrotoluene (TNT), 2-amino-4, 6-dinitrotoluene (2ADNT) and 4-amino-2, 6-dinitrotoluene (4ADNT) and health effects upon workers in an ammunition plant. MATERIAL AND METHOD: The urine samples from forty munition workers and forty office workers were monitored for TNT and its metabolites by gas chromatography-mass spectrometry. The workers were interviewed with a questionnaire. RESULTS: The median levels of TNT and its metabolites were 112.84 and ranged from non-detectable (ND) to 1,833.81 mg/L. Median levels for 2ADNT were 11.66, ranging from ND to 360.89 mg/L. Median levels for 4ADNT were 19.95 and ranged from ND to 314.28 mg/L. There were significant correlations between TNT and 2ADNT in urine (r = 0. 700, p-value < 0.001), as well as for TNT and 4ADNT (r = 0.783, p-value < 0.001). Exposed workers reported eye, nose and throat irritations, weakness and headaches with considerably higher frequency than non-exposed workers. CONCLUSION: TNT levels in urine were strongly associated with 4ADNT and 2ADNT levels. Workers exposed to TNT complained of nose, throat and eye irritation, along with overall weakness and headaches.

Exposure to particulate matter, CO2, CO, VOCs among bus drivers in Bangkok.

OBJECTIVE: To measure the exposure of particulate matter CO2, CO, VOCs among Bangkok Mass Transit Authority (BMTA) Bus Drivers. MATERIAL AND METHOD: The exposure of 60 bus drivers to PM2.5, PM10, VOCs, CO2, CO was monitored for full shifts on three routes of air-conditioned (A/C) and non-A/C buses. RESULTS: The average PM2.5 exposure concentrations among non-A/C bus drivers (323.81 mg/m3) were significantly higher than that of A/C bus drivers (206.46 mg/m3) (p-value = 0.016). The average benzene, toluene and xylene exposure concentrations were 429.15, 225.11, 127.60 mg/m for non-A/C bus drivers. The average CO2 levels in A/C buses were significantly higher than those in non-A/C buses (p-value < 0.001). The CO levels in non-A/C buses were significantly higher than those in A/C buses (p-value = 0.037). CONCLUSION: The bus drivers were exposed to high concentrations of air pollutants. The increase of ventilation and cleaning of buses will reduce the exposure of air pollutants.

The urinary cotinine and serum 25 hydroxyvitamin D levels in male smokers.

OBJECTIVE: To assess urinary cotinine and the effects of smoking on 25(OH)D levels in 67 male smokers. MATERIAL AND METHOD: Urine and blood specimens were analyzed for cotinine and serum 25 hydroxyvitamin D (25(OH)D) concentrations by high performance liquid chromatography (HPLC) and chemiluminescent immunoassay, respectively. The accuracy, precision and detection limit of the HPLC method were also tested. RESULTS: The detection limit of urinary cotinine was 0.02 microg/ml. The recoveries of cotinine concentrations of 0.15-2.0 microg/ml were greater than 95%. Only 23.9% of smokers had sufficient levels of serum 25(OH)D at least 30 ng/ml. The smokers were divided into dairy co-operative smokers and other smokers. The average urinary cotinine concentrations of 1,421.42 and 1,866.52 microg/g creatinine were not significant different in dairy co-operative smokers and other smokers whereas the average 25(OH)D of 29.09 and 22.65 ng/ml, respectively, were significantly different at p-value of < 0.001. CONCLUSION: The 42.86% and 10.26% of the diary co-operative smokers and other smokers had sufficient serum 25(OH)D levels to prevent osteoporosis.

Risk factors associated with hand tractor related injuries among rice farmers in Thailand.

Hand tractors are important machines used in the soil preparation process before sowing rice in the paddy's of Thailand. Previous research on injuries in rice farming indicated that working with a hand tractor may be one of main causes of injuries. This study investigated the prevalence of hand tractor-related injuries, their association risk factors and characteristic of injuries. The data were collected by face-to-face interview to 377 farmers from nearly all districts in Phra Nakhon Si Ayutthaya province. Among these rice farmers, the prevalence of injury was 41%. The most common type of injury was cuts (43.9%) and the most common source of injuries was stepping on a golden apple snail shell (33.1%). The bivariate Poisson regression models showed that self-reported normal working conditions that were associated with the risk of injury included sleeping problems (RR = 1.39), "Hustle Work (working quickly to complete plowing)" (RR = 1.48), feeling fatigue before work (RR = 1.60), and normal use of a leveler as attached plow equipment (RR = 1.41). However, a multivariate model showed only normal use of a leveler as attached equipment was associated with an increased use of injuries (RR = 1.47) after controlling for the other factors that were significant in the bivariate models. These results suggest that job stress protection should be recommended or redesign of the leveler attachment developed for hand tractors used in rice paddy fields.

Prevalence and Factors Associated with Musculoskeletal Disorders among Thai Burley Tobacco Farmers.

This cross-sectional analysis study aimed to identify the prevalence and factors associated with musculoskeletal disorders (MSDs) among Thai Burley tobacco farmers. Subjects included 603 burley tobacco farmers from Sukhothai province. Farmers were interviewed twice, (during planting and harvesting seasons), with a questionnaire consisting of demographic and health characteristics, musculoskeletal symptoms, and ergonomic exposure questions. The subjects average age was 49.5 years, more were female (58.5%), most had only a primary education (74.3%), 38% were overweight or obese. Farmers had a significantly higher prevalence of MSDs in the lower back (37.1%), knee (28.7%), shoulder (22.9%), wrist (19.9%), and hip (8.3%) during the harvesting season than in the planting season (p < 0.05). Models found that factors influencing MSDs prevalence during planting included long work hours in seedling, tasks such as topping tobacco plants, and using machine tools, after controlling for age, gender, and body mass index (BMI). While in the harvesting season, models found tasks conducted as a group had lower MSDs prevalence than individual work when carrying fresh tobacco to the barn, piercing/threading and curing the leaves, baling the bundles, and transporting the finished goods. We recommended working in groups to reduce workload and MSDs, especially during harvesting, in burley tobacco farming.

Phytoextraction Potential of Sunn Hemp, Sunflower, and Marigold for Carbaryl Contamination: Hydroponic Experiment.

The phytoextraction ability and responses of sunn hemp, sunflower, and marigold plants were investigated toward carbaryl insecticide at 10 mg L-1 and its degradative product (1-naphthol). All test plants exhibited significant carbaryl removal capability (65-93%) with different mechanisms. Marigold had the highest translocation factor, with carbaryl taken up, translocated and accumulated in the shoots, where it was biotransformed into 1-naphthol. Consequently, marigold had the least observable toxicity symptoms caused by carbaryl and the highest bioconcentration factor (1848), indicating its hyperaccumulating capability. Sunflower responded to carbaryl exposure differently, with the highest carbaryl accumulation (8.7 mg kg-1) in roots within 4 days of cultivation, leading to a partial toxicity effect. Sunn hemp exhibited severe toxicity, having the highest carbaryl accumulation (91.7 mg kg-1) that was biotransformed to 1-naphthol in the sunn hemp shoots. In addition, the different models were discussed on plant hormone formation in response to carbaryl exposure.

Ethion exposure and biological monitoring in vegetable farmers.

OBJECTIVE: To modify the method of analysis of urinary diethyl phosphate (DEP) in order to determine the relationship between atmospheric ethion concentration and urinary DEP concentration. MATERIALS AND METHOD: A cross-sectional study was conducted by collecting atmospheric ethion in the breathing zone of 28 farmers following the NIOSH 5600 method. Urine samples were also collected to analyze urinary DEP concentrations by a modified method using a Gas Chromatography-Flame Photometric Detector (FPD). RESULTS: The average atmospheric ethion concentration in the breathing zone of farmers was 0.036 +/- 0.018 mg/m3. The average urinary DEP in pre-shift and post-shift was 0.030 +/- 0.06 and 0.851 +/- 1.80 mg/g of creatinine respectively. The average DEP during work shifts was 0.53 +/- 0.27, and ranged from 0.12 to 1.16 mg/g of creatinine. A high correlation coefficient (r = 0.645) was found between atmospheric ethion concentrations and urinary DEP concentrations at p < 0.001. CONCLUSION: The modified method provided a reliable result and the urinary DEP during work shifts was found to be a reliable biomarker of ethion exposure.

Biomonitoring of heavy metals among nielloware workers in Nakhon Sri Thammarat Province.

OBJECTIVE: To determine lead and mercury concentrations in biological samples from nielloware workers, to describe the association between occupational lifestyle, workposition, work environment, behavioral factors, acute and chronic neurological symptoms, and levels of metals in biological samples. MATERIAL AND METHOD: A cross-sectional study was conducted by interviewing 45 nielloware workers and 45 matched nonexposed persons living in the municipality of Nakhon Si Thammarat Province, Thailand. Blood and urine samples were collected to determine lead and mercury concentrations by atomic absorption spectrophotometer. RESULTS: The blood lead levels (7.30 microg/dl) and urinary mercury levels (3.30 microg/g creatinine) of the nielloware workers were significantly higher than the control group (p < 0.001). Income, working environmental conditions, workposition, duration of work, personal protective equipment (PPE) and personal hygiene, had significant associations with blood lead and urinary mercury levels (p < 0.05). A significant positive correlation was found between income and blood-lead level (r = 0.968, p < 0.001) and urinary-mercury level (r = 0.661, p = 0.004). The nielloware workers developed acute and chronic symptoms, such as headaches, rash, fatigue, tightness in the chest, loss of consciousness, abnormal tiredness and headache at least once a week and those who developed symptoms had significantly higher heavy metal levels than those who did not at p < 0.05. CONCLUSION: The blood lead and urinary mercury levels in nielloware workers were significantly higher than those in the control subjects. The significant associations were found between income, work position, PPE and personal hygiene and blood lead and urinary mercury levels.

Application Intensity and Spatial Distribution of Three Major Herbicides from Agricultural and Nonagricultural Practices in the Central Plain of Thailand.

The herbicides glyphosate, paraquat, and 2,4-D play a significant role in Thailand. This paper is among the first study to describe the intensity of herbicide application and illustrate how the herbicides are extensively distributed over a large area through both agricultural and nonagricultural practices. Using a quick, economical, and simplified method of Material Flow Analysis together with spatial analysis, better data for the analysis of possible environmental herbicide contamination, human exposure, and related health risks for the general public and applicators can be developed. The findings from this study showed that in the study province, about 2.2 million kg of the active ingredients from the three targeted herbicides is applied annually. Pathway flow modeling with spatial analysis identified several local hotspots of concern based on the type of herbicide and crop/activity where it was used. Cassava planting was found to have the highest herbicide application activity, whereas rice cultivation was the major contributor of total herbicide mass, due to the wide area of cultivation in the province. The herbicide most likely to be applied at rates higher than recommended was 2,4-D, particularly on cassava and sugarcane farms.