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The informal recycling of electronic waste (“e-waste”) is a lucrative business for workers in low- and middle-income countries across the globe. Workers dismantle e-waste to recover valuable materials that can be sold for income. However, workers expose themselves and the surrounding environment to hazardous agents during the process, including toxic metals like lead (Pb). To assess which tools, tasks, and job characteristics result in higher concentrations of urine and blood lead levels among workers, ten random samples of 2 min video clips were analyzed per participant from video recordings of workers at e-waste recycling sites in Thailand and Chile to enumerate potential predictors of lead burden. Blood and urine samples were collected from participants to measure lead concentration. Boosted regression trees (BRTs) were run to determine the relative importance of video-derived work variables and demographics, and their relationship with the urine and blood concentrations. Of 45 variables considered, five job characteristics consisting of close-toed shoes (relative importance of 43.9%), the use of blunt striking instruments (14%), bending the back (5.7%), dismantling random parts (4.4%), and bending the neck (3.5%) were observed to be the most important predictors of urinary Pb levels. A further five job characteristics, including lifting objects <20 lbs. (6.2%), the use of screwdrivers (4.2%), the use of pliers/scissors (4.2%), repetitive arm motion (3.3%), and lifting objects >20 pounds (3.2%) were observed to be among the most important factors of blood Pb levels. Overall, our findings indicate ten job characteristics that may strongly influence Pb levels in e-waste recycling workers’ urine and blood.

Objectives To assess pesticide exposure and understand the resultant health effects of agricultural workers in Northern Thailand. Methods This was a cross‐sectional study. We quantified exposure to pesticides, including chlorpyrifos, methomyl, and metalaxyl, by air sampling and liquid chromatography/mass spectrometry. We estimated differences in self‐reported health outcomes, complete blood counts, cholinesterase activity, and serum/urine calcium and creatinine concentrations at baseline between farmworkers and comparison workers, and after pesticide spraying in farmworkers only. Results This study included 97 men between the ages of 22 and 76 years; 70 were conventional farmworkers; and 27 did not report any prior farmwork or pesticide spraying. None of the farmworkers wore standardized personal protective equipment (PPE) for the concentrated chemicals they were working with. Methomyl (8.4‐13 481.9 ng/m 3 ), ethyl chlorpyrifos (11.6‐67 759 ng/m 3 ), and metalaxyl (13.9‐41 191.3 ng/m 3 ) were detected via personal air sampling. When it came to reporting confidence in the ability to handle personal problems, only 43% of farmworkers reported feeling confident, which reflects higher stress levels in comparison to 78% of comparison workers ( P = .028). Farmworkers also had significantly lower monocyte counts ( P = .01), serum calcium ( P = .01), red blood count ( P = .01), white blood cell count ( P = .04), and butyrylcholinesterase activity ( P < .0001), relative to comparison workers. After adjusting for body mass index (BMI), age, and smoking, methomyl air concentrations were associated with a decrease in farmworker acetylcholinesterase activity (beta = −0.327, P = .016). Conclusions This population of farmworkers had significant alterations in stress measures and clinical biomarkers, including decreased blood cell counts and cholinesterase activity, relative to matched controls. These changes are potentially linked to occupational pesticide exposures. Improving PPE use presents a likely route for preventive intervention in this population.

Article SummaryObjectivesTo assess pesticide exposure and understand the resultant health effects of agricultural workers in Northern Thailand.DesignCross-sectional study.SettingThe entirety of this study was completed in Chiang Rai, Thailand, at Mae Fah Luang University, Chiang Rai Prachanukroh hospital, the village leader’s home, and the community center.Participants97 men between the ages of 22-76 years of age; 70 were conventional farmwokers and 27 did not report any prior farm or pesticide spraying.Primary Outcome MeasuresWe quantified exposure to pesticides including chlorpyrifos, methomyl, and metalaxyl, by air sampling and liquid chromatography/mass spectrometry. We estimated differences in self-reported health outcomes, complete blood counts, cholinesterase activity, and serum/urine calcium and creatinine concentrations at baseline between farmworkers and comparison workers, and after pesticide spraying in farmworkers only.Secondary Outcome MeasuresWe quantifiedResultsNone of the farmworkers wore standardized PPE for the concentrated chemicals they were working with. Methomyl, ethyl chlorpyrifos, and metalaxyl were detected air samples in varying amounts. When it came to reporting confidence in the ability to handle personal problems, only 43% of farmworkers reported feeling confident; which reflects higher stress levels in comparison to 78% of comparison workers (p = 0.028). Farmworkers also had significantly lower monocyte counts (p=0.01), serum calcium (p=0.01), red blood count (p=0.01), white blood cell count (p=0.04), and butyrylcholinesterase activity (p<0.0001), relative to comparison workers. After adjusting for BMI, age, and smoking, methomyl air concentrations were associated with a decrease in farmworker acetylcholinesterase activity (beta= −0.327, p =0.016).ConclusionsFarmworkers’ blood analytes, acetylcholinesterase, and self-reported symptoms differed from comparison workers. Improving PPE use presents a likely route for preventive intervention in this population.Strengths and Limitations: The US Occupational Safety and Health Administration (OSHA) generally recommends testing for baseline cholinesterase levels after not working with organophosphates for at least 30 days(1). However, this was not capable for our study, and baseline cholinesterase measurements may not actually represent a true baseline measurement due to their overlapping work schedulesThis pilot study did not take multiple baseline measurements, and the one baseline that was taken was likely taken before the OSHA recommended guideline of 30 days since pesticide use.Our study also focused on workplace sampling at a time when the specific farm of interest was expected to be spraying chlorpyrifos, therefore the study results show an over-representation of chlorpyrifos.This is the first study of its type that took a mixed-methods approach using survey, biomarker, and workplace observation data to analyze farmworker pesticide health effects in comparison to other workers in Northern Thailand.This pilot study is one of the larger studies on farmworker chemical exposures in Thailand. These data can inform the methods for future global occupational health research on farmworkers.This study is very generalizable to farmworkers in LMIC and Thailand.