Pesticide exposure and adverse health effects associated with farm work in Northern Thailand

Objectives: To assess pesticide exposure and understand the resultant health effects relative to non-agriculture workers in Northern Thailand. Methods: Collaborating with hospital staff and health care volunteers, we surveyed agricultural (n=70) and comparison workers (n=27) residing in Northern Thailand. 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 and urine calcium and creatinine concentrations at baseline between farmworkers and comparison workers, and after pesticide spraying in farmworkers only. Results: None 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 ability to handle personal problems, only 43% of farmworkers reported feeling confident, reflecting higher stress levels, in comparison to 78% of comparison workers (p = 0.028). Conventional 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