Health Effects of Acute Exposures to Methyl Bromide during Soil Fumigation Inside Greenhouses

Abstract

Health Effects of Acute Exposures to Methyl Bromide during Soil Fumigation Inside Greenhouses: Shigeki KODA, et al. Department of Public Health, Kochi Medical School-In order to estimate exposure to methyl bromide (CH₃Br) during soil fumigation inside greenhouses and examine health effects in agricultural workers, an interview survey, environmental monitoring and occupational exposure to CH₃Br were conducted. An interview survey of working conditions and subjective symptoms related to exposure to CH₃Br during soil fumigation was conducted on 241 agricultural workers between 1996 and 1998, and 225 agricultural workers were analyzed. The environmental monitoring during soil fumigation and occupational exposure to CH₃Br were conducted in cooperation with eight agricultural workers. Finally, the authors examined the exposure levels to CH₃Br after improving soil fumigation techniques. Many agricultural workers used a large amount of CH₃Br in soil fumigation within a short time period without personal protective equipment. The odds ratio for nausea was significantly increased by fumigation with mulch. The odds ratios for irritation of the eyes, feeling sick, cough and anxieties about health were significantly increased by wearing gas masks. The odds ratios for forgetfulness and ringing in the ears were significantly increased at ages over 50 yr. The concentrations of CH₃Br in greenhouses were changed from 5, 000 ppm to 1, 100 ppm during soil fumigation, and occupational exposure was 57.2 ppm while opening the sheets of greenhouses and below ACGIH-TLV (1 ppm) in CH₃Br ejection, piping and planting. The agricultural workers could avoid exposure to high concentrations of CH₃Br by improving in soil fumigation techniques. Soil fumigation inside greenhouses has occupational safety and health issues related to the large amounts of CH₃Br used within short fumigation periods, the lack of precautions for handling chemicals, improper use of protective equipment and lack of training in safety practices resulting in agricultural workers being at risk of acute exposure to CH₃Br.