Thyroid hormones and cytogenetic outcomes in backpack sprayers using ethylenebis(dithiocarbamate) (EBDC) fungicides in Mexico.
Steenland K; Cedillo L; Tucker J; Hines C; Sorensen K; Deddens J; Cruz V
Environ Health Perspect 1997 Oct; 105(10):1126-1130
A study of thyroid and cytogenetic changes in Mexican farmers who applied ethylenebis(dithiocarbamate) (EBDC) fungicides was conducted. The cohort consisted of 49 workers who sprayed EBDCs such as mancozeb (8018017) and maneb (12427382) from backpacks on tomato farms and 14 small land owners who sprayed small quantities of EBDCs on tomato crops in Cuernavaca in central Mexico. None of the subjects used protective equipment. The controls consisted of 31 construction workers from Cuernavaca. The mean ages of the backpack sprayers and landowners in the cohort and the controls were 26.2, 31.6, and 22.0 years, respectively. The proportion of smokers in the three groups was 70%, 50%, and 67%. Blood and urine samples were collected from the subjects. The blood samples were analyzed for serum thyroxine (T4) and thyroid stimulating hormone (TSH). Lymphocytes in the blood samples were scored for chromosome aberrations and sister chromatid exchanges (SCEs). The urine samples were analyzed for ethylene-thiourea (96457) (ETU), an EBDC metabolite. No ETU was detected in urine samples from the controls; the detection limit was 10 parts per billion (ppb). Urine samples from 13 backpack sprayers and six landowners also did not contain detectable levels of ETU. The mean ETU concentrations in the remaining backpack sprayers and landowners were 58 and 12ppb, respectively. Serum TSH concentrations in the backpack sprayers were significantly increased relative to the controls. T4 concentrations in all groups were similar. The SCE frequency was significantly increased in the backpack sprayers. This effect persisted after adjusting for age and smoking. The frequency of chromosomal translocations was significantly increased in the backpack sprayers after adjusting for age. The unadjusted translocation frequency was similar in all groups. The authors conclude that heavy exposure to EBDC fungicides appears to affect thyroid function and the lymphocyte genome.
NIOSH-Author; Dithiocarbamates; Pesticides; Agricultural-workers; Thyroid-gland; Hormone-activity; Occupational-exposure; Genotoxic-effects; Body-fluids; Blood-cells; Metabolites; Thioureas
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Environmental Health Perspectives