Plasma gamma-hexachlorocyclohexane concentrations in forestry workers exposed to lindane

Plasma gamma-hexachlorocyclohexane (gamma-HCH) and three urinary trichlorophenols were measured in forestry workers who were engaged in planting seedlings treated with gamma-HCH. These two procedures were assessed as potential biological monitoring methods and the data were compared with reported clinical symptoms. The measurement of plasma gamma-HCH was considered to be a feasible and valid monitoring method for use in routine practice and is a useful indicator of gamma-HCH absorption. The data were used to illustrate the need to be vigilant about personal hygiene and the efficacy of protective clothing. Plasma gamma-HCH concentrations above 70 nmol/l were measured in two workers which coincided with persistent non-specific clinical symptoms. Trichlorophenols were identified in urine but the extensive and variable metabolism of gamma-HCH makes this approach less suitable for biological monitoring.