A survey of arsenic levels in human hair and nails—exposure of wood treatment factory employees in Nigeria

Arsenic levels have been determined in the hair and nails of male employees of a wood preservative treatment factory in Nigeria. Mean As concentrations of 11·6, 7·5, 4·1 and 1·6 μg g⁻¹ were measured in hair samples from four groups of employees, depending on the nature of their work and the duration of their employment in the factory. Mean As levels of 7·4, 4·8, 2·7 and 1·0 μg g⁻¹ were also measured in nails for the same groups. The employees involved in the preparation of the treating fluids, the chemical impregnation process and handling of the treated timber showed consistently higher As levels in both tissues than those who were less exposed to the chemicals. No correlation between the measured As levels and age of the donors was established, nor was a reasonably good hair As—nail As correlation obtained for any of the four exposure groups. This study, however, minimized possible effects of age, sex, hair colour and chemical treatment. Mean As levels of 1·2 and 0·64 μg g⁻¹ as ‘control’ values were also determined in hair and nails, respectively of ‘non-exposed’ persons in the same age group as the factory workers. The elevated As levels measured in both tissues reflected a relatively high degree of exposure to the chemicals.