Mutagenicity in the vicinity of a lead smelter.

The mutagenicity of the environment in the vicinity of a lead smelter was examined for 3 years by studies of changes in the frequencies of male germinal mutations of the waxy-C system of Zea mays and somatic mutations of the stamen hair system of Tradescantia. A transect was run at 0.3, 1.7, 3.2, 7.4, and 11.4 km predominantly downwind from the smelter. The mutagenic responses vary between years, within a year, and with distance. Mutation frequencies are both directional and nondirectional with distance. Concentrations of Pb, Cd, Cu, and Zn measured in soil samples show directional changes with distance each of the 3 years, and joint monotonicity is observed in some cases between mutation frequency with distance and metal concentrations with distance. Of a total of ten experiments with both Zea mays and Tradescantia, eight show significantly higher mutation frequencies at one or more locations close to the smelter than at locations more distant or at other controls.