Lynn A. Brandvold, Barbara R. Popp, and Sandra J. Swartz, New Mexico Bureau of Mines and Mineral Resources, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801
Two primary lead smelters and one secondary lead smelter have been active in the Socorro, New Mexico area in the last 110 years: the Billing smelter from 1883 to 1894, the Cuba Road smelter from 1881 to 1900, and Cal West from 1979 to 1984. Samples of plants and surface soil under each plant from all three sites were analyzed for lead. The plants consisted of sparse grasses, cacti, creosote bush, snakeweed, mesquite and fourwing saltbush. Lead levels in the plants increased (2-440 Fg g-1) as the lead in the alkaline soils (25-10,000 Fg g-1) increased. However, the BAC (biological absorption coefficient), which is the ratio of lead content in the plant to the lead content in the soil, a measure of relative accumulation, decreased by one to two orders of magnitude, except for grasses and snakeweed. At background lead levels, there was little difference between lead in roots vs. foliage. At high lead levels, there was higher lead in roots vs. foliage at the Billing and Cuba Road sites. The reverse was noted at Cal West. Because this is a recent operation, the higher lead in foliage may be due to foliar uptake. Plant growth at all sites appeared healthy.