LEAD CONTENT OF PLANTS AND SOILS FROM 3 ABANDONED SMELTER AREAS IN AND NEAR SOCORRO, NEW-MEXICO

Two primary lead smelters and one secondary lead smelter have been act ive in the Socorro, New Mexico (USA) area in the last 110 years: the B illing smelter from 1883 to 1894, the Cuba Road smelter from 1881 to 1 900, and Cal West from 1979 to 1984. Samples of plants and surface soi l under each plant from all three sites were analysed for lead. The pl ants consisted of sparse grasses, cacti, creosote bush, snakeweed, mes quite and fourwing saltbush. Lead levels in the plants increased (2-44 0 mu g g(-1)) as the lead in the alkaline soils (25-10 000 mu g g(-1)) increased. However, the BAC (biological absorption coefficient), whic h 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 ord ers of magnitude, except for grasses and snakeweed. At background lead levels, there was little difference between lead in roots versus foli age. At high lead levels, there was higher lead in roots versus foliag e at the Billing and Cuba Road sites. The reverse was noted at Cat Wes t. Because this is a recent operation, the higher lead in foliage may be due to foliar uptake. Plant growth at all sites appeared healthy.