DISTRIBUTION OF COPPER SMELTER EMISSIONS IN SOUTHEASTERN ARIZONA - USING HONEY MESQUITE AS A BIOINDICATOR

Honey mesquite (Prosopis juliflora), a representative species of the Sonoran Desert ecosystem, was studied as a possible bioindicator for industrial smelter pollution. Samples from soils, leaves and bark were collected along distance and elevation gradients from the largest operating copper smelter in Arizona and analyzed for element concentrations of Zn, Cu, Fe, Ti, Mn, Al, Mg, Ca, Sm, Ce, U, Th, Yb, As, La, Hf, Sb, Sc, V, In, W, Ba, Br, K, Na, Cl and Au. Depending on the sample type - soil, leaf or bark - between 5 and 15 elements were identified as smelter immissions. Two distinct covariate element groups formed in samples from the study site could be related to the chemistry of different smelting processes. A common atmospheric transport pattern was found to exist for the smelter emittants Cu, Sb and As over long distances. The identification and specification of smelter immissions in honey mesquite makes this tree a well-suited bioindicator for industrial smelter pollution.