Atmospheric deposition of major ions and trace metals near an industrial area, Jordan

Abstract

Al, Cd, Cr, Cu, Fe, Mn, Pb, Zn, NH₄⁺, Mg²⁺, Ca²⁺, Na⁺, K⁺, Cl⁻, NO₃⁻ and SO₄²⁻, along with pH were determined in wet and dry deposition samples collected at Al-Hashimya, Jordan. Mean trace metal concentrations were similar or less than those reported for other urban regions worldwide, while concentrations of Ca²⁺ and SO₄²⁻ were the highest. The high Ca²⁺ concentrations were attributed to the calcareous nature of the local soil and to the influence of the Saharan dust, while the high concentrations of SO₄²⁻ were attributed to the influence of anthropogenic sources and Saharan dust soil. Except for SO₄²⁻, NO₃⁻, and Ca²⁺, dry deposition fluxes of measured metals and ions were higher than their corresponding wet deposition fluxes. The high annual average pH values recorded for wet and dry deposition samples were attributed to the neutralization of acidity by alkaline species. Cd, Cr, Cu, Pb, Zn, NO₃⁻ and SO₄²⁻ were enriched in wet and dry deposition samples relative to crustal material, and a significant anthropogenic contribution to these elements and ions is tentatively suggested. Finally, the possible sources and the main factors affecting the concentrations of the measured species are discussed.