[Chemical characteristics and sources of trace metals in precipitation collected from a typical industrial city in Northern China].

To investigate the chemical characteristics and possible sources of trace metals in precipitation of Tangshan, a typical industrial city in Northern China, precipitation samples were collected using an automated wet-only sampler for one year from December 2009 to November 2010 and subjected to chemical analysis using ICP-MS. The results showed that crustal elements (Ca, Mg, Na, K, Fe and Al) accounted for 97.72% of the total concentrations while heavy metals (Zn, Mn, Pb, Ba, Sb, Cu, Ni, As, V, Co and Se) only contributed 2.25% of the total. Zinc was the most abundant heavy metal and calcium had the highest concentration among the crustal elements, with volume-weighted mean concentrations of 88.7 microg x L(-1) and 4.5 mg x L(-1), respectively. Seasonal variations of trace metals were significant, with higher values observed in winter and spring than in summer and autumn. The calculation of crustal enrichment factors with Al as the reference element indicated that Tl, As, Ag, Zn, Pb, Cd, Se and Sb were mainly derived from anthropogenic sources and the enrichment factor values of those elements ranged from 10(2) to 10(5). In addition, the concentrations of heavy metals such as Pb, Cu and Ni in precipitation of Tangshan city were higher than those reported for Mt. Tai. The results of principle component analysis demonstrated that steel smelting emissions, fugitive dusts and coal combustion were probably the major contributors of trace metals in the precipitation of Tangshan City.