Heavy metal characteristics of stream sediments in the Xiaoqinling gold ore district

Abstract：Based on the division of water systems in the Xiaoqinling gold ore district, the authors studied the concentrations and distribution of seven kinds of heavy metals i.e., Hg, Pb, Cd, Cr, As, Cu and Zn, in the stream sediments and, in the light of the source of each element, analyzed the causes for different concentrations of these elements and probed into the influence of the gold mining on the variation of heavy metal concentrations. On such a basis, the factors affecting the occurrence and migration of heavy metals in stream sediments were revealed. Some conclusions have been reached: 1. In the light of regional distribution, the heavy metal concentrations of the stream sediments at the northern foot of the Xiaoqinling Mountains are generally higher than those at the southern foot, and the concentrations at the northern foot show characteristics of “high in the middle and low on both sides”. 2. In the light of the differences in element content in the stream sediments of the Xiaoqinling gold ore district, Pb has the highest content and most remarkably deviates from the background value, followed by Hg, whereas Cr and As continually maintain the low background values.