Intensity analysis of chromium cycling in south Jiangsu region of China.

Abstract

Suzhou (SZ), Wuxi (WX) and Changzhou (CZ) (collectively called the SXC area) in southern Jiangsu Province surround Tai Lake on three sides and have an important impact on its ecology. The emission and circulation of Cr in the three cities were quantified according to the six categories (including industry production, agricultural livestock, vehicle exhaust, solid waste, atmospheric subsidence and runoff) to analyze its regional characteristics and source category characteristics and to build a Cr cycle diagram to evaluate the pollution situation. The results showed that the Cr emissions from solid waste were the highest and mostly came from industrial sludge, accounting for 76.4% of the total circulation. The Cr emissions from SZ and WX were significantly higher than those of CZ, accounting for 47.0% and 42.9% of the regional total. The Cr in the excrement of pigs and poultry, dry sedimentation and surface runoff exceeded 100 tons every year, which needed to be valued. The Cr concentration in the surface water, soil and atmosphere in SXC area all met with the highest national standards. Studies have shown that the sediments and benthic organisms in the west and north of Tai Lake were already in a low-pollution state, but which was overall acceptable. Through this study, Cr circulation was clarified in typical areas, which was convenient for the monitoring and management of heavy metal pollution in the areas surrounding Tai Lake.