Heavy metal pollution and ecological risk assessment of soils from ancient Linglong gold mine area, China

摘要

Linglong gold-mining area has a history ofmining for over 1000 years. To understand the effect on heavy metal accumulation in soil by gold mining and smelting for a long term, the contents and the potential ecological risks of heavymetals in Linglong gold mine area were studied. The content range of Hg and Cd in soil varied respectively from0.094-4.04 mg/kg and 0.03-2.23 mg/kg. The corresponding average value was 0.36 mg/kg and 0.30mg/kg. The average Pb and Cr contentwas 64.37mg/kg and 23.23mg/ kg. Compared with Chinese Soil Reference (Grade II), the over standard rate ofHg and Cdwas 50.0%and 26.1%, respectively.The geoaccumulation index evaluation presented that Hg and Cd in soil demonstrated a comparatively high level of accumulation characteristics.Mediumor severe contamination was detected in most sample points. Cd content in soil was positively proportional to clay particles. The potential ecological risk assessment presented that the average ecological risk index of Hg and Cd was 344.3 and 221.9 respectively, indicating remarkable ecological risk. The average comprehensive risk index of heavy metal pollutant reached 632.2, showing significant comprehensive ecological risk of heavy metal pollutant.