Assessment on heavy metal contamination degree and potential ecological risk in Lake Dianchi

摘要

The heavy metals such as As, Hg, Cr, Cd, Pb, Zn and Cu in the top 20cm sediment of 22 sampling sites in Lake Dianchi were analyzed, and Index of Geoaccumulation (Igeo) and Potential Ecological Risk Index (RT) were employed to evaluate heavy metal contamination degree and potential ecological risk comprehensively. The results indicated that Lake Dianchi was seriously contaminated by heavy metals. Every element was in the "moderate" contamination degree except Cr and Zn (the contamination level of Cd was as high as 4 in the "strong" degree), and their contamination was in the descent order of Pb > as > Cd > Cu > Hg > Cr > Zn. The average RI was 231.8 that meant in the "moderate" risk level. The descent order was Hg > Cd > Pb > As > Cu > Cr > Zn, and Hg and Cd were in "very strong" level in the northern area of Lake Dianchi. The pollution was different in space. The most obvious characteristic was that the northern area was more serious than the southern area, and the west was more serious than the east.