岩溶地区隧道施工对水环境影响评价指标体系的建立

随着人们环保意识的不断提高,交通隧道施工期对周边水环境的影响也日益受到关注。针对岩溶地区隧道的施工特点建立了隧道施工期对水环境影响的评价指标体系。该体系研究了施工中含污废水排放对地表水体污染以及地下水疏排给隧道周边水资源流失两方面进行评价;指标体系各层指标数量随施工进展与现场情况变化进行增减,以满足施工期不断变化情况对水环境影响大小的准确评估;该指标体系充分考虑到"木桶理论"的原理,明确施工过程中对水环境影响最严重环节,有助于及时采取保护措施。

DISTRIBUTION,ENVIRONMENTAL IMPLICATION AND SOURCE CHARACTERISTICS OF HEAVY METALS IN WATER AND SEDIMENT IN NANFEI RIVER

The contents of heavy metals,including As,Cd,Cr,Cu and Pb,in the surface water and sediment during the wet and dry season in Nanfei River were analyzed.The results showed that the pollution degree of Cd in the five elements was the highest.The concentration of Cd in surface water was below class V.And the content of Cd in sediment was much more than the soil background values of Hefei City,and the maximum value was 7.5 times of the background value.The single factor water quality index method results showed that Cd did not reach the target of water body function area,and the remaining elements basically achieved the target of water body function area.The geo-accumulation index evaluation results showed that the pollution degree of sample sites was between no pollution and light pollution,and the potential ecological risk index of sample sites belonged to the moderate ecological risk level.Three evaluations results showed that Cd was the main pollution factor.The principal component analysis showed that sources of heavy metal pollution were differences and diversity in different periods.