Abstract: Diestrammena and part of environmental factors from Longjing cave and Bailong cave in Guizhou province,were investigated.The contents of heavy metals (Cu、Cr、Ni、Zn、Hg and As) in Diestrammena,in soil and waterfromtwo caves were measured,and the enriched coefficient of Diestrammena from two caves was studied,and the pollution index and the ecological risk of heavy metalsin soil from two caves were assessed.The results showed that the average content of Cu、Cr、Ni、Zn、Hg and As in two caves soil with light belt,reflection light belt and dark belt exceeds the background value of soil in China.The heavy metals Cu and Zn are significantly enriched in Diestrammena from two caves.Thepotential ecological risk of six heavy metals reachs a higher level in soil fromLongjing cave,and the order of potential ecological risk indexes of six heavy metals is Hg＞As＞Cu＞Ni＞Zn＞Cr.The potential ecological risk of six heavy metals reachs the highest level in soil from Bailong cave,and the order of potential ecological risk indexes of six heavy metals is Hg＞As＞Cu＞Ni＞Zn＞Cr,in which Hg isthe most important ecological risk factor in two caves.

Key words: Diestrammena, heavy metals enrichment, potential ecological risk, longjing cave, bailong cave, Guizhou province,China