@@ Study of ecology and biogeochemistry is helpful for understanding ecologicaltoxicology of As，Cd，Hg，Pb and Cr.Anthropogenic activities，such as mineexploitations，contaminate usually a large amount of water,soil and farmlands.Toxicelements from them wiU enter eventually plants and food chains，and cause damagesto human health．Dietary intake ofthe toxic metals has also a great impact on humanhealth．