On the basis of multi-targets geochemical survey and regional ecological and geochemical evaluation in regional areas in the lower reach of the Yellow reiver,chooing some special agricultual products areas and regional ecological and geochemical environment areas,geochemical evaluation is carried out in these areas.Selecting soil,shallow underground water,soil solution,microorganism and seed samples according to a certain method and sample selecting desity,heavy metals,such as As and Cd,useful elements,such...