单选题

　　1.【概括大意】There is a vital need to understand the potential risks and long-term health effects of living on naturally contaminated soils. Future environmental investigations of naturally polluted soils should concentrate on the potential pathways of metals into the food chain and human body. Geologists should be part of such studies as they can provide the essential background information on rock and soil chemistry as well as the chemical forms of heavy metal pollution.

　　The main idea of this paragraph is__________.

　　A.Long- term Health Effects on Children

　　B.Research on Channels of Heavy Metals Getting into Human Food Chain

　　C.Potential Hazards of Human Contaminated Soils

　　D.No Evidence to Indicate Bad Effects of Naturally Contaminated Soil