Li Jianchao, a teacher from Shaanxi Normal University, searched 2450 papers published in recent ten years about six kinds of heavy metal pollution (Cd, Pb, Zn, As, Cu, Cr) in soil in China, screened out the data of 850 papers, sorted out and analyzed them, drew a map of heavy metal pollution, and provided the detailed distribution of key polluted areas. This work was published in the Bulletin of Environmental Exposure and Toxicology from June 2006 to June 2006. The concentration limits selected by the author are cadmium.

-1mg/Kg, lead -80mg/Kg, zinc -300mg/Kg, arsenic -45mg/Kg, copper -200mg/Kg and chromium -350mg/Kg, which are roughly equivalent to GB 156 18.

In the lead pollution distribution map, the over-standard rate of points is 17.8%, which is extremely serious in Shanghai and Guangzhou, and also serious in Guizhou (Hezhang) and Fujian (Sanming) due to mining.

Zinc pollution is serious in Guizhou, Hunan (Jishou), Fujian (Sanming, Nanping) and Henan (Xinxiang). Soil arsenic pollution mainly comes from groundwater pollution, and the more serious areas are Tianjin, Shandong (Jinan) and Anhui (Tongling). Copper pollution is mainly distributed in the southeast coastal areas, especially in Guangzhou, and the highest value of copper pollution appears in Baoding, Hebei (exceeding the standard 165 times). The degree of cadmium pollution is low, and the highest value appears in Fuzhou, Fujian.

Heavy metal pollution source

Irrigation with wastewater rich in heavy metals is an important way for heavy metals to enter the soil. Another way for heavy metals to enter the soil is to fall into the soil with atmospheric deposition. Heavy metals mainly include mercury, copper, zinc, chromium, nickel and cobalt. Because heavy metals can not be distinguished by microorganisms, but can be enriched by microorganisms, once the soil is polluted by heavy metals, its natural purification process and manual management are very difficult. In addition, heavy metals can bioaccumulate and have great potential harm to human beings.

What is the harm of soil pollution?

Soil pollution has brought extremely serious consequences.

First of all, soil pollution makes the already tense cultivated land resources even scarcer.

Second, soil pollution is a great threat to human health.

Third, soil pollution has a great negative impact on agricultural development.

Fourthly, soil pollution is also an important cause of other environmental pollution.

Fifthly, pollutants in soil pollution are migratory and retentive, which may continue to cause new land pollution.

Sixth, soil pollution seriously harms the interests of future generations and is not conducive to the sustainable development of rural economy.