(5) Other pollution sources: soil pollution caused by manure from farmed animals. At present, feed in aquaculture contains a variety of additives, including heavy metal elements, most of which are discharged through feces and then enter the soil. Livestock and poultry manure with residual feed additives affects soil quality and ultimately food safety.A large number of contaminated sites exist. With the expansion of urban area, chemical enterprises that used to be far away from the suburbs have entered the urban area. After these enterprises move or stop production, the land disposal of the original site is a problem. In the past years, due to outdated equipment, industrial "three wastes" emission and "leakage" in the production process, a large number of toxic and harmful substances have entered the soil.Pollution of automobile exhaust to soil. Lead-containing substances in automobile exhaust gradually aggravate the pollution of soil, especially on both sides of roads.