Lawn mower: restoration of polluted farmland that cannot be ignored
If anyone is not clear about the harm caused by soil pollution, the "cadmium rice" incident that occurred in Guangdong some time ago is a living case. Heavy metals not only harm human health through air or water, but also enter people's table through agricultural products, directly threatening people's survival.
Although this case is shocking, it is the grim reality of current rural soil pollution. A large number of enterprises with high pollution and high emissions have moved to the countryside, becoming the major polluters of the soil; Urban polluted rivers flow to rural areas; Farmers use a large amount of chemical fertilizers and pesticides in the process of farming, causing non-point source pollution and pollution caused by mining. A variety of pollution factors have gathered together, and the farmland that was once a pure land has become riddled with holes.
Compared with the urban polluted land remediation, the rural polluted land remediation is still in the initial stage in terms of technology and successful cases. It is more urgent to repair it, but it also faces greater difficulties.
The function of urban polluted land restoration is to reuse the land after industrial withdrawal, or for business or residence. The rural land pollution is directly related to the growth of agricultural products, directly related to food safety, and has a close relationship with everyone. No one can guarantee that the food bought from the supermarket is grown on the polluted land. From this point of view, the sooner the better to repair the polluted farmland.
Desire and reality do not necessarily go side by side. In addition to the current laws, standards and technologies of contaminated land remediation are still imperfect, rural land remediation has more obstacles than urban contaminated land remediation.
The area of urban land pollution is relatively easy to determine, while the area of rural land pollution is larger, wider and more difficult to determine.
Land restoration requires a lot of money. After the withdrawal of polluting enterprises, many urban polluted land plots are located in the golden zone of the city and have greater commercial development value. They often attract developers to develop through the market mechanism. Whoever develops will pay for the repair. The introduction of market means makes many urban polluted land not lack of repair funds. As for the polluted land in rural areas, many of the pollution is accumulated over many years, and it is almost impossible to find the original polluter to be responsible. However, a large amount of money needs to be invested in the repair, and who will pay the money has become a difficult problem.
Technology adaptation is also a problem. Taking Shanghai as an example, the scientific research department has developed different remediation technologies for land remediation with different use functions. However, in terms of rural contaminated land remediation, the technologies that can be adapted are still very thin. The most successful and frequently reported in recent years is the bioremediation technology promoted by Chen Tongbin, director of the environmental remediation research center of the Institute of Geographical Sciences and resources of the Chinese Academy of Sciences, in Guangxi, Hunan and other places, However, due to the limitation of capital investment and engineering technology, it has not been popularized on a large scale.
The experience accumulated in soil remediation in Shanghai provides a reference for the remediation of urban polluted land. Compared with it, the remediation of rural land pollution needs more attention. After all, land and food safety are inseparable.