Study On Soil Pollution Factors Analysis And Countermeasures In China

With the development of science and technology, soil pollution has increased seriously, and has been a hot issue around world. Recently, soil pollution has been a severe threat to human health, and could be potentially hazardous to environment. Environmental problems due to soil pollution become more and more serious, because of the lack of attentions for a long time in China. However, it is difficult to take measures to bring it into control considering the high cost and the long time spent.Therefore it becomes much neccesary to pay more attention to the research and establishment of effective and normative managements to soil pollution.This paper summarizes the management system, laws and regulations, measurments taken to prevent and cure soil pollution at home and abroad, and makes a comprehensive survey on its causation, especially on chemical fertilizer pollution and pesticide pollution. Then an outline on how to prevent and cure the pollution is presented, meanwhile, according to a survey somewhere in China, an advice of detailed measurements is delivered in this paper, which could be a constructive suggest to bring soil pollution into control.Nowdays, about forty million hectares of soil has been polluted, of which 49.6 percent polluted by heavay metals, in China. And it is concluded that chemical fertilizers are applied into soil mainly in the proportion of 1:0.38:0.21 as N:P2O5: K2O in China. However, crops absorb N, P and K in a very different proportion of 1:0.45:1. Then it is obviously derived that chemical fertilizers are applied bad-proportionedly, which nitrogenous fertilizers are overfed, and phosphatic fertilizers fed insufficiently, and potassic fertilizers fed more insufficiently. Contents of heavy matels, Zn, Ni, Cu, Co, Cr, etc., will increase after soil polluted by chemical fertilizers. Furthermore, content of Cd will reach a level of 50～60mg in a kilogram of soil after it is fed with fertilizers of carbamide all long, which contains Cu,Zn,Mn,Mo,Pb and Cd by 7:10:10:4:80:20. About 11 kilograms of Cd would be fed into soil when 100 kilograms of phosphatic fertilizers fed. In another aspect, over-fed nitrogenous fertilizers will produce large amount of NO3-or NO2-, which can destroy physical and chemical function of soil heavily and appeared in some soils in which vegetables were planted, in the help of various microbes.In China, about 1.3 million tons of pesticids are sprayed, which is 2.5 times of average around the world.62 percent is spayed to kill pests and acarids, and 21 percent to kill bacteria, and 16 percent to weed, and 1 percent left to kill rats or to help plants growing. Nowdays, there are about 1360 million acres of soil polluted by pesticids in our country. After soil polluted, organophosphor easily residue in vegetables, which may cause cancer. 452 chemical compounds are considered to cause cancer easily by the Cancer Institute of USA, of which 17 percent are pesticids. It shows that more than 62.15 percent of vegetables contain harmful residants in our samples. And more than 80 percent of soil contain organophosphor because large amount of pesticids are sprayed into vegetables. They will harm human health after being eaten. There will alse be many beneficial insects and birds killed. Then serious ecological consequences will appear.