| With the development of modern industry,the release of heavy metals into the environment has been accelerating annually.Heavy metal contamination poses a threat to human health and life quality.So it has become a serious problem in environment and society.This study concentrated on the relationship between heavy metal and the soil enzymatic activiyies of the main types soils in Anhui province,the effect of system rape-paddy soil system treated by Cu,Zn was also studied. The growth and accumulation character of Cu Zn of rape in the paddy soil treated by Cu Zn has been investigated.Food safety evaluation on the rapeseed obtained from the rape grown in the soils polluted by Cu Zn may be concluded in this article.Successive extraction method was adoped to study the relationship between characteristics of chemical forms of copper,cadmium,zinc and four soil enzymatic activities (Calatase, Urease, Invertase, Neutral phosphatase) in Indicotic black (IB, Cambisols) by field sampling.The result showed that, the content of Cu,Cd,Zn residual form accounts for the proportion in the total quantity quite high in the soils, exchangeable form,organic form and carbonate combined form content obviously were lower than residual form. In three kind of elements,the Zn chemomorphosis change tendency was the most consistent, it displayed for the content of residual form>the content of carbonate combined form> the content of Fe-Mn oxide combined form>the content of organic form> the content of exchangeable form; the most contributions to inhibiting of soil enzymatic activities,especially to Urease activities in lowly polluted soils,was the exchangeable Cu,Cd and Zn,the next were the Fe-Mn oxide combined Cu,Cd and Zn.Whereas it were stimulative action that Organic forms to Urease.So we can use the exchangeable Cu,Cd,Zn ,Urease and Neutral phosphatase activities as primary biochemical index to evalute Cu,Cd,Zn polluted soils.Based on the field investigation and laboratory experiment,the relationship between characteristics of chemical forms,contents,distribution of Cu Zn Pb and four soil enzymatic activities (Calatase , Invertase, Urease, phosphatase) in paddy soil in a few different landform of Anhui province were studied.The results showed that the content of residual Cu Zn Pb and organic Cu Zn Pb occupied the highest proportion in the total in paddy soils of five kinds of different region.The content of organic Cu Zn Pb in paddy soil of plain and mound region were obviously higher than in mountain area. Whereas the relative content of Fe-Mn oxide combined Cu Zn Pb in paddy soil of mountain area were higher than in plain and mound region.In paddy soils,the most effect to inhibiting effect of Calatase activities were carbonate combined Cu Zn,the most effect to inhibiting effect of Urease activities were exchangeable Pb.It is feasible to use carbonate combined Cu Zn and Calatase activities as biochemical index to evaluate Cu Zn polluted soils,and use exchangeable Pb and Urease activities as biochemical index to evaluate Pb polluted soils.The study with pot experiment showed that the effect of Cu,Zn to enzymatic activities had different aspect, the ability of inhibiting Urease activities of Cu was superior to Zn.Cu had the most obvious influence on Urease activities, whereas Zn had the most obvious influence on Calatase activities.The study showed that there were more obvious influence on the dry weight of rape by Cu treatment than Zn treatment. The effect of damaging the growth of rape by Cu treatment exceeded Zn treatment. The inhibition of seedling resulted from the inhibition of root and material accumulation. The factor analysis disclosed that the dry weight of root was more sensitive than other indexes. Therefore, the dry weight of root could be perfectly adopted to monitoring Cu,Zn pollution. |
