Effects Of Cadium And Pyrene Combined And Simplex Pollution On Soil Microbial And Enzyme Activity In Solanum Nigrum Soil

Sewage irrigation is one of the most important way of wastewater reused,Soil heavy metals, PAHs pollution has become one of the major environmental problems in our country because of the unreasonable sewage irrigation,has posed a serious hazard to the ecosystems.Therefore,it is crucial to expand researches on heavy metal and PAHs pollution in sewage irrigation soils.This paper has studied by simulating sewage irrigation farmland in Shaanxi Province,We selected cadmium as the represtentative of the heavy metal and pyrene as the representative of PAHs,and the effects of cadmium and pyrene combined and simplex pollution on soil enzyme activities(dehydrogenase,urease,alkaline phosphatase) and microbial population were stuidied by pot experiment in greenhouse.Aims to provide a useful reference for the effects of the microecosystem environment and environmental quality assessment in sewage irrigation soils. The results showed that:(1) Effects of cadmium on soil enzyme activities: In five sampling test, cadmium plays activation on both soil sucrase and alkaline phosphatase; For the urease, cadmium plays activation all the time in each treatment except the 40 th day.(2) Effects of pyrene on soil enzyme activities:In five sampling test, pyrene plays activation on the alkaline phosphatase; For the urease, In 0-40 days, pyrene plays activation on the urease except moderate concentrations(50mg·kg-1), In 40-80 days,pyrene plays activation on the urease in each treatment; Pyrene plays inhibition on the sucrase except moderate concentrations in 40 th day and low concentration and high concentration in 80 th day.(3) Effects of cadmium pyrene combined pollution on soil enzyme activities: In five sampling test, cadmium pyrene combined pollution plays activation on soil alkaline phosphatase except the low concentration(Cd1mg·kg-1+pyrene10mg·kg-1); Cadmium pyrene combined pollution plays inhibition on urease in 0-40 days, plays activation on urease in 40-80 days; Cadmium pyrene combined pollution plays inhibition on sucrase except moderate concentrations(Cd5mg·kg-1+pyrene50mg·kg-1) in 40 th day and high concentration(Cd25mg·kg-1+pyrene250mg·kg-1) in 80 th day.(4) For the bacteria the minimum inhibitory rates both appear in 40 th day of cadium and pyrene simplex pollution, but for the combined pollution, it appears in 80 th day; For the fungi and actinomycetes the minimum inhibitory rates both appear in 40 th day in Cadium and Pyrene Combined and Simplex Pollution; Only the inhibitory rates of soil fungi exceed 50% in 80 th day, the soil actinomycetes and bacteria recovered to the control levels and remain stable, this showed that actinomycetes and bacteria were easy to form a patience bacterial species.