Effect Of Petroleum Contamination On Physic-chemical Properties And Enzymes Of Soils In Northern Shaanxi Oilfield

With the expansion of petroleum developments in northern shaanxi province, thepollution of environment in this region have increased. To understand the variation ofphysico-chemical properties in oil contaminated soil, the basis of surveyed and analyzedsamples of soil from oil well fields, contents of petroleum hydrocarbons and somephysico-chemical properties were investigated. The main results were summarized as follows:(1) Around the oil well, the soil were polluted in different degrees, and contents ofpetroleum hydrocarbons ranged from0.08to71.49g·kg-1. the soil quality was evaluated bythe nemerow pollution index, then the result showed that petroleum pollution level was up toserious pollution.(2) Compared with control, water content, pH and the contents of nitrate N, available P,total K and available K in oil-polluted soil decreased significantly, but unit weight and thecontents of organic matter and ammonium N in oil-polluted soil increased significantly.Petroleum contamination did not affect contents of soil total N and total P. In oil-polluted soil,petroleum hydrocarbons content were in significant correlation with water content, unitweight, pH, contents of organic matter, ammonium N, available P, total K and available K,and were not in significant correlation with contents of total N, nitrate N and total P.(3) With the increace of the petroleum hydrocarbons content, the content of Cu, Zn, Ni,Cr, Pb in soil decreased, while the content of Hg increased, and As has no significant change.Cu, Zn, Ni and Cr in soil are four trace elements in a very significant positive correlation. Pbwas in a very significant positive relationship with Cu and Cr, and was in a significantpositive relationship with Zn, but has no relationship with As. Hg and other trace elementsexcept As were in a very significan negative correlation. There was no relationship betweenAs and other elements.(4) Polyphenol oxidase, catalase, phosphatase and invertase in oil-polluted soil decreasedsignificantly, but lipase increased significantly, petroleum hydrocarbons content were insignificant correlation with polyphenol oxidase, catalase, phosphatase, invertase and lipase. polyphenol oxidase, catalase, phosphatase and invertase are in a very significant positivecorrelation, while lipase and other enzymes are in a very significant negative correlation.