Evaluation Method And Effects Of Crude Oil Pollution On Soil Properties

Soil contaminated with crude oil and its remediation has been focused bydomestic and international environmental and soil scientists. At present, most ofthe soil quality standards, which were used in different countries, are weighed bypollutant content. The lack of assessment criterion in soil pollution extent basedon the plant uptake, environmental risk and agricultural products qualityevaluation, limited the applicability of these standard. Therefore, the newdiscrimination method of crude oil pollution levels based on soil organic mattercontent was established and used to evaluate the effect of crude oil on soilproperties. Following researches were finished to prove the effectiveness andfeasibility of the new method,①adsorption-desorption mechanisms of organicpollutants onto crude oil contaminated soil;②effects of crude oil pollution onplant germination and growth;③the change of microbial content and communitystructure in crude oil polluted soil, to study systematically the impact of crude oilpollution on inland arid soil environmental. The contents of this paper wereconcluded as follows:1. The low organic matter soil in xinjiang was collected and used to prepare thecrude oil contaminated soil through simulation experiment. Alfalfa, white clover,tall fescue and ryegrass were conducted germination experiment. There was littleeffect on the germination and growth of tall fescue by the oil contamination level insoils used in this experiment. However, there was significant effect on thegermination and growth of alfafa and ryegrass when the oil contamination level insoils were high (>30％soil organic carbon).2. The sandy soil collected from xinjiang crude oil exploration area was usedto prepare the crude oil contaminated soil in different pollution degree. After agedfor two years, the sorption isotherms of dibromomethane and2,4-dinitrotolueneunder different temperature and ionic strength were drawn to study the influence of crude oil on sorption mechanism. Results indicated that the translocation ofdibromomethane and2,4-dinitrotoluene were decreased by high crude oilconcentration in soils, while as they are increased by low crude oil concentration.3. The impact of crude oil pollution intensity, plant rhizosphere effect and theageing time on soil microbial biomass (represented by PLFA total contents) andcommunity structure change were discussed. Results showed that the microbialbiomass was increased with the increasing of the aging time. Compared with the tallfescue, alfalfa rhizosphere effect more effectively alleviate the impact of crude oilpollutants on soil microbial community structure.