Distribution Characteristics Of Total Petroleum Hydrocarbons(TPH) Of Typical Greenbelt Soils In Shanghai And Research Of Phytoremediation

This study has researched the distribution of petroleum hydrocarbons (TPH) in typical types of greenbelt soils of Shanghai.We also discussed the relationship with some Physical properties,chemical properties and the number of microorganisms.And five typical soils(the yellow brown soil from Shanghai, the gray damp soil from Shanghai,the red soil from Yunnan,the black soil from Heilongjiang and the brown soil from Liaoning)from all over the country were selected and adding TPH pollution in these soils,to research the repair ability of green lawn plants(tall fescue, ryegrass and bermudagrass) which were used usually for TPH in different soils.The influence by different concentration of TPH and the amount of different improved materials to phytoremediation was studied to choose the best plant and addition amount.The study will provide a scientific reference about the governance,planning and management of urban soil for relevant institutions.The main conclusions obtained were summarized as follows:1)The average content of TPH in greenbelt topsoil in Shanghai is 306.85mg/kg,it's less then environmental capacity which is 500mg/kg.The TPH concentration in different types of greenbelt soils from high to low in the order:Outer Ring Road>Yan'an Road Viaduct>Gas station>Coking plant>Chemical plant>Middle Ring Road>University campus>Power station> Park>Residential area.The highest average content of TPH is 1196.56mg/kg in soils of Outer Ring Road,which has heavy traffic and the main vehicles with burning diesel.The C10?C14 segment of TPH is detected in Outer Ring Road,which has Potentially toxic.The more closer to the road and the soil surface, the more obvious of TPH accumulation.The C6-C9 segment of TPH is below the detection line which is high toxicity,the main part is high carbon segment,which is Less toxic.So overall pollution is not serious in ShanghaiThe main sources of pollution about TPH in greenbelt soils may be automobile exhaust.lt is should to be got more attentions on the potential contamination and poison.of TPH.2)The TPH content of greenbelt soils is no significant correlation with organic matter content,Cu content,fungi quantity,but it is highly significant correlation with Zn content,Cd content,bacteria quantity and microbial quantity,and it is also significant correlation with Pb content,actinomycetes quantity. The TPH could act as the sources of carbon and energy at low concentrations of TPH which will stimulate an increase in microbial quantity.3)In this study, the test plants include tall fescue, ryegrass and bermudagrass, which are grown for 90 days in five types of siols, the residues of TPH in soil are less than the control groups which are not growed plants.The TPH degradation rate of the treatment groups with growing plants in five types of soils is 1.16-2.80 times of the control groups. When the tall fescue are planted in yellow brown soil,red soil,black soil and brown soil,the TPH degradation rate is 34.27%,18.15%,52.63% and 30.67%.The best plant to repair the TPH pollution is ryegrass when they are planted in gray damp soil,the ryegrass is best repair plant,the TPH degradation rate is 33.43%.4)In all treatment groups,the change of TPH and PAH degrading bacteria number in parabolic distribution.In the stage of 0-30 days,Most degrading bacteria number in rapid increase stage.In the stage of 30-60 days,the degradation bacteria number has a small increase or decline,basically in a stable state.In the stage of 60?90 days,the degradation bacteria number has a dramatic decline.5)In the gray damp soil,the content of TPH is less than 3000mg/kg. Although the ability of plant repair TPH in high concentration of TPH soils is higher than which is in low concentration of TPH soils.The ryegrass has a best degradation effect both in high and low concentration of TPH soils,the tall fescue has a better effect and the bermudagrass has the badest effect,but they all better than contrast.6)The TPH degradation rate with plants is highly significant positive correlation with stem wet weight(r=0.827,P<0.01),is highly significant positive correlation with total wet weight (r=0.777,P<0.01),is significant positive correlation with stem dry weight(r=0.761, P<0.05),is significant positive correlation with total dry weight(r=0.705,P<0.05).7)For the amount of adding greening plant waste,the TPH degradation rate is significant or highly significant higher than the groups which adding 0%,5%and 20% greening plant waste when 10% greening plant waste is added in soils.The TPH degradation bacteria number and the biomass is higher than the groups which adding 0%% 5%and 20% greening plant waste.Adding 10% greening plant waste is best for improving the ability to repair TPH pollution in soils for tall fescue and ryegrass.