Study On The Effect Of Steroidal Estrogen On Soil Microbial Community In Vadose Zone

Steroidal Estrogens(SEs),as a kind of new environmental pollutant,have many characteristics,such as wide source,high content,low concentration and high toxicity.They are frequently detected in the soil and water environment at home and abroad.The main sources of SEs in environment are wastewater treatment plants and livestock farms.In this paper,time and space dynamic analysis of microbial community characteristics in vadose zone soil samples by PCR-DGGE fingerprinting.The planting vadose zone soils,the livestock vadose zone soils and steroids contaminated farmland soils are three main research soil samples.The planting vadose zone soils are from the corn field soil which use poultry manure as organic fertilizer in the fourth village of Xincheng town,Shenbei new district,Shenyang.The livestock vadose zone soils are from the livestock farm in Xiaozhaimen town,Liaozhong county,Liaoning Province.The main conclusions are as follows:1 The Dice coefficient(Cs),the diversity index(H’),richness(S)and evenness(E)of corn field and livestock farm vadose zone soil samples are show a decreasing trend with decreased depths.During descent,both are constantly fluctuating up and down,but the range of variation coefficient is fierce than Dice coefficient.The Dice coefficient,diversity index,richness and evenness of corn field samples are significantly increased from 2.0 m to 2.8 m and from 6.8 m to 7.6 m.The Cs,H’,S,and E of livestock farm soil samples are decreased obviously from 0.4 m to 0.5 m and 2.3 m to 2.5 m.These changes may be caused by a combination of changes in estrogen content and species,and changes in major soil components,at the corresponding soil depths.2 The Cs,H’,S,and E of soil samples with different concentrations of 17β-E2 and E1 at different exposure times are different from each other.At the exposure time,the Cs of soil samples with 500 ng/kg E1 decreased slowly,but its diversity showed an increasing trend.At the exposure time,the Cs of soil samples with 17β-E2 concentration of 300 ng/kg showed a general upward trend,and the diversity showed a gradual increase trend.The diversity of microbial community decreased with the increase of E1 concentration,and increased rapidly when the concentration of E1 exceeded a certain value,and with the concentration increased the trend of diversity increased gradually.Within a certain range,the diversity of microbial community increased with the increase of 17β-E2 concentration,then inhibited when the concentration is more than a certain value,and over time,the inhibition is reduced.This may be due to the emergence of new adaptive species which chould break this inhibition.Microorganisms which anti-SEs and/or have capable of efficiently degrading SEs can be enriched in SEs-contaminated soils.E1 can be converted to E2,E3 and E1-3G,E2 can be transformed into E1,E3,E2-3G and E1-3G,this mutual transformation will lead to more complex changes in microbial community structure diversity.