| Both positive and negative effects of Surfactants indwelling in soil enviroment.On the one hand,surfactants are enviromental pollutants due to heir trait of hard decomposition in soil, frequently used of which and heavy metal pollution would result in combined pollution inevitably; on the other hand,it is a remediation reagent for some pollutants such as some organic matter and heavy metals.Being remediation reagent,its toxicity must be considered,it may risk a secondary pollution.Research showed that surfactants have toxic effect on soil bioeffect and enzymic activity, which will influent the normal transformation and utilization of plant nutrients(nitrogen, phosphorus,organic material and so on) by soil organism and enzymes.Therefore,it had great significance to study the etffects of surfactants on chemical behavior of heavy metals,migration and transformation of nitrogen and phosphoru in soil,we will have a better understanding of the chemical behavior and ecological effects of surfactants,and the combined pollution effects between surfactants and heavy metals;also,the studies could provide reference for the assessment of ecological risk and rational use of surfactants,and offer fundamental basis for controlling heavy metal pollution with surfactants.Presently,synthetic anionic surfactants(SAS) was used widely,linear alkylbenzene sulphonic acid(LAS) was the most common forms.This thesis chosed Sodium Dodecyl Benzene Sulphonate(SDBS) as the object of study,explored two aspects through experiment simulated indoor.On the one hand,the properties of the leaching and transporting of soil nutrients(nitrogen and phosphorus) and heavy metals under SDBS wastewater leaching;on the other hand,the properties of the leaching and transporting of soil nutrients(nitrogen and phosphorus) and heavy metals by acid rain leaching.The single factor experiment was employed,conclusions were obtained as follows:(1) Effect of SDBS on the leaching and transporting of nitrogen in soil as follows:Under the condition of SDBS wastewater irrigating,the results showed that SDBS retrained the loss of ammoniacal nitrogen by leaching,and with the higher concentration of SDBS,the leaching amount was lower;the loss of nitrate nitrogen by leaching increased,the order of the largest leaching amount of which was SDBS100＞SDBS40＞CK＞SDBS5;the leaching amount of total nitrogen was lower by lower of concentration of SDBS relatively,but it increased dromatically when given higher concentration of SDBS,the increasing rate of SDBS40 and SDBS100 was 16.8%and 22.36%respectly.Analyzd the soil-column modelling at the end of leaching,compared with the control group,the amount of ammoniacal nitrogen,nitrate nitrogen and total nitrogen decreased in 0～20cm soil layer,it had evident tendency that nitrogen transported downward in soil,with the higher concentration of SDBS wastewater,the tendency was more obvious.Under simulated acid rain leaching,SDBS promoted the loss of the nitrogen and restrained the loss of nitrate nitrogen through the way of leaching in soil,and the higher SDBS content of soil,the more influence.The loss of total nitrogen increased,the order of the leaching amount of total nitrogen was SDBS100＞SDBS50＞SDBS7＞CK,the leaching amount of total nitrogen increased with the increasing SDBS content of soil.When the value of pH was 5.4,the increasing rate of total nitrogen was 7.52%～28.78%,and it was 5.34%～30.46%when the value of pH was 4.5.The order of the largest leaching amount of ammoniacal nitrogen,nitrate nitrogen and total nitrogen was pH=4.5＞pH=5.4 by the same SDBS group,the loss of nitrogen increased with decrease of pH.After the experment of leching,analysis the soil-column modelling showed that the content of total was lower in 0～20cm soil layer by adding SDBS,and it was little higher in 20～40cm and 40～60cm soil layer.the nitrogen trends to transport downward by impact of SDBS in soil was obvious.And the lower of the value of pH and the higher SDBS content in soil,the trend of transportion was the greater.(2) Effect of SDBS on the leaching and transporting of phosphorus in soil as follows:Under the condition of SDBS wastewater irrigating,the loss of the phosphorus was higher than the blank control obviously at the earlier stage of leaching,the loss rate of the phosphorus reduced with the content of SDBS in soil increased,the increasing rate of group SDBS40 was 24.8%than blank group.Analysed the soil-column modelling at the end of leaching,it was found that the difference of the total phosphorus between SDBS control and the blank control was not obviouse in every soil layer,the amount of available phosphorus cut down obviously in 0～20cm and 20～40cm soil layer, but it increased by 56.7%～80.7%in 40～60cm soil layer.The phosphorus trended to transport downward in soil in the whole.Under Simulated acid rain leaching,the leaching amount of phosphorus was promoted by SDBS impacted,the order of the largest leaching amount of phosphorus was SDBS100＞SDBS50＞SDBS7＞CK,when the value of pH was 5.4,the increasing rate of phosphorus was 1.92%～23.68%,and it was 17.21%～28.96%when the value of pH was 4.5. The order of the largest leaching amount of phosphorus was pH=4.5＞pH=5.4 by the same SDBS control,the total amount of phosphorus by leaching was greater as SDBS content in soil increased.The loss of phosphorus increased with decrease of pH.After analysis of the soil-column modelling,it showed that total phosphorus content was access to blank control in every soil layer, but the available phosphorus content increased by SDBS control,and finally SDBS promoted the downward transporting of phosphorus in soil.(3) Effect of SDBS on the releasing of transporting of heavy metals in soil as follows:Under the condition of SDBS wastewater irrigating,the time of Cu,Cd and Pb released was delayed in soil by the effect of SDBS,the leaching amount increased at the latter leaching stage at the vary degrees,the leaching amount increased with the concentration of SDBS.The largest cumulative leaching amount of Cu,Cd and Pb was higher by SDBS control than the blank control,the increasing rate was 2.85%～9.83%,8.85%～16.36%and 1.92%～6.55%respectly;analysis of the soil-column modelling at the end of leaching,it found that the total form of Cu,Cd and Pb residued in soil decreased by SDBS control in 0～20cm soil layer,it was little higher in 20～40cm and 40～60cm soil layer,but the available form of Cu,Cd and Pb residued in soil significantly decreased. The trend to transporting downward of the Cu,Cd and Pb in soil was obvious.Under Simulated acid rain leaching,SDBS inhibited the releasing of Cu,Cd and Pb by leaching,and the releasing amount decreased with the reducing SDBS content in soil.The largest anual cumulative of heavy metals was lower than blank control,when the value of pH was 5.4,the increasing rate of Cu,Cd and Pb was4.41%～11.20%,7.19%～10.62%and2.90%～8.21%respectly,anditwas4.89%～14.78%,0.7%～10.7 4%and 4.94%～13.19%when the value of pH was 4.5,The order of the largest leaching amount of Cu,Cd and Pb was pH=4.5＞pH=5.4 by the same SDBS control,with the decrease of pH values, caused the inhibitory effect of SDBS on the leaching of heavy metals decreased in Soil.The analysis of soil-column modelling at the end of leaching showed that the total form of heavy metals residued increased evidently in 0～20cm soil layer,concentration in 20～40cm and 40～60cm soil layer decreased relatively,but the available form of heavy metals decreased in every soil layer.The tendency of transporting downword of heavy metals was lower in soil by the effect of SDBS.
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