Toxic Effects Of Sulfadiazine And Copper On Soil Microorganism And Its Remediation

With the acceleration of industrialization,antibiotics and heavy metals are increasingly used.They enter the soil through variety of ways and affect soil enzyme activity or microbial diversity greatly.To evaluate the toxic effects of antibiotics and heavy metals on soil microorganisms,we choose sulfadiazine(SDZ)and copper(Cu)as the main pollutants and investigate their microbial toxicity effect in Wu Tu soil,paddy soil,black soil,brown soil and desert soil.At the same time,the remediation effect of biochar on Cu an SDZ contaminated soil is also researched.The main research results are as follows:1.The respiration of the five soils was significantly stressed under the single and combined pollution conditions of Cu and SDZ,and the stress under combined pollution was greater than single pollution.Soil respiration in paddy soil,black soil and brown soil is sensitive to single pollution stress of SDZ and Cu.2.The effects of SDZ and Cu single and combined pollution on soil enzyme activity are mainly related to soil original enzyme activity and soil types.Compared with SDZ,Cu has higher toxicity to soil enzyme activity.Besides,dehydrogenase and β-glucoside enzymes are subject to large changes in the soil environment and can be considered as sensitive indicators of soil environmental changes.3.Biolog analysis shows that the effect of single pollution of SDZ and Cu on soil microbial metabolic activity is related to soil type,Cu and SDZ combined pollution treatment can significantly inhibit the microbial metabolic activity of the soil.Furthermore,the diversity index analysis shows that the combined pollution of Cu and SDZ has little effect on the microbial community,but it can significantly change the homogeneity of microbial population.And principal component analysis(PCA)also show that the combined pollution can significantly change the composition of soil microbial community.4.The addition of biochar in the soil contaminated with SDZ and Cu can significantly change soil p H,cation exchange capacity,organic matter content and other soil physical and chemical properties,at the same time,the free SDZ and Cu content in the soil decrease significantly,and then the toxicity is reduced.The results of this study show that the addition of biochar to Cu and SDZ contaminated soil significantly increase soil enzyme activity,microbial community and microbe’s metabolic capacity to soil carbon sources.Therefore,it can be used as a modifier to repair antibiotics and heavy metals contaminated soil.In conclusion,single and compound pollution of SDZ and Cu change soil respiration,enzyme activity.Besides,soil p H is the main factor which can affect the response of soil respiration,enzyme activity to SDZ and Cu contamination.Biolog analysis shows that SDZ and Cu effect the microbial community through alter microbe’s metabolic capacity to soil carbon sources.In addition,biochar can reduce the toxic effects of SDZ and Cu on soil microorganisms,so it can be used for the remediation of soil contaminated by antibiotics and heavy metals.