Study On Bioassay Methods For Toxic Organic Pollutants In Sewage Sludge And Soil

Following the rapid development of economic and the progress of modern scienceand technology，environment is sufferring from contamination increasingly. The number andsize of sewage treatment plant is increasing because of the large number of sewage，Thesewage sludge is becoming a bottleneck，It is essential to study the Ecotoxicology of sewagesludge and the sludge be treated by different processes；Wastewater Reuse, sludge farmapplication, they will cause huge pollution to soil.As a fundamental part of ecological cycle, itis essential to make a risk assessment. This study adopted sewage sludge samples from18sewage treatment plants in Beijing、treated sewage sludge samples、13typical pollution soilfrom three province. Using recombinant gene yeast assay、 the ethoxyresorfin O-deethylasebioassay and SOS/umu test to evaluate the samples and gain several datas. This dissertationincludes three parts：1. The sewage sludge samples from18sewage treatment plants in Beijing werepretreated before bioassay. Then the risk assessment of them were tested using recombinantgene yeast assay and SOS/umu test evaluate.The results showed that15samples have positivereaction in estrogen disrupting effect except S4、S6and S7.The ER disrupting effect rangedfrom1.2to17.7ng.g-1dry soil; After exposing to a given amount of extract(corresponding to2.5mg/well),none of them showed positive response for direct genetoxicity, only one sampleshowed suspected indirect genotoxicity.2. The sewage sludge samples disposed by different techonology were pretreatedbefore bioassay. Then the risk assessment of them were tested using recombinant gene yeast assay、 the ethoxyresorfin O-deethylase bioassay and SOS/umu test. The results showed thattraditional composting techonology was not effective to remove ER disrupting effect;traditional composting techonology and traditional lime drying techonology were noteffective to remove AR disrupting effect; traditional composting techonology、traditionallime drying techonology、 the0.5kg/m2lime drying techonology、1kg/m2lime dryingtechonology and1kg/m2composting techonology were not effective to remove TR disruptingeffect; After exposing to a given amount of extract(corresponding to20mg/well),The sampledisposed by lime drying showed suspected direct genetoxicity and positive indirectgenetoxicity. The AhR disrupting effect ranged from15.66to78.9pg/g(2,3,7,8-TCDD),it iseffective to decrease the AhR disrupting effect after disposed by the11techonolgies.3. The soil samples from three province were pretreated before bioassay. The AhRdisrupting effect and TR disrupting effect of13typical pollution soil were assayed using theethoxyresorfin O-deethylase bioassay and receptor bioassay. The AhR disrupting effectranged from4.2to23.9pg/g2,3,7,8-TCDD;None of them showed thyroid receptorinductive activities，but four samples showed thyroid receptor antagonistic activities（the TRdisrupting effect ranged from51~183μg NH3/g dry soil）. Two kinds of contamination mayexist in the same area. Combined EROD test and TR yeast test can be an effective way toassess the potential ecological risks of complex environmental samples.