Toxicity Characteristics Of Pollution Sources And Sewage Systems In Industrial Town Based On Luminescent Bacteria

The toxic pollutants entering the environment present the trend of diversified type and frequent quantities with the industrial development,the traditional physicochemical detection methods for water quality are unable to indicate the toxic properties of pollution.In this study,detection method based on luminescent bacteria was used to analyze the single acute toxicity and combined toxicity of three categories of pollutants in the pollution source of a industrial town in jiangsu province.On this basis,the physical and chemical indicators and acute toxicity of wastewater from 11 enterprises s were evaluated.The acute toxicity of wastewater pipe network system in this town was preliminarily studied by using the on-line monitoring instrument of water acute toxicity.In this study,the logistics function was selected to fit the EC₅₀ value of single toxicity of three typical pollutants a town of Jiangsu Province.The EC₅₀ value was calculated to to compare the acute toxicity of pollutants to luminescent bacteria.The EC₅₀ values of six heavy metals Cu²⁺,Zn²⁺,Ni²⁺,Cr⁶⁺,Pb²⁺,Cd²⁺ were 13.72mg/L,2.56mg/L,16.18mg/L,150.71mg/L,5.15mg/L and 14.63mg/L.The sequence of acute toxicity from strong to weak was Zn²⁺>Pb²⁺>Cu²⁺>Cd²⁺>Ni²⁺>Cr⁶⁺.The EC₅₀ values of SDS and SDBS were 33.71mg/L and 31.76mg/L,and the acute toxicity to luminescent bacteria from strong to weak,was SDBS>SDS.The EC₅₀ values of two organic solvents,benzene and xylene were 394.23mg/L and 595.58mg/L,and the acute toxicity from strong to weak was benzene>xylene.17 kinds of combined toxicity of typical pollutants was evaluated by three methods:toxic unit method,additive index method and mixed toxicity index method.There are some differences in the evaluation results of toxicity unit method,additive index method and mixed toxicity index method.It can be seen that different evaluation results of mixture toxicity are related to the selected evaluation methods,in other words,different evaluation methods may lead to different evaluation results of mixture toxicity.The physical and chemical indexes and acute toxicity of industrial wastewater fromdifferent types of enterprises in a town were tested.The water quality of wastewater was evaluated by single factor index method and luminescent bacteria method.The results showed that the physical and chemical indexes of some wastewater samples exceeded the standard to some extent,and the acute toxicity intensity of wastewater samples also had some differences.Through the correlation analysis between the acute toxicity of raw water and the physical and chemical indexes,the acute toxicity of raw water to luminescent bacteria is the result of the joint action of all kinds of pollutants in the waste water,which is not directly and significantly related to one or one kind of pollutants.