Research Of The Biological Toxicity Of MSW Landfill Leachate In Wuhan

Landfill leachate contains a variety of toxic chemicals, have the potential hazards on animal and human health. Study of the biological toxicity of the landfill leachate is one hot spot in the environmental toxicology.Objective: With leachate have been sampled from five MSW landfill in different periods of year in Wuhan city, the biological toxicity of them on tetrahymena were tested and compared, then the relationship with the conventional monitoring indicators was discussed. The research provides the basic data for the ecological impact assessment of leachate.Method: With different leachate samples the conventional indicators,24hLC50 and influence on the growth curve of tetrahymena have been analyzed.Results:1)Five MSW landfill leachates all have strong acute toxicity on tetrahymena and the toxicity intensity as follows: Erfeishan Sanitary Landfill>Zixiaguan landfill> Liufang Landfill >Jinkou Landfill>Daishan landfill leachate. Besides the growth curve of tetrahymena was inhibited by leachates. Compared with pH, BOD, COD and NH3-N, the inhibited intensity has the same trending with NH3-N.2) The toxicity tested on leachate produced in different seasons shows that: Erfeishan sanitary landfill leachates have the greater acute toxicity than Liufang landfill and the 24hLC50 changed with the seasons. The inhibition on the growth curve of tetrahymena which was caused by the Erfeishan sanitary landfill leachate was less affected by the season but for the Liufang landfill leachate, because of the uncertainty garbage resource, the affection changed obviously; for the same leachate, the inhibition intensity have the same trending with the concentration of it. 3) There is correlation between the acute toxicity and the inhibition intensity on the growth curve of the Tetrahymena, when leachate's acute toxicity increased, the inhibition on the growth curve of the Tetrahymena become more obviously.Conclusion: Five MSW landfill leachates all have strong acute toxicity on tetrahymena, and inhibit the growth curve of it, the intensity strengthened with the concentration of NH3-N. The toxicity relationships of leachates as follows: sanitary landfill leachate>simple leachate; Leachate produced in summer and fall>Leachate produced in spring and winter; There is little linear correlation between the conventional indicators and the biological toxicity of landfill leachates. Therefore, it was necessary to combine the conventional indicators and biological toxicity of leachate to evaluate its ecological impact on the environment.