Development And Application Of New Bioassay Methods In Aquatic Ecotoxicology

In the thesis, a new lumino bioassay system for fresh water samples using Vibrio-qinghaiensis sp. Nov.--Q67 was established; a triolein-filled semipermeable membrane device (triolein-SPMD) was used as a passive sampling procedure for preconcentration of organic pollutants from water for further bioassay; bioassays for acute toxicity and mutagenicity were applied in assessing ecotoxicology of fresh water pollution and efficiency of detoxification processes in wastewater treatment. The major progresses were as follows: 1. The influences of pH, initial density, exposure time, ionic strength as well as the influence of the major cation and anion in natural fresh water to Q67 bioassay results were studied. A new lumino bioassay system for fresh water samples using Vibrio-qinghaiensis sp. Nov.--Q67 was established. The bioassay was then applied to evaluate the toxicity of heavy metal compounds, pesticides, chlorophenols, fresh water samples and water samples from treatment processes. The Q67 bioassay has advantages such as avoiding the limitations of Vibrio fischeri (T3 or Microtox) for using sodium chloride in the culture medium. 2. Combining the application of triolein-filled semipermeable membrane device (triolein-SPMD) as a passive sampling procedure for preconcentration of organic pollutants from water and bioassays was performed in natural waters and water treatment processes. The results showed that triolein-SPMD was an effective sample pretreatment tool for toxic evaluation of pollutants in aquatic environment. This work extended the application of triolein-SPMD and showed the effectiveness of monitoring POPs using triolein-SPMD. 3. Bioassays were applied for assessing the acute toxicity and mutageneicity of fresh water samples collected from Guanting reservoir and Yongdinghe River and samples from different treatment processes of Beijing water works. Through these cases studies, it was concluded that bioassays are complementary tool in addition to the chemical monitoring and a necessary tool in assessing the efficiency of detoxication processes. 4. Accumulation and growth inhibition of Cu to fresh water alga (Scenedesmus subspicatus 86.81 SAG) and the influences of copper speciation were evaluated. These results demonstrated that both complexation of copper in aqueous could reduce the adsorption and, therefore the acute toxicity of Cu to alga. It was concluded that the acute toxicity of copper to alga was due to the competition of copper with calcium for active sites or biotic ligands at cell wall and the results of blocking the Na-channel. It was proposed to use concentration of extracellular Cu (Cuextracellular) as predictor of copper toxicity in complex matrix to avoid the influences of solution chemistry.