The Application Of Photobacteria Toxicity Detection Method In Water Qualitv Assessment And Early Warning

As the impact of human activities on water environment augments, the variety and quantity of water pollution sources has been increasing. While conventional water environment monitor methods are having difficulty in satisfying the current needs of pollution prevention and control, the biological early warning technique has been gradually adopted in environment monitoring.This study employed the photobacteria, Vibrio Fischeri, in various water sources, surface water, and electroplating wastewater in Wenzhou area, to evaluate the effectiveness of the photobacteria online biological early warning toxicity detector (TOXcontrol), and also explored the feasibility of using the biological early warning toxicity criteria to assess the water quality in specific cases.Results indicated that under normal conditions, the water quality in drinking water sources fell into a safe luminescent inhibitory rate interval (±18%), and that water under abnormal conditions, such as pesticide, showed significant change in luminescent inhibitory rate, with the EC50levels of napropamide and triphenyltin acetate at0.14mg/L and0.039mg/L respectively. In terms of surface waters, photobacteria inhibitory rates had no significant correlations with conventional physical and chemical indicators and therefore it can be used as complementary indicators to conventional detection methods. Electroplating wastewater showed low toxicity inhibitory rate after treatment, but high toxicity before treatment, and its physical and chemical indicators showed significant correlations with toxicity indicators during each phase of the treatment process (wastewater inhibitory rate before treatment=100%, after treatment=15%; cyanogen wastewater toxicity EC50before treatment=9.23, after treatment=3.85). Photobacteria showed sensitivity during each phase of the tap-water purification process and therefore it can be used to indicate the safety of water.To sum up, photobacteria biological comprehensive toxicity detection method compensated for the weaknesses in conventional physical and chemical detection methods. Its applications and limitations were also discussed.