Study Of Biological Monitoring And Early Warning For Typical Pollutants In Urban Water Source

Nowadays more and more emergent water pollution accidents happen and the safety of drinking water are increasly concerned.Therefore,it becomes a hotspot to achieve realtime online monitoring of water pollution that may cause ecological and healthy effects.In this paper,the ecotoxicological effects of antibiotics,heavy metal and pesticide on Vibrio fischeri,Daphnia magna and Danio rerio were determined by toxicity test and Multispecies Freshwater Biomonitor(MFB) technology.The sensitivity of the three aquatic organsims using for monitoring typical pollutants in water environment had been compared and evaluated,and the feasibility of utilizing biological online monitoring had been explored too.Results showed that the sensitivity of Daphnia magna for most pollutants in this study is higher than the other two tested organisms.For Enrofloxacin,Vibrio fischeri is more sensitive than Daphnia magna,while Daphnia magna is more sensitive than Vibrio fischeri for Sulfadiazine.For heavy metals,the sensitivity of Daphnia magna for both Cr⁶⁺ and Cd²⁺ is better than Vibrio fischeri which is closed to Danio rerio. The sequence of the sensitivity of the three aquatic organisms for pesticides is as follows:Dimethoate:Daphnia magna＞Vibrio fischeri＞Danio rerio;Dichlorvos: Daphnia magna＞Danio rerio＞Vibrio fischeri;Malathion:Daphnia magna＞Vibrio fischeri＞Danio rerio;Cypermethrin:Daphnia magna＞Danio rerio＞Vibrio fischeri. Aquatic organisms play an important role in the stability and function of aquatic ecosystems,and organisms in different trophic levels exhibited different sensitivity to various pollutants.So it is necessary to chose more sensitive organisms to increase the efficiency and provide more information of biomonitoring.The choice of organisms can also depend on the expected sources of pollution.MFB used in this study is a new online water quality biomonitoring system which sets up a relationship between the change of behavior intensity of exposed organisms and pollutants concentration and exposed time.It can early warn the change of water quality by monitoring the change of behavior intensity of exposed organisms.Experimental results showed that the behavior intensity of exposed organisms and the exposed concentration and time are well correlated.Below the median lethal concentration,the behavior intensity of exposed organisms always go through a process with a declining after the first increasing,then restoring and decreasing.This iterative process accords with the Stepwise Stress Model(SSM).In this study,MFB was validated to monitor the changes of behavior intensity of exposed fish in water borne which contain heavy metals,organic phosphorous pesticides and anitibics pollutants.Result showed that the detection limit of MFB for Cr⁶⁺ is 57.9 mg·L^-1;Cd²⁺,0.99 mg·L^-1;Dimethoate,108.5 mg·L^-1;Dichlorvos,27.8 mg·L^-1;Malathion,2.0 mg·L^-1;Cypermethrin,71.9μg·L^-1.Comparing whth the standard methods of DeltaTox and acute toxicity test of Daphnia magna and Danio rerio,it is sensitive and feasible for using Danio rerio in MFB to online monitor pollutants in aquatic environment.