Study On Aquatic Organisms Toxicity Of Thallium

Thallium is a highly toxic heavy metal,is widely distributed on earth but the content is very low.In recent years,with the industrial production,thallium as a pollutant has caused some poisoning case in many places,which has attracted lots of attention on the international.Therefore,studies on the toxicity of earthworms are necessary.To evaluate the toxicity of heavy metals,the toxicology experiments of organisms are generally used in the world.As an important part of the aquatic environment,aquatic organisms play an important role in the study of the toxicity of heavy metals in water.The presence of thallium in nature is often influenced by minerals,so oxides of manganese have been used to simulate minerals in nature for experiments.In this article,two aquatic organisms were selected for experiments,zebrafish and chlorella.Through the accumulation of zebrafish body and various organs(liver,intestine,gill,brain),the toxic effects of thallium and oxides of manganese on zebrafish were analyzed.The results show that the largest accumulation of thallium is in the liver,because the liver is an important metabolic organ of the organism.At the same time,the concentration of manganese oxide added to the system during the experiment were all lower than those of a single thallium system,due to the adsorption of thallium by oxides of manganese.Through determining some oxidative stress indicators(active oxygen ROS,superoxide dismutase SOD,catalase CAT,lipid content MDA)and the neurotoxicity in various organs(liver,intestine,gill,and brain)of zebrafish.The results showed that the thallium could induce the increase of enzyme activity in various organs of zebrafish.However,with the increase of time,the activity of the enzyme decreased,but the level of enzyme activity was still higher than that of the blank control group.The mixed system of manganese and thallium is less stimulatory to enzyme activity.The mixed system also has a lower stimulatory effect than only thallium on the activity of ACh E.The growth of the chlorella can be promoted when it exposed to the thallium solution at low concentration,but inhibit growth in high concentration.The determination of SOD activity and the determination of MDA content are similar to those of zebrafish experiments.