The Toxicity Effect Of DEHP And Cd Combined Pollution On Zebrafish

Phthalic acid esters(PAEs)is a synthetic industrial organic compound.As the plasticizer of polymer plastic products,it is widely used in food packaging materials,plastic film,medical blood bags and hose,cosmetics and other materials.Among them,DEHP is the most used in the current class of plasticizers.Because PAEs and polyolefin plastic molecules are connected by hydrogen bonding or van der Waals forces,they are easily released into the environment.Cadmium(Cd)is a kind of heavy metal with high toxicity and accumulation,widely used in plastic stabilizers,pigments,solar panels,batteries and steel plate in order to improve the corrosion resistance.It is mainly through industrial emissions,natural weathering process or atmospheric subsidence,landfill,soil leaching into the water environment.In this study,the toxicity effects of DEHP and its conbination with Cd on zebrafish(Danio rerio)were studied by the method of semi static staining.In this study,we selected 0,0.25,0.5,1,2 mg/L DEHP and 0.1 mg/L Cd for single and compound tests,and the indexes were sampled at the 7th,14 th,21st and 28 th days after staining.The changes of superoxide dismutase(SOD),catalase(CAT),peroxidase(POD),glutathione s-transferases(GST)and acetylcholine esterase(AChE)activity and the content of malondialdehyde(MDA),the degree of DNA damage of zebrafish were studied to evaluate the toxicity of DEHP and its compound pollution,and provide the basis for the ecological risk assessment and early warning of DEHP pollution and organic-heavy metal compound pollution in water environment.The main experimental conclusions are as follows:(1)The effect of DEHP on the enzyme activity in zebrafish: With the increase of time,the change trend of SOD,CAT and POD activity in zebrafish were similar,the activity of low concentration(0.25,0.5 mg/L)DEHP showed a tendency to rise first and then decrease,and the activity in the high concentration group were inhibited.The GST activity of each DEHP treatment group appeared to be inhibited after activation,and finally close to the blank group level.AChE activity was induced to rise and then inhibited,and finally close to the blank group level.With the increase of time,the content of MDA in each treatment group increased markedly.(2)Effects of DEHP and Cd on enzyme activity in zebrafish: The changes of antioxidant enzymes,GST and AChE activity and MDA content in zebrafish were similar to those of DEHP single staining.In the early days of the experiment,DEHP and Cd showed a certain antagonism,and they were synergistic on the 28 th day.(3)DNA damage of the liver cells of zebrafish by DEHP single staining: In the DEHP group of 0.25 mg/l,the OTM value of DNA in the liver cells of zebrafish increased significantly.With the increase of concentration,the OTM value increased,and the DNA damage degree of zebra fish increased with time.(4)The damage of DNA in the liver cells of zebrafish by DEHP and Cd compound staining: With the combination of DEHP and Cd,the OTM value increased with the increase of DEHP concentration and time of infection.DEHP and Cd are synergistic effect in the later stage of drug infection.