A Study Of Genetic Damage On Zebrafish(Danio Rerio) By Uranium Mill Tailings Leaching Solution

Aim: In order to provide scientific data for the evalution of potential ecological riskand environmental monitoring of UMTLS, a study of DNA damage on zebrafish byUMTLS was performed.Methods: First,aflameatomicabsorptionspectrophotometer was used to measurethe concentrations of heavy mental in UMTLS and the acute toxicity effect onzebrafish was performed. Second, SOD, CAT, Na~+-K~+-ATPase activities and MDAcontent were determined and analyzed in the zebrafish gill, muscle, and liver,respectively. Third, RAPD was used to detecte the effect of UMTLS in genome ofmuscle, gonad, liver and gill zebrafish. Forth, the genetic damage on zebrafisherythrocytes was studied by SCGE and MN, respectively. The results of this study areas follows:Results:(1) UMTLS was identified to contain two radioactive elements (U andMo), nine heavy metal elements (Mg, Ca, Mn, Zn, Fe, Al, Ni, Cd and Cu), and fivenon-metallic materials (Cl-, SO42-, NO3-, F and sulfide). Among them, the content of Uis higher than others, and reached84mg/L.(2) The acute toxicity test indicated that the1,12,24,48,72,96-h LC50valuesof UMTLS to the zebrafish were12.1,7.1,4.4,3.8,3.4,2.9%, respectively.(3) After exposure to UMTLS, the results showed that the most sensitivityzebrafish tissues were gill. The changes of SOD and CAT in gill could be as indicatorsif repressed by UMTLS. Na~+-K~+-ATPase activity in liver show a good time-doseresponse, and may be considered as a reference biomarker of UMTLS stress onaquatic anamals.(4) The genome DNA of zebrafish was amplificated by30random primers. Themolecular size of amplified products was between160-2000bp. After exposure todifferent doses of UMTLS, there were significant difference in brightness and the number of the fragments. Compared to exposure groups, there were new fragments inrepairing groups.(5) The DNA tailing length of zebrafish was enhanced after treatment, andsignificant differences were found compared to the controls. When the zebrafish wasput back to the clean water, there was signicant difference between exposure andrepairing groups. In low concentration groups, there was signicant difference betweenthe third and the first repairing day. But it was still increased in high concentrationgroups, and then decreased at the end of the third day.(6) In general, the significant effects from both concentrations and time ofexposure were observed in the zebrafish erythrocytes compared to control group. Butthere were no significant differences between exposure groups and repairing groups.Conclusions: It can be concluded that UMTLS contains U and other harmfulfactors. This may pose a potential ecological risk to the surrounding ecologicalenvironment. The results of RAPD, SCGE and MN suggested that UMTLS caused thedifferent levels of DNA damage in different organization and cells of zebrafish.