铀尾矿浸出液成分分析及其对斑马鱼的氧化应激损伤
Uranium Tailings Leaching Liquid's Component Analysis and Effects on Oxidative Stress Injury of Zebrafish
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摘要:
目的 观察铀尾矿浸出液对斑马鱼zebrafish(Danio rerio)的毒性影响,为评价铀尾矿对机体的危害性及潜在环境风险提供科学依据。 方法 采用火焰原子吸收法测定铀尾矿浸出液中重金属的含量, TRPO-环己烷/2(-5-溴代-2-啶基偶氮) -5-间苯二酚分光光度法测定铀含量,其他成分的分析参照国际标准进行;标准稀释水将铀尾矿浸出液稀释为0.05%、0.25%、0.5%及1% 4个浓度组染毒斑马鱼,暴露7 d后,测定斑马鱼肌肉、鳃和肝脏三种组织中超氧化物歧化酶(SOD),过氧化氢酶(CAT),钠、钾离子三磷酸腺苷酶(Na+-K+-ATP酶)活性和丙二醛(MDA)含量的变化情况。 结果 铀尾矿浸出液中的铀含量为0.0628 mg/L,超过WHO规定的饮用水中铀浓度限值约4倍。斑马鱼在设计染毒液中暴露7 d后,三种组织中SOD活性显著降低(P<0.05),而肌肉及肝脏的SOD活性在低浓度组出现升高(P<0.05), SOD活性可能存在暴露时间与浓度效应关系。鳃CAT活性在暴露7 d后出现了下降(P<0.05),且随暴露浓度的升高而降低,最高抑制率为84.8%,表明腮内出现了早期的氧化应激反应。三种组织中,随着铀尾矿浸出液染毒浓度增大,Na+-K+-ATP酶活性下降(P<0.05),而MDA含量呈上升趋势。 结论 铀尾矿浸出液对机体危害可能主要是铀的毒性所致。降低氧化应激损伤水平可能是预防和保护机体免受铀尾矿浸出液毒害的有效靶点之一。 Abstract:Objective To evaluate the toxicity of uranium tailings leaching liquid (UTLL) on zebrafish (Danio rerio) and provide scientific basis for assessment on uranium tailings hazard and potential environmental risk. Methods Flame atomic absorption was used to measure the concentrations of heavy metals in UTLL. Uranium was determined by spectrophotometry using TRPO-cyclohexane/2-(5-bromo-2-pyridylazo)-5-diethyl-amino phenol. Other compositions of UTLL were analyzed according to the relevant international standards. Zabrafish were treated with 0.05%, 0.25%, 0.50%, and 1.00% UTLL for 7 d. Changes in the activities of superoxide dismutase (SOD), catalase (CAT), Na+-K+-ATPase and content of malondialdehyde (MDA) in the tissues of muscle, gill, liver of zebrafish samples were analyzed, respectively. Results The concentration of uranium in the UTLL was 0.0628 mg/L, which was nearly four times of the limits prescribed in World Health Organization's provisional drinking water guideline. After exposure for 7 d, the activity of SOD was decreased significantly in the three sampled tissues at the designed concentrations (P<0.05); however, it increased at the low concentrations in the tissue samples of muscle and liver (P<0.05), indicating that the activity of SOD may exhibit both time-response and concentration-response relationships. The CAT activity was reduced in the gill samples after exposure in a dose-dependent manner (P<0.05), and the highest inhibition rate was 84.8%, which suggested early oxidative stress in the gill tissue. The activity of Na+-K+-ATPase was decreased along with the concentration of UTLL increased (P<0.05), while the MDA concentrations displayed an increasing tendency. Conclusion The hazard of UTLL to organism may be mainly caused by the toxicity of uranium. Decreasing the level of oxidative stress injury may be one of the effective targets for preventing poisoning from UTLL.
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