MCN技术对水体中铀污染遗传毒性和污染程度的研究

Study on genotoxicity of uranium in water and classification of the pollution level by application of the micronucleus test in vicia faba root tip

铀具有化学毒性和放射性伤害。水合铀酰离子可以引起铀的化学毒性;而铀和衰变子核的放射性可以引起铀对人体的放射性伤害,人体吸入铀气溶胶后会对肺等器官形成内照射从而对人体健康构成威胁。利用蚕豆根尖微核(MCN)技术研究水体中铀的遗传毒性,为生态安全评价提供理论依据。结果表明:水体中ρ(U)在0.05μg/mL时,微核率0.367%,污染指数1.22。随水体ρ(U)的增加,蚕豆根尖微核率和污染指数逐渐加大。当ρ(U)为0.5、1、10μg/mL时,微核率分别为0.567%、0.667%、1.133%,与空白对照差异极显著(P<0.01),污染指数分别为1.89、2.223、3.78。根据统计结果及污染指数,初步确定水体中ρ(U)0.05μg/mL为安全值,ρ(U)0.5μg/mL为轻度污染,ρ(U)1μg/mL为中度污染,ρ(U)10.0μg/mL以上时为重度污染。

Uranium has chemical toxicity and radioactivity. The chemical toxicity of uranium is due to uranyl ion hexahydrate. And uranium＇s radiation damage on body is mainly caused by the radioactivity of uranium and uranium daughter isotopes. After human inhale uranium aerosol, one＇s health will be threatened since the long-time radiation emitted by the uranium which can harm lung and other organs. In this paper, the genetic toxicity of uranium in the water is studied by applying the micronucleus technique on the root tip of vicia faba to provide theoretical basis for evaluating ecological security. The result shows that if the uranium in water is 0.05 μg/mL, the micronucleus rate will be 0. 367%, and the pollution index is 1.22. Moreover, while increasing the content of uranium in the water, the micronucleus rate and the pollution index of the root tip of vicia faba are gradually increased. If the uranium content is 0.5,1,10 μg/mL, the micronucleus rate is 0. 567 %, 0. 667 %, 1. 133 % respectively and the pollution index is 1. 89,2. 223,3.78, respectively. Comparing with the control group, the differences are outstanding and statistically significant （P〈0.01）. According to the statistical results and pollution index, a preliminary conclusion can be drawn that when uranium concentration is 0.05μg/mL in the water, the water system is safe; while 0.5μg/mL uranium concentration in water, the water is defined as slightly polluted; if 1 μg/mL uranium concentration in water, the water is consid-ered as moderately polluted; and if 10.0 μg/mL uranium concentration in water, the water system is treated as heavily polluted.