RADON LADEN WATER EFFECTS ON MOUSE TESTES

氡-222（Rn-222），铀-238（U-238）衰变的子体产物 系列，存在于所有天然水中的浓度范围很广 用品. 来自地表水源的公共供水几乎为零 Rn-222浓度，地下水源有中等水平（上升 到几千Bq/m3），私人威尔斯井的最高水平（一些 超过10 6 Bq/M3）。 后两个来源提供约50%的 美国人口 尽管这些高水平， 饮用水中的氡很少引起人们的注意， 空气中的氡已经得到了大量的宣传。 这可能是由于缺乏风险所需的实验数据 沙利文和纳尔逊在1982年的备忘录中指出， 美国环保局 大多数关于含氡饮用水的数据 涉及全身，肺， 肾或胃。 很少或没有数据可以直接 量化哺乳动物组织从摄入的 氡。 拟议工作的中心目标是填补这一空白， 确定了氡水对小鼠睾丸的放射性毒性作用。 小鼠睾丸模型，用精原细胞杀伤和诱导 精子形状异常作为终点，是一个很好的 研究极低剂量（如 低至1毫戈瑞的α-辐射）， 放射性核素 因此，鉴于其敏感性和既定的 与人类相关，该模型特别适合本研究。 以来 Rn-222衰变为许多不稳定的子产物（Po-218，Pb-214， Bi-214和Po-214），它们存在于水中，可能有助于 睾丸剂量，睾丸摄取和清除的动力学， 氡及其子体将在口服后进行研究。 这些研究之后将进行放射毒性实验， 点，精原细胞存活和精子形状的诱导 异常 使用这些数据和动力学数据， 将获得曲线，从而将摄入的活性和 睾丸吸收剂量的生物反应。 这些数据， 量化具有遗传重要性的器官中的生物反应， 在评估氡含量超标的风险方面具有重要价值 水

Radon-222 (Rn-222), a daughter product in the uranium-238 (U-238) decay series, is present in a wide range of concentrations in all natural water supplies. Public water supplies from surface sources have near zero Rn-222 concentrations, ground water sources have intermediate levels (up to several thousand Bq/m3), and private wells the highest levels (some exceeding 10 6 Bq/M 3). The latter two sources serve about 50% of the U.S. population. Despite these high levels, the consequences of ingesting radon in drinking water has attracted little attention compared to those of airborne radon which has received a great deal of publicity. This is perhaps due to the lack of experimental data needed for risk estimation as pointed out by Sullivan and Nelson in a 1982 memorandum to the USEPA. The majority of the data on radon laden drinking water concerns calculation of the absorbed dose to the whole body, lung, kidney, or stomach. Little or no data are available which directly quantifies the biological response of mammalian tissue from ingested radon. The central aim of the proposed work is to f ill this gap by ascertaining the radiotoxic effects of radon laden water on mouse testis. The mouse testis model, with spermatogonial cell killing and induction of sperm-shape abnormalities serving as the end points, is an excellent biological dosimeter for studying the effects of extremely low doses (as low as 1 mGy of alpha-radiation) from minute quantities of incorporated radionuclides. Hence, in view of its sensitivity and its established relevance to man, this model is uniquely suited for this study. Since Rn-222 decays to a number of unstable daughter products (Po-218, Pb-214, Bi-214, and Po-214) which are present in the water and may contribute to the testis dose, the kinetics of testicular uptake and clearance of both radon and its daughters will be studied following oral administration. These studies will be followed by radiotoxicity experiments for each end point, spermatogonial cell survival and induction of sperm-shape abnormalities. Using these data and the kinetics data, dose response curves will be obtained thereby relating the ingested activity and testicular absorbed dose to the biological response. These data, which quantify the biological response in an organ of genetic importance, will be of significant value in assessing the risk from ingesting radon laden water.