EFFECTS OF RADON LADEN WATER ON MOUSE TESTES

铀238(U-238)衰变的子体产物--氡-222(Rn-222) 系列，在所有天然水中以广泛的浓度存在 补给。来自地表水来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/立方米)，私人油井水平最高(一些 超过106Bq/M3)。后两个来源提供了约50%的 美国人口。尽管有这么高的水平，但 相比之下，摄取饮用水中的氡几乎没有引起人们的注意 到空气中的氡，这已经得到了大量的宣传。 这可能是因为缺乏风险所需的实验数据。 正如Sullivan和Nelson在1982年的一份备忘录中指出的那样 美国环保局。大多数关于含氡饮用水的数据 涉及到全身，肺， 肾，或胃。很少或没有数据可用，这些数据直接 量化被摄取的哺乳动物组织的生物反应 氡气。拟议工作的中心目标是通过以下方式填补这一差距 确定含氡水对小鼠睾丸的辐射毒性效应。 小鼠睾丸模型，用精原细胞杀伤和诱导 精子形态异常作为终点，是一种极好的 研究极低剂量(As)效应的生物剂量计 低至1mGy阿尔法辐射) 放射性核素。因此，鉴于它的敏感性和它的既定 与人类相关，这个模型特别适合于这项研究。自.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)，它们存在于水中并可能对 睾丸的剂量、睾丸摄取和清除的动力学 口服给药后将对氡及其子体进行研究。 这些研究之后将进行每一端的辐射毒性实验。 点、精原细胞存活与精子形态诱导 异常现象。利用这些数据和动力学数据，剂量响应 将获得曲线，从而将摄取的活动和 睾丸吸收剂量对生物的反应。这些数据，即 量化具有遗传重要性的器官的生物反应，Will 在评估摄入氡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.