Investigation of the activity of Rn-222 along a small stream in the Representative Basin of Juatuba - MG

ABSTRACT For thousands of years, water has been the focus of experimentation toward solving the challenges associated with human water supply, navigation, irrigation, and sanitation. The use of tracers to study water resources is an efficient approach that can facilitate the modeling of many hydrological scenarios. The goal of this paper is to show results of research that tracked the presence of Rn-222, a natural tracer, in the surface waters of a small watercourse in southeastern part of Brazil. RAD 7, which is an electronic and portable radon detector, was the main instrument used in this survey. We analyzed 117 water samples and converted the radon activity results to effective radiation doses with respect to the hypothetical human consumption of these waters. We also analyzed the sediments of the watercourse. The obtained data showed that the radon activity in the studied waters varies between 0.52-76.96 Bq/m3. We determined the effective dose of all samples to be less than 1 mSv y−1, and its consumption to present no risk to human health. The existence of connections between surface and subsurface waters in the stream is possible, and radon peaks may indicate the existence of discharge zones into the surface water body.

【摘要】数千年来，人类始终将水体作为实验研究的核心对象，以解决供水、航运、灌溉与卫生领域的诸多挑战。利用示踪剂开展水资源研究是一种高效途径，可助力诸多水文场景的建模工作。本研究旨在呈现针对巴西东南部小型河道地表水的追踪研究成果，本次研究以天然示踪剂氡-222（Rn-222）的赋存状态为核心追踪目标。本次调查所用的核心仪器为RAD 7电子便携式氡探测器。本研究共分析117份水样，并基于假设的人类饮用该水体的场景，将氡活度检测结果换算为有效辐射剂量。同时，本研究还对该河道的沉积物开展了分析。所得数据显示，研究区域地表水的氡活度范围为0.52~76.96 Bq/m³。所有样本的有效辐射剂量均低于1 mSv y⁻¹，表明饮用此类水体不会对人体健康造成风险。本研究认为该河道地表水与地下水之间存在水力联系的可能性较高，氡活度峰值或可指示存在向该地表水排泄的地下水排泄区。