Parts of the coastal tracts of southern Kerala, India are among the well-known High Background Radiation Areas (HBRA) of the world, attributed to the presence of radionuclides in the monaziterich beach sand deposits. A comparative study of the radon concentrations in groundwater in the high and normal background radiation areas in the coastal tract has been taken up using analytical data of 24 ground water samples collected from tube wells of ranging in depth from 6.0 to 300.0 m. The radon concentration in the samples ranged from 0.88 to 25.80 Bq.L −1 . The mean radon concentration in the study area, including those from the HBRA are within the maximum contamination levels of 300 pCi.L −1 (11.10 Bq.L −1 ) recommended by the United States Environmental Protection Agency except for a sample collected from Chavara. Groundwater from the high background radiation areas has significantly higher concentrations of radon ranging from 2.84 — 25.80 Bq.L −1 when compared to the normal background areas where the concentrations range from 0.86 — 7.46 Bq.L −1 . Radon concentration does not show significant correlation with depth of sampled wells. The mean annual effective doses of ingestion and inhalation from water-borne radon, though comparatively higher in HBRA, are well below the average doses reported from all natural sources.

中文翻译：

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喀拉拉邦沿海高本底辐射区 (HBRA) 地下水中氡浓度的初步评价

印度喀拉拉邦南部的部分沿海地区是世界著名的高本底辐射区 (HBRA) 之一，这归因于 Monaziterich 海滩砂矿床中存在放射性核素。利用从深度为 6.0 到 300.0 m 的管井收集的 24 个地下水样品的分析数据，对沿海地区高和正常背景辐射区地下水中氡浓度进行了比较研究。样品中的氡浓度范围为 0.88 至 25.80 Bq.L -1 。研究区域的平均氡浓度，包括来自 HBRA 的平均氡浓度，均在美国环境保护署建议的 300 pCi.L -1 (11.10 Bq.L -1 ) 的最大污染水平内，但从 Chavara 收集的样本除外. 与浓度范围为 0.86 - 7.46 Bq.L -1 的正常背景区域相比，来自高背景辐射区域的地下水具有显着更高的氡浓度，范围为 2.84 - 25.80 Bq.L -1 。氡浓度与采样井的深度没有显着相关性。从水传播的氡摄入和吸入的平均年有效剂量，虽然在 HBRA 中相对较高，但远低于所有天然来源报告的平均剂量。