Contribution of (222)Rn-bearing water to indoor radon and indoor air quality assessment in hot spring hotels of Guangdong, China

Radon concentration and potential risks assessment through hot springs water consumption in the Gilgit and Chitral, Northern Pakistan

This study investigated the concentration of radon (²²²Rn) in hot springs water. For this purpose, ²²²Rn concentration was measured using the RAD7 (Durridge Company, USA) in the water of hot springs located in Tata Pani, Gilgit (n = 4), and Garam Chashma, Chitral (n = 6), northern Pakistan. Water samples from the springs (background, n = 3) were also collected and analyzed for ²²²Rn concentration 40-50 km away from the hot springs in Gilgit and Chitral, northern Pakistan, to be used as background/reference concentration. The determined ²²²Rn in hot springs water surpassed the threshold of maximum contamination level (MCL, 11.1 Bq/L) set by the United States Environmental Protection Agency (US-EPA) in 100% samples collected from Tata Pani, Gilgit, and Garam Chashma, Chitral sites. Soil ²²²Rn along with the hot springs exhibited a decreasing trend with increasing distance. ²²²Rn concentration in hot springs water was used to calculate the exposure doses of human health through ingestion and inhalation pathways. The total effective dose for human (E_WT) of ²²²Rn contaminated water consumption was 626 μSv/a in the Tata Pani, Gilgit and 34.7 μSv/a in the Garam Chashma, Chitral. Results revealed that hot springs water in the Tata Pani, Gilgit had surpassed the threshold limit (100 μSv/a) set by the World Health Organization (WHO). This study concluded that hot springs water should be avoided for drinking and other domestic uses.

A multiple isotope (H, O, N, C and S) approach to elucidate the hydrochemical evolution of shallow groundwater in a rapidly urbanized area of the Pearl River Delta, China

A comprehensive understanding of the impacts of natural and human activities on groundwater evolution is critical for sustainable groundwater resource management, as groundwater quality degradation from urbanization has raised widespread concerns. However, conclusions based only on basic hydrochemical data would be fragmentary because complex processes occur with high concentrations of pollutants in rapidly urbanized areas. Thus, the hydrogeochemical and multi-isotope approaches were combined to elucidate the groundwater hydrogeochemical evolution in such an area. The results demonstrated that the major hydrochemical types of groundwater were ClNa and HCO₃-Ca in 2018 and that the hydrochemical patterns had changed since 1980. The predominant controlling factors for groundwater hydrochemistry were rock weathering due to carbonic, sulfuric and nitric acids, while the cation exchange and evaporation processes acted as natural factors; redox reactions, including denitrification, sulfate reduction, and methanogenesis, also affected groundwater hydrochemistry. The impacts of anthropogenic activities on groundwater hydrochemistry consisted of direct impacts that referred to the infiltration of manure and septic waste responsible for the occurrence of high NO₃^- content and part of the SO₄^2- content in groundwater and indirect impacts that included the following issues: (1) acid rain accelerated water-rock interactions and resulted in the accumulation of SO₄^2-; (2) sulfate reduction and methanogenesis increased the HCO₃^- content and expanded the distribution of HCO₃-type water; (3) organic matter associated with manure and septic waste accelerated the development of a reducing environment in groundwater; and (4) the occurrence of a strong reducing environment promoted the release of Mn, aggravated heavy metal pollution and imposed adverse effects on the ecological system.

Radon as a potential health hazard for clients and workers of selected thermal spas in Poland

The radiation exposure due to 222Rn and its progeny inhalation for clients and employees of selected thermal water spas was assessed. The radon risk was calculated using the measured 222Rn activity concentrations in the investigated thermal waters and radon transfer coefficient, defined as a fraction of radon released from the swimming pool water to the indoor air of swimming pool. The total radon in air concentration was not measured. The annual effective doses for workers and clients of the studied spa centers excluding Lądek-Zdrój ranged from 0.02 to 2.69 mSv and 0.40 to 48 μSv, respectively. For thermal water from Lądek-Zdrój (Lądek-Zdrój L-2), significantly elevated doses were observed both for workers (10.8 mSv) and clients (194 μSv).

Radon Levels Measured at a Touristic Thermal Spa Resort in Montagu (South Africa) and Associated Effective Doses

Radon activity concentrations (in water and in air) were measured at 13 selected locations at the Avalon Springs thermal spa resort in Montagu (Western Cape, South Africa) to estimate the associated effective dose received by employees and visitors. A RAD-7 detector (DURRIDGE), based on alpha spectrometry, and electret detectors (E-PERM®Radelec) were used for these radon measurements. The primary source of radon was natural thermal waters from the hot spring, which were pumped to various locations on the resort, and consequently a range of radon in-water analyses were performed. Radon in-water activity concentration as a function of time (short term and long term measurements) and spatial distributions (different bathing pools, etc.) were studied. The mean radon in-water activity concentrations were found to be 205 ± 6 Bq L (source), 112 ± 5 Bq L (outdoor pool) and 79 ± 4 Bq L (indoor pool). Radon in-air activity concentrations were found to range between 33 ± 4 Bq m (at the outside bar) to 523 ± 26 Bq m (building enclosing the hot spring's source). The most significant potential radiation exposure identified is that due to inhalation of air rich in radon and its progeny by the resort employees. The annual occupational effective dose due to the inhalation of radon progeny ranges from 0.16 ± 0.01 mSv to 0.40 ± 0.02 mSv. For the water samples collected, the Ra in-water activity concentrations from samples collected were below the lower detection limit (~0.7 Bq L) of the γ-ray detector system used. No significant radiological health risk can be associated with radon and progeny from the hot spring at the Avalon Springs resort.