Objective To investigate radioactive levels in drinking water around a uranium mine and control areas (Chabuchar County and Urumqi City) and conduct health risk assessment.

Methods A total of 176 drinking water samples were randomly collected from the vicinity of a uranium mine (51 samples) and the control area (73 samples from Chabuchar County and 52 samples from Urumqi City) from 2020 to 2022. The radioactive levels of total α and total β and the concentrations of radionuclides ²³⁸U, ²³²Th, ²²⁶Ra ,⁴⁰K were determined. The total radioactive levels of drinking water from different areas (around the uranium mine, Chabuchar County, and Urumqi City), different water sources (surface water, surface water+groundwater, groundwater) and different distances from the uranium mine (5, 10, 15, 20, 25 km) were compared. Methods recommended by the United States Environmental Protection Agency (USEPA), the International Commission on Radiological Protection, and the World Health Organization were used to estimate the annual effective dose of adults exposed to drinking water in the vicinity of the uranium mine and control areas. Carcinogenic risk factors proposed by the USEPA were used to assess the lifelong carcinogenic risk of residents. Total radioactive levels were compared among drinking water samples from different regions, water sources, and distances from uranium mines through one-way ANOVA. Results that had statistically significant differences were further subjected to least significant difference test for multiple comparisons.

Results The difference of total α and total β radioactive levels in drinking water samples from different regions were statistically significant ((0.13±0.04) Bq/L vs. (0.12±0.08) Bq/L vs. (0.08±0.03) Bq/L, F=9.854, Ρ<0.01), ((0.17±0.06) Bq/L vs. (0.13±0.10) Bq/L vs. (0.10±0.03) Bq/L, F=10.522, Ρ<0.01). There were no significant difference in total α and total β radioactive levels in drinking water samples from different water sources (F=2.849, 1.352; both Ρ>0.05). The differences of total α and total β radioactive levels in drinking water samples with different distances from uranium deposits were statistically significant ((0.16±0.02) Bq/L vs. (0.07±0.02) Bq/L vs. (0.11±0.02) Bq/L vs. (0.15±0.03) Bq/L vs. (0.14±0.03) Bq/L, F=21.720, Ρ<0.01), ((0.24±0.04) Bq/L vs. (0.09±0.01) Bq/L vs. (0.19±0.01) Bq/L vs. (0.17±0.03) Bq/L vs. (0.13±0.04) Bq/L, F=46.364, Ρ<0.01). The average values of total α and total β radioactive levels in drinking water samples 5 km away from the uranium deposit are the highest. The average values of total α radioactive level in 176 drinking water samples was (0.11±0.06) Bq/L, and 0.5% of drinking water exceeded the national standard limit (0.5 Bq/L). The average annual effective dose caused by drinking water is estimated to be (0.040±0.003) mSv/years according to the total α radioactive level in drinking water samples. According to the concentrations of radionuclides ²³⁸U, ²³²Th, ²²⁶Ra, ⁴⁰K in drinking water samples, the average annual effective dose caused by drinking water were estimated to be (0.030±0.004), (0.018±0.003), (0.084±0.04), (0.005±0.003) mSv/years. The lifelong carcinogenic risk among residents caused by drinking this water ranged from 1.75×10⁻¹³ to 4.35×10⁻¹¹.

Conclusions The radioactive level of drinking water around a uranium mine and the control area (Chabuchar County and Urumqi City) is low, and the annual effective dose and lifelong carcinogenic risk caused by drinking water in this area are low, which will not cause observable adverse health effects, the health risk to the surrounding residents is low.