School of Water and Environment, Chang'an University, No. 126 Yanta Road, Xi'an, 710054, Shaanxi, China.
Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region of the Ministry of Education, Chang'an University, No. 126 Yanta Road, Xi'an, 710054, Shaanxi, China.
Environ Geochem Health. 2021 Feb;43(2):791-812. doi: 10.1007/s10653-020-00520-7. Epub 2020 Feb 25.
Datong Basin in China is a typical arid-semiarid inland basin, with high levels and wide distributions of arsenic (As), fluoride (F), and iodine (I). To better understand the presence of low-quality groundwater in Datong Basin and assess the health risks for local residents, groundwater samples were collected from the shallow aquifer and in medium-deep groundwater and analyzed for As, F, I, and nitrate (NO). Maxima of 1932 μg/L for As, 80.89 mg/L for F, 2300 μg/L for I, and 3854.74 mg/L for NO were detected in shallow groundwater, which greatly exceeded the WHO limits for drinking purpose. High-As groundwater was present in both shallow and medium-deep aquifers. High-F and high-NO groundwater was widely distributed in the shallow aquifer, and high-I groundwater was mainly present in the medium-deep aquifers. Poor-quality groundwater in the Datong Basin is mainly caused by local geological and climatic conditions, which are characterized by strong evaporation, active water-rock interactions, thick lacustrine sediment, low groundwater flow rate, and reducing and weak alkaline environments. However, groundwater quality was further impacted by agricultural activities in some areas, as shallow groundwater was also polluted by nitrate. Datong Basin inhabitants face high health risk caused by high concentrations of As, F, I, and NO. The mean noncarcinogenic risk values (HQ) were 18.40 for children, 10.94 for adult females, and 9.47 for adult males due to exposure to contaminants in shallow groundwater; and 13.76 for children, 8.18 for adult females, and 7.08 for adult males because of exposure to medium-deep groundwater. Further, the carcinogenic risks (CR) caused by exposure to As were very high for local inhabitants, with the mean and median CR values of 4.20×10 and 4.13×10 in shallow groundwater and 3.44×10 and 1.71×10 in medium-deep groundwater, respectively.
中国大同盆地是一个典型的干旱-半干旱内陆盆地，砷（As）、氟（F）和碘（I）含量高、分布广。为了更好地了解大同盆地劣质地下水的存在情况并评估当地居民的健康风险，采集了浅层和中深层地下水样本，并对 As、F、I 和硝酸盐（NO）进行了分析。在浅层地下水中检测到 As 的最大值为 1932μg/L，F 的最大值为 80.89mg/L，I 的最大值为 2300μg/L，NO 的最大值为 3854.74mg/L，均远远超过世界卫生组织（WHO）的饮用水标准。浅层和中深层地下水均存在高砷地下水。高氟和高硝酸盐地下水广泛分布于浅层含水层，高碘地下水主要分布于中深层含水层。大同盆地劣质地下水主要由当地的地质和气候条件造成，其特征是强蒸发、活跃的水岩相互作用、厚的湖相沉积物、低地下水流速以及还原和弱碱性环境。然而，在一些地区，农业活动也进一步影响了地下水质量，因为浅层地下水也受到硝酸盐的污染。大同盆地居民面临着由高浓度的 As、F、I 和 NO 引起的高健康风险。由于浅层地下水中污染物的暴露，儿童、成年女性和成年男性的非致癌风险值（HQ）平均值分别为 18.40、10.94 和 9.47；由于中深层地下水中污染物的暴露，儿童、成年女性和成年男性的 HQ 平均值分别为 13.76、8.18 和 7.08。此外，由于暴露于 As 引起的致癌风险（CR）对当地居民来说非常高，浅层地下水中的平均和中位数 CR 值分别为 4.20×10 和 4.13×10，中深层地下水中的平均和中位数 CR 值分别为 3.44×10 和 1.71×10。
