Department of Earth Science and Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.
State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an, 710069, China.
Environ Pollut. 2021 Oct 1;286:117287. doi: 10.1016/j.envpol.2021.117287. Epub 2021 May 4.
Fluoride (F) and nitrate (NO) in groundwater have caused serious health problems worldwide. However, in the Chinese Loess Plateau where groundwater is the primary source of drinking water, previous studies have rarely reported the health risks from fluoride and nitrate in groundwater. Therefore, we collected 105 groundwater samples (78 from shallow aquifers and 27 from deep aquifers) from the western district of the Loess Plateau for physicochemical and isotopic analysis to investigate the sources of F and NO in groundwater and associated health risks. Fluoride concentration in 73.1% of shallow groundwater and 22.2% of deep groundwater exceeds 1.5 mg/L, while NO content in 76.3% of shallow groundwater and 51.9% of deep groundwater surpasses 50 mg/L. High-F groundwater is associated with HCO-Na, SO-Na·Mg and Cl-Na·Mg types water. Fluorine-bearing minerals dissolution, cation exchange, calcite precipitation, evaporation, and anthropogenic activities contribute significantly F in groundwater. Mixing with shallow groundwater is an important source of F in deep groundwater. The NO content is highest in Cl type water, followed by SO type and HCO type water. NO mainly originates from soil organic nitrogen (SON), chemical fertilizers (CF), and manure and sewage (M&S). Nitrification is the dominant transformation process of nitrogen nutrients in groundwater. The hazard index (HI) values for shallow groundwater are 0.203-9.232 for adults, 0.253-11.522 for teenagers, 0.359-16.322 for children, and 0.507-23.043 for infants, while those for deep groundwater are 0.713-5.813 for adults, 0.890-7.254 for teenagers, 1.261-10.277 for children, and 1.780-14.508 for infants. Approximately 96.2% of shallow groundwater poses non-carcinogenic risks to infants and children, followed by 92.3% to teenagers, and 89.7% to adults. All deep groundwater poses non-carcinogenic risks to infants and children, followed by 92.6% to teenagers, and 74.1% to adults. This study is helpful to develop strategies for the integrated management of high fluoride or nitrate groundwater in arid areas.
地下水的氟（F）和硝酸盐（NO）已在全球范围内造成严重的健康问题。然而，在中国黄土高原地区，地下水是主要的饮用水源，之前的研究很少报道地下水氟和硝酸盐的健康风险。因此，我们采集了黄土高原西部地区 105 个地下水样本（78 个浅层地下水样本和 27 个深层地下水样本）进行理化和同位素分析，以调查地下水氟和硝酸盐的来源及其相关的健康风险。73.1%的浅层地下水和 22.2%的深层地下水的氟浓度超过 1.5mg/L，76.3%的浅层地下水和 51.9%的深层地下水的硝酸盐含量超过 50mg/L。高氟地下水与 HCO-Na、SO-Na·Mg 和 Cl-Na·Mg 型水有关。氟化物来源于含氟矿物溶解、阳离子交换、方解石沉淀、蒸发和人为活动。浅层地下水与深层地下水的混合是深层地下水氟的重要来源。NO 含量在 Cl 型水中最高，其次是 SO 型和 HCO 型水。NO 主要来源于土壤有机氮（SON）、化肥（CF）和粪便和污水（M&S）。地下水氮素的硝化作用是主要的转化过程。浅层地下水的危害指数（HI）值分别为成年人 0.203-9.232、青少年 0.253-11.522、儿童 0.359-16.322 和婴儿 0.507-23.043，深层地下水的 HI 值分别为成年人 0.713-5.813、青少年 0.890-7.254、儿童 1.261-10.277 和婴儿 1.780-14.508。约 96.2%的浅层地下水对婴儿和儿童有非致癌风险，其次是 92.3%的青少年和 89.7%的成年人。所有深层地下水对婴儿和儿童均有非致癌风险，其次是 92.6%的青少年和 74.1%的成年人。本研究有助于制定干旱地区高氟或高硝酸盐地下水综合管理策略。
