通过稳定氢氧同位素结合水化学的方法, 在 2017 年采集天津市主要区( 县) 自来水的基础上, 于 2019 年重点收集中心城区和西青区的直接供水和二次供水的自来水, 分析水样中的稳定氢氧同位素组分和主要阴阳离子质量 浓度。自来水中稳定氧同位素∮18 O 的范围为- 4.41 ‰~ - 10.06 ‰ , 氢同位素∮D 的范围为- 52. 4 ‰ ~ - 74. 4‰ 。 引江水为水源的自来水中的同位素位于全球大气降水线附近, 水库蓄存会导致水中同位素富集; 深层地下水为水源的稳定同位素贫化。天津市中心城区、西青、津南、北辰、武清和蓟州的自来水水化学类型为 Ca·Mg-HCO3 , 滨海新区和宝坻的水化学类型为 Na· Mg-SO4 , 宁河的水化学类型为 Na-HCO3。天津市自来水的主要阴阳离子质量浓度都符合国家饮用水标准, 二次供水对水化学组成无显著影响。引江水的自来水水质较地下水为水源的水质好; 滨海新区 由于水库蓄存, 自来水中 Na+ 和 SO4 2- 的离子质量浓度高; 宁河区的 Na+ 和蓟州区的 NO3- 质量浓度高。
The tap water samples were collected at main districts of Tianjin in 2017. The tap water samples were collected from the direct and seco ndary water supply in the central urban city and Xiqing District in 2019. All water samples were analyzed on the compositions of stable hydrogen and oxygen is otopes and majorions. The range of stable oxygen is otope (∮18 O) in the tap water was from - 4. 41‰ to - 10. 06 ‰ , and the range of hydrogen isotope (∮D) was from - 52. 4‰ to - 74. 4 ‰ , respectively. The isotopes in the tap water ( Hanjiang river as the water source) were located near the Global Meteoric Water Line ( GMWL) , however, the reservoir storage may cause the isotopic enrichment in the tap water. The stable isotopes were depleted in the tap water which used the deep groundwater as the w ater source. The water type of tap water in the central urban area and Xiqing , Jinnan, Beichen, Wuqing and Jizhou districts was Ca· Mg-HCO3. The water type of tap water in Binhai New Area andBaodi district was Na·Mg2SO4 . The tap water in Ninghe district was the type of Na-HCO3 . The tap water quality in Tianjin was under the national guideline of drinking water. There was no significant different in hydro chemical composition of tap water between the direct water supply and the secondary water supply . Thus, the water quality of tap water from Hanjiang river was better than that from the local deep groundwater. The ion mass concentrat ions of Na+ and SO4 2- in the t ap water were high at the Binha i New Area due to the reser voirstorage. The mass concentration of Na+ in the tap water at Ning he district and the NO3 - in the tap water at Jizhou district was the highest. Consequently, the protection of groundwater and the safety of drinking water in the centralized water supply areas should require more attention and improvement.
国家自然科学基金( 41971037) ; 天津市自然科学基金( 15 JCQNJC44200)