Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China.
Karst Dynamics Laboratory, Ministry of Natural Resources & Guangxi, Guilin, 541004, China.
Environ Sci Pollut Res Int. 2019 Oct;26(30):31354-31367. doi: 10.1007/s11356-019-06272-x. Epub 2019 Aug 31.
Springs are an important source of drinking water supply in mountainous karst areas of SW China. However, the quality of many spring waters has deteriorated greatly in recent years, which leads to a significant problem of drinking water scarcity. In this study, hydrochemistry and stable sulfur and oxygen isotopic compositions of SO (δS and δO) of 38 representative samples of waters (incl. spring water, surface water, rainwater, and sewage) from the Hongjiadu Basin, Guizhou province, SW China, were investigated in order to identify the sources of contaminates in spring waters and trace the processes affecting the karst groundwater quality. Approximately 28% of the total investigated springs has been suffered from serious contamination and the concentrations of NO, SO, and total iron (TFe) in many spring waters have exceeded the standards for drinking water. The springs that have NO concentrations of > 30 mg/L are concentrated in residential and agricultural areas, suggesting that NO in spring water are mainly derived from chemical fertilizers, manure, and sewage. δS and δO data indicate that SO in spring water mainly originates from sulfide oxidation, acid rain, and sewage. Furthermore, the high δS and δO values of SO in some spring waters may be related to the occurrence of bacterial sulfate reduction. Some springs that are discharged from abandoned coal mines have SO concentrations of > 250 mg/L, demonstrating that mining activities have accelerated the deterioration of spring water quality. Also, springs with TFe concentrations of > 0.3 mg/L are discharged from coal-bearing strata, revealing that iron in spring waters is mainly derived from the oxidation of pyrite. Our results show that the karst spring waters are highly vulnerable to anthropogenic contaminations and human activities, such as agricultural fertilizing and sewage and waste disposal as well as mining activities, which exert a great impact on the quality of groundwater in karst areas.
泉水是中国西南岩溶山区重要的饮用水水源。然而，近年来许多泉水水质急剧恶化，导致饮用水严重短缺。本研究对贵州省红鸡坝流域 38 个典型水样（包括泉水、地表水、雨水和污水）的水化学和稳定硫、氧同位素组成（δS 和 δO）进行了研究，以确定泉水污染的来源，追踪影响岩溶地下水质量的过程。大约 28%的泉水受到了严重污染，许多泉水的硝酸盐、硫酸盐和总铁（TFe）浓度超过了饮用水标准。NO 浓度大于 30mg/L 的泉水主要集中在居民区和农业区，表明泉水的 NO 主要来源于化肥、粪便和污水。δS 和 δO 数据表明，泉水的 SO 主要来源于硫化物氧化、酸雨和污水。此外，一些泉水的 SO δS 和 δO 值较高，可能与细菌硫酸盐还原的发生有关。一些来自废弃煤矿的泉水的 SO 浓度大于 250mg/L，表明采矿活动加速了泉水水质的恶化。同时，TFe 浓度大于 0.3mg/L 的泉水也来自含煤地层，表明泉水中的铁主要来源于黄铁矿的氧化。研究结果表明，岩溶泉水极易受到人为污染和人类活动的影响，如农业施肥、污水和废物处理以及采矿活动，这些活动对岩溶地区地下水质量有很大影响。
