| 硫氧同位素解析典型岩溶地下河流域硫酸盐季节变化特征和来源 |
| 摘要点击 1703 全文点击 662 投稿时间：2021-01-24 修订日期：2021-03-05 |
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| 中文关键词 硫氧同位素 硫酸盐 岩溶含水层 地下河 酸性矿坑水 来源解析 |
| 英文关键词 sulfur and oxygen isotopes sulfate karst aquifer subterranean stream acid mine drainage sources identification |
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| 中文摘要 |
| 全球约1/4的饮用水源为岩溶水，但岩溶含水层极易遭受人类活动污染.以八步地下河为例，利用硫酸盐（SO42-）浓度、硫氧同位素（δ34S-SO4和δ18O-SO4）和水中氧同位素（δ18O-H2O）研究岩溶小流域SO42-的丰、枯水期两个季节变化特征和来源.结果表明：①受酸性矿坑水（acid mine drainage，AMD）直接影响的采样点SO42-浓度较高（≥250 mg·L-1），枯水期>丰水期，其他采样点浓度季节变化相对较弱且浓度低.②地表水丰水期δ34S-SO4与δ18O-SO4平均值分别为-10.5‰和4.7‰，枯水期为-11.5‰和1.3‰；地下水丰水期δ34S-SO4与δ18O-SO4平均值分别为-2.9‰和7.1‰，枯水期为-3.2‰和6.2‰.地表水和地下水中δ34S-SO4与δ18O-SO4值都存在丰水期偏重、枯水期偏轻的特征.③丰、枯水期流域内地表水和地下水中各采样点δ34S-SO4值变化不明显，表明在特定的采样点SO42-的来源相对稳定.④地表水和地下水中SO42-主要来源于雨水、硫化物和石膏，地下河出口各来源丰水期所占的比例分别为13%、40%和47%，枯水期为18%、39%和43%. |
| 英文摘要 |
| Karst water, which provides approximately 25% of the world's drinking water, is especially vulnerable to anthropogenic pollutants. To determine the variations between high and low flow periods and the sources of dissolved sulfate (SO42-) in small karst basins, SO42- concentrations, stable sulfur and oxygen isotopes (δ34S-SO4 and δ18O-SO4), and oxygen isotopes of water (δ18O-H2O) were investigated in surface and groundwaters, during the high and low flow seasons, within the Babu subterranean stream basin. Analysis showed that: ① the water samples that were directly impacted by acid mine drainage exhibited high SO42- concentrations (≥250 mg·L-1) and significant seasonal variation, while the seasonal variation of non-AMD-impacted water with low SO42- concentrations was not significant. ② During the high flow season, the mean δ34S-SO4 and δ18O-SO4 values of surface water were -10.5‰ and 4.7‰, respectively, and -11.5‰ and 1.3‰ during the low flow period; the mean values of δ34S-SO4 and δ18O-SO4 in groundwater samples were -2.9‰ and 7.1‰ during the high flow period, respectively, and -3.2‰ and 6.2‰ during the low flow period. Both surface and groundwater samples exhibited higher δ34S-SO4 and δ18O-SO4 values during the high flow period than during the low flow period. ③ The values of δ34S-SO4 in the surface and groundwater samples were relatively stable, indicating that the sources of SO42- at specific sampling sites were stable.④ The main sources of SO42- in surface and groundwaters were rain, sulfide, and gypsum, accounting for 13%, 40%, and 47%, respectively, of SO42- in samples taken from the basin outlet during the high flow season, and 18%, 39%, and 43%, respectively, in samples obtained during the low flow season. |
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