Kumar Vivek, Paul Dibyendu, Kumar Sudhir
Department of Environmental Studies, North-Eastern Hill University, Shillong, India.
National Institute of Hydrology, Roorkee, India.
Isotopes Environ Health Stud. 2025 Mar;61(1):76-91. doi: 10.1080/10256016.2025.2456557. Epub 2025 Feb 5.
Sulphur and oxygen stable isotopes of sulphate have been used to trace the sources of sulphur into aquatic systems. These isotopes have also been used to understand the transformation and fate of sulphur in the water bodies contaminated by AMD discharge from active and/or abandoned mines. Stable isotopes of oxygen in dissolved sulphate (δO) and water (δO) have helped to decipher the sulphide oxidation pathways and estimate their contributions. The present study is focused on analysing the composition of sulphur and oxygen stable isotopes of sulphate and oxygen stable isotope in AMD and Lunar-Lukha River water flowing through the coal mining area of the East Jaintia Hills District, Meghalaya, in order to decipher the sulphide oxidation pathways. The results showed that the sulphur stable isotope of sulphate (δS) ranged between -12.5 and -8.0 ‰ (VCDT). The oxygen isotope of sulphate (δO) ranged between 1.4 and 2.0 ‰ (VSMOW). The oxygen isotope of water (δO) was distributed between -6.2 and -4.2 ‰ (VSMOW). Pyrite oxidation was found to be the dominant source of sulphate in the Lunar-Lukha Rivers. The results of the stoichiometric isotope balance model showed that 68-83 % of sulphate derived Fe oxidation pathway, with a high portion of sulphate oxygen derived from water. The sulphite-water oxygen exchange model revealed the release of intermediate sulphoxyanions, suggesting the presence of an oxidation pathway of sulphide minerals to sulphate via sulphoxyanions. The results from this study will be helpful in defining effective remediation strategies to mitigate AMD impacts.
硫酸盐的硫和氧稳定同位素已被用于追踪进入水生系统的硫源。这些同位素也被用于了解受活跃和/或废弃矿山酸性矿山排水（AMD）污染的水体中硫的转化和归宿。溶解硫酸盐（δO）和水中（δO）的氧稳定同位素有助于解读硫化物氧化途径并估算其贡献。本研究聚焦于分析流经梅加拉亚邦东贾因蒂亚山区煤炭开采区的AMD和卢纳-卢卡河水体中硫酸盐的硫和氧稳定同位素组成以及氧稳定同位素，以解读硫化物氧化途径。结果表明，硫酸盐的硫稳定同位素（δS）范围在-12.5至-8.0‰（VCDT）之间。硫酸盐的氧同位素（δO）范围在1.4至2.0‰（VSMOW）之间。水的氧同位素（δO）分布在-6.2至-4.2‰（VSMOW）之间。研究发现黄铁矿氧化是卢纳-卢卡河水中硫酸盐的主要来源。化学计量同位素平衡模型结果表明，68 - 83%的硫酸盐源自铁氧化途径，且大部分硫酸盐中的氧源自水。亚硫酸盐-水氧交换模型揭示了中间亚硫酸根阴离子的释放，表明存在硫化物矿物经亚硫酸根阴离子氧化为硫酸盐的途径。本研究结果将有助于确定有效的修复策略以减轻AMD的影响。
