Man Technology Environment Research Centre, Örebro University, SE-701 82, Örebro, Sweden.
Environ Sci Pollut Res Int. 2021 Jun;28(23):30219-30241. doi: 10.1007/s11356-021-12784-2. Epub 2021 Feb 14.
Worldwide, black shales and shale waste are known to be a potential source of metals to the environment. This project demonstrates ongoing weathering and evaluates leaching processes at a 100-m-high shale waste deposit closed in the 1960s. Some deep parts of the deposit are still burning with temperatures exceeding 500 °C. To demonstrate ongoing weathering and leaching, analyses of groundwater and solid samples of shale and shale waste have been undertaken. Largest impact on groundwater quality was observed downstream the deposit, where elevated temperatures also indicate a direct impact from the burning waste deposit. Groundwater quality is largely controlled by pH and redox conditions (e.g., for arsenic, nickel, molybdenum, uranium and vanadium), and the mixture of different waste materials, including pyrite (acidic leachates) and carbonates (neutralizing and buffering pH). Analyses of shale waste from the deposit confirm the expected pyrite weathering with high concentrations of iron, nickel and uranium in the leachates. No general time trends could be distinguished for the groundwater quality from the monitoring in 2004-2019. This study has shown that black shale waste deposits can have a complex long-term impact on the surrounding environment.
在全球范围内，黑色页岩和页岩废料被认为是环境中金属的潜在来源。本项目展示了一座于 20 世纪 60 年代关闭的 100 米高页岩废料场的持续风化过程，并评估了浸出过程。该废料场的一些深部仍在燃烧，温度超过 500°C。为了证明正在进行的风化和浸出过程，对地下水和页岩及页岩废料的固体样本进行了分析。在矿床下游观察到对地下水质量的最大影响，那里的高温也表明了燃烧的废料场的直接影响。地下水质量主要受 pH 值和氧化还原条件（例如砷、镍、钼、铀和钒）以及包括黄铁矿（酸性浸出液）和碳酸盐（中和和缓冲 pH 值）在内的不同废料混合物的控制。对矿床中页岩废料的分析证实了预期的黄铁矿风化，浸出液中含有高浓度的铁、镍和铀。从 2004 年至 2019 年的监测中，无法区分地下水质量的一般时间趋势。本研究表明，黑色页岩废料场可能对周围环境产生复杂的长期影响。
