Balci Nurgul, Gunes Yagmur
Department of Geological Engineering, Geomicrobiology and Biogeochemistry Laboratory, Istanbul Technical University, Istanbul, Türkiye; Department of Geology, University of Georgia, Athens, GA, USA.
Department of Geological Engineering, Geomicrobiology and Biogeochemistry Laboratory, Istanbul Technical University, Istanbul, Türkiye.
Sci Total Environ. 2024 Dec 1;954:176727. doi: 10.1016/j.scitotenv.2024.176727. Epub 2024 Oct 9.
This study deals with the generation, geochemical characteristics, and environmental impacts of acid rock drainage (ARD), a global environmental problem, on the Barton Peninsula. To elucidate the governing processes and to assess the environmental hazards of ARD, we present chemical data from lakes, ponds, and creeks with a wide range of pH values. We also provide mineralogical and geochemical compositions of sediments and bedrocks. Compared to weak-acidic and neutral waters, waters that display typical characteristics of ARD with low pH (3.7 to 4.2), high sulfate (46 to 92 mg/L), and Fe (0.8 to 16.5 mg/L) occur in the northern tip of the peninsula. Acidic waters with the highest cation (e.g., K, Na, Si, and Ca) and anion (e.g., SO) compositions indicate ARD-enhanced rock weathering in the peninsula. Consistently, quantifying of chemical weathering degree yields the highest chemical index of alteration (CIA) and the mafic index of alteration (MIA) with the lowest ICV values for sediments from the acidic waters. Enrichment factors (EFs) calculated for As, Co, Cd, Cu, Pb, Zn, and Ni indicate severe to minor enrichment for As and Pb metals, respectively in the acidic water-associated sediments. Heavy metal concentrations of acidic waters also display the highest values for the peninsula, with Fe, Cu, and Cd metals exceeding the chronic aquatic toxicity limit (CAT). Therefore, geochemical records of acidic waters and sediments, especially lakes, may help in tracing the long-term environmental impacts of ARD, while sediments obtained from the weak acidic and near-neutral waters, together with water chemistry data, may provide a better representative composition of the bedrocks with neutralizing potential. The data presented here may contribute to predicting the source/s, and extent of future ARD generation in the peninsula, which is likely to be enhanced by increased chemical weathering due to climate warming.
本研究探讨了酸性岩排水（ARD）这一全球性环境问题在巴顿半岛的产生、地球化学特征及环境影响。为阐明ARD的控制过程并评估其环境危害，我们给出了不同pH值湖泊、池塘和溪流的化学数据。我们还提供了沉积物和基岩的矿物学和地球化学组成。与弱酸性和中性水体相比，半岛北端出现了具有低pH值（3.7至4.2）、高硫酸盐（46至92毫克/升）和铁（0.8至16.5毫克/升）典型ARD特征的水体。阳离子（如钾、钠、硅和钙）和阴离子（如硫酸根）组成最高的酸性水体表明半岛存在ARD增强的岩石风化作用。同样，对化学风化程度的量化得出了酸性水体沉积物的最高化学蚀变指数（CIA）和镁铁质蚀变指数（MIA）以及最低的ICV值。对酸性水体相关沉积物中砷、钴、镉、铜、铅、锌和镍计算的富集因子（EFs）分别表明砷和铅金属存在严重至轻微的富集。酸性水体的重金属浓度在半岛上也呈现出最高值，铁、铜和镉金属超过了慢性水生毒性限值（CAT）。因此，酸性水体和沉积物（尤其是湖泊）的地球化学记录可能有助于追踪ARD的长期环境影响，而从弱酸性和近中性水体获得的沉积物以及水化学数据可能提供具有中和潜力的基岩更好的代表性组成。本文所呈现的数据可能有助于预测半岛未来ARD产生的来源和范围，由于气候变暖导致化学风化增加，未来ARD产生的范围可能会扩大。
