Abstract：
Pit lakes in the \'anthropogenic lake district\' in the Muskau Arch (western Poland; central Europe) are strongly affected by acid mine drainage (AMD). The studied acidic pit lake, ŁK-61 (pH <3), is also exposed to floods due to its location in the flood hazard area, which may significantly influence the geochemical behavior of elements. The elemental compositions of water and lake sediment samples were measured with ICP-OES and ICP-MS. The sediment profile was also examined for 137Cs and 210Po activity concentrations using gamma and alpha spectrometry, respectively. Grain size distribution, mineralogical composition, diatoms, and organic matter content in the collected core were also determined. The key factors responsible for the distribution of selected heavy metals (e.g., Cu, Ni, Pb, Zn) and radioisotopes (137Cs and 210Po) in the bottom sediments of Lake ŁK-61 are their coprecipitation/precipitation with Fe and Al secondary minerals and their sorption onto authigenic and allogenic phases. These processes are likely driven by the lake tributary, which is an important source of dissolved elements. The data also showed that the physiochemical parameters of Lake ŁK-61 water changed during an episodic depositional event, i.e., the flood of the Nysa Łużycka River in the summer of 2010. The flood caused an increase in the water pH, as interpreted from the subfossil diatom studies. The down-core profiles of the studied heavy metal and radionuclide (HMRs) contents were probably affected by this depositional event, which prevented a detailed age determination of the collected lake sediments with 137Cs and 210Pb dating methods. Geochemical modeling indicates that the flood-related shift in the physicochemical parameters of the lake water could have caused the scavenging of dissolved elements by the precipitation of fresh secondary minerals. Moreover, particles contaminated with HMRs have also possibly been delivered by the river, along with the nutrients (e.g., phosphorus and nitrogen).
摘要：
Muskau拱门（波兰西部；中欧）的“人为湖区”的坑湖受到酸性矿山排水（AMD）的强烈影响。研究的酸性坑湖，K-61（pH<3），由于其位于洪水危险区域，也暴露于洪水中，这可能会显著影响元素的地球化学行为。用ICP-OES和ICP-MS测量了水和湖泊沉积物样品的元素组成。还使用γ和α光谱法检查了沉积物剖面的137Cs和210Po活性浓度，分别。粒度分布,矿物学组成，硅藻,并测定了收集到的岩心中的有机质含量。负责选定重金属分布的关键因素(例如，Cu,Ni,Pb,K-61湖底部沉积物中的Zn）和放射性同位素（137Cs和210Po）是它们与Fe和Al次生矿物的共沉淀/沉淀，以及它们在自生和同种异体相上的吸附。这些过程可能是由湖泊支流驱动的，这是溶解元素的重要来源。数据还表明，在周期性沉积事件期间，LakekW-61水的理化参数发生了变化，即，2010年夏季，NysaVaultušycka河的洪水。洪水导致水的pH值升高,从亚化石硅藻研究中解释。所研究的重金属和放射性核素（HMR）含量的地下剖面可能受到此沉积事件的影响，这阻止了用137Cs和210Pb测年方法对收集的湖泊沉积物进行详细的年龄测定。地球化学模型表明，与洪水有关的湖水物理化学参数的变化可能导致新鲜次生矿物的沉淀清除溶解元素。此外，被HMR污染的颗粒也可能被河流运送，连同营养素(例如，磷和氮)。
