Lateral Deposition and Geochemical Evolution of Mining- Related Metals in Floodplain Sediments

这个研究项目将调查地球化学和地貌过程，这些过程决定了洪泛区金属污染物沉积的空间变异性。研究区域是密西西比河谷上游锌铅矿区（威斯康星州）的蓝河流域。研究区域提供了相对简单的物理景观和金属污染集中时期（1900-1920）的研究优势。研究设计要求从5个断面、4个点坝和几个根据地貌标准战略性选择的活动通道位置采集1310个样本。将绘制河漫滩沉积物的地层学和地球化学图，并确定沉积物与金属的联系。研究结果将用于校准流域尺度的污染物扩散模型，并确定具有最高毒性影响或再活化潜力的特定洪泛区位置。这项研究有望在两个方面取得进展：更清楚地了解沉积物停留时间和洪泛区污染物的原位化学变化；更好地预测金属污染物从点源到近端和远端洪泛区水槽的扩散。纵向和横向结合的研究解决了我们对流域有毒金属储存和再动员的理解的基本空白，它应该为未来的环境管理提供重要的信息。

Pavlowsky This research project will investigate the geochemical and geomorphic processes that determine the spatial variability of the sedimentation of metal contaminants in a floodplain. The study area is the Blue River watershed of the Upper Mississippi valley zinc and led mining district (Wisconsin). The study area affords the research benefits of a relatively simple physical landscape and a concentrated period of metal contamination (1900-1920). The research design calls for 1,310 samples to be taken from 5 cross-sections, 4 point bars, and several active-channel locations selected strategically according to geomorphological criteria. The stratigraphy and geochemistry of the floodplain deposits will be mapped, and the sediment-metal associations will be identified. The results will be used to calibrate watershed-scale models of contaminant dispersal and to identify specific floodplain locations that have the highest potential for toxic effects or remobilization. The research promises advances in two dimensions: a clearer understanding of sediment residence time and in situ chemical alterations to floodplain contaminants; and better predictions of the dispersal of metal contaminants from point sources to both proximal and distal floodplain sinks. The combined longitudinal-lateral study addresses fundamental gaps in our understanding of toxic metal storage and remobilization in watersheds, and it should provide information important for future environmental management.