Soil and Water Chemistry and Trace Metal Extractability and Speciation in Wetland Soils from Illinois and South Carolina and Stream Sediments from Tennessee

Dataset revised on October 15, 2021. This revision adds sulfur and iron X-ray absorption near-edge structure spectra for the wetland soils and stream sediments from the field areas. It also renames the sample locations in a way that is more intuitive to readers of the companion paper that is under review. Finally, the data filenames and organization have been updated in their labeling to parallel the data sources in the associated paper. The abstract text and methods were also revised to reflect the data that was added to the dataset. Trace metals are essential for microbially-mediated biogeochemical processes occurring in anoxic wetland soils and stream bed sediments, such as denitrification, methanogenesis, and mercury methylation. Low availability of these elements may potentially inhibit key components of anaerobic carbon and nitrogen cycling and contaminant transformation. The solid-phase speciation of trace metals likely plays an important role in controlling their bioavailability. Metal speciation is well studied in contaminated soils and sediments as well as those naturally elevated in trace metals. However, less is known regarding the chemical forms of trace metals in systems having concentrations similar to geological background levels, the very settings where metal limitations may be most prevalent. We have investigated trace metal concentrations, extractability, and solid-phase speciation in three freshwater subsurface aquatic systems: marsh wetland soils, riparian wetland soils, and the sediments of a streambed. Data are provided for marsh wetland soils at Argonne National Laboratory, riparian wetland soils in the Tims Branch watershed at Savannah River National Laboratory, and stream bed sediments from East Fork Poplar Creek near Oak Ridge National Laboratory. Soil and sediment elemental abundances, mineralogy, and extractable nutrients as well as dissolved major elements, anions, trace metals, and nutrients in the overlying surface waters are provided. In addition, the results of sequential chemical extraction for the trace metals cobalt, nickel, copper, and zinc from the soils and sediment are reported as well as X-ray absorption near-edge structure (XANES) spectra in these materials are reported. To aid interpretation of these data, XANES spectra of sulfur in the soils and sediments as well as both XANES and extended X-ray absorption fine structure (EXAFS) spectra of iron in these materials are reported. The data package also includes the XANES spectra of reference standards and a potential interferent in the measurements. All data are provided in text-based CSV format with header sections indicating the data contained in each file and the corresponding units. Note that "u" is used in place of Greek lower case mu to indicate the micro prefix on units.

本数据集于2021年10月15日完成修订。本次修订新增了研究区域内湿地土壤与河流沉积物的硫、铁X射线吸收近边结构（X-ray absorption near-edge structure, XANES）光谱数据；同时优化了采样点位的命名规则，使其更便于同行评审中配套论文的读者理解；此外还更新了数据文件名与组织形式，使其与关联论文中的数据来源保持一致。针对数据集新增的内容，摘要文本与方法部分也已同步修订，以准确反映本次新增的数据。

痕量金属是厌氧湿地土壤与河流底泥中微生物介导的生物地球化学过程（如反硝化作用、产甲烷作用与汞甲基化）的必需元素。此类元素的生物有效性不足可能会抑制厌氧碳、氮循环以及污染物转化的关键环节。痕量金属的固相形态是调控其生物有效性的核心因素。目前学界已对污染土壤、沉积物以及天然痕量金属富集体系中的金属形态开展了充分研究，但针对浓度接近地质背景值的体系中痕量金属化学形态的认知仍较为匮乏，而这类体系恰恰可能是金属限制效应最为普遍的场景。

本研究针对三类淡水地下水生系统展开了调查，分别为沼泽湿地土壤、河岸湿地土壤以及河流底泥，内容涵盖痕量金属浓度、可提取性与固相形态。

数据集包含以下采样点位的数据：阿贡国家实验室（Argonne National Laboratory）的沼泽湿地土壤、萨凡纳河国家实验室（Savannah River National Laboratory）廷斯分支流域的河岸湿地土壤，以及橡树岭国家实验室附近的波普卡里克东支流河流底泥。

本数据集提供了土壤与沉积物的元素丰度、矿物组成、可提取养分含量，以及上覆地表水中溶解态常量元素、阴离子、痕量金属与养分的检测数据。此外，还报告了从土壤与沉积物中提取的痕量金属钴、镍、铜、锌的连续化学萃取结果，以及这些样品中的XANES光谱。

为辅助上述数据的解译，本数据集还报告了样品中硫的XANES光谱，以及铁的XANES与扩展X射线吸收精细结构（extended X-ray absorption fine structure, EXAFS）光谱。

本数据包还收录了测量过程中所用参考标准物质与潜在干扰物的XANES光谱。

所有数据均以基于文本的CSV格式存储，每个文件的头部字段均标注了该文件包含的数据内容与对应单位。请注意，数据中使用字母"u"替代希腊小写字母μ来表示单位中的微（micro）前缀。