Distribution of dissolved, free and labile trace metal species and phosphorus in freshwater systems from the Quadrilátero Ferrífero, Brazil

This dataset is derived from a study aimed to investigate the distribution and lability of trace metals (Co, Cu, Cr, Mn, Ni, Pb and Zn) and P in freshwater systems from a mining area (Quadrilátero Ferrífero, Brazil). The samples were collected at six sampling sites in Upper Doce River catchment in February and October 2014. The physicochemical parameters conductivity, total dissolved solids, pH and temperature were measured in situ using a multi-parameter probe Ultrameter II (Myron L company). The water samples were filtered and ultrafiltered for determination of dissolved (&lt;0.45 µm) and free (&lt;1 kDa) fractions. Diffusive gradients in thin films (DGT) were deployed in situ for determination of the labile fraction of the analysed elements. The species in the free fraction are considered more mobile and potentially bioavailable. Determination of the trace metals and P were carried out by inductively coupled plasma optical emission spectrometry (ICP-OES, Agilent Technologies 700 Series). The data were analysed using a neural network (self-organising maps, SOM) and Spearman’s rank correlation. The concentrations of each fraction of the analysed elements, the file used to perform the SOM analysis and the rank correlations are available in this dataset. The P in the Carmo River occurred mostly in the free and labile fractions and therefore it was considered highly bioavailable. The concentrations of some trace metals such as Co, Cu, Mn, Ni and Zn were high due to natural and anthropogenic factors (e.g., lithology and mining).本数据集源自一项旨在探究巴西铁四角矿区（Quadrilátero Ferrífero）淡水系统中痕量金属（Co、Cu、Cr、Mn、Ni、Pb及Zn）与磷（P）的分布特征及活性的研究。研究于2014年2月与10月在多西河上游流域（Upper Doce River catchment）的6个采样点采集样品。研究人员使用Ultrameter II型多参数探头（Myron L公司）原位测定了电导率、总溶解固体、pH及温度等理化参数。对水样进行过滤与超滤处理，分别测定溶解态（<0.45μm）与游离态（<1kDa）组分。原位部署薄膜扩散梯度技术（Diffusive gradients in thin films, DGT）以测定分析元素的活性组分。游离态组分被认为具有更高的移动性与潜在生物可利用性。痕量金属与磷的含量采用电感耦合等离子体光学发射光谱法（inductively coupled plasma optical emission spectrometry, ICP-OES，安捷伦科技700系列）测定。数据分析采用神经网络（自组织映射（SOM））与斯皮尔曼秩相关分析方法。本数据集包含各分析元素各组分的浓度数据、用于SOM分析的文件以及秩相关分析结果。卡莫河（Carmo River）中的磷主要以游离态与活性组分形式存在，因此被认为具有极高的生物可利用性。部分痕量金属如Co、Cu、Mn、Ni及Zn的浓度偏高，这源于自然与人为因素（如岩性特征与采矿活动）。