Department of Earth Sciences and Research Center on Natural Resources, Health and the Environment, University of Huelva, Campus 'El Carmen', Fuerzas Armadas s/n, 21071 Huelva, Spain..
Department of Earth Sciences and Research Center on Natural Resources, Health and the Environment, University of Huelva, Campus 'El Carmen', Fuerzas Armadas s/n, 21071 Huelva, Spain.
Sci Total Environ. 2020 Jun 20;722:137905. doi: 10.1016/j.scitotenv.2020.137905. Epub 2020 Mar 12.
This study deals with the metal partitioning and bioavailability of metal/loids in the estuary Ria of Huelva (SW Spain) which is strongly affected by historical mining and industrial activities. To address this issue, traditional (i.e., grab samples) and passive sampling (i.e., diffusive gradient in thin films, DGTs) was carried out in the outer part of the estuary during different tidal cycles in order to determine the dissolved and particulate metal/loid concentrations. The dissolved concentrations exceeded, by several orders of magnitude, those reported in other estuaries worldwide that are affected by anthropogenic activities. A spatial pattern was observed in the metal distribution; a decrease seaward was recorded for some of the elements associated with mining (e.g., Cu, Zn, and Cd), the opposite tendency is observed for others associated with harbor emissions (e.g., Sn, Ni, or Pb). A different metal/loid partitioning pattern was also observed; Fe, and to a lesser extent Pb and Sn, were chiefly found in the particulate matter, while the rest of the elements were mainly found in the dissolved form. The bioavailability of the metal/loids was studied by speciation using both geochemical modeling and DGTs; while concentrations in DGTs supported metal/loid speciation for Zn, Cd, Mn, Co, As, and Sb according to their affinity to form strong or weak complexes, some discrepancies were observed for other elements such as Cu, V, Fe, and Pb, which are prone to forming strong complexes. The main reason behind the unexpectedly high Fe and Pb DGTs concentrations may be associated with their presence in the colloidal particles passing through the DGT. There was a strong positive correlation between dissolved and DGT concentrations for Cd and Mn, and to a lesser extent for Fe and Cu, highlighting the direct relationship between the concentrations in water and availability to living organisms in the estuary.
本研究探讨了西班牙西南部韦尔瓦河口（Ria de Huelva）的金属分配和金属/类金属的生物可利用性，该河口受到历史采矿和工业活动的强烈影响。为了解决这个问题，在不同的潮汐周期中，在外河口进行了传统（即抓斗样本）和被动采样（即薄膜扩散梯度，DGT），以确定溶解和颗粒态金属/类金属浓度。溶解浓度比受到人为活动影响的世界其他河口报道的浓度高出几个数量级。观察到金属分布的空间模式；与采矿有关的一些元素（例如 Cu、Zn 和 Cd）向海方向减少，而与港口排放有关的其他元素（例如 Sn、Ni 或 Pb）则相反。还观察到不同的金属/类金属分配模式；Fe 以及程度较小的 Pb 和 Sn 主要存在于颗粒物中，而其余元素主要以溶解形式存在。通过使用地球化学模型和 DGT 进行形态分析研究了金属/类金属的生物可利用性；虽然 DGT 中的浓度支持 Zn、Cd、Mn、Co、As 和 Sb 的金属/类金属形态，但对于 Cu、V、Fe 和 Pb 等其他元素则存在一些差异，这些元素容易形成强配合物。DGT 中出乎意料的高 Fe 和 Pb 浓度的主要原因可能与它们存在于通过 DGT 的胶体颗粒中有关。Cd 和 Mn 的溶解浓度与 DGT 浓度之间存在强烈的正相关，而 Fe 和 Cu 的相关性较弱，这突出了河口水中浓度与生物体内可利用性之间的直接关系。
