Chemical Speciation of Dissolved Cu, Ni, and Co in a Contaminated Estuary in Southwest Spain and Its Influence on Plankton Communities

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• 作者：Charlotte B. Braungardt ; Eric P. Achterberg ; Martha Gledhill ; Malcolm Nimmo ; Francoise Elbaz-Poulichet ; Antonio Cruzado ; Zoila Velasquez
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：June 15, 2007
• 年：2007
• 卷：41
• 期：12
• 页码：4214 - 4220
• 全文大小：339K
• 年卷期：v.41,no.12(June 15, 2007)
• ISSN：1520-5851

文摘

Four surveys of the Huelva Estuary in southwest Spainand its sources, the Tinto and the Odiel Rivers, were carriedout between 1996 and 1998. The surveys investigated theimpact of metalliferous mining of sulfide-rich ores inthe catchment area on metal speciation, metal concentrationsin a macrophyte, and phytoplankton diversity andabundance. Chemical speciation measurements in thelower Tinto Estuary showed that metals were predominantlyelectrochemically labile (>99% of total dissolved Cu, Co,and Ni at 10 M Cu, 424 nM Co, and 500 nM Ni, S = 28).Concentrations of Cu complexing ligands and free cupricions [Cu²⁺] in the Gulf of Cdiz ranged between 5.3 and 38nM and 0.2-7.9 pM, respectively, with conditionalstability constants of the ligands of log K'_CuL = 11.7-12.6.At enhanced dissolved Cu concentrations in the lowerHuelva Estuary, Cu complexing ligands were saturated withCu, resulting in nanomolar [Cu²⁺], which increasedupstream. Metal tissue concentrations of the macrophyteBlindingia marginata were high, and a clear relationshipbetween dissolved labile Cu and macrophyte tissue Cuconcentrations was observed. A low biodiversity wasobserved in the Huelva system (Shannon-Wiener indices(H) typically <0.2). Nevertheless, the maximum biomasswas observed in the lower Tinto Estuary, which showed highlabile metal and nutrient concentrations and a lowbiodiversity (H < 0.02), thereby suggesting adaptationthrough evolutionary processes of the phytoplanktoncommunity to the harsh conditions.