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

• Published in: Environmental science & technology 2007-06, Vol.41 (12), p.4214-4220
• Main Authors: Braungardt, Charlotte B, Achterberg, Eric P, Gledhill, Martha, Nimmo, Malcolm, Elbaz-Poulichet, Francoise, Cruzado, Antonio, Velasquez, Zoila
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Applied sciences; Aquatic plants; Biodiversity; Biological and medical sciences; Brackish; Chlorophyta - drug effects; Chlorophyta - metabolism; Cobalt - analysis; Cobalt - chemistry; Cobalt - pharmacology; Contamination; Copper; Copper - analysis; Copper - chemistry; Copper - pharmacology; Earth sciences; Earth, ocean, space; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; Engineering and environment geology. Geothermics; Environmental science; Estuaries; Exact sciences and technology; Freshwater; Fundamental and applied biological sciences. Psychology; Ligands; Marine; Natural water pollution; Nickel - analysis; Nickel - chemistry; Nickel - pharmacology; Phytoplankton - classification; Phytoplankton - drug effects; Phytoplankton - metabolism; Plankton; Pollution; Pollution, environment geology; Population Dynamics; Rivers; Seawater - chemistry; Seawaters, estuaries; Spain; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - pharmacology; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es063042h

Four surveys of the Huelva Estuary in southwest Spain and its sources, the Tinto and the Odiel Rivers, were carried out between 1996 and 1998. The surveys investigated the impact of metalliferous mining of sulfide-rich ores in the catchment area on metal speciation, metal concentrations in a macrophyte, and phytoplankton diversity and abundance. Chemical speciation measurements in the lower Tinto Estuary showed that metals were predominantly electrochemically labile (>99% of total dissolved Cu, Co, and Ni at 10 μM Cu, 424 nM Co, and 500 nM Ni, S = 28). Concentrations of Cu complexing ligands and free cupric ions [Cu2+] in the Gulf of Cádiz ranged between 5.3 and 38 nM and 0.2−7.9 pM, respectively, with conditional stability constants of the ligands of log K‘CuL = 11.7−12.6. At enhanced dissolved Cu concentrations in the lower Huelva Estuary, Cu complexing ligands were saturated with Cu, resulting in nanomolar [Cu2+], which increased upstream. Metal tissue concentrations of the macrophyte Blindingia marginata were high, and a clear relationship between dissolved labile Cu and macrophyte tissue Cu concentrations was observed. A low biodiversity was observed in the Huelva system (Shannon−Wiener indices (H) typically