کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4410891 1307568 2011 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Temporal variability in dynamic and colloidal metal fractions determined by high resolution in situ measurements in a UK estuary
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم محیط زیست شیمی زیست محیطی
پیش نمایش صفحه اول مقاله
Temporal variability in dynamic and colloidal metal fractions determined by high resolution in situ measurements in a UK estuary
چکیده انگلیسی

In recent environmental legislation, such as the Water Framework Directive in the European Union (WFD, 2000/60/EC), the importance of metal speciation and biological availability is acknowledged, although analytical challenges remain. In this study, the Voltammetric In situ Profiler (VIP) was used for high temporal resolution in situ metal speciation measurements in estuarine waters. This instrument simultaneously determines Cd, Cu and Pb species within a size range (ca. <4 nm) that is highly relevant for uptake by organisms. The colloidal metal fraction can be quantified through a combination of VIP measurements and analyses of total dissolved metal concentrations.VIP systems were deployed over tidal cycles in a seasonal study of metal speciation in the Fal Estuary, southwest England. Total dissolved concentrations were 4.97–315 nM Cu, 0.13–8.53 nM Cd and 0.35–5.75 nM Pb. High proportions of Pb (77 ± 17%) and Cu (60 ± 25%) were present as colloids, which constituted a less important fraction for Cd (37 ± 30%). The study elucidated variations in the potentially toxic metal fraction related to river flow, complexation by organic ligands and exchanges between dissolved and colloidal phases and the sediment. Based on published toxicity data, the bioavailable Cu concentrations (1.7–190 nM) in this estuary are likely to severely compromise the ecosystem structure and functioning with respect to species diversity and recruitment of juveniles. The study illustrates the importance of in situ speciation studies at high resolution in pursuit of a better understanding of metal (bio)geochemistry in dynamic coastal systems.


► Submersible voltammeter enables study of metal speciation at high temporal resolution.
► Estuarine bioavailable Cu and Cd concentrations change sharply within tidal cycles.
► Exchange between dissolved and colloidal phase influences Cu and Cd bioavailability.
► Iron colloids act as sedimentary sink and source for Pb in estuary with mining history.
► Bioavailable concentration of Cu impairs recruitment of juvenile higher organisms.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemosphere - Volume 84, Issue 4, July 2011, Pages 423–431
نویسندگان
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