Reaction rates, depositional history and sources of indium in sediments from Appalachian and Canadian Shield lakes

Towards improving the electroanalytical speciation analysis of indium

“…(3.3). In this particular case the calibration linked Ecalib = −0.580V with Ycalib = 1.6×10 4 and the new gain for the experiment in presence of humic acids at Ed = −0.630V was Y = 3.3×10 6 . In this way, four decades of free indium concentrations are probed by the AGNES technique with reasonable equilibrium times (less than 10 min).…”

“…While measured total amounts of indium in freshwaters are usually low e.g. ranging from 1 to 15 pM in Japanese rivers [5], more abundant concentrations are found in (i) groundwaters, with reported values of 81 nM and 0.18 µM in Canada [6] and in a polluted site in Taiwan [7], respectively, (ii) acid mine drainage waters, where the amount may reach up to 0.25 µM [8] (iii), soils with measured average values of 0.15 µmol kg -1 [9] and (iv) sediments, with measured values ranging from 0.13 to 0.87 µmol kg -1 [10].…”

“…In recent years, there is a growing interest in the environmental fate [6,9] and toxicity [11][12][13] of indium, but they remain mostly unknown [4]. The aqueous geochemistry of indium is very close to other trivalent ions such as gallium and scandium, elements that are all heavily influenced by hydrolysis reactions [14].…”

“…hydroxides, carboxylate and phenolate groups. As for other metal cations, the fate of indium will likely be controlled by its interaction with natural organic matter (NOM) and/or with the mineral surfaces, mostly clays or iron hydro-oxides [15]. Since the understanding of metal speciation is considered as a key issue for evaluating the adverse effects of metallic contamination in natural ecosystems and especially in aquifers, and there are growing demands for on-site indium detection, robust and versatile techniques for laboratory set-up need to be urgently developed.…”

Impact of Galvanic Anode Dissolution on Metal Trace Element Concentrations in Marine Waters

“…The chemical analysis on the settled tank sediments and its interstitial waters showed a huge enrichment in Al, Zn, and In at the end of the experiment compared to values measured in the reference sediment tank (Table 2). These values largely exceeded the measured concentrations in superficial marine sediments, even in those impacted by human activities: 10-33 mg g -1 for Al, 24-167 μg g -1 for Zn, and 2.9 10−3-5.7 ng g -1 for In (Boughriet et al 2007;Duan et al 2010;Gabelle et al 2012;Santos et al 2005;Tessier et al 2014). These results demonstrated that the cathodic protection by galvanic anodes could strongly impact metal concentrations in the solid fraction.…”