Heavy metal content of meltwaters from the Ross Dependency, Antarctica

Abstract

Twenty-eight meltwater samples were collected from Scott Base, Cape Evans, Cape Royds, Marble Point, Vanda Station, and along the length of the Onyx River, in the McMurdo Sound area of Antarctica during the summers of 1992/93 and 1993/94. Samples were analysed for major components, and for heavy metals at ultra-trace levels. The sample sites included biologically active ponds, glacier melt water, lake water, roadside drains, and rivers. Sample salinities varied widely, but heavy-metal concentrations were uniformly low except where significant human impacts would have been expected. Concentrations of silver, mercury, lead, copper, cadmium, chromium, nickel, and zinc were higher at Scott Base than in the other areas and were dominantly associated with coarse particulates. Natural sources of metals may be local lithology, but chemical and mechanical processes within the soils and solutions affect the distributions of different metals.

Opal (Zn/Si) ratios as a nearshore geochemical proxy in coastal Antarctica

“…Field studies based in the Alps show that subglacial water can be a significant source of Zn to stream waters [ Mitchell et al , 2001]. There are limited data for Antarctica, but one study in the Ross Sea showed elevated Zn content of glacial meltwater [ Sheppard et al , 1997]. A simple mass balance model can be used to assess the impact of freshwater inputs on total Zn concentrations (), where f FRESH is the fraction of meltwater, S FRESH is the salinity of freshwater (taken as 0.5), and S CDW is the salinity of UCDW (taken as 34.6) [ Meredith et al , 2008].…”

Comparative roles of upwelling and glacial iron sources in Ryder Bay, coastal western Antarctic Peninsula

“…Basal ice estimates from the Northern Hemisphere indicate a sediment load~80-400 times greater than "clean" ice (Raiswell et al, 2006, and references therein). Glacial runoff has been sampled in the Dry Valleys, Antarctica, with dFe concentrations of 1.1-3450 μM (Sheppard et al, 1997;Green et al, 2005;Mikucki et al, 2009). Thus if even a small proportion of the meteoric water is derived from basal ice or runoff, the estimate of glacial Fe input would increase significantly.…”

Heavy metal pollution in Antarctica: a molecular ecotoxicological approach to exposure assessment

“…For the most part, metals in the nearshore sea water and marine sediments of Antarctica are likely to reflect local lithology although chemical and mechanical processes may affect their distribution (Sheppard et al, 1997). Basaltic volcanic rocks dominate marine sediments around Ross Island with enrichment in Ni, Fe, Cu and Cr and depletion of Pb and Cd (Kennicutt et al, 1995), although there may be perturbation of local marine chemistry in the vicinity of research bases.…”