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.

Surface sediment samples (60 µm-2 mm, and < 60 µm fractions) from the Waiwhetu Stream, Lower Hutt City, New Zealand, were leached with dilute HC1 to remove the mobile heavy-metal fraction. Cd, Cr, Cu, Pb, Zn, Al, Fe, and Mn analyses of the leachates show that sediments of the upper reaches area of the stream are generally uncontaminated. In contrast, sediments in the lower reaches area are highly contaminated, despite clean-up measures in the late 1970s. Lead and Zn are the most significantly enriched metals with concentrations over 1000 mg kg -1 adjacent to some drains. In the polluted zone, metals originate from either upward remobilisation from underlying sediment (contaminated in the early 1960s and 70s) or more recent industrial spillages. Similar trends exhibited by Cd, Cu, Cr, Zn, Pb, and Al indicate that a proportion of the metal enrichment downstream probably results from a naturally higher clay content of sediments near the mouth of the stream. Fe and Mn show reverse trends to the other metals, indicating that a high proportion of these two metals occurs in substrate different to that of the other metals. The orange brick-coloured sediments of the upper reaches of the stream indicate oxides upstream; the black sediments in the lower reaches indicate sulphides downstream. M92020