Mitchell, A. C. and Brown, G. H. and Fuge, R. (2001)

Temporal Variations in the Minor and Trace Element Chemistry of Meltwaters Draining Haut Glacier d’Arolla, Switzerland: Implications for Downstream Water Quality

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58th Eastern Snow Conference, Ottawa, Canada
Concentrations of dissolved major ions in meltwaters draining glacial environments have been widely reported. However, minor and trace elements in outflow waters from glaciers have rarely been determined. Dissolved Al, Ti, Cr, Mn, Ni, Cd and U are present in meltwaters draining Haut Glacier d'Arolla at concentrations greater than the median composition of world stream waters. This suggests that river systems fed by glacierised headwaters may derive much of their dissolved minor and trace element load in the headwater region. Temporal variability in the concentrations of many dissolved minor and trace elements are inversely related to bulk discharge. However, instantaneous dissolved fluxes are positively correlated with discharge. Early meltseason waters are most concentrated in dissolved minor and trace elements. However, their contribution to the annual dissolved flux of minor and trace elements to downstream environments is small, since discharge is low. Conversely, maximum instantaneous dissolved fluxes occur in early August when annual discharges are at a maximum. Estimates of dissolved minor and trace element fluxes from Haut Glacier d’Arolla suggest that ~ 90% of the annual total is transported between mid-May and late-September. The enrichment of many of these elements in glacial meltwaters compared to world streamwaters, coupled with the timing of their delivery to downstream areas during the summer months, may have significant environmental implications.