Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Burgess, W. G. Articles by Pinto, L. Search for Related Content GeoRef GeoRef Citation

Preliminary observations on the release of arsenic to groundwater in the presence of hydrocarbon contaminants in UK aquifers

W. G. Burgess^* and L. Pinto

Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK

^* E-mail: william.burgess{at}ucl.ac.uk

Degradation of contaminant hydrocarbons in groundwater by microbially mediated oxidation, linked to the reduction of electron acceptors, is fundamental to the strategy of ‘monitored natural attenuation’ (MNA) for oxidizable hydrocarbons, which is increasingly being adopted at polluted aquifer sites throughout Europe and North America. Commonly, oxygen is depleted and following the reduction of nitrate, solid-phase Fe oxides become the dominant electron acceptors. Arsenic, associated with Fe and Mn oxides in soils and sediments, may therefore be mobilized to groundwater and pose an additional threat to environmental receptors. In a pilot study of three aquifers in England, we have examined the extent to which arsenic is released to groundwater under Fe(III)-reducing conditions imposed by contaminant hydrocarbons. Results show that arsenic is locally mobilized in the Chalk to <10 µg/l, in Quaternary gravels to 70 µg/l and in the Triassic sandstones to 160 µg/l. At the Chalk and Quaternary gravels sites arsenic mobilization is demonstrably linked to reduction of Fe- and Mn-oxides. This is not so at the Triassic sandstone site, where release of arsenic is related to elevated bicarbonate alkalinity. Redox-driven arsenic mobilization at other Triassic sandstone locations is possible. Further work is required on the solid-phase sources of arsenic in the aquifers, and to relate the hydrochemical observations to groundwater hydraulic conditions.

KEYWORDS: hydrocarbons, Chalk, Quaternary, arsenic, groundwater, aquifer, microbes

This article has been cited by other articles:

				E. Valsami-Jones, D. A. Polya, and K. Hudson-Edwards Environmental mineralogy, geochemistry and human health Mineralogical Magazine, October 1, 2005; 69(5): 615 - 620. [Full Text] [PDF]