a1 Department of Geography, University College of Wales, Aberystwyth, Cardiganshire.
During the nineteenth century several parts of Wales were intensively mined for lead, zinc and copper ores. Fields adjacent to and downstream from the mines became contaminated by air- and water-borne heavy metal compounds. Such fields still contain high concentrations of total lead, zinc and copper together with silver and cadmium, the chief ‘guest’ elements in lead and zinc ores. Extraction of the soils with dilute acetic acid suggested that contaminated soils contained more of these metals that were available to plants (Alloway, 1969; Alloway & Davies, 1971). Some studies of plant composition were made to confirm the evidence from soil extraction and to indicate the extent to which these metals were entering the food chain.
(Received November 09 1970)
p1 Present address: Applied Geochemistry Research Group, Geology Department, Imperial College, London, S.W. 7.