Arsenic distribution in the UK lake sediments

Abstract
Sediment cores were taken from six sites across the UK. Apart from Banbury Reservoir in London, all the other sites were relatively remote lakes. Arsenic, along with other chemical elements, was analysed in the sediments of all the cores. Arsenic concentrations in the surface sediments are high in most of the sites and up to 800  g g ^-l in a Welsh remote site, Llyn Llagi. The background (pre-industrial) values vary in different sites from about 1.2  g g ^-l in Lochnagg to about 53  g g ^-l in Llyn Llagi. The concentations of Fe and Mn strongly correlate with As, suggesting that Fe and Mn may control As distribution in the sediments at these sites. Arsenic in sediment trap samples taken from the lakes were also measured showing much higher concentrations than the background values at individual sites (1.6 - 8.6 enrichment factor), but lower than those in the surface sediments at most sites. This suggests anthropogenic As input to the lakes and the influence of post-sedimentation processes on As distribution in the surface sediments. In Lochnagar, there bas been a significant increase in the As content in annual sediment trap samples. This important signal needs to be confirmed.