Iron Transport and Retention in Ochre-Rich Watercourses

Ferrous and ferric iron concentrations were determined over two years in an ochre-rich watercourse originating from ferruginous strata in the Bagshot Sands, some 40 km to the west of London. The watercourse comprised a bog, 3 km stream and 200 years old wetland/lake system. The data were used to interpret iron transport and retention characteristics of this system and, by comparison and inference, of analogous systems contaminated by iron from other environmental and post-industrial processes. Assessments were made of the effectiveness and longevity of the wetland/lake system as a sediment trap and of the likely ageing behaviour, if left unattended, of modern constructed wetlands treating similar ferruginous discharges from abandoned coal mines.