The significance of pollution from historic metal mining in the Pennine orefields on river sediment contaminant fluxes to the North Sea

Historic lead and zinc mining in the Northern Pennines, Yorkshire Dales and Peak District significantly affects water and sediment quality in river basins in the LOIS study area. Sediment-associated contaminant metals are transported, often in pulses or slugs, as suspended load under flood conditions. Although downstream decreases in metal concentrations are observed in the river systems, a substantial proportion of the metals have been incorporated into alluvial deposits. These in turn are, and will continueu to act, as a major secondary source of metal contaminants over many hundreds of years. These processes need to be taken into consideration when modelling riverine metal fluxes to the North Sea, to avoid overestimation of metal contaminants from industrial and urban sources, and underestimation of contaminants from these mining-related sources.