Industrial mining heritage and the legacy of environmental pollution in the Derbyshire Derwent catchment: Quantifying contamination at a regional scale and developing integrated strategies for management of the wider historic environment

The Derwent Valley Mills World Heritage Site (DVMWHS) exemplifies and records the 18th century birth of the factory or mill technology for the industrial spinning of cotton. The site is therefore a key global heritage asset. The Derbyshire Derwent catchment also contains another significant cultural asset with a long history - that of mining and, in particular, lead (Pb) mining. In this paper research on mining- and non-mining related Pb contamination of the Derwent catchment is reviewed and used to identify the risks it poses to the DVMWHS. The upper Derwent soils, though not impacted by mining, have high sediment-borne Pb concentrations, and the Pb is sourced from local conurbations (principally Manchester) and carried to the upper Derwent on the wind. River sediments in the middle and lower parts of the Derwent catchment are contaminated with Pb mined mainly between the 18th and 19th centuries and before, possibly as far back as the Bronze Age. The potential for large-scale, acidity-related chemical remobilization of this Pb is low in the Derwent catchment due to the largely alkaline nature of the underlying soils, but the potential for oxidation-reduction-related, and physical (flood-related), remobilization, is higher. Management guidelines for mining heritage assets and the DVMWHS are developed from the reviewed information, with the view that these will provide a framework for future work in, and management of, the DVMWHS that will be applicable to other World Heritage Sites affected by ongoing and past metal mining. Focused collaborative work between archaeologists, geochemists, geomorphologists and mineralogists is vital if the risks to the DVMWHS and other similarly-affected World Heritage Sites are to be quantified and, if necessary, mitigated.