Abandoned metal mines and their impact on receiving waters: A case study from Southwest England

Abstract

Historic mine sites are a major source of contamination to terrestrial and river environments. To demonstrate the importance of determining the significance of point and diffuse metal contamination and the related bioavailability of the metals present from abandoned mines a case study has been carried out. The study provides a quantitative assessment of a historic mine site, Wheal Betsy, southwest England, and its contribution to non-compliance with Water Framework Directive (WFD) Environmental Quality Standards (EQS) for Cd, Cu, Pb and Zn. Surface water and sediment samples showed significant negative environmental impacts even taking account of the bioavailability of the metal present, with lead concentration in the stream sediment up to 76 times higher than the Canadian sediment guidelines 'Probable Effect Level'. Benthic invertebrates showed a decline in species richness adjacent to the mine site with lead and cadmium the main cause. The main mine drainage adit was the single most significant source of metal (typically 50% of metal load from the area, but 88% for Ni) but the mine spoil tips north and south of the adit input added together discharged roughly an equivalent loading of metal with the exception of Ni. The bioavailability of metal in the spoil tips exhibited differing spatial patterns owing to varying ambient soil physico-chemistry. The data collected is essential to provide a clear understanding of the contamination present as well as its mobility and bioavailability, in order to direct the decision making process regarding remediation options and their likely effectiveness.

Evaluating water quality and ecotoxicology assessment techniques using data from a lead and zinc effected upland limestone catchment

“…Metal bioavailability and toxicity have long been recognized to be a function of water chemistry (Paquin et al, 2002). Until recently environmental regulations considered only hardness-based conditions to derive EQS (Beane et al, 2016). However, latest research has increased understanding of the influence of physicochemical variables in metal speciation, and ecotoxicological studies have extended our knowledge of metal effects on biota.…”

Mining-contaminated estuaries of Cornwall – field research laboratories for trace metal ecotoxicology

“…The River Tavy has its own smaller upper estuary along the eastern side of the Bere Alston peninsula (Figure 2). The Tavy drains a mining region of Dartmoor just north of Tavistock, receiving, for example, the waters of the Cholwell Brook draining the Wheal Betsy Mine near Mary Tavy, a historic source of tin, lead, zinc and silver (Beane et al ., 2016). After passing through Tavistock, the Tavy drains the eastern end of the Gunnislake region and the eastern side of the Bere Alston peninsula.…”

Abandoned metalliferous mines: ecological impacts and potential approaches for reclamation

“…are exposed to very high concentrations of heavy metals (Pereira et al 2004;Ji et al 2011;Khalil et al 2013). Potentially toxic heavy metals present in the tailings or 'spoils' of abandoned mines migrate to the surroundings and cause severe and widespread contamination of farmland soils and water bodies including the geo-environment disasters (Wong 2003;Beane et al 2016;Ma et al 2016). Another endemic problem with abandoned and derelict mines is the generation of large-scale acidic waters containing elevated concentrations of metals and metalloids (Clarke 1995;Naidu et al 2013).…”