Risk assessment and remediation of contamination in legacy mine sites: experiences from Cartagena-La Union (SE Spain

Resumen

The legacy mining site of Cartagena-La Union in SE Spain posesconsiderable threat to human health, safety and the environment. Largeamounts of wastes characterised by high concentration of metals (mainlyAs, Cd, Pb and Zn) and poor conditions for plant development arespread over an area characterised by low rainfall and high erosion andevapotranspiration rates. The Sustainable Use, Management andReclamation of Soil and Water Research Group (GARSA) atUniversidad Politécnica de Cartagena (Spain) has a long history indealing with such issues. The approaches comprise the characterisationof the contamination, evaluation of the environmental/human health riskand proposal of remediation solutions. This manuscript introduces to theenvironmental and human health risk related to the legacy miningdistrict of Cartagena-La Union in SE Spain. Our aim is to provide anoverview of the research activity of the GARSA group (past, present andfuture) to respond to such challenge. We have a long-term activity in thecharacterisation of tailings ponds in mine sites and assessment of theirenvironmental and health risk. New approaches involve the use of fieldspectroscopy techniques (i.e. X ray fluorescence and infraredspectroscopy) for better, quicker and cheaper access to tailings pondscharacterisation and condition. We have been involved in a number ofprojects related to the restoration mine and processing sites. One of thefocuses has been related to the development of Technosols from miningwastes following the amendment with different by-products. This hascomprised both laboratory and real-scale restoration projects, and monitoring the latter. We have recently demonstrated that biochar andmarble waste amendments improve mine waste structural stability whichresults in a strong impact in reclaiming the physical quality of minetailings. We are currently evaluating plant effect in the evolution ofproperties of those Technosols and metal retention (phytostabilisation).In summary, this manuscript shows results of studies that havesuccessfully helped to solve or improve our understanding aboutcomplex issues observed in the mining district of Cartagena-La Union