Effects of Mine Waste Dumps on the Exchange Processes of Potentially Toxic Elements at the Water/Sediment Interface in an Abandoned Sulfide Mine.

Abstract

Caveira's mine, an abandoned sulfide Cu-Pb-Zn-Ag-Au mine, is situated in the southern part of the Iberian Pyrite Belt in Portugal. Historically exploited since the period of Roman Empire, the mine was ultimately abandoned in the late 1960s without any implementation of environmental remediation strategies. In February 2023, following a prolonged drought and subsequent rainfall, samples of sediment, water, and interstitial water were collected. This study specifically selected samples influenced by mine waste piles to investigate chemical exchanges at the sediment/water interface in a sulfide-rich environment. The objectives are to (i) compare the chemical composition of water and sediment, (ii) correlate potentially toxic elements (PTE) concentrations in sediments and water to elucidate the linear relationships among PTE, and (iii) identify the most effective approach for sediment reclamation.