Diel changes in water chemistry in the Baccu Locci stream (Sardinia, Italy) affected by past mining

Diel variations in dissolved As and Zn concentrations in the Baccu Locci stream (Sardinia, Italy), affected by past mining, were studied. Sorption/desorption to/from streambed material, in particular ferrihydrite, is believed to be the main process controlling the diel cycles of trace elements. Another possible process that deserves an in-depth assessment is co-precipitation of As and Zn with calcite. Both processes should be carefully considered to assess the effectiveness of remediation actions currently in progress at Baccu Locci.