5. Conclusion
A few months after remediation, the potential positive effects on water contamination in the Baccu
Locci mine watershed are not yet visible. The presence of inflows from hidden sources must be better
investigated in the upper BLs course, where punctual As increases with respect to pre-remediation
conditions occur. In particular, further investigations are needed to exclude leaking from the Storage Site.
To quantify in-stream loads from the untreated As-rich lake water, its contribution should be evaluated
both in term of chemistry and discharge. Overall, it can be argued that the planned remediation actions
were affected by an underestimation of the widespread source of contamination represented by the
“hidden” flotation tailings. If the current situation remains unchanged in the coming years, other remedial
measures will be needed to attenuate As contamination.