Discontinuous Geochemical Monitoring of the Galleria Italia Circumneutral Waters (Former Hg-Mining Area of Abbadia San Salvatore, Tuscany, Central Italy) Feeding the Fosso Della Chiusa Creek

• DOI: 10.3390/environments8020015
• Publication Date: 2021-02-22T02:15:01Z
• Authors: Orlando Vaselli; Marta Lazzaroni; Barbara Nisi; Jacopo Cabassi; Franco Tassi; Daniele Rappuoli; Federica Meloni
• Keywords: Mercury; Cinnabar; Anhydrite

The Galleria Italia waters drain the complex tunnel system of former Hg-mining area Abbadia San Salvatore (Tuscany, central Italia) and feed 2.5 km-long Fosso della Chiusa creek. mining exploitation was active for more than one century 100,000 tons liquid mercury were produced by roasting processes cinnabar (HgS). In this work, a discontinuous geochemical monitoring circumneutral carried out from February 2009 to October 2020, during which main physicochemical parameters, minor dissolved species trace elements (including Hg) determined. observation period, significant variations in water chemistry recorded, particularly when flooding waves, due intense precipitations, occurred, with two events being recorded January 2010. chemical composition Ca(Mg)-SO4 related congruent dissolution gypsum/anhydrite at contribution carbonatic silicatic minerals partial solubilization CO2 H2S oxidation is be added. Regarding elements, Al, Mn Fe up 1500, 768 39520 μg L−1, these also showing high contents sediment precipitating waters. most cases, below instrumental detection limit (<0.1 L−1), although occasionally it reached >1 L−1. Considering mean flow rate 40 L s−1 discharged water, amount released computed, occurring (1.2 mg kg−1). A realistic computation should involve sampling network along before entering riverine Tiber basin, into suspended are determined that sediments.