## 1 Introduction  
The worldwide sources of heavy elements in surface environments mostly originate in mining activities such as mine exploitation, ore processing and waste disposal in land-fills [1]. According to [2, 3], tailings accumulated during ore processing have often been stored in steep piles prone to erosion, thus becoming a potential pollution source for the surrounding environment. The impact of mine waste on the environment can pose serious risks since it can contain reactive mineralogical phases able to generate acidic drainage (e.g., [4, 5]) and release toxic elements to the surface and groundwater systems [6, 7].  
In contaminated soils, heavy metals can be mobilized and transferred to surface and ground waters and absorbed by soil biota [8, 9]. According to [1], mobilization of heavy metals is affected by several factors, e.g., redox potential, pH, and bacterial activity.  
Specifically, in soils heavy metals can be: (1) associated with water-soluble phases; (2) adsorbed on the surface of solid phases (e.g., clay minerals, organic compounds); (3) related to acid-soluble solid phases (e.g., carbonates) by precipitation and/or co-precipitation; (4) fixed to the surface of reducible solid phases, such as Fe-oxy-hydroxides; (5) bound to insoluble organic matter, e.g., humic acids, or precipitated and/or co-precipitated such as sulfides and (6) included in the crystalline lattice of minerals, stable in soils as residual and newly formed minerals.  
The Mt. Amiata district (central Italy) has been classified as the fourth largest producing Hg-district ([10], and references therein). According to [11], in 1925 about 50% of mercury worldwide was provided by the Mt. Amiata mining areas, and about 70% of it was from the Abbadia San Salvatore (ASS) mine (Figure 1).  
Several presently-inactive mines are distributed in the Mt. Amiata district [12,13] from where cinnabar(HgS)-rich ore deposits were exploited, although they also contained As-Sb sulfides [1,14]. The origin of Hg mineralization in this area was interpreted as being due to shallow hydrothermal convective systems related to geothermal anomalies that, in turn, were associated with the emplacement of granitoid rocks in the mid- and upper-crustal levels of southern Tuscany during the Pliocene-Pleistocene [15,16]. The ascent of hydrothermal fluids and the consequent emplacement of hydrothermal breccia bodies also allowed the formation of Hg-rich ore deposits in argillitic and calcareous levels [1]. The circulating hydrothermal fluids favored the precipitation of cinnabar and Sb- and As-(e.g., realgar: As\({}_{4}\)S\({}_{4}\))-sulfides. The Hg-rich ore deposits were exploited from the nineteenth century until about forty years ago [17,18].  
In this paper, we present and discuss the geochemical results obtained from the toposils developed on the waste material from Le Lame mining landfill. In addition to mercury (Hg), arsenic (As) and antimony (Sb) were also considered because these heavy metals are usually associated with Hg-mineralized areas in Tuscany [18]. The main goals of this study were aimed at: (1) determining the total amount of Hg, As and Sb in 35 waste toposils; and (2) quantifying the release of Hg, As, and Sb from leaching tests carried out with CO\({}_{2}\)-saturated Milli-Q water, and comparing the data with those reported by the Italian Legislative Decree 152/2006 for drinking waters; (3) assessing the speciation of As, Hg, Sb and (4) defining whether the three chalcophile elements were preferentially partitioned in solution or were co-precipitating with other minerals. Such simulations were carried out by the PHREQC geochemical code.