Trace elements leaching from Pb Zn mine waste (Plombières, Belgium) and environmental implications

Abstract

The geochemical and mineralogical characterization of mine waste provides essential information to understand the environmental and health impacts and to adequately manage present and historical mine waste sites. In the present study, mine waste samples from a former Zn-Pb mining site were subjected to different types of leaching tests, an in-vitro bioaccessibility test, and a mineralogical analysis. The samples were characterized by elevated pseudo-total Pb (up to 51,800 mg/kg), Zn (up to 60,100 mg/kg), Cd (up to 430 mg/kg), and As (up 3,170 mg/kg) concentrations, and contained, among other minerals, cerussite (PbCO 3 ) and galena (PbS). Lead is not only present in abundant concentrations, but also in highly bioaccessible forms, as determined from the in-vitro bioaccessibility test. This indicates the high risks

Geochemical and Mineralogical Characterisation of Historic Zn–Pb Mine Waste, Plombières, East Belgium

“…This was confirmed by the macroscopic description of the materials made during the sampling campaign, and by the shapes and textures observed by scanning electron microscopy (SEM) (Figure 10c). Helser and Cappuyns (2020) came to the same conclusion about the amorphous phases being slags when studying materials from Plombières [8].…”

“…They concluded that the highest leaching of metal(loid)s occurred under acidic and highly alkaline conditions, while metal(loid) leaching was low in neutral and alkaline conditions. The highly acidic and alkaline pHs are not likely to occur in a natural environment [8], and therefore, the potential for acidic and metal-rich waters leaching from the Plombières mine site is low. Overall, the mineralogical results are consistent with the geochemical analyses for all material types.…”

“…Not only this, but the often-high heavy metal content of tailings combined with the propensity for sulphidic-rich tailings materials to produce acid mine drainage (AMD) means that tailings could also pose a significant risk to the environment [6,7]. Furthermore, mine wastes represent a potential risk for humans, as the contained metals and metalloids (e.g., Pb, Cr, Cd, As) can enter the human body via inhalation, digestion or even direct contact, to contribute towards a range of illnesses [8,9].…”

“…However, there are often multiple mine waste or tailings dumps of the same or similar material at a single historical mine site. Historical mining regions have the potential for economic recoverability of metals and re-use of material and often show high risk to the environment [8]. When combining these vast quantities of mine wastes with the potential for both economic recovery of metals and environmental pollution, it is of great importance to investigate historic tailings, particularly in Europe, where there is a long legacy of mining, in order to contribute to a more sustainable circular economy [2,5,11].…”

Solid-Phase Partitioning and Leaching Behavior of Pb and Zn from Playground Soils in Kabwe, Zambia

“…The correlations between the leachable water-soluble Pb and Zn with the exchangeable, labile phases and the total content suggests that the release of Pb and Zn into the environment from the SPs was mainly attributed to the exchangeable phase and not so much from the total content of Pb and Zn (Figures S2 and S3). In addition, the Pb bound to carbonate phase is usually influenced by the pH of the environment; for example, under gastric conditions, cerussite (PbCO3) might significantly dissolve in the acidic conditions [43], which increases the bioaccessibility of ingested PTEs. However, the present study could not identify the host minerals for the PTEs; electron microprobe analysis might be a possible approach to identifying the mineral phases [44].…”