Evolution of the Speciation and Mobility of Pb, Zn and Cd in Relation to Transport Processes in a Mining Environment

• DOI: 10.3390/ijerph17144912
• Publication Date: 2020-07-08T15:47:46Z
• Authors: Intissar Elmayel; José María Esbrí; García-Ordiales E...; Eva-María García-...; Zouhair Elouear; Bouzid Jalel; Alessandro Farieri; Nieves Roqueñí; Pablo Cienfuegos; Pablo Higueras
• Keywords: Genetic algorithm; Biota

Elements in mining extracts can be potentially toxic if they are incorporated into soils, sediments or biota. Numerous approaches have been used to assess this problem, and these include sequential extractions selective extractions. These two methods limitations advantages, their combined use usually provides a rough estimate of the availability (bio)availability elements and, therefore, real potential as toxicants food chains. indirect speciation data interesting absolute terms, but work described here, aspect was developed further by assessing evolution availability-related relation transport processes from emission source, which mainly fluvial- wind-driven. This objective achieved characterizing tailings samples source soils at increasing distances investigate certain elements. The standard procedures employed included five-step extraction with ammonium acetate. results show that highest percentages Zn Pb tailings, sediment associated oxyhydroxides, along significant presence resistant mineralogical forms. In case Cd, its association organic matter is second-most important trapping mechanism area. physicochemical mechanisms did not transform main associations (oxyhydroxides forms) transects, produced chaotic pattern for other minor matrix decrease exchangeable carbonate-bound forms soils. Interestingly, sediments, mobile showed Pb. most probable reason observations Zn2+ form smithsonite (ZnCO3) hydrozincite (Zn5(CO3)2(OH)6), explains retention soil transect. contrast, Cd appear different mineral phases. order > involved produce an increase (bio)availability. trend bioavailability on moving away (tailings), maximum values obtained near area (200–400 m).