Nanoscale examinations on the sequestration of Cu by organic material in contaminated surface soils in Timmins, Ontario
Date
2018-07-24
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Abstract
The deposition and alteration of particulate matter (PM) in soils is a world-wide health concern.
This study investigates the fate of Copper in organic-rich surficial soil layers (0-5 cm)
contaminated by mining related activity at the Timmins Kidd Creek metallurgical site, Canada.
The sequestration and mobilization of Cu by organic material (OM) in the soil layer is investigated
using focused ion beam (FIB) technology and transmission electron microscopy (TEM). Copper
occurs as incidental metallic Cu and covellite (CuS) nanoparticles (NPs), formed via ion reduction
by humic substances and magnetite. Additionally, TEM analysis of the colloidal fraction, extracted
via ultracentrifugation from the surface soil layer, indicates the occurrence of incidental covellite
NPs in close association with dissolved OM. This study shows for the first time that Cu is
sequestered as incidental metallic Cu and covellite NPs within OM and magnetite in surficial
organic-rich soil layers. Furthermore, the mobility of Cu is facilitated through the transport of
covellite nanoparticles embedded within organic colloids.
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Keywords
metallic, copper, covellite, incidental, nanoparticles, particulate matter, transmission electron microscopy, organic material, humic substances, magnetite, mobile, sequester, Timmins, Kidd Creek