2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference


Title
Arsenic bioremediation: Importance of sample preparation for environmental arsenic species identification.

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Author(s)
Mr. Saif Rafi, University of Saskatchewan (Presenter)
Dr. Kerry McPhedran, University of Saskatchewan
Dr. Ali Motalebi Damuchali
Dr. Aslan Hwanhwi Lee, University of Saskatchewan
Dr. Wonjae Chang, University of Saskatchewan
Dr. Raquibul Alam
Abstract

Industrial development and increasing anthropogenic activities such as mining continue to be of concern as they lead topollution of waters. Mine wastes contain heavy metals, such as arsenic, that can contaminate surface waters and groundwater. Arsenic is found in four oxidation states in species including inorganic and organic compounds that are dependent on the existence of sorbent materials, pH, redox potential, and microbial metabolic activity. The As(III)/As(V) states dominate in water given their solubility’s with As(III) being 10 times more toxic than As(V). Thus, knowing the specific arsenic species in wastes is important for understanding both their toxicity potential and for development of specific treatment technologies. The problem with determining arsenic speciation is the need for advanced analytical instruments for the analysis that are not readily available. Thus, suitable sample processing and storage procedures are vital to preserve the species from the time of sampling to analysis. Currently, we used three methods for preservation including: (1)no acid; (2)ethylene diaminete tetra acetic acid (EDTA); and (3) 2% nitric acid (HNO3). The overall objective of our research program is to investigate and mitigate arsenic from mine waste rock that will be stored in water in Saskatchewan, Canada, withfocus on bioremediation of arsenic at relevant in situ temperatures. Thus, the samples preserved we taken from these experimental reactors for the current study. Overall, the no acid treatment resulted in the most consistent speciation preservation for experimental samples. Interestingly, both standard method acid treatments resulted in unexpected oxidation of arsenic.