RESEARCH ARTICLE
An eco-friendly method for heavy metal removal from mine tailings
Fereshteh Arab
1
&
Catherine N. Mulligan
1
Received: 20 October 2017 / Accepted: 13 March 2018 /Published online: 29 March 2018
#
Springer-Verlag GmbH Germany, part of Springer Nature 2018
Abstract
One of the serious environmental problems that society is facing today is mine tailings. These byproducts of the process of
extraction of valuable elements from ores are a source of pollution and a threat to the environment. For example, mine tailings
from past mining activities at Giant Mines, Yellowknife, are deposited in chambers, stopes, and tailing ponds close to the shores
of The Great Slave Lake. One of the environmentally friendly approaches for removing heavy metals from these contaminated
tailing is by using biosurfactants during the process of soil washing. The objective of this present study is to investigate the effect
of sophorolipid (SL) concentration, the volume of washing solution per gram of medium, pH, and temperature on the efficiency
of sophorolipids in removing heavy metals from mine tailings. It was found that the efficiency of the sophorolipids depends on its
concentration, and is greatly affected by changes in pH, and temperature. The results of this experiment show that increasing the
temperature from 15 to 23 °C, while using sophorolipids, resulted in an increase in the removal of iron, copper, and arsenic from
the mine tailing specimen, from 0.25, 2.1, and 8.6 to 0.4, 3.3, and 11.7%. At the same time, increasing the temperature of
deionized water (DIW) from 15 to 23 °C led to an increase in the removal of iron, copper, and arsenic from 0.03, 0.9, and 1.8 to
0.04, 1.1, and 2.1%, respectively. By increasing temperature from 23 to 35 °C, when using sophorolipids, 22% reduction in the
removal of arsenic was observed. At the same time while using DI water as the washing solution, increasing temperature from 23
to 35 °C resulted in 6.2% increase in arsenic removal. The results from this present study indicate that sophorolipids are
promising agents for replacing synthetic surfactants in the removal of arsenic and other heavy metals from soil and mine tailings.
Keywords Mine tailing
.
Heavy metals
.
Metalloids
.
Bioremediation
.
Biosurfactants
.
Sophorolipids
Environmental Science and Pollution Research (2018) 25:16202–16216
https://doi.org/10.1007/s11356-018-1770-3
Introduction
Environmental pollution is a major concern, and if steps are
not taken to solve this problem, it will have dire consequences
for the future of our planet. Mine tailings are considered one of
the major environmental contamination sources (Dushenko
et al. 1995). In a report by Nriagu and Pacyna (1988), 22%
of the arsenic released to the environment could be traced
directly back to the mining and metallurgy industries. In the
process of mining and extracting valuable minerals, some of
the heavy metals and metalloid byproducts are released into
the air and water, and the rest remain in sulfide minerals,
discarded as mine tailings. These sulfide minerals are unstable
under typical atmospheric conditions (Paktunc 2013). After
some time, oxidation and microbial activity within the mine
tailings convert the sulfide compounds and make the mine
tailings acidic, thus making metals/metalloids more soluble
and producing acid mine drainage (AMD). Although the
presence of neutralizing minerals, such as dolomite, cal-
cite, and siderite can reduce/delay the acid generation
(Smedley and Kinniburgh 2002), heavy metals and metal-
loids can migrate to surface and groundwater after runoff
by precipitation or overflowing rivers. This pollutes a
greater area and puts the health of more inhabitants in
jeopardy. Although the release of some elements, such as
arsenic, has been associated with the generation of AMD,
there have been reports of the release of arsenic in neutral
and alkaline conditions as well (Razo et al. 2004).
Mine tailings from the historical gold mine, Giant Mine,
Yellowknife, NWT, Canada, are deposited in large tailing
ponds near the shores of The Great Slave Lake. It has been
estimated that mine tailings produced during the 50 years of
mining activities in the Giant Mine in Yellowknife contain a
quarter-million tons of arsenic. The concentrations of heavy
Responsible editor: Philippe Garrigues
* Catherine N. Mulligan
mulligan@civil.concordia.ca
1
Department of Building, Civil, and Environmental Engineering,
Concordia University, Montreal, Quebec, Canada
@Phil_Robichaud
@deepthiw
@JoseServera