Keywords Toxicity pathways · Bioremediation · Bioseparation · Toxic metals ·
Bioengineering · Enzyme kinetics
1 Background
Metals are used in industrial processes either as structural components such as steel
or as additives for modification of strength properties, corrosion resistance, and
control of chemical reactions and for ornamental purposes. Metals such as chromium
(Cr) and radium (Rd) have been used in the making of paints and pigments, wood
preservation, and luminescence in displays (Beszedits 1988). Addition of metals and
carbon compounds is critical in the formation of stronger alloys that are less
susceptible to corrosion. For example, metals such as chromium, silver, and tin
have been widely used to give steel a polished silvery mirror coating or to galvanize
it against corrosion. Ornamental use of Cr and Pb includes the production of emerald
green (glass) and synthetic rubies in the case of Cr (Morrison and Murphy 2010) and
giving glass a reddish tinge in the case of Pb (Francis and Croft 1849). The discovery
and utilization of metals by humans is so important such that at least three of the
human eras of civilization have been named after a metal, i.e., iron age, bronze age,
and nuclear age. One evolutionary epoch, the Anthropocene age, is associated with
the humans’ ability to harness the power of the atom through fission of the uranium
atom which is also loosely associated with our ability to impact the global climate
(Wilke and Johnstone 2017).
The production of metals and utilization of dissolved metals typically produces
contaminated wastewater (Goutam et al. 2018; Bharagava et al. 2017a; Gautam et al.
2017; Saxena and Bharagava 2015; Saxena et al. 2016). Metals can serve as oxidants
or reductants in environmental systems resulting in damage to cells or inhibition of
cellular processes (Jaishankar et al. 2014). At high concentrations, metals such as
Cr, U, Pb, Hg, Se, and As can cause acute toxicity resulting in death of organisms
(Chirwa and Molokwane 2011; Mtimunye and Chirwa 2013; Brink et al. 2017;
Bansal 2010; Wessels 2017). At low concentrations, metals can cause mutagenicity,
carcinogenicity in organisms, and teratogenicity in mammals (Flessel 1979). For this
reason, all national and international environmental regulatory organizations place
stringent regulations on the disposal of metals to the environment (Federal Register
2014; Hiz and Aki 2015; Gao et al. 2014; ACGIH 2004).
2 Mining of Ores and Environmental Impacts
During the mining operation for any particular metal, the target metal is extracted
together with several metal pollutants from geological seams. For example,
chromium is mined from seams containing trace amounts of platinum group
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E. M. Nkhalambayausi-Chirwa et al.
Bioengineering · Enzyme kinetics
1 Background
Metals are used in industrial processes either as structural components such as steel
or as additives for modification of strength properties, corrosion resistance, and
control of chemical reactions and for ornamental purposes. Metals such as chromium
(Cr) and radium (Rd) have been used in the making of paints and pigments, wood
preservation, and luminescence in displays (Beszedits 1988). Addition of metals and
carbon compounds is critical in the formation of stronger alloys that are less
susceptible to corrosion. For example, metals such as chromium, silver, and tin
have been widely used to give steel a polished silvery mirror coating or to galvanize
it against corrosion. Ornamental use of Cr and Pb includes the production of emerald
green (glass) and synthetic rubies in the case of Cr (Morrison and Murphy 2010) and
giving glass a reddish tinge in the case of Pb (Francis and Croft 1849). The discovery
and utilization of metals by humans is so important such that at least three of the
human eras of civilization have been named after a metal, i.e., iron age, bronze age,
and nuclear age. One evolutionary epoch, the Anthropocene age, is associated with
the humans’ ability to harness the power of the atom through fission of the uranium
atom which is also loosely associated with our ability to impact the global climate
(Wilke and Johnstone 2017).
The production of metals and utilization of dissolved metals typically produces
contaminated wastewater (Goutam et al. 2018; Bharagava et al. 2017a; Gautam et al.
2017; Saxena and Bharagava 2015; Saxena et al. 2016). Metals can serve as oxidants
or reductants in environmental systems resulting in damage to cells or inhibition of
cellular processes (Jaishankar et al. 2014). At high concentrations, metals such as
Cr, U, Pb, Hg, Se, and As can cause acute toxicity resulting in death of organisms
(Chirwa and Molokwane 2011; Mtimunye and Chirwa 2013; Brink et al. 2017;
Bansal 2010; Wessels 2017). At low concentrations, metals can cause mutagenicity,
carcinogenicity in organisms, and teratogenicity in mammals (Flessel 1979). For this
reason, all national and international environmental regulatory organizations place
stringent regulations on the disposal of metals to the environment (Federal Register
2014; Hiz and Aki 2015; Gao et al. 2014; ACGIH 2004).
2 Mining of Ores and Environmental Impacts
During the mining operation for any particular metal, the target metal is extracted
together with several metal pollutants from geological seams. For example,
chromium is mined from seams containing trace amounts of platinum group
22
E. M. Nkhalambayausi-Chirwa et al.