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Bioremediation for Sustainable Environmental Cleanup

Table 9.1. Metal(loid)s sources and toxicity to humans.

Metal and

Metalloids

Toxicity to human

Sources

References

Arsenic (As)

Carcinogenesis, cardiac

dysfunction, skin infection,

lung damage, gastrointestinal

problems

Paints, timber, pesticides industries, natural/

geogenic process, thermal, geothermal,

smelting operation, burning fuels

Chandra et al. 2017,

Lone et al. 2008,

Gupta and Kumar 2017

Lead (Pb)

Mental disorders, kidney

damage and affecting the

nervous system

Metal products, electronic waste, petroleum

additives, thermal power plants operated

with coal, Bengal and ceramic industries

Chandra et al. 2017,

Lone et al. 2008,

Gupta and Kumar 2017

Cadmium

(Cd)

Renal disorders, carcinogens

and bone degeneration

Electronic industries, smelting and

electroplating industries, paint industries

Chandra et al. 2017,

Lone et al. 2008,

Gupta and Kumar 2017

Copper (Cu)

Wilson disease, liver damage

and insomnia

Electroplating, mine industries, timber,

electronic waste, paint and pigment

industries

Chandra et al. 2017,

Lone et al. 2008,

Gupta and Kumar 2017

Chromium

(Cr)

Allergic reaction, dermal

infection, carcinogen, DNA

mutation, gastrointestinal

hemorrhage

Leather industries, chromium salt

industries, dye industries, pesticides, timber

Chandra et al. 2017,

Lone et al. 2008,

Gupta and Kumar 2017

Manganese

(Mn)

The steel industry, municipal

wastewater, fertilizers

industries

Cardiovascular, respiratory and central

nervous disorder

Chandra et al. 2017,

Lone et al. 2008,

Gupta and Kumar 2017

Mercury (Hg)

Mental retardation, deafness,

blindness and kidney damage

E-waste, medical waste, thermal power

plant and geothermal, fumigants

Chandra et al. 2017,

Lone et al. 2008,

Gupta and Kumar 2017

Nickel (Ni)

Cardiovascular damage,

chronic asthma, nausea

Thermal power plants, smelting operations,

e-waste, alloys, battery industries

Chandra et al. 2017,

Lone et al. 2008

contamination with meta(loids). The biosolid treatment has little effect on Ni and Cr contents in

soil (Illera et al. 2000). The occurrence of these metals in biosolids caused a significant rise in Zn,

Cd, Cu and Pb levels. It has been noticed that grazing and immobilization of soil are harmful to the

soil’s microflora. It can rise the concentration of metal(oids) Zn, Pb and Cu whereas decreasing C

and N in plants, animals and soil microbes (Haynes et al. 2009, Kao et al. 2006). Various metals and

metalloid sources and their toxicity to human beings are shown in Table 9.1.

9.3 Heavy Metal(loid)s Reaction Mechanisms

Prior knowledge of the reaction mechanism between the binder substrate and metalloid is necessary

for the development of sustainable treatment technology. The existing report confirms that the reaction

mechanism plays a vital part in metalloid removal (Park et al. 2011). These detailed mechanisms will

help in better understanding and development of technologies for real environmental applications.

The systematic research on the metalloid’s removal mechanisms is discussed below.

9.3.1 Adsorption

Adsorption, according to Sposito (1984), is the accumulation of a solute at the interface between

a liquid solution and a solid. The process of forming a chemical connection with metal ions on

the surface of adsorbents is known as adsorption. The adsorption is categorized dominantly into

two sets, i.e., specific adsorption and non-specific (Bolan et al. 2014). By using functional groups,

specific adsorption binds the solute to the adsorbents (Sposito 1984). Solutes are bound by non­

specific adsorption through electrostatic attraction (Bolan et al. 2014). The adsorbent’s properties