Page 25 - Materials Chemistry, Second Edition

6 Life Cycle Assessment of Wastewater Treatment

1.3.1.5 Arsenic
Arsenic is an unhealthy heavy metal, which is found extensively in the earth’s crust
and also in the deeper regions of the earth (El-Moselhy et al., 2017). Basically, this
toxic heavy metal is released into our ecosystem through natural activities, such as
volcanic eruption and leakage of arsenic from deposits in the earth’s crust, and also
some anthropogenic activities, such as pesticide production, glass production, min-
ing of metals, the metallurgical industry, and increasing amounts of municipal waste
(Jia et al., 2016; Heppa et al., 2017). As arsenic is abundantly found in nature, it has a
higher possibility of affecting living beings by entering into their food chain through
air, water, and soil (Kampouroglou and Economou-Eliopoulos, 2017). According to
the directions of the WHO, the acceptable limit of arsenic in drinking water is 10 µg
L . Arsenic is one of the heavy metals that even in minute concentrations can cause
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serious damage to living beings (Ali et al., 2016).
1.3.1.6 Chromium
Chromium is an important heavy metal, used across the board in several industries,
and hence, the concentration of chromium in the environment is increasing due to
the untreated release of chromium into nearby water bodies and inadvisable storage
of chromium waste by the industries. Of the different forms of chromium, it has been
found that hexavalent chromium (+VI) is the most toxic to living beings, and it is
easily transportable (Gheju et al., 2017). Chromium stands out among the most infa-
mous excess metals discharged by different businesses: for example, the tanning and
calfskin businesses, the electroplating industry, fabricating enterprises, fungicides,
earthenware production, creates, glass, photography, impetus, and colors (Dehghani
et al., 2016). USEPA has strictly established the allowable limit of Cr(VI) ions in
shallow water as 0.1 mg L and in drinking water as 0.05 mg L (Rangabhashiyam
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and Selvaraju, 2014).
1.3.1.7 Zinc
Zinc is a prudential heavy metal, often used in industrial practices among other
heavy metals such as iron, aluminum, and copper. It is generally used as a part
of several applications, for example, in metallurgy, development, electrical and
chemical divisions, and oil businesses, because of its resistance to erosion and its
trademark mechanical properties. Due to the unique molecular nature of zinc, it is
widely used in the dye industries in pigments to reduce corrosion, and it is also used
to increase the reaction speed of chemical reactions (Ebin et al., 2016). According
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to the WHO regulations, the desirable limit of zinc in drinking water is 5 mg L
(Kumar and Puri, 2012).
1.3.1.8 Copper
Copper is a significant heavy metal that is dangerous to human wellbeing and its
aura. It is used generally in industry and is accumulating in nearby water bodies
(Al-Harahsheha et al., 2015). Copper ions are discharged into nature by means of
distinctive industrial activities such as mining, electroplating, oil refining, manure
production, wood mash, breaking down of rocks, and metal purifying and composite
producing units. On the one hand, copper ions are fundamental to the good health of