• The shallow-rooted plants are preferred for surface contamination of soil and
water.
3 Heavy Metal Toxicity
3.1 Definition
The heavy metals are defined as the elements or components which rectify the
properties of metal and possess an atomic number greater than 20. Metals are
naturally occurring elements found in soil. However, when the normal level exceeds,
the metal can be toxic to animals, plants, and microbes (Lasat 2000). The more
common and principal heavy metals which account to the contamination of the
environment include arsenic (As), Strontium (Sr), Caesium (Cs), Uranium
(U) (Raskin et al. 1997), Mercury (Hg), Chromium (Cr), lead (Pb), Manganese
(Mn), Nickel (Ni), Cobalt (Co), Cadmium (Cd) Lead (Pb) and zinc (Zn) (Raskin
et al. 1997; Lasat 2000). Among these certain metals is an inevitable micronutrient
for the development of plants. Zn, Cu, Mn, and Ni are very important for the growth,
and Cd, Pb, and Hg are important for the functioning of the plant (Gaur and
Adholeya 2004).
3.2 Sources of Heavy Metals in the Environment
There are two main sources of heavy metals which include; (Ali et al. 2013)
(Table 16.1)
• Natural source.
• Man-made source (Anthropogenic sources).
3.3 Health Hazards in Heavy Metal Toxicity
The consumption of higher amounts of heavy metal leads to severe health effects in
human health (Table 16.2).
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water.
3 Heavy Metal Toxicity
3.1 Definition
The heavy metals are defined as the elements or components which rectify the
properties of metal and possess an atomic number greater than 20. Metals are
naturally occurring elements found in soil. However, when the normal level exceeds,
the metal can be toxic to animals, plants, and microbes (Lasat 2000). The more
common and principal heavy metals which account to the contamination of the
environment include arsenic (As), Strontium (Sr), Caesium (Cs), Uranium
(U) (Raskin et al. 1997), Mercury (Hg), Chromium (Cr), lead (Pb), Manganese
(Mn), Nickel (Ni), Cobalt (Co), Cadmium (Cd) Lead (Pb) and zinc (Zn) (Raskin
et al. 1997; Lasat 2000). Among these certain metals is an inevitable micronutrient
for the development of plants. Zn, Cu, Mn, and Ni are very important for the growth,
and Cd, Pb, and Hg are important for the functioning of the plant (Gaur and
Adholeya 2004).
3.2 Sources of Heavy Metals in the Environment
There are two main sources of heavy metals which include; (Ali et al. 2013)
(Table 16.1)
• Natural source.
• Man-made source (Anthropogenic sources).
3.3 Health Hazards in Heavy Metal Toxicity
The consumption of higher amounts of heavy metal leads to severe health effects in
human health (Table 16.2).
342
T. G. Nithya et al.