pollution of water and soil. Currently, very large population is affected by arsenic
contamination worldwide, therefore, the toxicity problem arising from its contamination in drinking water is a matter of global concern [52]. The World Health
Organization (WHO) and U.S. EPA have suggested 10 lg/L of arsenic concentration in drinking water as the safety limit for human consumption.
Both natural and anthropogenic sources are responsible for arsenic contamination into surface and groundwater. Arsenic is a rare crystal element constituting
approximately (0.00005%) of the Earth crust [53]. The arsenic content in soils of
different countries has been reported to range from 0.1 to 40 mg kg
−1 with an
average value of 6 mg kg
−1 (Bowen 1979). Its higher concentration present in
certain minerals such as pyrite (up to 5–10% by weight) causes its release in
environment. In addition to its natural occurrence, many microbes in nature
transform arsenic into various oxidation states. During anaerobic respiration certain
microbes respire As (V) and release As (III) in surrounding groundwater [54].
Among anthropogenic sources mining operations, copper smelting industries, fossil
fuel burning and other combustion processes are known to release arsenic into
environment. Presence of arsenic containing sulfide minerals has significantly
contributed to its release into the environment [55]. Arsenic has been commonly
used in variety of dyes, paints, herbicides, pesticides, insecticides, wood preservatives and animal feeds [56].
Inorganic arsenic is extremely noxious and ingestion of big magnitude directs to
gastrointestinal signs, cruel anarchy of the cardiovascular and central nervous
systems, and ultimately death. In survivors, bone marrow despair, haemolysis,
hepatomegaly, melanosis, polyneuropathy and encephalopathy may be experienced. Populations exposed to arsenic via intake water confirm intemperance risk of
death from lung, bladder and kidney cancer, the risk rising with escalating exposure. There is also an augmented threat of skin cancer and other skin lesions, such
as hyperkeratosis and pigmentation alterations. Arsenic (As) is a notorious carcinogenic element and its intake severely affects various human organ systems
including hepatic system, cardiovascular system and central nervous system (Farrell
et al. 2001) [57, 58].
Manganese (Mn)
Mn is found in the association of Fe because chemically it is very similar to Fe. Mn
is an essential element. Mn is found in manganese dioxide form in the soil.
Manganese dioxide is very insoluble in water containing CO 2 . Mn is positively
correlated with Fe and it is an essential component of plants and animals [50].
Ferromagnesium minerals release the Mn in groundwater. High concentration of
Mn causes damage of central nervous system.
Zinc (Zn)
Zn is also an necessary trace element acting as a micronutrient for human health. Zn
is essential for male reproductive activity therefore consider as masculine element
[59]. Zn is also helpful for plant growth as it reduces the Ni toxicity and increase
ATP/chlorophyll ratio [60]. Zn is utilized as an anticorrosion agent where it is
Water Pollutants: Sources and Impact on the Environment …
49
contamination worldwide, therefore, the toxicity problem arising from its contamination in drinking water is a matter of global concern [52]. The World Health
Organization (WHO) and U.S. EPA have suggested 10 lg/L of arsenic concentration in drinking water as the safety limit for human consumption.
Both natural and anthropogenic sources are responsible for arsenic contamination into surface and groundwater. Arsenic is a rare crystal element constituting
approximately (0.00005%) of the Earth crust [53]. The arsenic content in soils of
different countries has been reported to range from 0.1 to 40 mg kg
−1 with an
average value of 6 mg kg
−1 (Bowen 1979). Its higher concentration present in
certain minerals such as pyrite (up to 5–10% by weight) causes its release in
environment. In addition to its natural occurrence, many microbes in nature
transform arsenic into various oxidation states. During anaerobic respiration certain
microbes respire As (V) and release As (III) in surrounding groundwater [54].
Among anthropogenic sources mining operations, copper smelting industries, fossil
fuel burning and other combustion processes are known to release arsenic into
environment. Presence of arsenic containing sulfide minerals has significantly
contributed to its release into the environment [55]. Arsenic has been commonly
used in variety of dyes, paints, herbicides, pesticides, insecticides, wood preservatives and animal feeds [56].
Inorganic arsenic is extremely noxious and ingestion of big magnitude directs to
gastrointestinal signs, cruel anarchy of the cardiovascular and central nervous
systems, and ultimately death. In survivors, bone marrow despair, haemolysis,
hepatomegaly, melanosis, polyneuropathy and encephalopathy may be experienced. Populations exposed to arsenic via intake water confirm intemperance risk of
death from lung, bladder and kidney cancer, the risk rising with escalating exposure. There is also an augmented threat of skin cancer and other skin lesions, such
as hyperkeratosis and pigmentation alterations. Arsenic (As) is a notorious carcinogenic element and its intake severely affects various human organ systems
including hepatic system, cardiovascular system and central nervous system (Farrell
et al. 2001) [57, 58].
Manganese (Mn)
Mn is found in the association of Fe because chemically it is very similar to Fe. Mn
is an essential element. Mn is found in manganese dioxide form in the soil.
Manganese dioxide is very insoluble in water containing CO 2 . Mn is positively
correlated with Fe and it is an essential component of plants and animals [50].
Ferromagnesium minerals release the Mn in groundwater. High concentration of
Mn causes damage of central nervous system.
Zinc (Zn)
Zn is also an necessary trace element acting as a micronutrient for human health. Zn
is essential for male reproductive activity therefore consider as masculine element
[59]. Zn is also helpful for plant growth as it reduces the Ni toxicity and increase
ATP/chlorophyll ratio [60]. Zn is utilized as an anticorrosion agent where it is
Water Pollutants: Sources and Impact on the Environment …
49