above the BIS- (50 μg/l) and WHO (10 μg/l)-approved limits. Keeping the guidelines of the WHO for As content in potable water, nearly 100 million people in South
and Southeast Asia alone are at arsenic-induced risk. Added to it, above 200 million
people universally are at danger of As poisoning (Rahman et al. 2009; Roberge et al.
2009; Singh et al. 2015). Twenty districts of Assam have As content above 50 μg/l
(Bordoloi 2012), in a study conducted by Northeastern Regional Institute of Water
and Land Management (NERIWALM). Seawater usually has less than 2 μg L
À1 of
As (Seow et al. 2012). Different sources of freshwater, such as streams, rivers, and
lakes have As concentrations ranging from 0.15 to 0.45 μg L
À1 depending on the
sources and geochemical characteristics of the district (Singh et al. 2015). Compared
to river waters, the lake waters possess a lower As contamination (Smedley and
Kinniburgh 2012). Most As-polluted areas are existing around great estuaries and
the proximate areas of main rivers that instigate from the Himalayan mountain range.
Reportedly being the highest As concentration at Bengal delta, nearly 45 million
(88%) people are affected with high (>50 μg L
À1 ) levels of As poisoning
(Ravenscroft et al. 2009; Singh et al. 2015).
3 Arsenic Contamination and Its Effects on Human
Well-Being
Arsenic is a toxic pollutant that raises much concern from both the ecological and
human health perspectives. Human being may get exposed to arsenic in water from
wells bored into arsenic-rich ground layers or in water polluted by agrochemical and
industrial waste (Hughes et al. 1988). They may come in contact with arsenic in
contaminated mists, fumes, or dusts. There are possibilities of human consumption
of food cultivated with arsenic-contaminated groundwater or in arsenic-rich soil or
polluted with pesticides derived with arsenic (Nriagu and Azcue 1990). However, it
is still unknown to the scientific community how the milk is free from As contamination from the milk of arsenic-affected cows. Similarly a food grown in arseniccontaminated areas, arsenic is not found inside the food like cereals, pulses/grains,
and fruits but may be found in the external layer of fruits or food due to spraying of
arsenic-polluted water. A few stray reports of arsenic in cow’s milk are most likely
due to adulteration of milk by arsenic-polluted water. Acclimatization of low dose
through food or water is the principal path of this metalloid into the organism, where
absorption takes place in the gastrointestinal track, followed by its release into the
bloodstream. Liver converts the toxic form to less toxic form and is eventually
excreted in the urine. Only very high exposure can, in fact, lead to considerable
accretion in the body. Acute levels of As entry are reportedly through dermal
exposure and inhalation (Caroli et al. 1996). For many decades, severe/prolonged
arsenic poisoning and its medical use are known. Arsenic was recommended orally
as Fowler’s solution in stimulant combinations against leukemia, asthma, and other
malignancy treatment (Leslie and Smith 1978; Zachariac et al. 1974). Parentally, As
242
P. Narayanasamy and R. K. Subramanian
and Southeast Asia alone are at arsenic-induced risk. Added to it, above 200 million
people universally are at danger of As poisoning (Rahman et al. 2009; Roberge et al.
2009; Singh et al. 2015). Twenty districts of Assam have As content above 50 μg/l
(Bordoloi 2012), in a study conducted by Northeastern Regional Institute of Water
and Land Management (NERIWALM). Seawater usually has less than 2 μg L
À1 of
As (Seow et al. 2012). Different sources of freshwater, such as streams, rivers, and
lakes have As concentrations ranging from 0.15 to 0.45 μg L
À1 depending on the
sources and geochemical characteristics of the district (Singh et al. 2015). Compared
to river waters, the lake waters possess a lower As contamination (Smedley and
Kinniburgh 2012). Most As-polluted areas are existing around great estuaries and
the proximate areas of main rivers that instigate from the Himalayan mountain range.
Reportedly being the highest As concentration at Bengal delta, nearly 45 million
(88%) people are affected with high (>50 μg L
À1 ) levels of As poisoning
(Ravenscroft et al. 2009; Singh et al. 2015).
3 Arsenic Contamination and Its Effects on Human
Well-Being
Arsenic is a toxic pollutant that raises much concern from both the ecological and
human health perspectives. Human being may get exposed to arsenic in water from
wells bored into arsenic-rich ground layers or in water polluted by agrochemical and
industrial waste (Hughes et al. 1988). They may come in contact with arsenic in
contaminated mists, fumes, or dusts. There are possibilities of human consumption
of food cultivated with arsenic-contaminated groundwater or in arsenic-rich soil or
polluted with pesticides derived with arsenic (Nriagu and Azcue 1990). However, it
is still unknown to the scientific community how the milk is free from As contamination from the milk of arsenic-affected cows. Similarly a food grown in arseniccontaminated areas, arsenic is not found inside the food like cereals, pulses/grains,
and fruits but may be found in the external layer of fruits or food due to spraying of
arsenic-polluted water. A few stray reports of arsenic in cow’s milk are most likely
due to adulteration of milk by arsenic-polluted water. Acclimatization of low dose
through food or water is the principal path of this metalloid into the organism, where
absorption takes place in the gastrointestinal track, followed by its release into the
bloodstream. Liver converts the toxic form to less toxic form and is eventually
excreted in the urine. Only very high exposure can, in fact, lead to considerable
accretion in the body. Acute levels of As entry are reportedly through dermal
exposure and inhalation (Caroli et al. 1996). For many decades, severe/prolonged
arsenic poisoning and its medical use are known. Arsenic was recommended orally
as Fowler’s solution in stimulant combinations against leukemia, asthma, and other
malignancy treatment (Leslie and Smith 1978; Zachariac et al. 1974). Parentally, As
242
P. Narayanasamy and R. K. Subramanian