Several studies reported the occurrences and sources of different HMs in water
systems as illustrated in Table 11.1. The sources of As in water systems were mainly
geogenic and associated with natural anoxic conditions in the aquifers and subsurface contamination due to floodplain deposits. Furthermore, Cd, Cr, Cu, Fe, Hg, Ni,
and Pb are primarily released from agricultural and industrial activities, domestic and
tannery effluents, corrosion of coolers, water tanks, pipes and pipe coatings, wastewater, mining, and incineration.
11.3 Toxicity of the HMs due to Their Exposures in Water
Carcinogenicity of arsenic has been reported by several studies (Smith et al. 2000;
Litter et al. 2019). Chronic exposure to arsenic through ingestion route may lead to
lung, bladder, and kidney cancers. It was estimated that about 20 Â 10
4 to 27 Â 10
4
deaths from cancer were associated with As exposure via drinking water in
Bangladesh (Chowdhury et al. 2016). Acute toxicity of As via drinking water
exhibits excess risks of gastrointestinal symptoms, severe disturbances of the cardiovascular and central nervous systems, hypertension, bone marrow depression,
hemolysis, hepatomegaly, melanosis, polyneuropathy, encephalopathy and peripheral vascular disease with gangrenous changes (known as black foot disease),
diabetes, and reproductive and neurological effects (Fowler et al. 2007, 2015).
Furthermore, dermal exposure to arsenic in water poses an increased risk of skin
lesions such as hyperkeratosis and pigmentation changes and skin cancer (WHO
2001). Long-term exposure to Cd at higher level via ingestion may cause renal
tubular dysfunction, kidney malfunction bronchitis, anemia, skeletal damage (itaiitai disease, which is a permutation of osteoporosis and osteomalacia), and fractures
(Järup 2003; Wu et al. 2016; Mukherjee et al. 2020). Animal and human studies
reported higher risks of cardiovascular disease (CVD) due to Cd exposure in water
(Alissa and Ferns 2011; Tellez-Plaza et al. 2013; Hudson et al. 2019). The cancer
risks associated with Cd in drinking water is relatively insignificant compared to its
occupational exposure on humans (WHO 2010; Nordberg et al. 2018). The oral
exposure of Cr can affect the gastrointestinal, immune, kidney, and liver systems
(Saha et al. 2011). The exposure may also induce hematological effects such as
decreasing total red blood cell count and mean corpuscular hemoglobin (MCH) and
microcytic anemia to the vulnerable populations (Mohammed et al. 2011; Ray
2016). Dermal exposure of Cr causes skin ulcers, increased skin sensitivity, and
dermatitis. The exposure of Pb may cause damages to the central and peripheral
nervous systems resulting in anxiety, depression, and increased aggression; gastrointestinal and urinary tracks resulting in bloody urine; dysfunctions in the cardiovascular, reproductive, and endocrine systems and kidneys and joints; or even
neurological disorder and brain damage to the vulnerable populations (Mohammed
et al. 2011; Wang et al. 2017). Development (stunted growth), behavioral (such as
inattentiveness, hyperactivity, and irritability), and emotional problems can also be
260
I. Mukherjee et al.
systems as illustrated in Table 11.1. The sources of As in water systems were mainly
geogenic and associated with natural anoxic conditions in the aquifers and subsurface contamination due to floodplain deposits. Furthermore, Cd, Cr, Cu, Fe, Hg, Ni,
and Pb are primarily released from agricultural and industrial activities, domestic and
tannery effluents, corrosion of coolers, water tanks, pipes and pipe coatings, wastewater, mining, and incineration.
11.3 Toxicity of the HMs due to Their Exposures in Water
Carcinogenicity of arsenic has been reported by several studies (Smith et al. 2000;
Litter et al. 2019). Chronic exposure to arsenic through ingestion route may lead to
lung, bladder, and kidney cancers. It was estimated that about 20 Â 10
4 to 27 Â 10
4
deaths from cancer were associated with As exposure via drinking water in
Bangladesh (Chowdhury et al. 2016). Acute toxicity of As via drinking water
exhibits excess risks of gastrointestinal symptoms, severe disturbances of the cardiovascular and central nervous systems, hypertension, bone marrow depression,
hemolysis, hepatomegaly, melanosis, polyneuropathy, encephalopathy and peripheral vascular disease with gangrenous changes (known as black foot disease),
diabetes, and reproductive and neurological effects (Fowler et al. 2007, 2015).
Furthermore, dermal exposure to arsenic in water poses an increased risk of skin
lesions such as hyperkeratosis and pigmentation changes and skin cancer (WHO
2001). Long-term exposure to Cd at higher level via ingestion may cause renal
tubular dysfunction, kidney malfunction bronchitis, anemia, skeletal damage (itaiitai disease, which is a permutation of osteoporosis and osteomalacia), and fractures
(Järup 2003; Wu et al. 2016; Mukherjee et al. 2020). Animal and human studies
reported higher risks of cardiovascular disease (CVD) due to Cd exposure in water
(Alissa and Ferns 2011; Tellez-Plaza et al. 2013; Hudson et al. 2019). The cancer
risks associated with Cd in drinking water is relatively insignificant compared to its
occupational exposure on humans (WHO 2010; Nordberg et al. 2018). The oral
exposure of Cr can affect the gastrointestinal, immune, kidney, and liver systems
(Saha et al. 2011). The exposure may also induce hematological effects such as
decreasing total red blood cell count and mean corpuscular hemoglobin (MCH) and
microcytic anemia to the vulnerable populations (Mohammed et al. 2011; Ray
2016). Dermal exposure of Cr causes skin ulcers, increased skin sensitivity, and
dermatitis. The exposure of Pb may cause damages to the central and peripheral
nervous systems resulting in anxiety, depression, and increased aggression; gastrointestinal and urinary tracks resulting in bloody urine; dysfunctions in the cardiovascular, reproductive, and endocrine systems and kidneys and joints; or even
neurological disorder and brain damage to the vulnerable populations (Mohammed
et al. 2011; Wang et al. 2017). Development (stunted growth), behavioral (such as
inattentiveness, hyperactivity, and irritability), and emotional problems can also be
260
I. Mukherjee et al.