cadmium in high quantities affects kidney and liver. Cd can replace calcium from bones, which is the reason for different bone diseases like painful bone disorders, renal failure, and insinuation in human hypertension. The long period exposure of Cd can cause chronic anaemia (Järup 2003; Burke et al. 2016).
Intake of Pb over the acceptable limit is carcinogenic for humans. The short‐term as well as long‐term exposure to lead affects children more than adults. The intake of Pb through water, food and other resources causes various diseases like damage to the foetal brain, kidney disease, and circulatory and nervous system damage. Pregnant people exposed to lead through food and water can experience miscarriage, stillbirth, premature delivery, and low birth weight (Järup 2003).
Generally, the toxicity of Sb is similar to the toxicity of arsenic. The Sb(III) is more carcinogenic than Sb(V). The inhalation of antimony leads to carcinogenic disease and respiratory system problems. The intake of Sb in higher quantities leads to premature delivery, miscarriage, liver damage, etc. (WHO 2003; Sundar and Chakravarty 2010).
Zn is as an essential element to intake up to an acceptable limit; it helps in various metabolic processes, embryonic development, cellular differentiation, and cell proliferation. Moreover, it also delivers the substrates for the manifestation of genetic potential like optimum growth, health, reproduction, and development. However, the consumption of high doses of Zn is hazardous and leads to depression, lethargy, neurological signs, and thirst increment diseases (Plum et al. 2010).
Chromium (Cr) is also a more toxic element. Both forms, Cr(III) and Cr(VI), are carcinogenic for humans. But Cr(VI) is more lethal than Cr(III) because of its more powerful oxidizing agent, which has a tendency to be irritating and corrosive and it is easily inhaled by human cells, which have seen the carcino‐toxicity. The long‐term consumption of Cr affects the respiratory system, cardiovascular system, haptic system, gastrointestinal system, etc. It can also cause carcinogenic diseases (Zhitkovich 2011; Mcneill et al. 2012; Wilbur et al. 2012).
Overall, the consumption of heavy metal/metalloids over the permissible limit by humans through drinking water leads to skin problems, stomach problems, and carcinogenic problems. It produces different types of cancer like lung, kidney, skin, etc. The intake of heavy metals causes brain‐related diseases like Parkinson’s disease, disturbances in nerve cells, brain tumours, depression, and more (Momodu and Anyakora 2010; Mebrahtu and Zerabruk 2011; Mohod and Dhote 2013). Day by day, human health is deteriorated by consuming the contaminated water and toxic food. Keeping in mind their toxicity, several researchers are working to overcome this problem and demonstrate the methods to decontaminate the water bodies. The government has propounded some strategies to stop water pollution and water problems, which are discussed in Section 4.5.
4.4.1 Impact of Heavy Metal Pollution in Groundwater: Some Case Studies
Groundwater resources are world's largest freshwater sources. They provide adequate water supply for domestic, agricultural and industrial practices. Uniquely, their role in sustainability of ecosystems is immensely vital. Therefore, the sustainability of groundwater quality and quantity itself is very important for the above‐mentioned phenomena. However, owing to various anthropogenic activities in the recent past, groundwater resources are undergoing catastrophic depletion and deterioration. Particularly, the overexploitation and continuous groundwater pollution works in a synergic fashion and cause non‐availability of groundwater and making it unfit for any use. Here, in this section we are putting forward few global examples that illustrates the devastating impacts of polluted groundwater on smaller and bigger scales.
Boateng et al. have studied the extent of heavy metal contamination in Oti landfill site, Kumasi, and further evaluated the effect of this contamination on human health. Through the standard methods and procedures for the examination of water and wastewater, authors reported that the concentration of many metals like Pb, Cd, Fe, and Cr was above the acceptable limits as set by the WHO for drinking water. It was reported that only the concentration of Zn and Cu was within the permissible limit. Further, it was revealed that this high level of heavy metal contamination in groundwaters of Oti has grave health consequences and water needs to be pretreated before its consumption (Boateng et al. 2019).
In a recent report, a meta‐analysis on the impact of consumption of polluted groundwater on health of children was executed in 10 developing countries including India. The research shows that blood of the children from these countries have relatively higher levels of heavy metals than normal cases and this problem is only attributed to the polluted groundwater by the researchers Horton et al. (2013); (Singaraja et al. 2015; Mohankumar et al. 2016). The groundwater pollution problem is a very serious concern across the world, however, the situation in developing economies, especially heavily populated ones, is very critical. In these countries, industrial growth and agricultural practices are rapidly increasing and consequently, offering more and complex hurdles in the sustainable management of groundwater resources. For instance, the Kurichi Industrial Cluster near Coimbatore city does not have agricultural activities and waste dumping nearby it, however, it has given a comprehensive Environmental Pollution Index (CEPI) score of 58.75 by the Central Pollution Control Board (CPCB, India) in 2009, which implies that the water was critically polluted (Action plan for critically polluted area, Tamilnadu Pollution Control Board, 2010, www.tnpcb.gov.in/pdf/Action_plan_cbe.PDF). This is because of the release of unchecked wastewater streams of local industries in groundwater. This transformed the local groundwater and nearby groundwater tables into highly toxic systems. The groundwater sources are not suitable for domestic and agricultural practices. Further, many ill effects on human health, soil fertility, bioaccumulation, and biomagnification of the toxic heavy metals are spreading with a higher pace in the region. To mitigate the issues, the local authorities had imposed stronger legislations on the industries and wastewater treatment plants were commissioned in many industries.
Many such studies are now published by many research groups, NGOs (nongovernmental organizations), environmentalists, and local governments. However, the real scenario is even worse than that reported in these studies, especially in the areas where infrastructure is not that strong. Moreover, many examples of the hazardous effects of consumption of groundwater contaminated with heavy metals are presented throughout the chapter.
Therefore, a comprehensive review on such aspects and illustration of the true picture of the problem is required for making the sustainable policies and strategies to propagate the sustainability of groundwater resources and their uses.
4.5 Recent Strategies to Control Heavy Metals
As discussed, the main sources of heavy metal pollution are anthropogenic sources, which are the major concern for contaminants in groundwater as well as surface water resources. To overcome these problems, government must take appropriate action to solve these issues. In this regard, government has taken a decision to prevent and overcome heavy metal pollution in water.
NEERI (National Environmental Engineering Research Institute) has addressed the technique to decontaminate the water from heavy metals as well as for waste management of the land sector. The kit is also receommended to check the quality of drinking water (Marg 2011).
For preventing Hg pollution, the major Hg pollution sources like medical devices and CFL (compact fluorescent light) bulbs should be replaced by non‐mercury containing products (Marg 2011). The industries should set up treatment technology for spontaneous remediation of the heavy metal‐based wastewater before discharging the wastewater into water bodies.
Domestic wastage like municipal and sewage waste should be prevented from discharging in water. It should be monitored and made a rule to stop the disposal of waste in water. To cure the drinking water, the metal‐based pesticides and insecticides should be bonded within the agricultural field. Government must give proper attention to organic farming. Phytoremediation is a best tool to control the heavy metal contamination. Other spontaneous chemical and physical treatments have been utilized to