Abstract
This chapter is a review of published research papers, books, book chapters, unpublished scientific reports prepared by research organisations, and expert talk about heavy metal pollution. This chapter also summarises the research studies conducted in Coimbatore and a summary of the studies says that very tiny information is available on heavy metals in soil, water, and air components. Till now heavy metals in plants, plant products, animals, animal products, bioaccumulation in humans, and its impacts are not accounted in this region. Further, these chapters identify the research gaps, and research interventions are required to assess the heavy metals contaminations in different ecosystems. It also highlights the need for long-term monitoring of heavy metals in the ground, surface water, food materials, agricultural products produced in the contaminated regions. The chapter concludes with a need for study on human health impacts, restoration, and remediation measures required in Coimbatore regions.
TopNaturally, heavy metals are present in the Earth’s crust, some metals are very useful to human biological system and few metals are damage humans’ system. Heavy metals like Copper (Cu), Selenium (Se), Zinc (Zn) are vital in very small quantity for the proper functioning of the biological systems. Lack of these vital heavy metals could cause various disorders in the human body (Azeh Engwa et al., 2019). While others like Mercury (Hg), Cadmium (Cd), Arsenic (As), Chromium (Cr), Thallium (Tl) and Lead (Pb) toxic to living organisms and can cause severe health disorders if exposed for long term even in minimal quantities. Presence of toxic heavy metals in water, soil and air is an important issue as they can undergo geoaccumulation in due course of time (Ali, Khan and Ilahi, 2019). They can enter biological (plant and animal) tissue through food chain and undergo bioaccumulation and biomagnification in long term, causing severe health issues in human beings (Jaishankar et al., 2014). The unplanned, rapid urbanization and industrialization carried out without giving due consideration for the environment is the root cause for the presence of heavy metals in quantities larger than what natural ecosystem can absorb and clean.
The bioaccumulation and geoaccumulation of heavy metals are significantly alter the quality of abiotic components and impacted the biotic components of an ecosystems (Jaiwan and Ajay, 2011). The numerous researchers are stated the impacts of heavy metals (Tchounwou et al., 2014; Masindi and Muedi, 2018; Sall et al., 2020). Well documented evidence on bio-toxic effects to human on long-term exposure of heavy metals causes gastrointestinal disorders, vomiting, depression, diarrhea, stomatitis, tremor and paralysis (Verma and Dwivedi, 2013). The long-term exposure of Cd dysfunction the kidneys. Lung disease by Pb in dust and fumes, chest pain, cough with foamy and bloody sputum is an effects of chronic exposure of Pb. Metal like Cd associated with bone defects, increased blood pressure and mycocardic dysfunctions. Zn causes symptoms like Pb, but impair the growth, reduce the function of reproductive organs of humans. The clinical signs of Zn are bloody urine, icterus, liver, kidney failure and anemia (Verma and Dwivedi, 2013). The inorganic forms mercury is highly toxic to human, causes spontaneous abortion, congenital malformation and gastrointestinal disorders. Information on heavy metals reduces the quality of water, air and soil components is required study in in-depth, but through abiotic component it accumulates into plants, animals causes damages, at higher level it affects the human (Jaiwan and Ajay, 2011).
Key Terms in this Chapter
Remediation: An action on controlling heavy metal contaminations or distributions by adopting physical, chemical, and biological methods to reduce harm to human and the environment.
Heavy Metals: Naturally occurring chemical substances found in the earth crust. It exposed or distributed in environment due to anthropogenic activities like industrial operations, mining, smelting operations and other technological applications.
Electro-Kinetic (EK) Method: An approach by using electrical current and acidic and alkalophilic microbes to precipitate heavy metals from the soil.
Bioaccumulation: Accumulation of heavy metals or any other chemicals in the trophic levels.
Phyto-Remediation: The process that uses the different types of plants to control, remove, detoxify pollutant or contaminants from the environmental components.
Restoration: The efforts to create the healthy habitats by creating physical, chemical, and biological structures to safeguard the environment, people and improving ecosystem functions.
Long-Term Monitoring (LTM): A regular systematic data collection on amount of heavy metals in air, water and soil and other biological components in contaminated site over an extended period of time.