Heavy metal pollution in the environment and their toxicological effects on humans
Environmental pollution of heavy metals is increasingly becoming a problem and has become of great concern due to the adverse effects it is causing around the world. These inorganic pollutants are being discarded in our waters, soils and into the atmosphere due to the rapidly growing agriculture and metal industries, improper waste disposal, fertilizers and pesticides. This review shows how pollutants enter the environment together with their fate. Some metals affect biological functions and growth, while other metals accumulate in one or more different organs causing many serious diseases such as cancer. The pharmacokinetics and toxicological processes in humans for each metal is described. In summary, the review shows the physiological and biochemical effects of each heavy metal bioaccumulation in humans and the level of gravity and disquieting factor of the disease.To get more news about Emeramide buy, you can visit fandachem.com official website.
The environment is the surroundings where humans, plants, animals and micro-organisms live or work. It is composed of the land, the Earth's atmosphere and the water. The Earth's system is defined by the four spheres: the biosphere (living things), the atmosphere (air), the lithosphere (land) and the hydrosphere (water) which all work in harmony together as shown in Figure 1. Environmental contaminants, as well as pollutants, are chemicals that are present at higher levels than in any section of the environment [1, 2, 3].
During the last hundred years, industrialisation has grown at a fast rate. It has thus increased the demand for exploitation of the Earth's natural resources at a careless rate, which has exacerbated the world's problem of environmental pollution [4]. The environment has been seriously polluted by several pollutants such as inorganic ions, organic pollutants, organometallic compounds, radioactive isotopes, gaseous pollutants and nanoparticles [2]. Heavy metal pollution will be discussed further in this article.
They are defined as heavy metals either due to their high atomic weight or because of their high density. Nowadays, the word ‘heavy metal’ has been used to describe metallic chemical elements and metalloids which are toxic to the environment and humans. Some metalloids and also lighter metals such as selenium, arsenic and aluminium are toxic. They have been termed heavy metals while some heavy metals are typically not toxic such as the element gold [5, 6, 7, 8].
These heavy metals are found naturally on the Earth's crust since the Earth's formation. Due to the astounding increase of the use of heavy metals, it has resulted in an imminent surge of metallic substances in both the terrestrial environment and the aquatic environment [4]. Heavy metal pollution has emerged due to anthropogenic activity which is the prime cause of pollution, primarily due to mining the metal, smelting, foundries, and other industries that are metal-based, leaching of metals from different sources such as landfills, waste dumps, excretion, livestock and chicken manure, runoffs, automobiles and roadworks. Heavy metal use in the agricultural field has been the secondary source of heavy metal pollution, such as the use of pesticides, insecticides, fertilisers, and more. Natural causes can also increase heavy metal pollution such as volcanic activity, metal corrosion, metal evaporation from soil and water and sediment re-suspension, soil erosion, geological weathering [1, 2, 4, 5, 9, 10, 11].
Metalloids tend to form covalent bonds, making them show toxicological properties. The two most important consequences of this property are that they can bind covalently with organic groups. Hence they form lipophilic ions and compounds, and they can generate toxic effects when they bind to nonmetallic elements of cellular macromolecules. Due to becoming lipophilic, the metalloids distribution within the biosphere and their toxic response vary from the action of simple ionic forms of the same element. Examples of lyophilic compounds are tributyltin oxide and methylated forms of arsenic which are highly toxic. Examples of binding to nonmetallic elements are the binding of lead and mercury to sulphydryl groups of the protein. Heavy metals may enter a human in four ways from; ingestion of contaminated food; inhalation from the atmosphere, drinking contaminated water; and due to skin contact from agriculture, pharmaceutical, manufacturing, residential and industrial areas [1, 2].
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