In the context of environmental toxicology, what does 'heavy metal' Essay

In the context of environmental toxicology, what does 'heavy metal' actually mean - Essay Example However, this assumption has no fundamental basis on the available toxicological or chemical data. Legal regulations have specified an inventory of heavy metals applied in various situations. There is no definition that is authoritative in literatures that are relevant. There is a tendency of assuming that all heavy metals in conjunction with their compounds have properties that are highly eco-toxic or toxic. Arguably, this assumption has no prove in toxicological or chemical data. Hence, the term heavy metal is misleading and meaningless. Furthermore, the word metal is also misused in legislation and toxicological data. In these literatures it is used to mean a metal that is pure and the entire species chemical in which it occurs. This is untrue because, all pure metals can not exhibit similar toxicological and chemical properties. For purposes of avoiding the term heavy metal, there is need for reclassification of the periodic table as people refer to the term heavy metal as mislea ding and meaningless. The change in classification should mirror individuals understanding of toxicity chemical basis and provide room for the prediction of toxic impacts. Classification of heavy metals The increased worry on environmental pollution reduction has triggered the continued literature and research on heavy metals toxicology (Rabajczyk et al., 2011). Heavy metals emit their toxic substances through the formation of complexes with compounds that are organic. These eventually results to formation of modified biological molecules that lose their functioning ability. The outcome is affected cell malfunction or death. The most common heavy metals that form organic compounds that are complex are such as oxygen, sulfur and nitrogen. Classification of heavy metals is done depending on which class it lies. For example class A belong to the hard metals, class be identifies soft metals and lastly we have the intermediate metals. Heavy metals such as Mercury, Lead and cadmium fall u nder class B which represents soft metals. On the other hand chromium is an intermediate metal. The classification of these metals varies depending on their chemical formula. How Heavy Metal Occurs in the Environment Through causes that are both anthropogenic and natural, heavy metals find their way into the environment. The major emission causes are human sources such as mining operations. Heavy metals are exposed into the environment in forms that are both inorganic and organic. Anthropogenic sources of emissions occur from both point and non-point sources such as industrial areas such as present and previous sites of mining, smelters and foundries and by-products and traffics combustion. The pollution of the environment by heavy metals is acute in mining locations and it decreases as the distance widens from those mining sites. The heavy metals are often leached into the soil and ground water. Those in sloppy areas find their way into the water bodies through surface runoff. The heavy metals eventually attach themselves to the sediments whilst some leak into the waters underground resulting to their contamination. Underground and surface water sources heavy metal contamination leads to soil pollution. Exposure of the heavy metals to air and rain is via dumping on the surface soil. Pollution of Agricultural soils results to the uptake of the heavy metals by plants resulting to their accumulation in the plant tissues. These consequently happen to those marine animals and domestic