Heavy metal pollution: causes, effects, analytical methods - Term Paper Example

They enter the body through air, food, water and bioaccumulate over a period of time. They exist as ores in rock and some of the examples of such ores are sulphides and oxides. When these ores are subjected to mining, they become pollutants of the environment leading to various environmental problems. heavy metals can also get emitted into the environment by both anthropogenic and natural causes. Mining operations are the main causes of emission of heavy metals into environment. In some cases, heavy metals continue to persistent in the environment long after mining operations have ceased.

mercury is introduced into the environment as a byproduct of manufacture of cosmetics and also in the manufacture of sodium hydroxide (Duruibe et al, 2007). Heavy metals can get emitted both in elemental or compound form which can be organic or inorganic. Industrial point sources also are important sources of emission. Cadmium is released as a byproduct of zinc refining and lead from automobile exhausts, smelting activities, old lead paints, degassing of earth's crust and mining (Duruibe et al, 2007).

(Source: Duruibe et al, 2007) (Source: Duruibe et al, 2007) (Source: Duruibe et al, 2007) Pollution of environment by heavy metals is prominent in mining areas and old mine sites. The metals are leached out. In areas which are sloppy, the acid water carries them downstream or run-off to sea. Thus, downstream water get polluted easily in mining areas. From these water bodies, the polluted water is transported to other areas through river and sea. Even wells are a source of contamination in this regard (Duruibe et al, 2007).

Heavy metals are essential for biological functions in the body. However, in levels of toxicity, they have several adverse effects. General side effects of heavy metals include diarrhoea, stomatitis, hemaglobinuria, tremors, ataxia, vomiting, paralysis and convulsion. Depression and pneumonia can also occur. The nature of effects depends on the organ system involved. Cadmium is one heavy metal that is toxic even in extremely low levels. Long term exposure can lead to renal dysfunction manifesting as tubular proteinuria.

Other effects include cadmium pneumonitis, obstructive lung disease, bone defects like osteomalacia and osteoporosis, myocardic dysfunctions and hypertension. The most significant toxin among heavy metals is lead. It has a wide range of toxic effects including teratogenic effects, inhibition of synthesis of hemoglobin, dysfunction of kidneys and other organs and chronic damage to the nervous system. It can also cause damage to the gastrointestinal system and also to the urinary tract system. In children, lead can cause intellectual deficits and learning disabilities.

Both acute and chronic lead toxicities can lead to psychosis (Lenntech, 2004). Zinc toxicity has similar side effects as lead and is often mistakenly diagnosed as lead toxicity. However, when taken orally, it is considered to be relatively non-toxic. Systemic damage can occur in high doses of toxicity and some of them include growth impairment, developmental delay, reproductive problems and failure of liver and kidneys. Mercury is highly toxic. It has no known biological effect and it can lead to devastating consequences.

It can lead to congenital malformation, spontaneous abortion and gastrointestinal problems. It can cause allergic reactions, some of which can be