Heavy metals are natural components of the Earth's crust. They occur in ecosystem. To a small extent, they enter our bodies via food, drinking water and air. As trace elements, some heavy metals are essential to maintain the metabolism of the human body. Yet at higher concentrations, heavy metals can lead to poisoning.

 

The top two most pollutant heavy metals are lead (Pb) and mercury (Hg). They negatively affect people's health. With scarce public recognition for the harm they cause, these toxic metals do untold damage to people's lives.

 

In humans, exposure to lead can result in a wide range of biological effects depending on the level and duration of exposure. It causes kidney and gastrointestinal damage and mental retardation in children. It is a dangerous element. It is harmful even in small amounts.  It can be inhaled in dust from lead paints, or waste gases from leaded gasoline.  It is found in trace amounts in various foods, notably fish, which are heavily subject to industrial pollution.  Some old homes may have lead water pipes, which can then contaminate drinking water.

 

Meanwhile, mercury is a global pollutant with complex and unusual chemical and physical properties. It can damage to nervous system and can cause protoplasm poisoning. High exposures to this metal could eventually result to death. In its pure form, it is generally not harmful to humans, but if it is allowed to combine with other elements (as the oxygen and hydrogen in water or air), it can form organic compounds which is very dangerous.   In aquatic environments, eating too much fish from streams and rivers contaminated with mercury is a dangerous way of life.

 

Heavy metal contamination have devastating effects on the ecological balance of the recipient environment and a diversity of aquatic organisms (Farombi, et al., 2007 Vosyliene and Jankaite, 2006 Ashraj, 2005). Among animal species, fishes are the inhabitants that cannot escape from the detrimental effects of these pollutants, (Olaifa et al., 2004 Clarkson, 1998 Dickman and Leung, 1998).

 

We, humans, are the cause of heavy metal contamination in some areas. Improper disposal of mercury in mining is one cause. The improper use of leaded gasoline is also another thing. We must always be vigilant. We must not allow our environment to be polluted. We must find ways to protect our environment while achieving a sustainable economic growth. The solutions are all in our hand. We must work together to achieve a community we all want.

 

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References

Ashraj, W. (2005). Accumulation of heavy metals in kidney and heart tissues of Epinephelusmicrodon  fish from theArabian Gulf. Environ. Monit.Assess., 101 (1-3), 311-316. 

Clarkson, T. W. (1998). Human toxicology of mercury. J . Trace. Elem. Exp. M ed., 11(2-3),303-317

Dickman, M. D. & Leung, K. M.,  (1998 ). Mercury  and organo chlorine   exposure from  fish consumption  on  in n  Hong Kong. Chemosphere,  37  (5 ), 991-1015 .

Farombi, E.O, Adel Owo, O.A. Ajimok o., Y.R., (2007). Biomarkers of oxidative stress and heavy metal levels as indicators of environmental pollution in African Catfish (Clariasgariepinus) from Nigeria ogun river. Int. J. Environ. Res. Public Health ., 4  (2 ), 158-165 Res. Public Health ., 4  (2 ), 158-165.

Olaifa, F. G. Olaifa, A. K. Onwude, T. E., (2004). Lethal and sublethal effects of copper to the African Cat fish (Clariasgariepnus). Afr. J. Biomed. Res., 7, 65-70.

Vosyliene, M. Z. Jankaite, A., (2006). Effect of heavy metalmode l  mixture on rainbow troutbiological parameters.Ekologija., 4, 12-17.