Drinking water is a basic necessity for sustenance of life. We consume more water in comparison to other liquids. It is very important that drinking water be free of toxic heavy metals. Metals such as Calcium, Sodium, Potassium, Copper, Zinc, Manganese, Barium, Cobalt, Iron, etc are essential nutrients but
heavy metals can lead to severe health problems. These are metallic elements which are toxic and have high density or atomic weight.
Heavy metals are naturally found in Earth’s crust and do not degrade but tend to bioaccumulate over long time periods. These metals find their way into the human body through food, water or air. Common heavy metals are Aluminium, Antimony, Arsenic, Beryllium, Bismuth: Arsenic, Lead, Mercury, Uranium, Tin, Vanadium, etc.
Sources of Heavy Metals
The heavy metals find their way into water bodies through natural processes like volcanic eruptions, storms, earthquakes, floods, weathering of rocks, etc. Human activities such as mining, processing of minerals, use of metals as containers and transportation through metallic pipelines also are responsible for contamination of drinking water.
Water used in Food and Beverage Manufacturing
Water used for manufacturing of foods and beverages does not fall directly into the category of drinking water but can lead to deleterious effects on health of consumer if it contains trace metals beyond safe limits. All food industries using water as a raw material should have testing and removal facilities for heavy metals before using in manufacturing processes..
Toxic Effects of Some Heavy Metals
Heavy metals are known to harm kidneys, liver, nervous system and bone structure. Infants and aged persons are more vulnerable.
Lead poisoning in humans can cause problems in synthesis of haemoglobin, kidneys, gastrointestinal tract, joints and reproductive systems and acute or chronic damage to the nervous system. Lead can also cause osteoporosis and weekend bones because it starts replacing Calcium in the bones
Long-term exposure of cadmium leads to renal dysfunction. High exposure can least to lung cancer and osteodystrophy
Nickel has numerous reported mechanisms of toxicity including redox – cycling and inhibition of DNA repair as well as exhibiting allergic effects
Exposure to mercury can lead to tremors, gingivitis and other psychological changes with spontaneous absorption and congenital malformation. Mono methyl mercury causes damage to the brain and the central nervous system, congenital malformations and development changes in young children
Vanadium has toxic effects on the liver, kidney, nervous and cardiovascular systems and blood forming organs.
Removal of Heavy Metal Impurities
It is not possible to completely eliminate heavy metal contamination in drinking water but commercial processes are available which can lead to significant decrease in concentration levels. Ion exchange and activated carbon adsorption technologies provide viable options
This article has briefly introduced you to the potential harmful effects of toxic metals in drinking water. In a subsequent article you will be introduced to the limits specified by different standardization bodies and techniques for quantification of toxic heavy metals in drinking water.
Please share your experience and leave comments.