Lead is regarded as a potent occupational toxin and its toxicological manifestations are well known. The non biodegradable nature of lead is the prime reason for its prolonged persistence in the environment. Human exposure to lead occurs through various sources like leaded gasoline, industrial processes such as lead smelting and coal combustion, lead based paints, lead containing pipes or lead based solder in water supply systems, battery recycling, grids and bearings, etc. Although lead toxicity is a highly explored and comprehensively published topic, complete control and prevention over lead exposure is still far from being achieved. There is no such level of lead that appears to be necessary or beneficial to the body and no “safe†level of exposure to lead has been found. Lead toxicity is a particularly insidious hazard with the potential of causing irreversible health effects. It is known to interfere with a number of body functions and it is primarily affecting the central nervous, hematopoietic, hepatic and renal system producing serious disorders. Acute toxicity is related to occupational exposure and is quite uncommon. Chronic toxicity on the other hand is much more common and occurs at blood lead levels of about 40–60 ug dL. It can be much more severe if not treated in time and is characterized by persistent vomiting, encephalopathy, lethargy, delirium, convulsions and coma. Young children are particularly vulnerable to the toxic effects of lead and can suffer profound and permanent adverse health effects, particularly affecting the development of the brain and nervous system. Lead also causes long term harm in adults, including increased risk of high blood pressure and kidney damage. Exposure of pregnant women to high levels of lead can cause miscarriage, stillbirth, premature birth and low birth weight. Young children are particularly vulnerable to lead poisoning because they absorb 4–5 times as much ingested lead as adults from a given source. Moreover, children’s innate curiosity and their age appropriate hand to mouth behaviour result in their mouthing and swallowing lead containing or lead coated objects, such as contaminated soil or dust and flakes from decaying lead containing paint. This route of exposure is magnified in children with a psychological disorder called pica persistent and compulsive cravings to eat non food items , who may, for example pick away at, and eat, leaded paint from walls, door frames and furniture. Exposure to lead contaminated soil and dust resulting from battery recycling and mining has caused mass lead poisoning and multiple deaths in young children in Nigeria, Senegal and other countries. Once lead enters the body, it is distributed to organs such as the brain, kidneys, liver and bones. The body stores lead in the teeth and bones where it accumulates over time. Lead stored in bone may be remobilized into the blood during pregnancy, thus exposing the fetus. Undernourished children are more susceptible to lead because their bodies absorb more lead if other nutrients, such as calcium or iron, are lacking. Children at highest risk are the very young including the developing fetus and the economically disadvantaged. Lead poisoning occurs when lead builds up in the body, often over a period of months or years. Research indicates about 500,000 U.S. children between the ages of 1 and 5 have blood lead levels above 5 micrograms per deciliter, the reference level at which the CDC recommends public health actions be initiated. Children under the age of 6 are especially vulnerable because their growing bodies absorb more lead than adults and because they tend to put their hands or other objects, which may be contaminated with lead dust, into their mouths. The signs and symptoms of lead poisoning often dont appear until dangerous amounts of lead have accumulated. Even low levels of lead in blood have been shown to affect IQ, the ability to pay attention and academic achievement. At very high levels, lead poisoning can be fatal. The effects of lead exposure cannot be corrected. Lead pollution can also cause irreversible encephalopathy, seizure, coma and even death. Fatigue, memory loss, high blood pressure, nephropathy, gastrointestinal disturbances, weight loss and immuno suppression are other common toxic effects of lead exposure in animals. Prenatal exposure to metal may also cause birth defects, miscarriage and underdeveloped babies.
by Dr. Rana Taj "Impact of Lead Toxicity on Body Defense"
Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021,
URL: https://www.ijtsrd.compapers/ijtsrd43613.pdf
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