Lead is a highly toxic metal found in small amounts in the earth's crust. Because of its relative abundance, low cost, and physical properties, lead and lead based compounds are frequently used in a wide variety of products including paint, ceramics, pipes, solders, gasoline, batteries, and cosmetics.

Both adults and children can suffer from the effects of lead poisoning, but childhood lead poisoning is much more frequent. Lead poisoning leads to a medical condition, also known as saturnism or plumbism (which is a toxic condition produced by the absorption of excessive lead into the system) or painter's colic, caused by increased blood lead levels. Lead may cause irreversible neurological damage as well as renal disease, cardiovascular effects, and reproductive toxicity.

Lead contamination can happen through deteriorating paint, household dust, bare soil, air, drinking water, food, ceramics, home remedies, hair dyes and other cosmetics. While lead paint that is in intact condition does not pose an immediate concern, lead paint that is allowed to deteriorate creating a lead-based paint hazard. It can contaminate household dust as well as bare soil around the house. In either situation, any person or animal that comes into contact with lead-contaminated dust or soil is easily poisoned. All it takes is the lead dust equivalent of a single grain of salt for a child to register an elevated blood lead level.

The lead produced by vehicle emissions continue to pose a serious threat even today as lead use goes unchecked in many countries across the globe. Much of the lead emitted by vehicles is directly inhaled by humans and a significant part remains in the soil where it keeps on accumulating over the years, especially near busy roads & highways. Not just humans, plants and animals are also equally contaminated with lead and may enter our food chain. Even our pets can come into contact with lead-contaminated soil and cause human exposure to lead.

The symptoms of chronic lead poisoning include neurological problems, such as reduced cognitive abilities, or nausea, abdominal pain, irritability, insomnia, metal taste in oral cavity, excess lethargy or hyperactivity, headache and, in extreme cases, seizure and coma.

Lead is known to affect peripheral and central nervous system. The most common sign of peripheral neuropathy due to chronic lead poisoning is painless wristdrop i.e. weakness of the extensor muscles of hand which usually develops after many weeks of exposure to lead. A direct link between early lead exposure & learning disability has been confirmed by multiple studies & child advocacy groups.

In humans, lead toxicity sometimes causes the formation of a bluish line along the gums, which is known as the "Burton's line", although it is quite uncommon in teenagers. Blood film examination may reveal "basophilic stippling" of red blood cells, as well as the changes normally associated with iron deficiency anemia i.e. microcytosis & hypochromia.

Lead has no known biological role in the body. The toxicity comes from its ability to mimic other biologically important metals, the most notable of which are calcium, iron and zinc. Lead is able to bind to and interact with the same proteins and molecules which can bind with metals and this interaction may cause those molecules to function differently. As a result, some set of reactions fail to attain completion e.g. disability of an enzyme function which is necessary for certain biological process.