Lead poisoning

Lead (Pb) is a natural component of the earth's crust with trace amounts existing in soil, water and plants. It has many uses, including in the manufacture of lead-acid batteries for motor vehicles and energy storage, in pigments and paints, solder, ammunition, ceramic glazes, jewelry, toys and also in some cosmetics and traditional medicines.

Lead is the most important toxic heavy element in the environment. Globally it is an abundantly distributed, important yet dangerous environmental chemical. According to WHO lead poisoning refers to excessive human exposure to lead.

Lead enters the body via ingestion or inhalation from sources such as soil, food, lead dust and contact with lead in products of everyday use and in the workplace. In the work environment, the main route of absorption of Pb and its compounds is through the respiratory system, although lead is also absorbed via the digestive system.

Lead has been used for thousands of years and its poisoning effects have been recognized for several centuries. Leaded gasoline and paints were thought to be the main sources of lead pollution in the environment.

Though its widespread use has discontinued in many countries of the world, it is still used in many industries like car repair, battery manufacturing and recycling, refining, smelting, etc. Lead is a highly poisonous metal affecting almost every organ in the body.

Lead has no biological function in the body. It accumulates in the body and affects practically all organ systems. Long-time exposure to lead has been reported to cause anemia, along with an increase in blood pressure, and that mainly in old and middle-aged people.

Lead exposure can cause chronic and debilitating health impacts in all age groups, but it is particularly harmful to young children. This is because the developing nervous system is vulnerable to the toxic effects of lead, even at levels of exposure that do not cause obvious symptoms and signs.
Lead poisoning

Cadmium toxicity

Cadmium is an inorganic metal that is naturally present in the environment. Like lead, cadmium accumulates in the body and has varying degrees of toxicity.

Cadmium can contaminate food by its presence in pesticides, pigments, plaints, plastics, and cigarettes.

Cadmium’s toxic effects are kept under control when balanced by adequate body stores of zinc.

The human body can tolerate low levels of cadmium, but long term chromic exposure can lead to serious health problems.

Hazardous cadmium levels lead to nephrotoxic effects, i.e. renal tubular dysfunction. Cadmium furthermore inhibits several SH-containing enzymes in the brain, while chronic cadmium exposure leads to reduced levels of norepinephrine, serotonin and acetylcholine.

High exposure has been linked to osteomalacia, a softening of the bones.

Cadmium is a potent antagonist of several essential minerals, including zinc, copper, iron and calcium.

Cadmium cam accumulate to toxic levels over a lifetime because the mineral is not well excreted by the human body. However cadmium is poorly absorbed, so normal dietary intake does not warrant concern for toxicity.

The absorption of cadmium from food varies, depending on genetic factors, age, and nutritional factors.

Infants absorb and accumulate more cadmium than adults.

Cadmium deposits in the kidneys, causing kidney tissue damage and high blood pressure or hypertension as well as calcium kidney stones.
Cadmium toxicity