Tetrachlorodibenzodioxin

Tetrachlorodibenzodioxin (TCDD), a chemical that is classified as a member of the chlorinated polycylclic aromatic hydrocarbon family, is oftentimes referred to as dioxin, the moniker that actually applies to this whole chemical family. TCDD is an environmental pollutant that is formed as a byproduct of the manufacturing process of other chemicals, such as chlorobenzene and chlorophenol compounds, oftentimes becoming a toxic contaminant. These compounds are commonly used as herbicides with the most infamous TCDD-contaminated herbicide being Agent Orange, the chemical that was used in the defoliation program during the Vietnam War that has been associated with numerous adverse health effects. TCDD may also be created in chemical reactions occurring during PCB transformer fires, the improper disposal of some chlorinated chemical waste products, and the burning of leaded gasoline.

The World Health Organization classifies TCDD as carcinogenic (capable of causing cancer) to humans. It awarded it this classification for a variety of reasons including the fact that TCDD causes cancer in a variety of different organs in animals, and acts through a cancer-causing mechanism in animals that functions the same way in humans. Research has shown that individuals who have had heavy exposure to TCDD, levels considered carcinogenic to animals, are at increased risk of developing cancer.

Some of TCDD's potential carcinogenicity may also come from its ability to cause toxic disruption of cell signaling, a process where chemical information is transferred from one cell to another or between different structures within the same cell. Improper cellular communication has not only been linked to the development of atherosclerosis, inflammation and psoriasis, but researchers also believe that poor communication between cells may be one of the causes of the excessive cell division, a condition which eventually leads to cancer.

TCDD causes a host of disruptions to the bodys physiological functions. Since it has been found to inhibit the enzymes that phagocytes (white blood cells) use to destroy bacteria, TCDD disrupts the proper functioning of the immune system with evidence of cell-mediated immunity suppression found in animals. TCDD has been shown to disrupt hormnone balance by affecting hormone receptors as well as upregulating several liver enzymes that are responsible for metabolizing hormones. These effects apply to various hormones including estrogen, leading to a state of estrogen level imbalance that can cause upset a variety of different metabolic functions. TCDD is also capable of causing lipid (fat) peroxidation, which damages cellular membranes since they are largely made up of lipids. Since a cell's membranes act like its gatekeepers, allowing in needed molecules while keeping out potentially harmful molecules and helping to remove the cell's waste products, TCDD's damage to cell membranes compromises the structure and function of cells, the basic building block of tissues and organs. Additionally, one of the hallmark symptoms of TCDD exposure is skin-related conditions including chloracne, a type of acneiform dermatitis caused by exposure to chlorine-containing chemicals.

TCDD is recognized as a teratogen (chemical that causes birth defects) in animals, causing such notable symptoms as cleft palate and kidney dysfunction. Its association with cleft palate seems to be enhanced with the co-administration of high doses of vitamin A, which is also teratogenic at high doses.

The main source of TCDD exposure in the general population is considered to be municipal waste and other incineration processes, and exhausts from cars using leaded gasoline. Yet, since TCDD is persistent, not readily breaking down into less toxic compounds, and has also been noted as a contaminant of several herbicides, sources of exposure may be considered more widespread as an environmental contaminant of soil, air and water. As such, dietary sources of TCDD have been identified. Both fish from contaminated water sources and animal products, such as milk, have been identified as sources. Since TCDD is highly soluble in fat, it is more likely found in fat-containing foods.

The main sources of TCDD exposure to the general population are considered to be municipal waste and other incineration processes and exhausts from cars using leaded gasoline. Soil, air and water are exposed to additional sources of this toxin because some herbicides breakdown into TCDD. TCDD is persistent in its environmental contamination, not readily breaking down into less toxic compounds. Both fish from contaminated water sources and animal products, such as milk, have also been identified as sources. Since TCDD is highly soluble in fat, it is more likely found in fat-containing foods.

The World Health Organization classifies TCDD as carcinogenic (capable of causing cancer) to humans. It awarded it this classification for a variety of reasons including: TCDD causes cancer in a variety of different organs in animals; it acts through a cancer-causing mechanism in animals that functions the same way in humans; and research has shown that individuals who have had heavy exposure to TCDD, levels considered carcinogenic to animals, are at increased risk of developing cancer. Some of its potential carcinogenicity may also come from its ability to cause toxic disruption of cell signaling, a process where chemical information is transferred from one cell to the other or between different structures within the same cell. Improper cellular communication has not only been linked to the development of atherosclerosis, inflammation and psoriasis but researchers also believe that poor communication between cells may be one of the causes of the overproliferation of cells, a condition which eventually leads to cancer.

TCDD causes a host of disruptions to the bodys physiological functions. Since it has been found to inhibit the enzymes that phagocytes (white blood cells) use to destroy bacteria, TCDD disrupts the proper functioning of the immune system with evidence of cell-mediated immunity suppression found in animals. TCDD has been shown to disrupt endocrine balance through modulating hormone receptors as well as upregulating several liver enzymes that are responsible for metabolizing hormones. These effects apply to various hormones including estrogen, leading to a state of estrogen level imbalance that can cause upset a variety of different metabolic functions. TCDD is also capable of causing lipid peroxidation, which can damage cellular membranes and compromise the structure and function of cells, the basic building block of tissues and organs. Additionally, one of the hallmark symptoms of TCDD exposure is skin-related conditions including chloracne, a type of acneiform dermatitis caused by exposure to chlorine-containing chemicals.

TCDD is recognized as a teratogen (chemical that causes birth defects) in animals causing such notable symptoms as cleft palate and kidney dysfunction. Its association with cleft palate seems to be enhanced with the co-administration of high doses of vitamin A, another teratogenic compound.