Dioxins-iron

Sophia M, Christine Walden, Alex McGrorty Abstract: Dioxins are a group of toxic chlorinated chemicals. They differ in toxicity levels, depending on molecular structure. Tetrachlorodibenzo – para – dioxin in the most toxic and most tested of the group. Dioxins are produced commonly by burning chlorine with hydrocarbons. They are not produced for any purpose, and can occur naturally or during industrial manufacturing. Dioxins are not usually made in large quantities, but can build up over time and take many years to break down. They are more commonly found in soil and sediments, but can also be in water or air. In animals and humans, dioxins tend to build up in the fat and liver tissue. Humans can inhale, ingest or absorb dioxins. They often begin in small plants and gradually pass up through the food chain. Once in the body, dioxins can hard the reproductive and immune system, as well as general healthy development. Dioxins were around for a while, but closely tested during the 1980s for harmful effects. People started trying to avoid dioxins and reduce emissions. Dioxin levels have lowered significantly since the 1980s everyone became aware of the hazards.

Write up: Dioxins are a group of highly toxic chemicals that are a produced as a result of various chemical combustions during industrial manufacturing. They are produced usually by burning chlorine with hydrocarbons. Such causes include waste incineration, forest fires, cigarette smoke, burning plastics, paper bleaching and pesticide manufacturing.

Dioxins are named based on the chlorine atoms within them: how many there are, and where they are positioned. “The group with one chlorine atom is called the mono-chlorinated dioxin(s). The groups with two through eight chlorine atoms are called di-chlorinated dioxin (DCDD), tri-chlorinated dioxin (TrCDD), tetra-chlorinated dioxin (TCDD), penta-chlorinated dioxin (PeCDD)...etc” The numbers represent the one of the 8 positions of the chlorine atoms.

The best known and most toxic of dioxins is TCDD (2,3,7,8- tetrachlorodibenzo - para - dioxin.) tetra-dichlorobenzene has four chlorine atoms attathed at positions 2,3,7 and 8. Additional examples of dioxins are polychlorinated biphenyls (PCBs), polychlorinated dibenzo dioxins (PCDDs), and polychlorinated dibenzo furans (PCDFs.)

These toxins are not produced 'on purpose' or for any specific usage, but merely as a bi product. Dioxins are mostly produced in small amounts, but can build up over time. They are most commonly found in soils or the air, but are not very soluble in water. Dioxins found in the air can travel long distances, and travel furthest in warm/hot air because it lifts them higher off the ground.

Dioxins are technically unsafe at any level of exposure. They can actually put one at more risk for cancer as well as harm the endocrine system, male reproductive system/fertility, growth development and possibly the immune system. Based on studies by the EPA, dioxins “may mimic natural hormones, inhibit the action of hormones, or alter the normal regulatory function of the immune, nervous, and endocrine systems.”

2, 3, 7, 8- TCDD is considered a group 1 human carcinogen. Humans are exposed by: inhaling the toxin, coming into skin contact, consuming dirt or eating other animals that have previously ingested the dioxin, such as fish. Dioxins are built up in all body tissues, but largely target fat tissue and the liver. It can take about 20 years for a human to fully rid them self of TCDD.

Dioxins are harmful to wildlife as well as humans. Most of the same human effects have also appeared in animals. They harm fertility in mammals, “hatching success in fish, birds and reptiles,” afflict the immune system and general healthy development.

For a while, people were generally ignorant to the presence and effects of dioxins. They became more aware once problems such as cancer and genetic defects began to display themselves and were tested. These discoveries were made in about the 1980’s, allowing people to try and avoid dioxins and address they’re release.

When data was spread on how dioxins go into the environment and people, industries became more wary of their combustion practices and were able to instate stricter rules, and more effective methods were introduced. The dioxin levels in the environment and humans changed, with studies showing that the level of dioxins in the environment are at more than safe levels in most areas and the dioxins in humans have decreases by nearly 80% from the 1980s. However because it takes so long for dioxins to degrade and it is hard to completely cut back on production, they will still be present for quite some time to come.

http://www.ecy.wa.gov/pubs/0104010.pdf http://www.atsdr.cdc.gov/toxprofiles/phs104.html#bookmark01 http://cqs.com/edioxin.htm http://www.greenfacts.org/en/dioxins/l-3/dioxins-1.htm http://science.jrank.org/pages/2102/Dioxin-TCDD-other-dioxins.html