decsribe the chararcteristics of dioxins and PCBs.?

Answer 1

Dioxins are among the most toxins on earth. Dioxin is the popular name for halogentated organic compounds, the most common being PCDFs or polychlorinated dibenzofurans. The basic structure is two benzene rings joined by a single or double oxygen bridge.

Dioxins can be tolerated in low doses and the main source is through the food chain as they are fat soluble. Herbicides is another source, as well as when organic material is burned in the presence of chlorine.

According to the EPA 80% of all dioxin comes from: coal fired utilities; metal smelting; diesel trucks; sewage sludge; burning treated wood; and trash barrel burns.

Dioxins accumulate in the body and have a half live of 7 years in humans and can cause: acne, damage to teeth enamel; cancer; nervous system disorders; thyroid conditions; immune system damage; endometriosis; birth defects; chronic pulmonary disease; and diabetes.

Generally not a good thing to ingest. See the Wikipedia article for complete information.

PCBs are polychlorinated biphenyls. They are highly stable compounds and do not degrade easily, hence there accumulation in nature and the atmosphere.

The have similar health effects as that of dioxins and again is one of the most toxic substances known to man. They can cause skin conditions; liver damage; acne; thyroid injury and so on - much the same list as for dioxins. Again Wikipedia has a complete description.