ABSTRACT
Dioxins and PCBs are among the most dangerous chemicals known to man. The exposure to these compounds can result in biochemical and biological effects in animals and humans. They are toxic, persistent, and they can bioaccumulate up the food chain, putting humans and higher predators at increased risk. They are also able to affect the body’s chemical messengers or hormone system and are therefore considered to be endocrine disruptors (EDCs). Dioxins and PCBs therefore have all the properties of persistent organic pollutants (POPs) and are two of the 12 agreed “worst” or “most toxic chemicals known to man.” They have been listed as priority pollutants by the United Nations Environment Program (UNEP) because of their potential carcinogenicity, mutagenicity, and toxicity to aquatic and terrestrial animals and humans. The risks posed by POPs for human health have become of increasing concern and are actually object of a worldwide agreement among several governments, including measures to reduce or eliminate their release in the environment. Because over 90% of human exposure comes from the food supply, recent regulatory initiatives have focused on monitoring food and animal feed for these harmful contaminants. Despite the downward trend in human exposure to dioxins, the risks posed by these substances are now considered to be greater than in the past because research shows effects at lower levels of exposure than previously suggested. Further it needs, when assessing the risks of these substances, to group dioxins with certain PCBs (dioxin-like) because they have a similar mechanism of action.
