Dioxins/Furans, Dioxin-Like & Non Dioxin like PCBs
Poly Chlorinated dioxins and furans are formed two different ways, either by combustion or chemical processes. Either way these compounds are bi-products and are formed more by accident than choice. There are 210 polychlorinated dioxins and furans, however we only look for the 17 most toxic congeners which are 2,3,7,8 chloro positioned congeners.
Poly Chlorinated Biphenyls are different in their formation to dioxins/furans, were as they are purposely man made products used in electronics and utility industries. PCB manufacture is now banned, however there is still a world wide inventory , and due to their inert properties are still within the environment. There are 209 PCBs, however we only look at three ‘groups’ – Dioxin-Like PCBs, which are of a similar chemical structure and therefore produce the same toxic responses to dioxins, Non-Dioxin-Like PCBs, and total mono-deca PCBs.
There are many toxic responses of dioxins and PCBs which include it being a carcinogen, immune system suppressant, effecting fertility, and a cause of dermal disorders (chloracne)
Limits on maximum permitted levels of dioxins & PCBs have been in use since 2002 for a range of food and feed ingredients including; meats, fish, fats & oils, minerals, trace elements, premixtures, compound feeds, dairy products (milk, eggs, butter), offal, and infant foods.
Both dioxins and PCBs are extremely stable in terms of chemical and thermal qualities , they have a very good lipo-solubility and are biologically non degradable – this makes them Persistent.
They enter the food chain in many different ways, including heat processes used in manufacture, or simply by contamination of oils used in foods and feeds.