Octachlorodibenzodioxin

Octachlorodibenzodioxin is one of polychlorinated dibenzodioxins. When compared to 2,3,7,8-tetrachlorodibenzodioxin, its toxicity is about 3000 times weaker.
It is one of the dominant PCDD congeners in smoke emissions, but because it is much less soluble than TCDD, it is not bioaccumulated as effectively and it is toxicologically less important than the most prevalent dioxins. .
Chlorinated pesticides can also contain impurities of polychlorinated dibenzodioxins and polychlorinated dibenzofurans and their precursors. "Precursor formation of PCDD/Fs can also be mediated by ultraviolet light " from sun. Changes in congeners ratio after UV exposition suggest that pesticide sources of dioxines-like after sunlight exposure "may not be recognized based on matching source fingerprints established from manufacturing impurities. These changes also provide preliminary insights into the possible formation routes and types of precursors involved".