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2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a polychlorinated dibenzo-p-dioxin (sometimes shortened, though inaccurately, to simply 'dioxin') [3] with the chemical formula C 12 H 4 Cl 4 O 2. Pure TCDD is a colorless solid with no distinguishable odor at room temperature.
2,3,7,8-Tetrachlorodibenzofuran (TCDF) is a polychlorinated dibenzofuran with a chemical formula of C 12 H 4 Cl 4 O. TCDF is part of the chlorinated benzofuran (CDF) family that contains between 1 and 8 chlorine atoms attached to the parent dibenzofuran ring system. The CDF family includes 135 compounds, of which only a few have been studied.
By far most toxicity studies have been performed using 2,3,7,8-tetrachlorodibenzo-p-dioxin. The LD 50 of TCDD varies wildly between species and even strains of the same species, with the most notable disparity being between the seemingly similar species of hamster and guinea pig.
One of the most toxic compounds known, 2,3,7,8-tetrachlorodibenzo[p]dioxin, a PCDD, is assigned a TEF of 1. [54] In June 2020, State Impact of Pennsylvania stated that "In 1979, the EPA banned the use of PCBs, but they still exist in some products produced before 1979. They persist in the environment because they bind to sediments and soils.
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is the reference chemical to which the toxicity of other dioxins and DLCs are compared. TCDD is the most toxic DLC known. TCDD is the most toxic DLC known. Other dioxins and DLCs are assigned a scaling factor, or TEF, in comparison to TCDD.
[2] [3] For general population the most important source is food of animal origin like with other dioxin-like compounds. [ 4 ] [ 5 ] [ 6 ] The most relevant congener is 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PCDF) which is more toxic and based on relative toxicity more prevalent than other PCDFs.
The 2,4,5-T used was contaminated with 2,3,7,8-tetrachlorodibenzodioxin (TCDD), an extremely toxic dioxin compound. During the Vietnam war, between 1962 and 1971, the United States military sprayed 20,000,000 U.S. gallons (76,000,000 L) of chemical herbicides and defoliants in Vietnam, eastern Laos and parts of Cambodia, as part of Operation ...
1,2,4,5-tetrachlorobenzene once was used as intermediates in the production of pesicides, [3] specifically trichlorophenols. This method has been discontinued because it also produced 2,3,7,8-tetrachlorodibenzo-p- dioxin .