Search results
Results From The WOW.Com Content Network
Infobox references. 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 contain 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.
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 ...
One of the most toxic compounds known, 2,3,7,8-tetrachlorodibenzo[p]dioxin, a PCDD, is assigned a TEF of 1. 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.
It resulted in the highest known exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in residential populations, which gave rise to numerous scientific studies and standardized industrial safety regulations, including the European Union's Seveso III Directive.
Toxic equivalency factor ( TEF) expresses the toxicity of dioxins, furans and PCBs in terms of the most toxic form of dioxin, 2,3,7,8-TCDD. [1] The toxicity of the individual congeners may vary by orders of magnitude . With the TEFs, the toxicity of a mixture of dioxins and dioxin-like compounds can be expressed in a single number – the toxic ...
Additionally, the manufacturing process for 2,4,5-T contaminates this chemical with trace amounts of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). TCDD is a carcinogenic persistent organic pollutant with long-term effects on the environment. With proper temperature control during production of 2,4,5-T, TCDD levels can be held to about .005 ppm.