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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. Other dioxins and DLCs are assigned a scaling factor, or TEF, in comparison to TCDD. TCDD has a TEF of 1.0. Sometimes PCB 126 is also used as a reference chemical, with a TEF of 0.1.
The uncertainty and variability in the dose–response relationship of dioxins in terms of their toxicity, as well as the ability of dioxins to bioaccumulate, have led WHO experts to recommending very low tolerable daily intake (TDI) of dioxin, 1-4 pg/kg body weight per day, i.e. 7x10 −11 to 2.8x10 −10 g per 70-kg person per day, to allow ...
Dioxins build up primarily in fatty tissues over time (bioaccumulation), so even small exposures may eventually reach dangerous levels. In 1994, the US EPA reported that dioxins are a probable carcinogen, but noted that non-cancer effects (reproduction and sexual development, immune system) may pose a greater threat to human health.
The EPA said that it would require Norfolk Southern to “test directly” for dioxins and to perform a cleanup anywhere levels are found that are unacceptable for human health. The EPA has said ...
[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 Dioxin Reassessment Report refers to the United States Environmental Protection Agency's scientific reassessment of the health effects of exposure to dioxins. It began in April 1991, and in 1994 was published for public review.
“Dioxins are heavy compounds that like to stick to stuff,” Whelton said. ... The EPA said it began testing air quality in the East Palestine area within 24 hours of the derailment and is also ...
Chemical compounds containing such rings are also referred to as furans. Furan is a colorless, flammable, highly volatile liquid with a boiling point close to room temperature. It is soluble in common organic solvents, including alcohol, ether, and acetone, and is slightly soluble in water. [2] Its odor is "strong, ethereal; chloroform-like". [3]