Carcinogen dioxin

For some animal species 2,3, T,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD dioxin ) is one of the most toxic synthetic compounds known to man (1 ). In addition to being toxic, 2,3,7,8-TCDD is also a suspected carcinogen, Dioxins can enter the environment in a variety of ways, generally as a contaminant of a product, as a waste byproduct, or as a product of combustion. For these rea-... 

In Europe, in the 1970s one major chemical accident in particular prompted the adaption of legislation aimed at the prevention and control of major accidents in the chemical process industry. The Seveso accident in northern Italy in 1976 occurred at a chemical plant manufacturing pesticides and herbicides. A dense vapor cloud containing dioxin was released due to an uncontrolled exothermic reaction. The poisonous and carcinogenic dioxin is lethal in microgram quantities and contaminated ten square miles, and more than 2,000 people were treated for exposure. Luckly, there were no immediate fatalities. 

Since 1979 the use of 24 5 T has been regu lated in the United States It is likely that the United States Environmental Protection Agency will classify some dioxins as known and others as probable human carcinogens and recommend further controls be placed on processes that produce them It appears from decreasing dioxin levels in some soils that exist mg regulations are having some effect ... 

Dioxin and Furan Emissions. The emissions of polychlorinated dibenzo-/)-dioxins (PCDD) and polychlorinated dibenzo-furans (PCDF) from incinerators (4) are of interest to the pubHc, scientists, and engineers. The U.S. EPA classifies 2,3,7,8-tetrachlorodibenzo-/)-dioxin (2,3,7,8-TCDD) as the most potent carcinogenic compound it has evaluated. It is also Hsted as the agency s most potent reproductive toxin (4). 

In the United States, the Clean Air Act of 1990 requires plants to reduce emissions of 189 toxic and carcinogenic substances such as chlorine, chloroform, and 2,3,7,8-TCDD (dioxin) by 90% over the 1990s. The U.S. Environmental Protection Agency is working to develop standards based on maximum achievable control technologies and the industry has invested bUHons of doUars in capital investments to retrofit or rebuUd plant equipment to meet these measures. 

Dioxins are prominent members of the class of polychlorinated hydrocarbons that also includes diben-zofuran, biphenyls and others. Dioxins are highly toxic environmental contaminants. Like others small planar xenobiotics, some dioxins bind with high affinity to the arylhydrocarbon (Ah) receptor. Dioxins activate the receptor over a long time period, but are themselves poor substrates for the enzymes which are induced via the Ah-receptor. These properties of the dioxins and related xenobiotics may be important for the toxicity of these compounds. Dioxins like 2,3,7,8-tetrachloro-p-dibenzodioxin can cause persistent dermatosis, like chloracne and may have other neurotoxic, immunotoxic and carcinogenic effects. 

Polychloro-benzenes, polybromo-benzenes, and dioxins (TCDD) are among these compounds. They were discovered when the analysis techniques improved. Especially the development of GC-MS has contributed to the knowledge of the distribution of these compounds. Effects on humans are the development of chloracne, suppression of the immune system, and some compounds are probably carcinogens (Shaw 1993). As a consequence of the ubiquitous nature of PCBs, humans are exposed via many sources. 

Owing to the fact that ethyl ethers are especially effective substrates for CYP1A1 [184], the probe possesses an ethyl group on the phenolic oxygen of the trimethyl lock. In vitro, fluorescence was manifested by CYP1A1 isozyme with Kcat/KM 8.8 x 103 M-1s 1 and KM 0.09 pM. In cellulo, the probe revealed the induction of cytochrome P450 activity by the carcinogen 2,3,7,8-tetrachlorodi-benzo-p-dioxin (TCDD), and its repression by the chemoprotectant resveratrol. 

Sunscreens and their degradation metabolites analyzed in this study are potential inducers of the oestrogen (ER) and aryl hydrocarbon receptors (AhR, also known as Dioxin Receptor). Ectopic activation of these pathways can cause severe damage to organisms and their ecosystem by altering reproduction, hormonal and/or circulatory systems [73-75] as well as they have been associated with carcinogenic and mutagenic effects [76-78]. 

Keywords carcinogenicity chemical terrorism chlororganic production dioxins ... 

Dioxin carcinogenicity for rodents and primates was proved by experiments. In rats, tumors of adipose tissues are mainly observed in mice, skin application of dioxin causes fibrosarcoma cutis at the place of exposure [3],... 

A second major advantage is that furan and dioxin compounds are not formed during gasification. Combustion of organic matter is a major source of these highly toxic and carcinogenic pollutants. The reasons why furans and dioxins are not formed in gasification are ... 

In the USA, the National Toxicology Program has declared dioxin a known human carcinogen - but injection moulder Brevet Inc. (who manufactures medical devices from PVC) plans to challenge the action in court. Brief details are given here. 

This includes bioremediation cases of contaminated sites with several toxic and carcinogenic pollutants, such as petroleum hydrocarbons, PAHs, dichlorobenzene, chlorinated hydrocarbons, carbon tetrachloride, Dicamba, methyl bromide, trinitrotoluene, silicon-based organic compounds, dioxins, alkyl-phenol polyethoxylates, nonylphenol ethoxylates, and polychlorinated biphenyls. The following is a brief summary of each case. 

Dioxin has been shown to be extremely carcinogenic to some animals. As well, it is suspected of disrupting hormone activity in the body, leading to reduced fertility and birth defects. 

Think how many carcinogens are household names asbestos, cigarette smoke (a mixture of several thousand chemical compounds), DES, dioxin, saccharin, arsenic, PCBs, radon, EDB, Alar. Hundreds more of these substances, some very obscure, are known to the scientific and medical community, and many of these are scattered throughout the land at thousands of hazardous waste sites similar to Love Canal. People are exposed to these dreadful substances through the air they breathe, the water they drink and bathe in, and the foods they eat. Chemicals can also produce many other types of health damage, some very serious, such as birth defects and damage to our nervous and immune systems. 

One of the pollutants known to interfere with cardiovascular development is 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD). TCDD is a persistent, bioaccumulative environmental contaminant, as well as a potent developmental toxicant and human carcinogen [30]. Piscine, avian, and mammalian cardiovascular systems are sensitive to TCDD toxicity, with effects including cardiac enlargement, edema, and several dysfunctions. In zebrafish embryos, these effects include areduction in cardiomyocyte number at 48 hpf, decreased heart size, altered vascular remodeling, pericardial edema, and decreased ventricular contraction culminating in ventricular standstill [31-34]. 

---