Dioxin problem

The detection of a potent dioxin impurity in a major herbicide has focused attention on the nature of chlorinated impurities in pesticides, and in a larger sense, impurities in all chlorinated industrial compounds used extensively in man s environment. The present 2,4,5-T controversy is overshadowed by the dioxin problem. Major disagreement still exists on their relative contributions to the teratogenic effects observed in chicks and the validity of interpretation of high dosage rates used to achieve these effects. We have avoided any assessment of the health-related aspects of dioxins but have dealt almost exclusively with dioxins as an environmental entity. 

PCDD/Fs are emitted or spilled from many processes, but as they were found in the emissions from all combustion processes, thermal processes are recognized to be a main source, and a major public concern, especially waste incineration. But dioxins problem is attributed to all human activities, connected either with production or utilization of solid wastes and wastewaters. One of the crucial examples of the problem is sewage sludge contamination. 

Stief-Tauch HP (1994), Fresenius J. Anal. Chem. 348 47-52. The response of the EEC to the dioxin problem"... 

Kimura Y (1994), Organohalogen Compounds 20 571-574.. .Japan s experience in dealing with dioxin problems", Eds. University of Kyoto, Japan... 

The origin of the dioxin problem can be traced back to the Second World War when the production of polychlorophenol-based pesticides was launched. In particular, the industrial production of 2,4,5-trichlorophenol and its corresponding herbicide 2,4,5-trichlorophenoxyacetic acid has led to a number of accidents resulting in the release of... 

EPA also had rulemaking proceedings underway to address various aspects of the dioxin problem. 

EPA Is sensitive to the concerns of those residents whose communities have been contaminated with dioxin. We are moving forward with cleanup activities and tremendous progress has already been made toward our overall goal, which Is a comprehensive, final solution to the Missouri dioxin problem. 

Analysis problems for dioxin at the parts per trillion level in human fat would be similar to parts per quadrillion (1000 times more remote) in water because with water one works usually with a much larger sample size. Since few work at the parts per quadrillion level in water, it is expected that the dioxin problem should be extremely severe. Another study quoted by Dr. Crummett involved analysis at this level in five private water wells performed by four different laboratories. As Dr. Crummett relates ... 

Dioxin attracted attention as a carcinogen. The dioxin problem with regard to paper and pulp first became serious in the United States. However, the US Federal Drug Administration (FDA) later testified at a Congressional Subcommittee on Health and Environment that as far as the available information is concerned the extremely small amount of dioxin cannot... 

The principal PIC for penta and penta-treated wood would include volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), dioxins and furans, as well as SOj, COj, NO, and HCl. Penta would be expected to have undergone a very high destruction efficiency (DRE) during the fire (> 99.99%). Among the VOC emissions, the following chemicals likely contributed to air pollution problems benzene, bromobenzene, chloromethane, 1,3-butadiene, iodomethane, acetone, chloroform, and 1,2-dichloroethane. 

Of great concern for air pollution problems resulting from the incident are dioxin-like compounds. In general, dioxin-like compounds can be generated when chlorine donor compounds are present. Depending on the source of the coal tar, chlorine content may range between 1 and 5000 ppm. 

Polymer disposal in an inappropriate manner creates environmental problems such as dioxin formation, catastrophic fires, breeding of rats, and mosquitoes. Several methods have been explored to utilize plastics and mbber waste in an environment-friendly manner. Some of the recent advances in mbber recycling are reviewed in this chapter with special emphasis to waste mbber reutilization in plastics and mbbers. The utilization of waster mbber powder in polymer matrices provides an attractive strategy for polymer waste disposal. 

Variations in the manufacturing process of 2,4,5-trichloro- and pentachlorophenol (but not 2,4-dichlorophenol) have sometimes resulted in contamination of the product by small amounts of heterocyclic impurities (4,5). Of these, the chlorinated dibenzo-p-dioxins such as TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) have received much scientific and public attention because of their real or potential toxicity 6, 7), [Chick edema factor, a curious toxicological problem to poultry producers for several years, has been shown to be composed of chlorodibenzo-p-dioxins (8).]... 

Secondary metal production is advantageous not only with respect to energy consumption but also to environmental impact as compared to primary metal production. The important environmental problems pertain to the formation of dioxins during thermal processing and the generation of dusts of the oxides of zinc, lead, and other metals in secondary steel, copper, and zinc production. 

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