Storage, dioxin contamination

Current Cleanup Options for Dioxin Wastes. Governmental regulations and dioxin s negative image currently prevent off-site disposal or treatment of dioxin-contaminated wastes. In response to a need to destroy dioxin wastes, a number of novel process adaptations have been proposed and tested. These processes include incineration, physical-chemical, and biological processes. In addition, on-site containment, storage, and monitoring remain economic alternatives. 

E Consumers of animal-based foods Incineration emissions Dioxins Uptake into animals through contaminated feed, storage in animal tissues Ingestion... 

TCDD and other chlorinated dibenzo-J -di-oxins are released during the combustion of many polychlorophenols and also occur as contaminants in various chemicals such as the herbicide 2,4,5-trichlorophenoxyacetic acid. Most high-level exposure to 2,3,7,8-TCDD and other dioxins results from accidental releases or explosions in chemical plants or storage facilities for dioxin-containing chemicals. Because of the persistence of dioxin congeners in the environment and their potential for bioaccumulation, exposure may occur via the soil, air (especially when dioxins occur as combustion products), or water. When bound to components of the soil, the health hazard from 2,3,7,8-TCDD is reduced compared to ingestion of the pure compound. However, its bioavailability varies with the specific media in which it occurs. 

One class of compounds does deserve special attention—those chemicals that are very fat soluble. These include the older chlorinated pesticides, such as DDT, and some environmental contaminants, such as the PCBs (the polychlorinated biphenyls) and dioxins. In these cases, low levels of intact chemicals, if absorbed, may encounter the body s final defense mechanism. This defense is to store the compounds in fat and milk, a paradoxical strategy that the body uses to sequester away chemicals into a storage site (or depot) where they can do no harm to the rest of the body, ft s conceptually the prison system of the body. The absorption and distribution into fat greatly reduces the concentration of chemicals at other body sites and thus serves to blunt the impact of the exposure. Similarly, this simple method of diluting the absorbed chemical often keeps the concentration below an effect level and gives the overworked liver time to try to destroy them. 

EPA sampled in the locations most likely to be contaminated with dioxin (i.e., loading, storage, or production areas). If offsite migration of contaminated material was suspected, EPA sampled outside the facility boundary. Quality assurance/quality control protocols, following Superfund-authorized procedures, were developed to ensure that all data generated would be of known quality. 

Cleanup, Excavation, Transportation and Storage - Based on health advisories from the Centers for Disease Control, and the state health agency, contaminated materials are excavated until no dioxin Is left behind In the soil at a cleanup level of 1 ppb and, where excavation takes place, clean soil is put down so that people will not come In contact with dioxln-contamlnated soil. The basic approach Involves Innovative excavation of 4- to... 

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