Environmental destroyers

Demilitarization and Disposal of Explosive Material. An important consequence of international agreements to greatiy reduce the stockpiles of conventional and nuclear munitions is the intensification of a program to develop procedures to destroy, recycle, and/or reclaim explosives, propellants, and pyrotechnic material efficientiy and without significant environmental impact. 

Environmental Impact of Ambient Ozone. Ozone can be toxic to plants, animals, and fish. The lethal dose, LD q, for albino mice is 3.8 ppmv for a 4-h exposure (156) the 96-h LC q for striped bass, channel catfish, and rainbow trout is 80, 30, and 9.3 ppb, respectively. Small, natural, and anthropogenic atmospheric ozone concentrations can increase the weathering and aging of materials such as plastics, paint, textiles, and mbber. For example, mbber is degraded by reaction of ozone with carbon—carbon double bonds of the mbber polymer, requiring the addition of aromatic amines as ozone scavengers (see Antioxidants Antiozonants). An ozone decomposing polymer (noXon) has been developed that destroys ozone in air or water (157). 

In a series of papers (175) comparing chlorination and o2oni2ation, reactive and acid dyes were readily destroyed, but direct and disperse dyes reacted more slowly o2one was more effective in some instances. Although chlorination is cheaper than o2oni2ation, the possible formation of chlorinated compounds such as dioxin and its environmental impact caimotbe overlooked (see Chlorocarbonsandchlorohydrocarbons, TOXIC AROMATICS). 

Zinc is often used as a protective coating over iron to form galvanized iron. In industrial settings exposed to SOj and humidity, this zinc coating is subject to sufficient corrosion to destroy its protective capacity. Haynie and Upham (5) used their results from a zinc corrosion study to predict the useful life of a zinc-coated galvanized sheet in different environmental settings. Table 9-2 shows the predicted useful life as a function of SO concentration. 

Detoxification. Destroys or reduces toxics that may otherwise create adverse environmental impacts. 

Urban, rural and industrial developments may have profound effects on the surrounding environment. Such effects can defeat the object of development, in that the negative environmental impact may outweigh the benefits. In the case of natural resources, inappropriate development may even destroy the resource base. If environmental matters are accorded adequate consideration during the planning and management of development programs and projects it is possible for pollutants to be assimilated. As a result, the whole development can be accommodated by the environment in such a way that adverse effects are minimized and the economic and social benefits of development are maximized. 

The half-life, f1/2, of a substance is the time needed for its concentration to fall to one-half its initial value. Knowing the half-lives of pollutants such as chlorofluoro-carbons allows us to assess their environmental impact. If their half-lives are short, they may not survive long enough to reach the stratosphere, where they can destroy ozone. Half-lives are also important in planning storage systems for radioactive materials, because the decay of radioactive nuclei is a first-order process. 

The clouds around Venus contain relatively large droplets of sulfuric acid, which occasionally rain down on the surface of the planet, or at least they try to, because the temperature is so high that the droplets evaporate before they actually reach the surface. (This almost rain is called virga, the term for any kind of precipitation that evaporates before it reaches the ground.) On Earth, however, the sulfuric acid does not evaporate but falls to the ground as acid rain, an environmental pollutant that can destroy buildings and harm plants and animals. 

The United States Environmental Protection Agency (U.S. EPA) has identified several hundred MTBE-contaminated sites that have performed treatment of soil and groundwater to remove or destroy MTBE.1 Many of these sites have also treated other fuel components, primarily benzene, toluene, ethylbenzene, and xylene (BTEX), and some have treated fuel oxygenates other than MTBE. Although others have reported about treatment technologies for MTBE cleanup,2 only limited information has been published about cleanup of other oxygenates. These oxygenates include ether compounds, such as ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), diisopropyl ether (DIPE), and tert-amyl ethyl ether (TAEE), as well as alcohol compounds, such as tert-butyl alcohol (TBA), tert-amyl alcohol (TAA), ethanol, and methanol. 

The usual method for disposing of pesticides in the USSR was walling them into spent quarries and mine shafts. For example, more than 3000 tons of pesticides were walled into unfitted vertical boreholes in the Krasnodar Krai. The complete destruction of pesticides has become a large environmental problem, comparable in scale to the problem of destroying chemical weapons stocks. About 40,000 tons of unused pesticides (banned or too old to be used) had accumulated in the countries of the former Soviet Union, about half of which are located in Russia. 

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