Burial

Once in a wetland environment, toxic organics are subject to both biological and nonbio-logical processes. 

Many processes affect the transformation, transport, and accumulation of toxic organics. The processes included biotic and abiotic transformations. Both these processes can occur simultaneously in wetlands. 

Biotic transformation or microbial metabolism is generally the most effective in degrading toxic compounds in wetlands. 

Wetlands can efficiently degrade or process toxic organics. The rate of degradation and turnover is governed by the nature of the organic chemical and soil-sediment biogeo-chemical properties. 

Rates of degradation in the wetland systems depend on a number of environmental factors including redox, pH, nutrient availability, temperature, contaminant bioavailability, and microbial biomass density. 

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Resistance to Microorganisms and Insects. Resistance of triacetate to microorganisms, based on soil-burial tests, is high, approaching that of polyester, acryUc, and nylon fibers. Sod-burial test results on acetate, triacetate, and cotton are shown in Figure 8. Neither acetate nor triacetate fiber is readdy attacked by moths or carpet beedes. 

Fig. 8. The resistance of cellulose fibers to biological attack via sod-burial testing.

Chemical analysis of the metal can serve various purposes. For the determination of the metal-alloy composition, a variety of techniques has been used. In the past, wet-chemical analysis was often employed, but the significant size of the sample needed was a primary drawback. Nondestmctive, energy-dispersive x-ray fluorescence spectrometry is often used when no high precision is needed. However, this technique only allows a surface analysis, and significant surface phenomena such as preferential enrichments and depletions, which often occur in objects having a burial history, can cause serious errors. For more precise quantitative analyses samples have to be removed from below the surface to be analyzed by means of atomic absorption (82), spectrographic techniques (78,83), etc. 

Materials that have been buried underwater cause a special problem. Waterlogged woods and leathers (139), although quite stable under such burial conditions, are ia danger of irreversible damage through drying out upon recovery. Indeed, after excavations from bogs or upon recovery from underwater sites, these items need to be stored underwater until laboratory treatment. 

Sur cia.1 Deposits. Uraniferous surficial deposits maybe broadly defined as uraniferous sediments, usually of Tertiary to recent age which have not been subjected to deep burial and may or may not have been calcified to some degree. The uranium deposits associated with calcrete, which occur in Australia, Namibia, and Somaha in semiarid areas where water movement is chiefly subterranean, are included in this type. Additional environments for uranium deposition include peat and bog, karst caverns, as well as pedogenic and stmctural fills (15). 

The geologic aspects of waste disposal (24—26), proceedings of an annual conference on high level waste management (27), and one from an annual conference on all types of radioactive waste (28) are available. An alternative to burial is to store the spent fuel against a long-term future energy demand. Uranium and plutonium contained in the fuel would be readily extracted as needed. 

The Shallow land Burial ofEow-Eevel Radioactively Contaminated Solid Waste, Committee on Radioactive Waste Management, National Academy of Sciences, Washiagton, D.C., 1976. 

Other simple tests include the soil burial test used to demonstrate the biodegradabiUty of polycaprolactone (25), following its disappearance as a function of time, and the clear 2one method which indicates biodegradation by the formation of a clear 2one in an agar medium of the test polymer or plastic as it is consumed (26). The burial test is still used as a confirmatory test method in the real-world environment after quantitative laboratory methods indicate bio degradation. 

In 1980, Congress deterrnined that each state should be responsible for ensuring the proper handling and disposal of commercial low level nuclear wastes generated in their states. Regional disposal sites have also been estabHshed at BamweU, South Carolina, and Ward Valley, California. These wastes are handled by Hcensed disposal faciHties where they are packaged, placed in burial trenches, and covered with soil. Less than half of the low level nuclear waste produced annually in the United States comes from nuclear power plants. Low level nuclear power plant wastes include contaminated equipment. 

According to the autochthonous, in situ theory of coal formation, peat beds and subsequently coal were formed from the accumulation of plants and plant debris in place. According to the allochthonous theory, the coal-producing peat bogs or swamps were formed from plant debris that had been transported, usually by streams or coastal currents, to the observed burial sites. 

Unlike the famous royal Pazyryk Kurgans, the ancient burials on the Ukok Plateau have been untouched by grave robbers they were discovered in their original state. Among numerous unique finds, the most remarkable ones are well-preserved human hair and nails, tails and manes of the horses buried together with the people and also the ash from the censer. 

Fig. 10-3 Section through an insulated eoupling for direet burial.

The general purpose of ultimate disposal of hazardous wastes is to prevent the contamination of susceptible environments. Surface water runoff, ground water leaching, atmospheric volatilization, and biological accumulation are processes that should be avoided during the active life of the hazardous waste. As a rule, the more persistent a hazardous waste is (i.e., the greater its resistance to breakdown), the greater the need to isolate it from the environment. If the substance cannot be neutralized by chemical treatment or incineration and still maintains its hazardous qualities, the only alternative is usually to immobilize and bury it in a secure chemical burial site. 

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