Fates of Hazardous Wastes

The effects of hazardous wastes in the environment can be divided among effects on organisms, effects on materials, and effects on the environment. These are addressed briefly here and in greater detail through Section 15.15. 

The ultimate concern with wastes has to do with their toxic effects on animals, plants, and microbes. Virtually all hazardous waste substances are poisonous to a degree, some extremely so. The toxicity of a waste is a function of many factors, including the chemical nature of the waste, the matrix in which it is contained, circumstances of exposure, the species exposed, manner of exposure, degree of exposure, and time of exposure. The toxidties of some of the substances found in hazardous wastes are discussed in more detail in Chapter 2. 

As defined in Section 15.6, many hazardous wastes are corrosive to materials, usually because of extremes of pH or because of dissolved salt content Oxidant wastes can canse combustible substances to bum uncontrollably. Highly reactive wastes can explode, cansing damage to materials and structures. Contamination by wastes, such as by toxic pestiddes in grain, can result in substances becoming unfit for use. 

In addition to their toxic effects in the biosphere, hazardous wastes can damage air, water, and soil. Wastes that get into air can cause deterioration of air quality, either directly or by the formation of secondary pollutants. Hazardous waste compounds dissolved in, suspended in, or floating as surface films on the surface of water can render it unfit for use and for sustenance of aquatic organisms. 

Soil exposed to hazardous wastes can be severely damaged by alteration of its physical and chemical properties and ability to support plants. For example, soil exposed to concentrated brines from petroleum production may become unable to support plant growth so that the soil becomes extremely susceptible to erosion. 

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Apps, J.A., Current Geochemical Models to Predict the Fate of Hazardous Wastes in the Injection Zones of Deep Disposal Wells, Lawrence Berkeley Laboratory, Report LBL-26007, 1988. 

Jaffe, R., and Hites, R.A (1986). Fate of hazardous waste derived organic compounds in Lake Ontario. Environ. Sci. Technol. 20, 267-274. 

Apps, J.A., 1992. Current geochemical models to predict the fate of hazardous wastes in the injection zones of deep disposal wells. Lawrence Berkeley Laboratory report, LBL-26007. 

Manahan S., (1989), Humic Substances and the Fates of Hazardous Waste Chemicals, Chapter 6 in Influence of Aquatic Humic Substances on Fate and Treatment of Pollutants, Advances in Chemistry Series 219, American Chemical Society, Washington, DC. 

The fates of hazardous waste substances in the atmosphere are often determined by photochemical reactions. Ultimately, such substances may be converted to nonvolatile, insoluble matter and precipitate from the atmosphere onto soil or plants. 

The fates of hazardous-waste substances are addressed in more detail in subsequent sections. As with all environmental pollutants, such substances eventually reach a state of physical and chemical stability, although that may take many centuries to occur. In some cases, the fate of a hazardous-waste material is a simple function of its physical properties and surroundings. 

The major processes affecting the geochemical fate of hazardous inorganics are acid-base adsorption-desorption, precipitation-dissolution, complexation, hydrolysis, oxidation-reduction, and catalytic reactions. The significance of these processes to inorganic wastes is discussed only briefly here additional information on individual elements is given in Table 20.16. 

On the other hand, Aboul-Kassim [1] assessed the environmental impact of hazardous waste materials in landfills by (1) characterizing the different organic compound fractions present in such wastes and their leachates, (2) determining the toxic effect of each fraction and individual organic compounds, and (3) studying the chemodynamics (i.e., fate and transport) of such leachates by using a battery of laboratory experiments (such as sorption/desorption, photolysis, volatilization, biodegradation). 

The USEPA surveys identified 17 pesticide plants using deep well injection for the disposal of wastewater [7]. One plant used incinerators to remove pesticides as well as benzene and toluene from the wastewater before disposal by deep well injection. Using deep well injection to dispose of hazardous wastes is expected to decrease in the future because of more stringent regulatory requirements and increased concerns about the long-term fate of these wastes in the injection zone. 

N. F. Surprenant and co-workers, The Fate of Hazardous and Nonha ardous Wastes in Used Oil Disposal and RjeycBng, DOE/BC/10375-6, Department... 

David T. Allen and Ravi K. Jain, National Hazardous Waste Databases Generation and Fate of Hazardous Materials in the USA, Liebert, New York, 1992. 

Gerdes C, Meier D, Kaminsky W, Flash pyrolysis of industrial biomass wastes , Meier D, Ollesch T, Faix 0, Fast pyrolysis of impregnated waste wood - The fate of hazardous components ,... 

Meier D., Ollesch T.. Faix O. (2000) Fast Pyrolysis of Impregnated Waste Wood-the Fate of Hazardous Components. In Progress in Thermocbemicai Biomass Conversion, (Ed, by T. Bridgwater), submitted for publication,... 

Fast Pyrolysis of Impregnated Waste Wood - The Fate of Hazardous Components... 

Physical and chemical tests of the final product may need to address two concerns (1) whether the solidified waste exhibits any RCRA defined toxicity characteristics or could be delisted and (2) the potential long term fate of treated materials in the disposal environment. Three tests are available which address the first concern. These are the Extraction Procedure (EP Tox) (40 CFR 261, Appendix II, 1980) and the Toxicity Characteristic Leaching Procedure (TCLP) (40 CFR 261, Appendix II, 1986), and the Multiple Extraction Procedure Test (40 CFR 261, Appendix II, January 1989). It is important to note that these tests are not indicators of expected leachate quality but of potentials. A solidified product which cannot pass the appropriate test (EP Tox or TCLP) would be subject to classification as a hazardous waste. 

Endosulfan enters air, water, and soil when it is manufactured or used as a pesticide. Endosulfan is often applied to crops using sprayers. Some endosulfan in the air may travel long distances before it lands on crops, soil, or water. Endosulfan on crops usually breaks down within a few weeks. Endosulfan released to soil attaches to soil particles. Endosulfan found near hazardous waste sites is usually found in soil. Some endosulfan in soil evaporates into air, and some endosulfan in soil breaks down. However, it may stay in soil for several years before it all breaks down. Rainwater can wash endosulfan that is attached to soil particles into surface water. Endosulfan does not dissolve easily in water. Most endosulfan in surface water is attached to soil particles floating in the water or attached to soil at the bottom. The small amounts of endosulfan that dissolve in water break down over time. Depending on the conditions in the water, endosulfan may break down within 1 day or it may take several months. Some endosulfan in surface water evaporates into air and breaks down. Because it does not dissolve easily in water, only very small amounts of endosulfan are found in groundwater (water below the soil surface for example, well water). Animals that live in endosulfan-contaminated waters can build up endosulfan in their bodies. The amount of endosulfan in their bodies may be several times greater than in the surrounding water. More information on the chemical and physical properties of endosulfan can be found in Chapter 3. More information on its occurrence and fate in the environment can be found in Chapter 5. 

Source U.S. EPA, Assessing the Geochemical Fate of Deep-Well-Injected Hazardous Waste A Reference Guide, EPA/625/ 6-89/025a, U.S. EPA, Cincinnati, OH, June 1990. 

This section examines the major processes that affect the fate of deep-well-injected hazardous wastes. The focus is on processes that (1) are known to occur in the deep-well environment or (2) have not been directly observed but are theoretically possible. 

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