Fate of Organics

In Chapter 2, the fate of organic pollutants in living organisms and the processes involved were described. In this section, the relationship between the properties of chemicals and the operation of those processes will be briefly reviewed. Many examples of the influence of properties of a chemical on its own metabolic fate will be encountered in Part 2 of this book. 

Although the major concern about the fate of organic pollntants in soil has been about pesticides in agricultural soils, other scenarios are also important. The disposal of wastes on land (e.g., at landfill sites) has raised questions about movement of pollutants contained in them into the air or neighboring rivers or water conrses. The presence of polychlorinated biphenyls (PCBs) or PAHs in snch wastes can be a significant source of pollution. Likewise, the disposal of some industrial wastes in landfill sites (e.g., by the chemical industry) raises questions about movement into air or water and needs to be carefully controlled and monitored. 

Considerable attention has been given to the persistence and fate of organic compounds in the troposphere, and this has been increasingly motivated by their possible role in the production of ozone by reactions involving NO. ... 

Results of volatilization and leaching estimations are reported for six pesticides that span a wide range of the physical/chemical properties that affect fate at the soil/air interface. The pesticides are Mirex, toxaphene, methoxychlor, lindane, malathion, and dibromochloropropane (DBCP). These particular pesticides were chosen for discussion here because they illustrate the methods for assessing the fate of organics at the... 

Mackay D, Paterson S (1991) Evaluating the multimedia fate of organic chemicals a level III fugacity model. Environ Sci Technol 25 427-436... 

Rogers HR (1996) Sources, behavior and fate of organic contaminants during sewage sludges. Sci Total Environ 185 3-26... 

Atkinson R, Carter WPL, Aschmann SM, et al. 1985. Atmospheric fates of organic chemicals Prediction of ozone and hydroxyl radical reaction rates and mechanisms. Research Triangle Park, NC U.S. Environmental Protection Agency, Office of Research and Development. 

Klopffer, W., Rippen, G., Frische, R. (1982) Physicochemical properties as useful tools for predicting the environmental fate of organic chemicals. Ecotoxicol. Environ. Saf. 6, 294—301. 

James, B.R. and R.J. Bartlett. 1983a. Behavior of chromium in soils V. Fate of organically complexed Cr (III) added to soil. Jour. Environ. Qual. 12 169-172. 

Factors affecting the fate of organic compounds applied to soil... 

Brusseau, M.L. and Koakana, R.S. (1996) Transport and Fate of Organic Contaminants in the Subsurface, in Contaminants and the Soil Environment in the Australasia-Pacific Region, (eds. R.Naidu, R.S.Kookana, D.P.Oliver, S.Rogers and M.J.McLaughlin) Kluwer, Dordrecht, pp. 95-125. 

Kaminsky R, Kaiser K LE, Hites RA. 1983. Fates of organic compounds from Niagara Falls dumpsites in Lake Ontario (USA, Canada). Journal of Great Lakes Research 9(2) 183-189. 

Ann McNichol is a Research Specialist at the National Ocean Sciences Accelerator Mass Spectrometry Facility at the Woods Hole Oceanographic Institution, which produces high-precision 14C measurements from small-volume samples. Dr. McNichol s research interests include the study and use of carbon, nitrogen, and oxygen isotope techniques to quantify bio-geochemical processes, the study of the fate of organic matter (both natu-... 

Adsorption mechanisms represent probably the most important interaction phenomena exerted by solid surfaces on the environmental fate of organic pollutants [65, 127-130]. Adsorption controls the quantity of free organic components in solution and thus determines their persistence, mobility, and bioavailability. The extent of adsorption depends on the amount and properties of both solid phase-humic substances (SPHS) and organic pollutants. Once adsorbed on an SPHs >an organic pollutant may be easily desorbed, desorbed with difficulty, or not at all. Thus sorption phenomena may vary from complete reversibility to total irreversibility. 

This development contributes to a still-increasing body of knowledge about the fate of organic molecules upon oxidation and reduction. 

The fate of organic matter in the marine environment is largely related to its molecular structure, as this determines chemical reactivity. Compoimds characterized by high concentrations in seawater and the sediments typically have slow loss rates relative to their production. These compounds tend to exhibit low chemical reactivity in the marine environment and can persist in seawater fiar thousands of years. Conversely, compounds with low concentrations typically have high loss rates relative to their production. Their high reactivity is generally due to rapid biotic uptake and transformation, leading to turnover times that are on the order of minutes to days. Thus, to imderstand... 

Fries, G.F. Degradation of chlorinated hydrocarbons under anaerobic conditions, in Fate of Organic Pesticides in the Aquatic Environment, Advances in Chemistry Series, Gould, R.F., Ed. (Washington, DC American Chemical Society, 1972), pp. 256-270. 

Gherini, S.A., Sutmners, K.V., Munson, R.K., and Mills, W.B. Chemical Data for Predicting the Fate of Organic Compounds in Water, Volume 2 Database (Lafayette, CA Tetra Tech, 1988), 433 p. 

Lesage, S., Jackson, R.E., Priddle, M.W., and Riemann, P.G. Occurrence and fate of organic solvent residues in anoxic groundwater at the Gloucester landfill, Canada, Environ. Sci. Technol, 24(4) 559-566, 1990. 

Plastourgou, M. and Hoffman, M.R. Transformation and fate of organic esters in layered-flow systems the role of trace metal catalysis. Environ. Sci Techno , 18(10) 756-764, 1984. 

Klupinski et al. (2004) report a laboratory experiment on the degradation of a fungicide, pentachloronitrobenzene (C Cl NO ), in the presence of goethite and iron oxide nanoparticles this study was intended to illustrate the fate of organic agrochemical contaminants in an iron-rich subsurface. To compare the effects of iron with and without a mineral presence, experiments were performed using... 

In this paper, the volatilization of five organophosphorus pesticides from model soil pits and evaporation ponds is measured and predicted. A simple environmental chamber is used to obtain volatilization measurements. The use of the two-film model for predicting volatilization rates of organics from water is illustrated, and agreement between experimental and predicted rate constants is evaluated. Comparative volatilization studies are described using model water, soil-water, and soil disposal systems, and the results are compared to predictions of EXAMS, a popular computer code for predicting the fate of organics in aquatic systems. Finally, the experimental effect of Triton X-100, an emulsifier, on pesticide volatilization from water is presented. 

EXAMS (Exposure alysis Modeling stem) is an elaborate computer program that predicts the fate of organic chemicals in aquatic systems (24). Most input data can be easily measured, calculated, or obtained from literature sources. For this reason, the program is readily accessible to chemists for use as a predictive tool. 

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