Adsorption of pesticides in soil

Gerstl, Z. and Helling, C. S. Evaluation of molecular connectivity as a predictive method for the adsorption of pesticides in soils. 

Soil temperature influences chemical degradation, microbial decomposition, and volatilization. For example, no aldrin or heptachlor was lost from frozen soils, but at 6°C, 16-27% of the dose applied to soil was lost in 56 days at 26°C, 51-55% disappeared and at 46°C, 86-98% was lost. Diazinon was also degraded faster at higher temperatures than at low ones (Edwards, 1973b). Temperature also influences the adsorption of pesticide in soils because adsorption is a exothermic process, so that increased temperatures decrease adsorption and release pesticides. 

In the present work, the emphasis of the experiments will be on the adsorption of cationic surfactants on kaolinite. Apart from the arguments given in the introduction this choice was motivated by the theme of the meeting it is likely that this system functions as a model for the adsorption of pesticides in soils. Moreover, we want to learn how far thermodynamics can take us with difficult systems. Because of our intention to analyze the date thermodynamically, adsorption isotherms under a variety of conditions (temperature, salt concentration) will be supplemented by directly measured enthalpies. 

E1 Beit lOD, Wheelock JV, Cotton DE. 1981c. Factors involved in the dynamics of pesticides in soils The effect of pesticide concentration on leachability and adsorption. Int J Environ Stud 16 181-187. 

Huggenberger, F. "Adsorption and Mobility of Pesticides in Soils." Ph. D. Thesis University of California, Riverside,... 

Ponec V, Knor Z, Cemy S (1974) Adsorption on solids. Butterworth, London Prost R, Gerstl Z, Yaron B, Chaussidon J (1977) Infrared studies of parathion attapulgite interaction. In Behavior of pesticides in soils. Israel-France Symposium INRA, Versailles, pp I08-II5... 

The flux of DOC from terrestrial landscapes to surface runoff has wide-ranging consequences for aquatic chemistry and biology. DOC affects the complexation, solubility, and mobility of metals (Perdue et al., 1976 Driscoll et al., 1988 Martell et al., 1988 see Chapter 8) as well as the adsorption of pesticides to soils (Senesi, 1992 Worrall et al., 1997). Formation of trihalomethanes when drinking water is disinfected with chlorine, a worldwide threat to water supplies, is also linked to DOC concentrations (Siddiqui et al., 1997). DOC attenuates ultraviolet-B (UV-B) radiation and thus provides some protection to aquatic biota from exposure to harmful UV radiation (e.g., Williamson and Zagarese, 1994). Finally, DOC affects the heat balance and thus stratification in lakes, which is an important constraint for aquatic organisms with limited habitats (Schindler et al., 1996, 1997). 

Ramos, L., J. Vreuls, and U.A. Brinkman (1999). Simultaneous filtration and liquid chromatographic microextration with subsequent GC-MS analysis to study adsorption equilibria of pesticides in soil. Environ. Science Technol., 33(18) 3254—3259. 

Bailey, G. W., and White, J. L, (1970). Factors influencing adsorption, desorption and movement of pesticides in soil. Residue Rev. 32, 29-92. 

Acheta domestlcus. toxicity of aminocarb, 218-20 Additives for spray dispersion performance, 100-15 ecotoxicity, 351-61 Adsorption of pesticides in aquatic sediment, 267 in soil, 195-96 Aerial applicators, exposure monitoring, 323-29... 

Freed, V.H., Haque, R. (1973) Chapter 10, Adsorption, movement, and distribution of pesticides in soil. In Pesticide Formulations. Van Valkenburg, Editor, pp. 441 159, Marcel Dekker, New York. 

Factors affecting the movement and persistence of pesticides in soils can involve leaching, fixation by soil colloids, chemical and microbial decomposition, adsorption, photodecomposition, etc. 

This book focuses on the chemical persistence and ocotoxicological behavior of pesticides In soil, water, and plants. Recent research data are presented on transport, adsorption and absorption, accumulation, degradation, biological effects, aquatic toxicity, air pollution, exposure, and risk estimation. 

Several mathematical models have been proposed for representing the overall adsorption of pesticides by soils. The most comprehensive one appears to be that of Lambert et al. (9), in which the partition of pesticides between soil water and soil is represented by a linear adsorption equation similar to the Langmuir equation. In this model they have assumed that the active adsorbent for pesticides in soils is the soil organic matter. This approach has been successful in modeling the adsorption of nonionic pesticides on soils (12), Lambert (13) has introduced an index of soil adsorption of pesticides which is intended to indicate the amount of active organic matter in a soil and therefore may be used to compare the adsorption capacity of one soil with that of another. Lambert states that the index is independent of the pesticide being adsorbed. 

EPA. 1980c. Adsorption, movement and biological degradation of large concentrations of selected pesticides in soils. Cincinnati, OH U.S. Environmental Protection Agency. EPA-600/2-80-124. 

Albanis, T.A., Pomonis, P.J., and Sdoukos, A.T. The influence of fly ash on pesticide fate in the environment. I. Hydrolysis, degradation and adsorption of lindane in aqueous mixtures of soil with fly ash, Toxicol Environ. Chem., 19(3-r4) 161-169, 1989. 

Bollag JM, LoU Ml (1983) Incorporation of xenobiotics in soil humus. Experentia 39 1221-1225 Bollag JM, Myers CJ, Minard RD (1992) Biological and chemical interactions of pesticides with soil organic matter. Sci Total Environ 123/124 205-217 Bolt GH (1955) Ion adsorption by clays. Soil Sd 79 267-278... 

An example of the kinds of data required for land disposal options would be Information on soll/pestlclde Interactions to determine the effect of the pesticide on the soil and soil on the pesticide. The physical composition of the soil and the physical properties of the pesticide and Its formulation will determine the adsorption, leaching, water dispersal, and volatilization of the pesticide which. In turn, determine the mobility of the pesticide In soil. Even pesticides of closely related structures may have very different soil retention properties. Much of this data will be available from that developed to meet other registration data requirements with the exception that disposal rates are often orders of magnitude higher than normal application rates and the difference must be considered. 

Rothwell, D.F. "Adsorption, Movement, and Biological Degradation of Large Concentrations of Selected Pesticides In Soils" EPA-600/2-80-124 Municipal Environmental Research Laboratory, U.S. Environmental Protection Agency Cincinnati, OH, August 1980 pp. 15-42. 

Because of the large volume of water Involved, Incineration Is not a preferred method. Adsorption of pesticides onto media such as activated charcoal, as well as biological and chemical treatment, are feasible methods, but they require frequent monitoring and maintenance. Evaporation ponds and soil pits have the advantages of less maintenance, applicability to a broad range of chemicals, and the ability to reduce the volume of waste via water evaporation. (1-3). In addition, these latter two methods have been estimated to be the least expensive on a per gallon basis of waste (J ). This Is of considerable Importance because the wastes are... 

Pussemier, L., R. DeBorger, P. Cloos, and R. VanBladel. 1989. Relation between the molecular structure and the adsorption of arylcarbamate, phenylurea and anilide pesticides in soil and model organic adsorbents. Chemosphere 18(9/10) 1871-1882. 

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