Biodegradable factors

Biodegradation factor = (Substructures factor x No. factors) + intercept (8)... 

Biodegradation factor (B) = (Substructures factor x No. factors) + intercept B = X[one aryl OH substructures factor (+0.003) + two aryl R3 - branched alkyl chains (-0.500)] + intercept(+0.380)... 

Biodegradation factor (B) = (standardized Substructures x no. factors) + intercept (4) standardized substructure = (substr.-MV of substructure)/SD... 

Aldrin from Rice. The maximum amount of insecticide that can be emptied from a paddy planted with aldrin-treated rice is below 1 gram per acre. At the end of a growing season, the paddy water and the top 3 inches of soil are the same as before the planting with respect to insecticide residue. The concentration of the drainage entering a waterway rapidly diminishes to a few p.p.t. by dilution and by physicochemical and biodegradation factors. 

In 1977 Stauffer Chemical Company began field trials in the Missouri River bottoms of Iowa and Nebraska to determine if cultural practices and alternate herbicide treatments could increase weed control in fields where EPTC performance was less than expected. Many test fields did not develop enhanced biodegradation. Factors such as application and incorporation methods, tillage practices, herbicide rotation and use of herbicide combinations had major impacts on herbicide performance and also influenced the development of enhanced biodegradation. These results are further discussed in this paper. 

Exposure studies have been made using mice and rats (257). These experiments have demonstrated species differences in butadiene toxicity and carcinogenicity. Butadiene was found to be a potent carcinogen in the mouse, but only a weak carcinogen in the rat. The interpretations have focused on differences in toxification rates and detoxification metaboHsms as causative factors (257). The metaboHsm is beHeved to proceed through intermediates involving butadiene monoepoxide and butadiene diepoxide (257). A similar mechanism has been proposed for its biodegradation pathway (258). 

Typical precautions with trichloroethylene are summarized in Table 5.52. An important factor is that the vapours are much heavier than air they will therefore spread and may accumulate at low levels, particularly in undisturbed areas. Because of its volatility, releases to the environment usually reach the atmosphere. Here it reacts with hydroxyl or other radicals (estimated half-life for reaction with hydroxyl radicals is less than a week) and is not therefore expected to diffuse to the stratosphere to any significant extent. There is some evidence for both aerobic and anaerobic biodegradation of trichloroethylene. 

The biodegradation of surfactants is studied by means of many different tests and sometimes under different conditions. Some factors with significant influence on the results are uncontrollable factors and in other cases are not controllable. This causes a dispersion in biodegradability data that makes comparisons difficult. For this reason only general conclusions can be obtained from the data available. Swisher carried out an exhaustive collection of available data in his complete study on surfactant biodegradation [385]. Some basic and significant features of biodegradation of alcohol and alcohol ether sulfates are discussed below. 

The lime soap dispersing properties are very important for the dispersal of Ca soap, which is used to achieve among others, lower foam [60,64,66,181]. In addition, nontoxicity as well as good dermatological properties and biodegradability have been factors in the increased use of ether carboxylates [60,66]. 

Peculiar characteristics of chitins and chitosans are hemostatic action, anti-inflammatory effect, biodegradability, biocompatibihty, besides antimicrobial activity, retention of growth factors, release of glucosamine and M-acetylglucosamine monomers and oligomers, and stimulation of cellular activities [11,12,295-297]. 

Biodegradable films made from edible biopolymers from renewable sources could become an important factor in reducing the environmental impact of plastic waste. Proteins, lipids, and polysaccharides are the main biopolymers employed to make edible films and coatings. Which of these components are present in different proportions and determine the properties of the material, as a barrier to water vapor, oxygen, carbon dioxide, and lipid transfer in food systems (Gomez-Guillen et al. 2002 and 2009). 

Pitt, C. G., Gratzl, M. M., Jeffcoat, A. R., Zweidinger, R., and Schindler, A., Sustained drug delivery systems. II. Factors affecting release rates from poly( e-caprolactone) and related biodegradable polyesters, J. Pharm. Sci.. 68, 1534-1538, 1979. 

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