Soil Pollution and Their Effects

Owing to the impossibility of compiling partition coefficients for a substance into every possible set of solvents/phases, a reference that is commonly accepted is the octanol/water partition coefficient, Kj0tW. This solvent (i.e., the 1-octanol) is a good reference choice as it mimics (to a reasonable extent) the solvent behavior of lipids in biota as well as that of humic substances in soils. Extensive tables of Kio w values are readily available (see for example, the CRC Handbook for Chemistry and Physics). Such data help predict the environmental fate of many substances (see Casey and Pittman, 2005). 

If one has the value of Kio w for a given substance i as well as its partition coefficient between water and a different medium (x), one can calculate the value of the partition coefficient between 1-octanol and x, Kio x by noting that the AG values are additive, assuming that the values of A and T are constant  

x AGjO W T AGiWjX -AT In Ki0yX = —AT n Ki0yW + (-AT In KiWiX) 

The pollution of air, water, or soil may or may not be intentional. Deliberate contamination may involve a myriad of paths, such as the disposal of pollutants into water, or the control of animals, plants, or microorganisms with biocides, open-air incineration, and distorted industrial disposal practices. Non-intentional routes mainly involve biogenic and 

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Chemical Effects of Temperature. Changes in temperature also affect the chemical properties of materials. The rate at which most chemical reactions take place, for example, is roughly doubled when the temperature of the reactants increases by 10°C. Consequently, any increase in temperature intensifies the rate at which most materials react with substances in the environment such as oxygen, water, and atmospheric and soil pollutants, and hastens their chemical degradation. 

Dumontet, S., Dinel, H., Levesque, P.E.N., 1992. The distribution of pollutant heavy metals and their effect on soil respiration and acid phosphatase activity in mineral soils of the Rouyn-Noranda region. Quebec. Sci. Total Environ. 121, 231-245. 

Some damage is caused by direct mechanisms, that is the emitted pollutant(s), or chemical derivative(s), interact(s) biochemically with building material or the plant leaf/stomata itself (themselves) - Section 2. However, the pollutants and their derivatives can also have effects via indirect mechanisms on flora and fauna by causing change in soil or aquatic ecosystems (Sections 5.3 and 5.4). The situation with respect to different observed effects is shown in Figure 2 overleaf. 

Heavy metals, toxic organics and other pollntants have often freqnently been added to wetlands both accidentally and on pnrpose, exploiting their buffering and storage capacities. The chemistry of snbmerged soils and sediments is such that pollutants may be effectively removed from the percolating water in redox, sorption and precipitation reactions. But the effects of long-term accumulation of pollutants on nutrient cycles and other wetland functions are not well understood. 

Chapter 5 of the document reviews the UFs used by UK Government departments, agencies, and their advisory committees in human health risk assessment. Default values for UFs are provided in Table 3 in the UK document with the factors separated into four classes (1) animal-to-human factor, (2) human variability factor, (3) quality or quantity of data factor, and (4) severity of effect factor. The following chemical sectors are addressed food additives and contaminants, pesticides and biocides, air pollutants, drinking water contaminants, soil contaminants, consumer products and cosmetics, veterinary products, human medicines, medical devices, and industrial chemicals. 

Incorporating allelopathy into agricultural management may reduce the use of herbicides, cause less pollution, and diminish autotoxic hazards. Authentic inhibitors isolated from plant material have been subjects for examination in, vitro, but attempts to compare their effects in soils are limited. Soils contain a heterogeneous collection of organic matter of various origins. 

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