Soil, composition

Acid deposition refers to the transport of acid constituents from the atmosphere to the earth s surface. This process includes dry deposition of SO2, NO2, HNO3, and particulate sulfate matter and wet deposition ("acid rain") to surfaces. This process is widespread and alters distribution of plant and aquatic species, soil composition, pH of water, and nutrient content, depending on the circumstances. 

The impact of acid deposition on forests depends on the quantity of acidic components received by the forest system, the species present, and the soil composition. Numerous studies have shown that widespread areas in the eastern portion of North America and parts of Europe are being... 

When a forest system is subjected to acid deposition, the foliar canopy can initially provide some neutralizing capacity. If the quantity of acid components is too high, this limited neutralizing capacity is overcome. As the acid components reach the forest floor, the soil composition determines their impact. The soil composition may have sufficient buffering capacity to neutralize the acid components. However, alteration of soil pH can result in mobilization or leaching of important minerals in the soil. In some instances, trace metals such as Ca or Mg may be removed from the soil, altering the A1 tolerance for trees. 

Soil composition Calcareous, marly limestone Sandy marl, not stratified sand + 2... 

Cinders and acid peaty soils are obviously among the soils most corrosive toward copper. There is, however, no direct relationship between the rate of corrosion and any single feature of the soil composition or constitution". For instance, in the American tests corrosion in several soils with either low pH or high conductivity was not particularly severe, while the British tests show that high chloride or sulphate contents are not necessarily harmful. 

The consumption rate of HSI anodes buried directly in soils will vary depending upon the soil composition and will be excessive in chloride-containing soils. In quicksands consumption rates of approximately 0-35 kg A y have been reported, whilst in other soils consumption rates in the region of 1 kg A y... 

The liquid in which the SAH swelling takes place in real soil (the soil solution) always contains a more-or-less wide set of dissolved salts. Their nature and amount depend on the soil composition, the degree of its salinity, the nature of water entering the soil (rainfall, irrigation, river, or groundwater), the fertilizers used. As a rule, alkali cations, Ca2 +, Mg2+, Fe3+, Al3+, and anions CP, CO, SO4, etc. are the main components of the soil solution there exist various models of soil solution and nutrient mixtures employed in research, including SAH testing. 

Spark KM, Swift RS (2002) Effect of soil composition and dissolved organic matter on pesticide sorption. Sci Total Environ 298(1-3) 147-161... 

Chapter 3 Role of Bacteria and Bacteria-Soil Composites in Metal Biosorption and Remediating Toxic Metal-Contaminated... 

Heavy metals bound to bacteria-soil composites may not be as easily released to the environments as those sorbed by pure bacteria. Flemming et al. (1990) reported that the order of remobilization of heavy metals from bacteria-clay composites was Cr Ag < Cu. Chromium was veiy stable when sorbed by bacterial cell walls, clay, and bacterial wall-clay... 

It is also astonishing how the rich blue of a cornflower (Centaurea cyanus) and the majestic red flame of the com poppy (Papaver rheas) each derive from the same chromophore - again based on an anthrocyanidin. The pH of cornflower and poppy sap does not vary with soil composition, which explains why we see neither red cornflowers nor blue com poppies. 

Interfering ions are problematic when analyzing environmental samples, particularly soil and soil extracts. These samples may contain unknown combinations and concentrations of ions. For these reasons, ISEs are most useful in two situations. The first is where the soil composition is well known and routine repetitive analysis is to be made. The second is where a preliminary screening is to be done and followed by detailed laboratory analysis. In the latter case, potential interfering ions will be determined and the validity of the original screening assessed [7,8],... 

The extent of kerosene trapping was determined quantitatively in a series of laboratory and outdoor experiments with Swedish soils (Jarsjo et al. 1994), yielding an empirical equation for the kerosene residual content as a function of soil composition ... 

Smee, B.W. 1999 The effect of soil composition on weak leach solution pH a potential exploration tool in arid environments. Explore, 102, 4-7. 

Treat a wide range of contaminants in soil compositions of varying permeability, water content, and depth. 

The moisture content of the morama bean is very low as the dry matter (dm) content ranges from 93.4% to 98.7% (Bower et al., 1988 Holse et ah, 2010 Wehmeyer et ah, 1969). Variations may arise from external factors such as soil composition, climate, harvest time, and maturation state of the beans. 

The Clementine orbiter obtained high-resolution multispectral reflectance data. In comparing spectra with soil compositions at 39 locations sampled by Apollo astronauts, Blewett et al. (1997) determined a correlation between specific spectral features and chemical composition. This enabled Lucey et al. (1998) to develop an algorithm to estimate accurate FeO and Ti02 abundances from Clementine spectra. 

An accurate evaluation of kxa is complicated by the heterogeneous nature and poor definition of contaminant/soil systems. Some success has been achieved in modeling mass transfer from a separate contaminant phase. During degradation these nonaqueous phase liquids (NAPLs) often dissolve under conditions where phase equilibrium is not achieved and dissolution is proportional to k a. Experimental determinations and correlations for k-p depend on interfacial area of the NAPL and liquid velocity at the interface (Geller Hunt, 1993). For adsorbed contaminants, kxa varies with soil composition and structure, concentration and age of contamination, and therefore with time. For example, slurry reactor tests indicate that the rate of naphthalene mass transfer decreases with time, with media size, and with aging of the tar prior to testing (Luthy et al., 1994). 

A variety of factors affect the horizontal and vertical migration of PAHs, including contaminant volume and viscosity, temperature, land contour, plant cover, and soil composition (Morgan Watkinson, 1989)- Vertical movement occurs as a multiphase flow that will be controlled by soil chemistry and structure, pore size, and water content. For example, non-reactive small molecules (i.e., not PAHs) penetrate very rapidly through dry soils and migration is faster in clays than in loams due to the increased porosity of the clays. Once intercalated, however, sorbed PAHs are essentially immobilized. Mobility of oily hydrophobic substances can potentially be enhanced by the biosurfactant-production capability of bacteria (Zajic et al., 1974) but clear demonstrations of this effect are rare. This is discussed below in more detail (see Section 5 5). 

A second area of concern is that of reduced tree growth in forests. The leaching of nutrients from the soil by acid deposition may cause a reduction in future growth rates or changes in the type of trees to those able to survive in the altered environment. In addition to the change in soil composition, there are the direct effects on the trees from sulfur and nitrogen oxides as well as ozone. 

Lopez-Avila et al. [107] showed that microwave-assisted extraction of pesticides and polycyclic aromatic hydrocarbons from soil is a viable alternative to Soxhlet extraction and needs a smaller sample volume and extraction time [108,109]. These techniques have also been compared in the case of chlorophenols. Lopez-Avila et al. compared microwave-assisted extraction with electron capture gas chromatography to ELISA for the determination of polychlorinated biphenyls in soils. Both techniques are applicable to field screening and monitoring applications. Microwave-assisted extraction [111, 112] and solid-phase microextraction [113] have been applied to the extraction of pesticides from soil. It was observed by these and other workers [114] that the selectivity of microwave-assisted extraction is highly dependent on the soil composition. 

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