Lipids natural organic matter

The octanol-water partition coefficient KqW provides a direct estimate of hydrophobicity or of partitioning tendency from water to organic media such as lipids, waxes and natural organic matter such as humin or humic acid. It is invaluable as a method of estimating KoC, the organic carbon-water partition coefficient, the usual correlation invoked being that of Karickhoff (1981)... 

Natural organic matter in aquatic media are complex mixture of substances such as polysaccharides, proteins, peptides, lipids, and humic substances (Duursmu and Dawson, 1981 Buffie, 1984). Humic material is itself a mixture of polymers of a wide range of molecular weights (Buffle, 1988). Besides naturally occurring substances, various artificial compounds are introduced in natural water as the result of human activities. 

Due to variations in the soil, such as humic constituents, sand fractions, clay minerals, peat minerals, wood rests, algal toxins, and deposits of shell lime, different reactions take place. The natural organic matter (NOM) in an aquifer is a complex mixture of substances, such as humic acids, fulvic acids, amino acids, carbohydrates, lipids, lignin, and waxes. 

The adsorption of natural organic matter such as humic acid and lipids that have large molecular dimensions but also have polar groups in their molecule, has been attributed to the pore-size distribution in carbons and to the nature of the carbon surface charge. The former determines the availability of the pore for adsorption, and the latter determines the electrostatic interactions between the carbon surface and the adsorbate molecule. Many natural organic materials have molecular diameters of about 3 nm so that only activated carbons with a large proportion of mesopores will be more suitable for their adsorption. 

Simoneit BRT, Mazurek MA, Organic matter of the troposphere — 11. Natural backgroimd of biogenic lipid matter in aerosols over the rural western United States, Atmosph Environ 16 2139—2159, 1982. 

Metals are widely distributed in the aquatic environment and may be from either natural and/or anthropogenic sources. They are present in wide range of forms or species including freely dissolved metal, salts, organometalics, and bound to colloids and particulates. Factors such as pH and redox potential of the water and sediment, and presence of particulate material or organic matter, and microbial activity will determine in what form a particular metal is present in the environment. Since the different forms of a metal can have different bioavailabilities and toxicities, it is important to ensure that biologically relevant species are measured. Metals are generally bioavailable when present as free ions, bound to weak complexes or in a lipid soluble form (Hudson, 1998 Luider et al., 2004). Low concentrations of some metals, such as Cu and Zn,... 

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