Organic content relation

In several cases, such as shellfish areas and aquatic reserves, the usual water quaUty parameters do not apply because they are nonspecific as to detrimental effects on aquatic life. Eor example, COD is an overall measure of organic content, but it does not differentiate between toxic and nontoxic organics. In these cases, a species diversity index has been employed as related to either free-floating or benthic organisms. The index indicates the overall condition to the aquatic environment. It is related to the number of species in the sample. The higher the species diversity index, the more productive the aquatic system. The species diversity index is computed by the equation K- = (S — 1)/logjg I, where S is the number of species and /the total number of individual organisms counted. 

The chemical and physical aspects of crud can dilfer for each separate operation and will vary in inorganic composition, organic content, color, and density. The composition of many cruds appears to have in common such constituents as Si, Al, Fe, P, SO4, particles of gypsum, clay, and other fine particles together with the solvent. Often there is a direct relation between the feed liquor and the crud compositions, indicating possible aqueous carryover as well as inefficient clarification before solvent extraction [33]. Various researchers have reported on the formation of crud and its characterization in their circuits [42-45]. 

Because organic nonpolar compounds have stronger attraction to organic matter than to mineral content, the amount of adsorption of an organic contaminant is more dependent on the organic content of the soil. The adsorption partition coefficient is generally used to determine this adsorption amount, as it is empirically related to the organic fraction of the soil (/ ,), and the normalized partition coefficient Koc can be expressed as follows ... 

A related test method (ASTM D-5368) describes the standard procedures for gravimetricafly determining the total nonvolatile and semivolatile organic content of solvent extracts from soils or solid wastes. As written, the test method is used after a solvent extract is obtained from a soil or solid waste. For these methods to be applicable, the extraction solvent must have a boiling point less than that of water at ambient pressure. Again, the total solvent extractable content (TSEC) of a soil, sediment, sludge, or solid waste depends on the solvent and method used for the extraction. 

The tests were conducted in an open, mixed and aerated reactor to maintain constant values of pH, DO, and temperature. Thus the difference in COD drop may not be related to pH, temperature. Aeration and mixing maintained DO around saturation in all tests, thus the effect of oxygen production at the anode is minimized. The only other process (other than microbial activity) that may relate to COD drop is abiotic transformation by electrolysis reactions at the electrodes. If abiotic redox of the organic content occurs in this study, then increasing the current density should increase the... 

There are significant differences in the nitrogen and organic sulfur contents related to the concentrations of these elements in the starting coals. 

An organism s fossilized hard parts (for example, the shell of a clam), through their composition, provide clues to the environment as well. A clam shell s trace element content relates to the concentration of trace elements in the aquatic environment. The concentration in the environment is a product of environmental variables such as salinity and water temperature. So, by studying the trace element chemistry of a fossil, it may be possible to determine the approximate climatic conditions where the organism lived, as well as its latitude. 

Estuarine environments in particular are often sites of intense human and animal activity (e.g. sites of leisure pursuits and breeding grounds for many species of birds) so the level of contamination of intertidal sediments is of particular interest in relation to environmental health. Total concentrations of individual trace elements in UK estuaries, for example, vary widely (Table 2.1), reflecting the natural sediment characteristics (e.g. organic content and surface area), and the level of anthropogenic contamination of individual systems (Bryan Langston, 1992). The order of variability of concentrations of individual elements in Table 2.1 is Sn > As > Cu > Pb > Hg > Ag > Zn > Cd > Se > Cr > Mn > Co > Ni > Fe, which to some extent can be considered as the order of anthropogenic influence. 

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