Sediments determination

Reducing and oxidizing conditions m a sediment determine the chemical stability of the solid compounds and the direction of spontaneous reactions. The redox state can be recognized as a voltage potential measured with a platinum electrode. This voltage potential is usually referred to as E or Eh defined by the Nemst equation, which was introduced in Chapter 5, Section 5.3.1 ... 

Seiber, N.J., S.C. Madden, M.M. McChesney, and W.L. Winterlin. 1979. Toxaphene dissipation from treated cotton field environments component residual behavior on leaves, and in air, soil and sediments determined by capillary gas chromatography. Jour. Agric. Food Chem. 27 284-290. 

Olsen et al. [71] have reviewed the determination of inorganic, organic and total phosphorus in soil and sediments. Determination of total phosphorus in aqueous samples commonly involves a hot acid oxidation type digestion procedure, although various other dry-ashing, fusion and UV... 

The surfactant partition coefficient in natural sediments determined in laboratory experiments ranges from 1.9 to 2100 L kg-1 for non-ionic, 780 to 2900 L kg-1 for anionic (LAS) and 3800 to 2.5 X 105Lkg 1 for cationic surfactants (see Table 5.4.4). The partition coefficients of cationic surfactants are one or two orders of magnitude higher than for... 

An additional method identified as sediment by extractions involves the use of toluene as an extracting medium prior to determining the sediment value. This method may result in removal of some compounds such as asphaltenes from the final sediment determination. 

Wolbach, W. S., and Anders, E. (1989). Elemental carbon in sediments determination and isotopic analysis in the presence of kerogen. Geochim. Cosmochim. Acta 53, 1637-1647. 

Martens, DA. and Suarez, D.L. (1997) Selenium speciation of soil/sediment determined with sequential extractions and hydride generation atomic absorption spectrometry. Environ. Sci. Technol., 31, 133. 

DeMaster, D.J., and Cochran, J.K. (1982) Particle mixing rates in deep-sea sediments determined from excess 210Pb and 32Si profiles. Earth Planet. Sci. Lett. 61, 257-271. 

Nielsen, L.P. (1992) Denitrification in sediment determined from nitrogen isotope pairing. FEMS Microbiol. Ecol. 86, 357-362. 

As introduced above, the interaction between the hydrosphere and the lithosphere frequently results in mass exchange. In this way rocks get dissolved, sediments build-up, stalactites and stalagmites form, materials get transported, and so on. The pH of water and of sediments determines the mobility and solubility of different elements, which may in turn modify the redox potential of the aqueous medium. For example, aluminum, calcium, magnesium, iron, manganese, and other metals become more soluble at low pH if pH increases, their solubility decreases and precipitation occurs. 

The particle size of any sediment - determined by filtering the mixture through wire screens of 50-, 100-, and 325-mesh size. The 50- and 100-mesh screens are used because these are the smallest mesh sizes which would be used in spray rigs. The 325-mesh screen is used to obtain all sediment which has formed. 

Jensen, K., Revsbech, N. P., and Nielson, L. (1993). Microscale distribution of nitrification activity in sediment determined with a shielded microsensor for nitrate. Applied and Environmental Microbiology... 

Kana, T. M., SuUivan, M. B., CornweU, J. C., and Groszkowski, K. (1998). Denitrification in estuarine sediments determined by membrane inlet mass spectrometry. Limnol. Oceanogr. 43, 334-339. 

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