Sediments fractions

Chlorinated hydrocarbons Kd = K0C [0.2 (1 -/)XqC +/Aqc] where/is the mass fraction of fine sediments (d < 50 mm), Xoc is the organic carbon content of coarse sediment fraction, and Xf)C is organic carbon content of fine sediment fraction b... 

Isaacson PU, Frink CR. 1984. Nonreversible sorption of phenolic compounds by sediment fractions ... 

Isaacson, P.J. and Frink, C.R. Nonreversible sorption of phenolic compounds by sediment fractions the role of sediment organic matter. Environ. Sci Technol, 18(l) 43-48, 1984. 

When water flows over a contaminated land surface, pollutants released from higher elevations are transported, as dissolved solute or adsorbed on suspended particles, and accumulate at lower elevations. This behavior is reflected in the spatial variability of contaminant concentration, which affects contaminant redistribution with depth following leaching. If a sorbed contaminant is not of uniform concentration across all soil-size ranges but is higher in the fine sediment fraction, the deposition of this soil fraction controls contaminant redistribution in the subsurface. 

In addition, selected rare elements, such as precious metals, were extracted from matrix elements and preconcentrated to avoid isobaric interferences with polyatomic ions as demonstrated for platinum determination in the presence of a relatively high concentration of Hf, resulting in isobaric interferences at m/z = 194, 195 and 196 due to HfO+ diatomic ion formation.17 An improved method for extracting marine sediment fractions and its application for Sr and Nd isotopic analysis is described by Bayon et al.ls... 

Organic carbon content of bottom sediments (fraction) 0.025... 

In rivers and streams heavy metals are distributed between the water, colloidal material, suspended matter, and the sedimented phases. The assessment of the mechanisms of deposition and remobilization of heavy metals into and from the sediment is one task for research on the behavior of metals in river systems [IRGOLIC and MARTELL, 1985]. It was hitherto, usual to calculate enrichment factors, for instance the geoaccumulation index for sediments [MULLER, 1979 1981], to compare the properties of elements. Distribution coefficients of the metal in water and in sediment fractions were calculated for some rivers to find general aspects of the enrichment behavior of metals [FOR-STNER and MULLER, 1974]. In-situ analyses or laboratory experiments with natural material in combination with speciation techniques are another means of investigation [LANDNER, 1987 CALMANO et al., 1992], Such experiments manifest univariate dependencies for the metals and other components, for instance between different metals and nitrilotriacetic acid [FORSTNER and SALOMONS, 1991], but the interactions in natural systems are often more complex. 

Slavek, J., Waller, P. and Pickering, W.F. (1990) Labile metal content of sediments -fractionation scheme based on ion exchange resins. Talanta, 37, 397-406. 

Krueger, J. M. and Cagan, R. H., Biochemical studies of taste sensation. IV. Binding of L-[3H]alanine to a sedimentable fraction from catfish barbel epithelium, J. Biol. Chem., 251, 88, 1976. 

PR-6 can also separate B-receptors from A-receptors that have been transformed to the 4S species by treatment with salt. Approximately half of the radioactivity seen in the 4S peak in the presence of control antibody is shifted to heavier aggregates upon addition of PR-6 and a secondary antibody. The control 4S peak contains both A and B, but only A remain at 4S after PR-6 addition while all the B-receptors shift to heavier sedimenting fractions. It appears then, that antibody PR-6 cross-reacts both with the native 8S as well as the transformed 4S form of B-receptors, and that... 

An example of the application of this procedure to a complex chromatogram is shown in Figure 6.13 [34]. The sample is a mixture of polynuclear aromatic hydrocarbons from river sediments fractionated by capillary gas chromatography in the laboratory of Dr. M. L. Lee [40]. A count of peak maxima yields p = 145. Component numbers estimated from the slope and intercept give m = 234 and 267, respectively, yielding an average estimate of m = 250 for the number of components, which exceeds the number of peaks... 

Hlavay, J., T. Prohaska, M. Weisz, W. W. Wenzel, and G. J. Stingeder. 2004. Determination of trace elements bound to soils and sediment fractions. Pure Appl. Chem. 76 415 442. 

An approximate relationship between the degree of undersaturation of seawater with respect to calcite and the extent of dissolution can be established by comparing the saturation state at the various sediment marker levels with estimates of the amount of dissolution required to produce these levels. In Figure 9 the "distance from equilibrium (1 - 2) has been plotted against the estimated percent dissolution of the calcitic sediment fraction. Within the large uncertainties that exist in the amount of dissolution required to produce the FL and Rq levels, a linear relation between the degree of undersaturation and extent of dissolution can be established. The intercept of the linear plot with the FL and Rq levels indicates that approximately 15 percent more material has been lost than Berger s (12) minimum loss estimate of 50% and 10%, respectively. 

Hemming S. R., Broecker W. S., Sharp W. D., Bond G. C., Gwiazda R. H., McManus J. F., Klas M., and Hajdas I. (1998) Provenance of Heinrich layers in core V28-82, northeastern Atlantic Ar-40/Ar-39 ages of ice-rafted hornblende, Pb isotopes in feldspar grains, and Nd—Sr—Pb isotopes in the fine sediment fraction. Earth Planet. Sci. Lett. 164(1-2), 317-333. 

Hemming S. R., Hall C. M., Biscaye P. E., Higgins S. M., Bond G. C., McManus J. E., Barber D. C., Andrews J. T., and Broecker W. S. (2002a) Ar-40/Ar-39 ages and Ar-40 concentrations of fine-grained sediment fractions from North Atlantic Heinrich layers. Chem. Geol. 182(2-4), 583-603. 

Chichester F. W. (1970) Tranformations of fertilizer nitrogen in soil II. Total and N15-labelled nitrogen of soil organo-mineral sedimentation fractions. Plant Soil 33, 437-456. 

To ensure that only the finer fraction of the sediment slurry was processed, a shipboard centrifugal cone separator was connected to the slurry transfer hose to remove the coarse-sediment fraction. The cone separator was a 101.6-mm diameter, urethane-coated centrifugal cone (Demco 275). Under a normal operational pressure of 221 kPa the cone separator is capable of delivering 57.0 L/min of sediment slurry, whose sediment particle size ranged from 2 to 32 jitm as measured on the particle data Model 111 analyzer. 

Table III shows the XRF analysis of the fine-sediment fraction of the sediment samples listed in Table II made into 100-mg wafers. These samples were biased to the fine fraction, as were the F samples in Table II, and were analyzed on filter paper, identical to what would be prepared by the CS system. This information was used primarily to relate the concentration of the elements in the standard pellets of Table II of known thickness and composition to the CS wafers shown in Table IV.

The results of this study support three basic conclusions (1) The CS system is a valid means for collecting surficial seafloor samples for pollution studies (2) the basic assumption of this study—that the fine-sediment fraction of marine sediments are the primary host of heavy metal contaminants injected into the marine waters—is correct and (3) the shipboard XRF system formerly designed as a qualitative means for assisting in selecting more precise sampling areas while at sea can now be considered as a valid analytical tool capable of producing quantitative data. 

For example, an alumina coating with a median pore size of typically 100 nm can be prepared from a suspension (in water) of commercially available submicron alumina powder with a mass based median diameter of 500 nm. In such a suspension colloidal interactions determine to a large extent the properties of the suspension. The particle packing properties are disturbed by the presence of a fraction of aggregates which always exist in such commercial powders. This fraction can be removed from a colloidally stable suspension by means of sedimentation fractionation (see Ref. [5] for an example). 

Laboratory experiments on sorption have shown that even over a short period of time sorption may be irreversible or exhibit hysteresis illustrative examples are provided by chlorophenols in sediment fractions (Isaacson and Frink 1984), naphthalene and... 

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