Fine-grained particles, contaminants

In the case of harbor areas the accumulated (mostly contaminated) sediments have to be removed and dumped elsewhere this means that they may end in places they never would reach by natural processes, and in a different geochemical environment (Salomons, 1987 see also Chapter 7). Typical locations, where sediment-associated pollutants can be accumulated, are shown in Figure 4-2 (Shea, 1988). Of particular interest are those sites, where - due to the hydrodynamic situation - fine-grained particles are deposited, which usually contain highest concentrations of toxic chemicals (Chapter 3.3). 

Screens may be vibrating or stationary and operate by selectively allowing particles to pass througih them. As the slurry passes over the screen, fine-grained particles and water sift througih the screen and larger particles slide over the screen. Screens come in a variety of types with a variety of applications to contaminated sediments. 

Electroosmotic soil processing is an in situ separation/removal technique for extracting heavy metals and organic contaminants from soils.17 55 89 The fluid between the soil particles moves because a constant, low DC current is applied through electrodes inserted into the soil mass. The electroosmosis (EO) remedial method provides an advantage over conventional pumping techniques for in situ treatment of contaminated fine-grained soils and is more efficient in saturated conditions. 

One approach to the direct analysis of sohds is to form a slurry of the sample in a suitable solvent and introduce the slurry directly into a graphite furnace atomizer. A slurry is a suspension of fine solid particles in a liquid. Slurry preparation requires that the sample either is in the form of a fine powder or can be ground to a fine powder without contamination from the grinding process. This can be done successfully for many types of samples, such as foods, grains, pharmaceuticals, and sediments. A key... 

Illites are very fine-grained minerals, particles as small as 0.05[x in radius having been reported. They are said to be slightly plastic, although it is not certain whether this plasticity is due to contamination with clay mineral. Because of their alkali content, clays containing illite have a comparatively low refractoriness. 

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