Search results
Results from the WOW.Com Content Network
A grab dredge. Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing dams, dikes, and other controls for streams and shorelines; and recovering valuable mineral deposits or marine life having commercial value.
Canal dredged in a wetland area Wetlands are dynamic systems that undergo a variety of chemical reactions depending greatly on the specific physicochemical properties of the area, such as temperature, pressure, dissolved organic matter, pH, salinity, and dissolved gases (CO 2 and O 2 ).
Nearly all of the ocean dumping that takes place today is dredged materials at the hands of the Corps of Engineers and due to the fact that they are the entity primarily responsible for the dredging, they issue permits for ocean dumping of such materials. [3] [10] The dredged materials are sediments removed from the bottom of water bodies, but ...
Bottom trawling can both resuspend and bury biologically recyclable organic material, changing the flow of nutrients and carbon through the food web and thereby alter geomorphological landscapes. [15] Ocean sediments are the sink for many persistent organic pollutants, usually lipophilic pollutants like DDT, PCB and PAH. [24]
Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...
Another factor is the types of dredged materials. A dredge plume of coarse sand has different properties and dynamics than a similar plume of fine sand. Dredge plumes usually contain different constituents, each of which affects the plume's character. For example, denser material settles faster than less dense material.
In water, the main pollution source is sediment spill from dredging, the transportation of dredged material on barges, and the deposition of dredged material in or near water. Such deposition may be made to get rid of unwanted material, such as the offshore dumping of material dredged from harbours and navigation channels.
The substances on the reverse list include dredged material; sewage sludge; industrial fish processing waste; vessels and offshore platforms or other man-made structures at sea; inert, inorganic geological material; organic material of natural origin; and bulky items including iron, steel, concrete and similar materials for which the concern is ...