Interactive Sediment Remedy Assessment Portal
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Glossary
advection:the process of transfer of fluids (vapors or liquid) through a geologic formation in response to a pressure gradient that may be caused by changes in barometric pressure, water table levels, wind fluctuations, or infiltration.
benthic:adjective describing the biologically active sediment zone, generally at the sediment surface at the bottom of a water body such as an ocean, lake, or river (e.g., benthic organism, or sediment benthic layer).
bioaccumulation:the process by which chemicals are taken up by an organism either directly from exposure to a contaminated medium or by consumption of food containing the chemical.
bioavailability:degree or ability of a chemical to be absorbed and to readily interact in organism metabolism.
bioconcentration:the process by which there is a net accumulation of a chemical directly from an exposure medium into an organism.
biodegradation:a process by which microorganisms transform or alter (through metabolic or enzymatic action) the structure of chemicals introduced into the environment; usually refers to chemical decomposition. See also biotransformation.
biomagnification:the process of bioaccumulation and biological transfer by which tissue concentrations of chemicals in organisms at one trophic level exceed tissue concentrations in organisms at the next lower trophic level in a food chain.
biota:the animal and plant life of a given region.
biotransformation:alteration of the structure of a compound by a living organism or enzyme.
bioturbation:the natural activity of living organisms, such as worms, to move particles and pore water from inside soil or sediment beds toward the surface and circulate them in the upper layers of the sediment bed.
capping:an engineered sediment remedy involving the placement of a subaqueous covering or cap of clean material over contaminated sediment; the cap physically isolates contaminated sediment to reduce exposure through direct contact and stabilizes contaminated sediment to protect against erosion, resuspension, and transport.
chemical precipitation:formation of a separable solid substance from solution, either by converting the substance into an insoluble form or by changing the composition of the solvent to diminish the solubility of the substance in it.
chemical sequestration:a chemical process by which a compound or metabolite is locked away so as to not to be readily available. For example, long-term hydrophobic sorption of organic chemicals can lead to their sequestration from the environment and from biological exposures.
contaminant:any physical, chemical, biological, or radiological substance or matter that has an adverse effect on air, water, or soil.
degradation:to reduce the complexity of or to impair in respect to some physical property.
diffusion:the movement of suspended or dissolved particles (or molecules) from a more concentrated to a less concentrated area. The process tends to distribute the particles or molecules more uniformly.
dilution:the process of reducing the concentration of a solute in solution, usually simply by mixing with more solvent.
dispersion:to spread or distribute from a fixed or constant source.
dredging:the mechanical or hydraulic removal of sediments from the aquatic environment.
ecological risk:the likelihood that adverse ecological effects are occurring or may occur as a result of exposure to one or more stressors.
ecosystem:the interacting system of a biological community and its non-living environmental surroundings.
erosion:the wearing away of land surface by wind or water, intensified by land-clearing practices related to farming, residential or industrial development, road building, or logging.
flux:the rate of transfer of fluid, particles, or energy across a given surface.
geographic information system:a computer system designed for storing, manipulating, analyzing, and displaying data in a geographic context.
hot spot:an area of contamination in which the level of contamination is considered to be much higher than in the surrounding area.
human health risk:the likelihood that a given exposure or series of exposures may have damaged or will damage the health of individuals.
in situ:in its original place; unmoved unexcavated; remaining at the site or in the subsurface.
isotope:a variation of an element that has the same atomic number of protons but a different weight because of the number of neutrons. Various isotopes of the same element may have different radioactive behaviors, some are highly unstable.
kinetics:referring to the rate of physical or chemical reactions
monitored natural recovery (MNR):a remedy that involves leaving contaminated sediments in place and allowing ongoing physical, chemical and biological processes to reduce contaminant exposure to receptors through physical isolation, dispersion, offsite transport, chemical transformation and/or reduction in bioavailability. MNR is not a passive process, as it incorporates extensive monitoring to document the performance of natural recovery processes.
monitoring:the collection of data over space or time to evaluate physical, chemical, or biological trends or to compare the physical, chemical, or biological state with a predetermined goal or regulatory requirement.
organic:referring to or derived from living organisms; in chemistry, any compound containing carbon.
oxidation:process through which oxygen is added to a compound; the atomic or molecular loss of electrons in biochemical or geochemical electron-transfer reactions; always accompanied by reduction. See also reduction.
phytoremediation:the use of plants to contain, sequester, remove, or degrade organic or inorganic contaminants in soils, sediments, surface water and groundwater.
reduction:process by which electrons are added to a compound; the atomic or molecular gain of electrons in biochemical or geochemical electron-transfer reactions; always accompanied by oxidation. See also oxidation.
sedimentation:process by which sediment is deposited into surface waters such as streams and lakes.
sorption:the process in which one substance takes up or holds another (either through hydrophobic or electrochemical bonding).
volatilization:the conversion of a chemical substance from a liquid or solid state to a gaseous or vapor state, either as evaporation (liquid to vapor) or sublimation (solid to vapor).