GLOSSARY - Bioaugmentation for Groundwater Remediation - page 374

Siderophore ‐ A molecule that binds and transports iron in microorganisms.

Soil vapor extraction (SVE, soil venting) ‐ An established technology for the in situ
remediation of volatile organic compounds (VOCs) in soils. The process removes soil vapor
contaminated with VOCs and enhances the mass transfer of VOCs from the soil pores to the
vapor phase by applying a vacuum to extract soil contaminants and gasses.

Solubility ‐ Ability of a substance to dissolve (or solubilize). The solubility of a specific solute
is its maximum concentration in a given solvent at a reference temperature.

Sorption ‐ Collection of a substance on the surface of a solid by physical or chemical
attraction. Can refer to either absorption (in which one substance permeates another) or
adsorption (surface retention of solid, liquid, or gas molecules, atoms, or ions).

Source zone ‐ A subsurface zone that serves as a reservoir of contaminants to sustain a
dissolved plume. The source includes the material that is or has been in contact with the
separate phase (DNAPLs for chlorinated solvents); the source zone mass includes the sorbed
and aqueous phase contaminants, as well as any residual NAPL.

Specific activity ‐ A measure of the amount of target contaminant that can be degraded per
unit of culture within a given time.

Stakeholder ‐ A person other than regulators, owners or technical personnel, who has a
legitimate interest in a contaminated site.

Steady-state ‐ A condition of a physical system or device that does not change over time or in
which any one change is continually balanced by another, such as the stable condition of a
system in equilibrium.

Stoichiometry ‐ The calculation of quantitative (measurable) relationships of the reactants
and products in a balanced chemical reaction.

Substrate ‐ A compound that microorganisms can use in the chemical reactions catalyzed by
their enzymes.

Sulfate reducing bacteria (SRB, sulfate reducer) ‐ Bacteria that convert sulfate to hydrogen
sulfide. SRB often play important roles in the oxygen-limited subsurface.

Surfactant ‐ A material that can greatly reduce the surface tension of water when used in
very low concentrations. Primary ingredient of many soaps and detergents.

Synteny ‐ The co-location of genes along the chromosome.

Syntrophic (syntrophism) ‐ A biological relationship in which organisms of two different
species or strains are mutually dependent upon one another for nutritional requirements.

Temperature gel gradient electrophoresis (TGGE) ‐ A form of electrophoresis that uses a
temperature gradient to denature a sample as it moves across a gel. Similar to DGGE, TGGE is
commonly used to separate DNA or RNA into smaller fragments.