Contaminated and Hazardous Waste Site Management

Glossary I

Ice Contact Deposits: Drift sediment deposited in contact with its supporting ice.

Igneous Rock: A rock or mineral which solidified from molten or partly molten material i.e. from a magma.

Imaging Work Station: Consists of a microcomputer with a high-resolution colour monitor and accompanying software which allows the manipulation, enhancement and visual display of digital data.

Immiscible: Pertaining to two or more phases which, at mutual equilibrium, cannot dissolve completely in one another.

Impermeable: A material which does not easily transmit a fluid. It is often defined arbitrarily and in relation to more permeable materials present in the same area. For example, a shale may be impermeable relative to a nearby sandstone. An impermeable boundary is assumed to be the edge of impermeable material.

Impoundment: A body of water or sludge confined by a dam, dike, floodgate or other barrier.

Incineration: A group of treatment technologies involving destruction of waste by controlled burning at high temperatures, e.g., burning sludge to reduce the remaining residues to an ash that can be disposed of safely on land, in some water, or in underground locations.

Incrustation: Mineral matter deposited by water. One of the major causes of well failure is the chemical and biological incrustation of well screen through precipitation of calcium and magnesium carbonates or sulphates. The precipitation of iron and manganese compounds and slime producing iron bacteria will also plug well screens.

Independent Standard: A Contractor-prepared standard solution that is composed of analytes from a different source than those used in the standards for the initial calibration.

Indigenous: Living or occurring naturally in a specific area or environment; native.

Induced Magnetization: Magnetization caused by an applied magnetic field. Contrast with remanent magnetization.

Induced Polarization (IP): A geophysical effect whereby electrical charge is momentarily polarized within a material, usually a disseminated ore or a clay. This effect is the basis for the IP method, in which a decaying voltage due to this polarization is measured following the turn-off of the activating current in time domain surveying. See also complex resistivity.

Induction (EM), Induce: The process, described by Faradays Law, whereby a variable magnetic field generates an electric field (voltage) that, in the presence of a conductor, will produce electric currents.

Induction Number: A quantitative measure of the quality of a target for EM methods. The formulation varies for different targets but in general it involves the product of target conductivity, magnetic permeability, frequency of the transmitter and a cross-sectional dimension of the target. Dimensionless.

Inductively Coupled Plasma (ICP): a technique for the simultaneous or sequential multi-element determination of elements in solution. The basis of the method is the measurement of atomic emission by an optical spectroscopic technique. Characteristic atomic line emission spectra are produced by excitation of the sample in a radio frequency inductively coupled plasma.

Indurated: A compact rock hardened and solidified by post depositional chemical and physical alterations.

Infiltration: The movement of water or other liquid down through soil from precipitation (rain or snow) or from application of wastewater to the land surface.

Infiltration Gallery: An engineered structure that facilitates infiltration of water into the subsurface. Infiltration galleries may consist of one or more horizontal or vertical perforated pipes, a single gravel-filled trench or a network of such trenches, or a combination of these.

Infiltration Rate: The rate at which water permeates the pores or interstices of the ground.

Infiltrometer: An instrument which measures the infiltration of water into soil.

Influent: Water, wastewater, or other liquid flowing into a reservoir, basin or treatment plant.

Information Repository: A designated building where a file containing current information, technical reports, reference documents and TAG application information is available. The information repository is usually located in a public building that is convenient for local residents, such as a public school, city hall or library.

Initial Calibration: Analysis of analytical standards for a series of different specified concentrations; used to define the linearity and dynamic range of the response of the mass spectrometer or electron capture detector to the target compounds.

Injection: Introduction of the analytical sample into the instrument excitation system for the purpose of measuring absorbance, emission, or concentration of an analyte. May also be referred to as exposure.

Injection Well: A well used for injecting fluids into a subsurface soil or rock layer.

Inlet Well: A well through which a fluid (liquid or gas) is allowed to enter the subsurface under natural pressure.

In-line Rotameter: A flow measurement device for liquids and gases that uses a flow tube and specialized float. The float device is supported by the flowing fluid in the clear glass or plastic flow tube. The vertical scaled flow is calibrated for the desired flow volume/time.

Inoculate: To implant microorganisms on to or into a culture medium.

Inorganic Constituents/Inorganics: Any substance which is not a compound of carbon, with the exception of carbon oxides. They include metals and other ions (e.g. chloride, sulfate, nitrate).

In-phase: That part of a periodic signal that has zero phase shift with a reference signal. See also quadrature.

In situ: In its original place; unmoved; unexcavated; remaining in the subsurface.

Instrument Check Sample: a solution containing both interfering and analyte elements of known concentration that can be used to verify background and interelement correction factors.

Instrument Check Standard: A multi-element standard of known concentrations prepared by the analyst to monitor and verify instrument performance on a daily basis.

Instrument Detection Limit (IDL): Determined by multiplying by three the standard deviation obtained for the analysis of a standard solution (each analyte in reagent water) at a concentration
of 3x-5x IDL on three nonconsecutive days with seven consecutive measurements per day.

Interfacial Tension: The strength of the film separating two immiscible fluids (e.g., oil and water) measured in dynes (force) per centimeter or millidynes per centimeter.

Interferents: Substances which affect the analysis for the element of interest.

Intergranular: Between the individual grains in a rock or sediment.

Internal Standards: Compounds added to every standard, blank, matrix spike, matrix spike duplicate, sample (for VOAs), and sample extract (for semivolatiles) at a know concentration prior to analysis. Internal standards are used as the basis for quantitation of the target compounds.

Interpolation: A method to determine intermediate values from surrounding known values.

Interpretation: Transforming geophysical measurements into subsurface structure. More general term than inversion.

Intrinsic Permeability: A measure of the relative ease with which a permeable medium can
transmit a fluid (liquid or gas). Intrinsic permeability is a property only of the medium and is
independent of the nature of the fluid.

Inversion, Inverting: The process of deriving a model of the subsurface that is consistent with the geophysical data obtained. Generally refers to a more specific methodology than interpretation.

Isothermal: Being at constant temperature.

Isotope: One of two or more atoms which have the same atomic number, but different mass number.

Isotropic: Having properties which are the same in all directions.

Isotropy: The condition in which the properties of interest (generally hydraulic properties of the aquifer) are the same in all directions.