Contaminated and Hazardous Waste Site Management

Glossary F

Facultative: Used to describe organisms that are able to grow in either the presence or absence of a specific environmental factor (e.g., oxygen). See also Facultative Anaerobe.

Faculative Anaerobes: Microorganisms that can grow in either the presence or the absence of molecular oxygen. In the absence of oxygen these microorganism can utilize another compound (e.g., sulfate or nitrate) as a terminal electron acceptor.

Fan Shooting: A seismic refraction technique where the sensors (geophones) are deployed on a segment of a circle centred on the seismic source. Variations in the time of arrival are caused by radial variations in the velocity structure. Could be used, for example, to search for low velocity anomalies caused by buried waste.

Fate: The immediate or ultimate change in a chemical typically brought about by chemical or biological reaction.

Fault: A fracture or zone of fractures along which there has been a displacement of the sides relative to one another and parallel to the fracture.

Feasibility Study (FS): The analysis of the potential cleanup alternatives for a site. The FS usually starts as soon as the RI is underway; together, they are commonly referred to as the RI/FS.

Ferrimagnetic: Substances having positive and relatively large magnetic susceptibility as well as generally large hysteresis and remanence. This is due to the interaction of atoms and the coupling of magnetic moments aligned in opposition, which result in non-zero net moments.

Fick's First Law: An equation describing the rate at which a gas transfers into solution. The change in concentration of gas in solution is proportional to the product of an overall mass transfer coefficient and the concentration gradient.

Fick's Second Law: An equation relating the change of concentration with time due to diffusion to the change in concentration gradient with distance from the source of concentration.

Field: That space in which an effect, such as gravity or magnetism, is measurable.

Field Capacity: The maximum amount of water that a soil can retain after excess water from saturated conditions has been drained by the force of gravity. Also called specific retention.

Field Blank: Any sample submitted from the field identified as a blank.

Field Sample: A portion of material received to be analyzed that is contained in single or multiple containers and identified by a unique Sample Number.

Filter Pack: Clean, uniform and well-rounded sand or gravel which is placed between the borehole wall and well screen to prevent formation material from entering through the well screen. It also serves to stabilize the adjacent formation.

Filtering: a) The attenuation of a signal's components based on a measurable property (usually frequency). Filtering usually involves a numerical operation which enhances only a portion of the signal. b) Fluid passage through a material which retains particles or colloids above a certain size.

Filtration: A treatment process for removing solid (particulate) matter from water by passing the water through sand, activated carbon, or a man-made filter. The process is often used to drain and disperse wastewater.

Finite Element Model: An advanced numerical technique for solving partial differential equations, most useful for hydrogeological sites with complex geometry. As with finite difference models, a finite element model solves the hydrogeological system over a grid of many subregions, or elements.

Flame Atomic Absorption (AA): Atomic absorption which utilizes flame for excitation.

Flash Point: Lowest temperature at which the vapour above a liquid can be ignited in air.

Floodplain: The flat land adjacient to a river, formed by deposition of fluvial materials.

Flowing Artesian Well: A well where the water level is above the ground surface.

Flow Lines: Flow lines indicate the direction of groundwater flow towards points of discharge. They are perpendicular to equipotential lines in homogeneous media. Also known as streamlines.

Flow Net: A geometric representation of a two-dimensional steady-state flow field using intersecting lines joining points of equal hydraulic head and flow lines.

Flow Tube: A calibrated flow measuring device made for a specific range of flow velocities and fluids.

Fluid Flow: The movement of a liquid or gas.

Fluid Flux: The volume of fluid flowing through a specified cross-sectional area per unit time.

Fluvial Deposits: Deposits related to a river or stream.

Flux: The rate of movement of mass through a unit cross-sectional area per unit time in response to a concentration gradient or some advective force.

Foundry Sand: Waste sand often contaminated by metal processing and forming occurring in foundries.

Fraction: A specific subunit of an analytical protocol. For example, for full organics the fractions are VOAs, SVs, and pesticides/Arochlors.

Fraction of Organic Carbon (foc): The portion or fraction of the solid material that is organic carbon. Typically ranges from 0.05 (5%) in organic-rich soils to less than 0.0001 (0.01%) in pure quartz beach sands.

Fracture: A break in a rock formation as a result of structural stresses (e.g. faults, joints, shears). If they are open, fractures may provide pathways for fluid movement.

Free Product: A petroleum hydrocarbon in the liquid ("free" or non-aqueous) phase (see also
non-aqueous phase liquid, NAPL).

French Drain System: A crushed rock drain system constructed of perforated pipes, which is used to drain and disperse wastewater.

Frequency Domain: In geophysics, refers to measurements analyzed according to their constituent frequencies. The usual alternative is time domain measurements.

Fresh Water/Salt Water Transition Zone: The interface zone occurring between fresh water and saltwater undelying marine islands and coastal areas with groundwater occurring below the surface of the ground in geologic formations under saturated conditions.

Fungi: Aerobic, multicellular, nonphotosynthetic, heterotrophic microorganisms. The fungi include mushrooms, yeast, molds, and smuts. Most fungi are saprophytes, obtaining their nourishment from dead organic matter. Along with bacteria, fungi are the principal organisms responsible for the decomposition of carbon in the biosphere. Fungi have two ecological advantages over bacteria: (1) they can grow in low moisture areas, and (2) the can grow in low pH environments.