Contaminated and Hazardous Waste Site Management

Glossary M

m/z: Mass to charge ratio, synonymous with "m/e".

m/e: Mass to charge ratio, synonymous with "m/z".

Magnehelic Gauge: A sensitive differential pressure or vacuum gauge manufactured by Dwyer Instrument Co. that uses a precision diaphragm to measure pressure differences. This gauge is manufactured in specific pressure or vacuum ranges such as 0 to 2 inches of water column. Magnehelic gauges are typically used to measure the vacuum of SVE systems.

Magnetics, Geomagnetics: Geophysical methodology for studying anomalies in the geomagnetic field due to non-uniform magnetization of the subsurface. Uses magnetometers.

Magnetic Permeability: Characteristic of a material, it is proportional to the magnetism induced in that material divided by strength of the magnetic field used.

Magnetic Susceptibility: A measure of the extent to which a substance may be magnetized; it represents the ratio of magnetization to magnetic field strength.

Magnetization: The magnetic moment per unit volume. It is a vector quantity. See also Magnetic Susceptibility.

Magnetometer: A device for measuring the earth's magnetic geomagnetic field. Variations in the field strength may indicate changes in magnetic properties of soil and rock or presence of ferrous metals.

Manifold: A pipe with several aperatures for making multiple connections.

Manometer: A tubular device for measuring fluid (or vapour) pressures. A liquid or is introduced into the tube, the level of which is determined by fluid pressure; height of the liquid may be read from a scale.

Mapping: Locating geological, chemical or geophysical information in space (as opposed to time, which is monitoring). The results are usually summarized os maps.

Marine Deposits: Mostly silt and clay materials deposited under a marine environment.

Mass Flux: Like fluid flux, but the mass of a chemical dissolved in groundwater which moves through a specified cross-sectional area per unit time.

Matrix: The solid framework of a porous medium.

Mechanical Pump: A device that brings water to the surface by mechanical means.

Meltwater Channel: A channel shaped by water coming from the melting of snow or glacier ice.

Metabolism: A term that encompasses all of the diverse reactions by which a cell processes food material to obtain energy and the compounds from which new cell components are made.

Metamorphic Rocks: Any rock derived from pre-existing rocks by mineralogical, chemical, and/or structural changes, essentially in the solid state, in response to marked changes in temperature, pressure, shearing stress, and chemical environment, generally at depth in the EarthÕs crust.

Meteoric Water Line (MWL): A plot of the 18O versus 2H isotopes in water samples will plot along this line if that water has not be effected by interaction with minerals and has not undergone significant evaporation.

Methanogenic: Referring to the formation of methane by certain anaerobic bacteria during the process of anaerobic fermentation.

Method Blank (previously termed "reagent blank"): An analytical control consisting of all reagents, internal standards, and surrogate standards, that is carried through the entire analytical procedure. The method blank is used to define the level of laboratory background and reagent contamination.

Method of Standard Additions (MSA): The addition of 3 increments of a standard solution (spikes) to sample aliquots of the same size. Measurements are made on the original and after each addition. The slope, x-intercept, and y-intercept are determined by least-squares analysis. The analyte concentration is determined by the absolute value of the x-intercept. Ideally, the spike volume is low relative to the sample volume (approximately 10% of the volume). Standard addition may counteract matrix effects; it will not counteract spectral effects. Also referred to as Standard Addition.

Microaerophilic: Obligate aerobes that function best under conditions of low oxygen concentration.

Microbiological Transformation: The conversion of a chemical to other chemicals (products) and biological cell mass.

Microcosm: A diminutive, representative system analogous to a larger system in make-up, development, or configuration. As used in biodegradation treatibility studies, microcosms are typically constructed in glass bottles or jars.

Micro-Gravity Survey: A surface geophysical survey method, undertaken on a very small scale (typically station spacings of a few metres), and requiring a high meter sensitivity. Measures the earth's gravitational field at different points over an area of interest. Variations in the field are related to differences in subsurface density distributions, which in turn are associated with changes in soil, rock, and cultural factors. Typically used for cavern or fracture detection.

Microorganisms: Microscopic organisms including bacteria, protozoans, yeast, fungi, mold, viruses, and algae.

Migration: The movement of chemicals, bacteria, gases, etc. in flowing water or vapour in the subsurface. Also, a seismic/radar term whose general meaning is the correction of the recorded image for the effects of reflector dip. A very typical result of migration is the removal of hyperbolic events on the record resulting from diffractions from faults and other discontinuities.

Mine Tailings: Portions of washed or milled ore which are too poor for further treatment.

Mineralization: The release of inorganic chemicals from organic matter in the process of aerobic or anaerobic decay.

Mineralogy: The study of minerals; formation, composition, properties, classification and occurrence.

Mitigation: Actions taken to improve site conditions by limiting, reducing, or controlling toxicity and contamination sources.

Model: A conceptual, mathematical, or physical system intended to represent a real system. A model's behaviour is used to understand processes in the physical system to which it is analogous.

Moisture Content: The amount of water lost from a soil upon drying to a constant weight, expressed as the weight per unit weight of dry soil or as the volume of water per unit bulk volume of the soil. For a fully saturated medium, moisture content equals the porosity.

Molecular Diffusion: Process whereby molecules of various gases tend to intermingle and eventually become uniformly dispersed.

Molecular Weight: The amount of mass in one mole of molecules of a substance as determined by summing the masses of the individual atoms which make up the molecule.

Monitoring: Observing the change in a geophysical, hydrogeological or geochemical measurement with time.

Monitoring Wells: Special wells drilled at specific locations within, or surrounding, a hazardous waste site where groundwater can be sampled at selected depths and studied to obtain such information as the direction in which groundwater flows and the types and amounts of contaminants present.

Monoaromatic: Aromatic hydrocarbons containing a single benzene ring.

Monte Carlo Analysis: In this modelling approach, parameter uncertainty is addressed by varying the input parameters systematically and repeating the simulations for each set of parameters, or each realization. The results can then be averaged or interpreted statistically.

Moraine: An accumulation of unsorted unstratified glacial drift mainly till, deposited by glacial ice. Drift deposited in the flanks of a valley glacier form a lateral moraine. Glacial deposits which have accumulated at the front of a glacier form a terminal moraine. Deposits of drift which have been dragged along beneath the ice form ground moraine.