Technical Glossary - M

M85: A blend of 85 percent methanol and 15 percent unleaded regular gasoline, used as a motor fuel.

M100: 100 percent (neat) methanol used as a motor fuel in dedicated methanol vehicles, such as some heavy-duty truck engines.

Macropores: Secondary soil features such as root holes or desiccation cracks that can create significant conduits for movement of NAPL and dissolved contaminants, or vapour-phase contaminants.

Magma: The molten rock and elements that lie below the earth's crust. The heat energy can approach 1,000 degrees Fahrenheit and is generated directly from a shallow molten magma resource and stored in adjacent rock structures. To extract energy from magma resources requires drilling near or directly into a magma chamber and circulating water down the well in a convection- type system. California has two areas that may be magma resource sites: the Mono- Long Valley Caldera and Coso Hot Springs Known Geothermal Resource Areas.

Magnetic Separation: Use of magnets to separate ferrous materials from mixed municipal waste stream.

Magneto Hydro Dynamics (MHD):
A means of producing electricity directly by moving liquids or gasses through a magnetic field.

Major Marketer:
Any person who sells natural gas or oil in amounts determined by the commission as having a major effect on energy supplies.

Major Modification:
This term is used to define modifications of major stationary sources of emissions with respect to Prevention of Significant Deterioration and New Source Review under the Clean Air Act.

Major Natural Gas Producer:
Any person who produces natural gas in amounts determined by the commission as having a major effect on energy supplies.

Major Oil Producer:
Means any person who produces oil in the amount determined by the commission as having a major effect on energy supplies.

Major Stationary Sources: Term used to determine the applicability of Prevention of Significant Deterioration and new source regulations. In a nonattainment area, any stationary pollutant source with the potential to emit more than 100 tons per year is considered a major stationary source. In PSD areas the cutoff level may be either 100 or 250 tons, depending upon the source.

Man-Made (Anthropogenic) Beta Particle and Photon Emitters:
All radio-nuclides emitting beta particles and/or photons listed in Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radio-nuclides in Air and Water for Occupational Exposure.

Managerial Controls: Methods of nonpoint source pollution control based on decisions about managing agricultural wastes or application times or rates for agrochemicals.

Mandatory Recycling:
Programs which by law require consumers to separate trash so that some or all recyclable materials are recovered for recycling rather than going to landfills.

Manual landfill:
A landfill in which most operations are carried out without the use of mechanized equipment.

Manual Separation:
Hand sorting of recyclable or compostable materials in waste.

Manufactured Gas:
Gas produced by certain processes from oil, coal or coke.

Manufacturer's Formulation:
A list of substances or component parts as described by the maker of a coating, pesticide, or other product containing chemicals or other substances.

Manufacturing Use Product: Any product intended (labeled) for formulation or repackaging into other pesticide products.

Margin of Safety:
Maximum amount of exposure producing no measurable effect in animals (or studied humans) divided by the actual amount of human exposure in a population.

Margin of Exposure (MOE):
The ratio of the no-observed adverse-effect-level to the estimated exposure dose.

Marginal Cost:
The sum that has to be paid the next increment of the product of service. The marginal cost of electricity is the price to be paid for kilowatt-hours above and beyond those supplied by presently available generating capacity.

Marine Sanitation Device:
Any equipment or process installed on board a vessel to receive, retain, treat, or discharge sewage.

Market-Based Price:
A price set by the mutual decisions of many buyers and sellers in a competitive market.

Market Clearing Price: The price at which supply equals demand. The Day Ahead and Hour Ahead Markets.

Market Participant (MP): An entity, including a Scheduling Coordinator, who participates in the energy marketplace through the buying, selling, transmission, or distribution of energy or ancillary services into, out of, or through the ISO-controlled grid.

Market Waste:
Primarily organic waste, such as leaves, skins, and unsold food, discarded at or near food markets.

Marketer: An agent for generation projects who markets power on behalf of the generator. The marketer may also arrange transmission, firming or other ancillary services as needed. Though a marketer may perform many of the same functions as a broker, the difference is that a marketer represents the generator while a broker acts as a middleman.

Marginal Cost: In the utility context, the cost to the utility of providing the next (marginal)kilowatt-hour of electricity, irrespective of sunk costs.

A type of wetland that does not accumulate appreciable peat deposits and is dominated by herbaceous vegetation. Marshes may be fresh or saltwater, tidal or non-tidal.

Marsh Gas: A common term for gas that bubbles to the surface of the water in a marsh or swamp. It is colorless, odorless and can be explosive.

Mass-Burn: A type of combustion process in which solid waste is burned without sorting or processing being done at the facility.

Mass-Burn Incinerator: A type of incinerator in which solid waste is burned without prior sorting or processing.

Material Category: In the asbestos program, the broad classification of materials into thermal surfacing insulation, surfacing material, and miscellaneous material.

Material Type: Classification of suspect material by its specific use or application; e.g., pipe insulation, fireproofing, and floor tile.

Materials Recovery:
Operation consisting of collecting and/or sorting waste with a view to recycling the goods and materials it contains.

Materials Recovery Facility (MRF):
A facility that processes residentially collected mixed recyclables into new products available for market.

Materials Recovery Facility (MRF):
Line of business where recyclable material is processed, separated, and sold. This is a facility where recyclable materials are sorted and processed for sale. This process includes separating recyclable materials (manually or by machine) according to type, and baling or otherwise preparing the separated material for sale. Operating costs and revenues for MRF's are accounted for as a separate line of business.

Material Safety Data Sheet (MSDS):
A compilation of information required under the OSHA hazard communication standard, including a listing of hazardous chemicals, health and physical hazards, exposure limits and handling precautions.

Maximum Acceptable Toxic Concentration: For a given ecological effects test, the range (or geometric mean) between the No Observable Adverse Effect Level and the Lowest Observable Adverse Effects Level.

Maximum Available Control Technology (MACT): The emission standard for sources of air pollution requiring the maximum reduction of hazardous emissions, taking cost and feasibility into account. Under the Clean Air Act Amendments of 1990, the MACT must not be less than the average emission level achieved by controls on the best performing 12 percent of existing sources, by category of industrial and utility sources.

Maximum Contaminant Level: The maximum permissible level of a contaminant in water delivered to any user of a public system. MCLs are enforceable standards.

Maximum Contaminant Level Goal (MCLG):
Under the Safe Drinking Water Act, a non-enforceable concentration of a drinking water contaminant, set at the level at which no known or anticipated adverse effects on human health occur and which allows an adequate safety margin. The MCLG is usually the starting point for determining the regulated Maximum Contaminant Level.

Maximum Exposure Range:
Estimate of exposure or dose level received by an individual in a defined population that is greater than the 98th percentile dose for all individuals in that population, but less than the exposure level received by the person receiving the highest exposure level.

Maximum Residue Level:
Comparable to a U.S. tolerance level, the Maximum Residue Level the enforceable limit on food pesticide levels in some countries. Levels are set by the Codex Alimentarius Commission, a United Nations agency managed and funded jointly by the World Health Organization and the Food and Agriculture Organization.

Maximum Tolerated Dose:
The maximum dose that an animal species can tolerate for a major portion of its lifetime without significant impairment or toxic effect other than carcinogenicity.

MCF: One thousand cubic feet or natural gas, having an energy value of one million Btu. A typical home might use six MCF in a month.

Measure of Effect/ Measurement Endpoint: A measurable characteristic of the ecological entity that can be related to an assessment endpoint; e.g. a laboratory test for eight species meeting certain requirements may serve as a measure of effect for an assessment endpoint, such as survival of fish, aquatic, invertebrate or algal species under acute exposure.

Measure of Exposure:
A measurable characteristic of a stressor (such as the specific amount of mercury in a body of water) used to help quantify the exposure of an ecological entity or individual organism.

Mechanical Aeration: Use of mechanical energy to inject air into the water to cause a waste stream to absorb oxygen.

Mechanical Separation: Using mechanical means to separate waste into various components.

Mechanical Turbulence:
Random irregularities of fluid motion in the air caused by buildings or other nonthermal, processes.

Media: Specific environments--air, water, soil--which are the subject of regulatory concern and activities.

Medical Waste: Any solid waste generated in the diagnosis, treatment, or immunization of human beings or animals, in research pertaining thereto, or in the production or testing of biologicals, excluding hazardous waste identified or listed under 40 CFR Part 261 or any household waste as defined in 40 CFR Sub-section 261.4 (b)(1).

Medical Waste: Medical waste is generated by hospitals and healthcare professionals. It includes syringes, needles, and other sharp instruments. Under no circumstances can these be put in conventional waste bins. Medical waste must be disposed of in compliance with national regulations.

Medium-size Water System:
A water system that serves 3,300 to 50,000 customers.

Megawatt (MW):
One-thousand kilowatts (1,000 kW) or one million (1,000,000) watts. One megawatt is enough electrical capacity to power 1,000 average homes. That number fluctuates because electrical demand changes based on the season, the time of day, and other factors.

Megawatt Hour (MWh): One-thousand kilowatt-hours, or an amount of electrical energy that would supply 1,370 typical homes for one month.

Meniscus: The curved top of a column of liquid in a small tube.

Mercury (Hg): Heavy metal that can accumulate in the environment and is highly toxic if breathed or swallowed.

Mesotrophic: Reservoirs and lakes which contain moderate quantities of nutrients and are moderately productive in terms of aquatic animal and plant life.

Metabolites: Any substances produced by biological processes, such as those from pesticides.

The middle layer of a thermally stratified lake or reservoir. In this layer, there is a rapid decrease in temperature with depth. It is also called thermocline.

Methane (CH4):
A colorless, non-poisonous, flammable gas created by anaerobic decomposition of organic compounds. A major component of natural gas used in the home. The simplest of hydrocarbons and the principal constituent of natural gas. Pure methane has a heating value of 1,1012 Btu per standard cubic foot.

Methane: A light hydrocarbon that is the main component of natural gas and marsh gas. It is the product of the anaerobic decomposition of organic matter, enteric fermentation in animals and is one of the greenhouse gasses. The chemical formula is CH4.

Methane Gas Plant:
A plant where methane gas (generated from decomposing solid waste) is collected and transported to a gas-processing facility at the landfill site. Once processed, the methane gas is sold directly to industrial users or to an Affiliate of WMI to use as a fuel to power electricity generators.

Methane Production: A natural method for treating organic waste. It leads to the production of gas (biogas) that can be converted into energy. The gas comes from the biological decomposition of organic matter in an air-deprived environment (known as "anaerobic digestion" because it is without oxygen). A digestate ("digested" waste) is also produced and can be used raw or after treatment (dewatering and composting, sanitization) as a compost. Organic waste, which has high water content and is highly biodegradable, is used primarily for methane production. Organic waste includes putrescible household waste, wastewater treatment plant sludge, oil, grease and night soil, some agrifood industry waste and some agricultural waste.

Methanol (also known as Methyl Alcohol, Wood Alcohol, CH3OH):
A liquid formed by catalytically combining carbon monoxide (CO) with hydrogen (H2) in a 1:2 ratio, under high temperature and pressure. Commercially it is typically made by steam reforming natural gas. Also formed in the destructive distillation of wood.

Methanol: An alcohol that can be used as an alternative fuel or as a gasoline additive. It is less volatile than gasoline; when blended with gasoline it lowers the carbon monoxide emissions but increases hydrocarbon emissions. Used as pure fuel, its emissions are less ozone-forming than those from gasoline. Poisonous to humans and animals if ingested.

Methoxychlor: Pesticide that causes adverse health effects in domestic water supplies and is toxic to freshwater and marine aquatic life.

Methyl Orange Alkalinity:
A measure of the total alkalinity in a water sample in which the color of methyl orange reflects the change in level.

Methyl Tertiary Butyl Ether (MTBE):
An ether manufactured by reacting methanol and isobutylene. The resulting ether has a high octane and low volatility. MTBE is a fuel oxygenate and is permitted in unleaded gasoline up to a level of 15 percent. It is one of the primary ingredients in reformulated gasoline. A clean burning oxygenates with high octane and low volatility added to unleaded gasoline to reduce carbon monoxide emissions.

Microbial Growth: The amplification or multiplication of microorganisms such as bacteria, algae, diatoms, plankton, and fungi.

Microbial Pesticide:
A microorganism that is used to kill a pest, but is of minimum toxicity to humans.

1. Localized climate conditions within an urban area or neighborhood. 2. The climate around a tree or shrub or a stand of trees.

Well-defined surroundings such as the home, office, or kitchen that can be treated as uniform in terms of stressor concentration.

Electromagnetic radiation with wavelengths of a few centimeters. It falls between infrared and radio wavelengths on the electromagnetic spectrum. The radio wave beam can deliver electrical energy over long distances.

Million-Gallons Per Day (MGD): A measure of water flow.

Minimum Generation:
Generally, the required minimum generation level of a utility systems thermal units. Specifically, the lowest level of operation of oil-fired and gas-fired units at which they can be currently available to meet peak load needs.

A comprehensive program to minimize or eliminate wastes, usually applied to wastes at their point of origin.

Mining of an Aquifer:
Withdrawal over a period of time of ground water that exceeds the rate of recharge of the aquifer.

Mining Waste: Residues resulting from the extraction of raw materials from the earth.

Miscible Liquids: Two or more liquids that can be mixed and will remain mixed under normal conditions.

Missed Detection:
The situation that occurs when a test indicates that a tank is "tight" when in fact it is leaking.

Liquid particles measuring 40 to 500 micrometers (pm), are formed by condensation of vapor. By comparison, fog particles are smaller than 40 micrometers (pm).

Mitigation: Measures taken to reduce adverse impacts on the environment.

Mixed Glass:
Recovered container glass not sorted into categories (e.g. color, grade).

Mixed Liquor: A mixture of activated sludge and water containing organic matter undergoing activated sludge treatment in an aeration tank.

Mixed Metals: Recovered metals not sorted into categories such as aluminum, tin, or steel cans or ferrous or non-ferrous metals.

Mixed Municipal Waste: Solid waste that has not been sorted into specific categories (such as plastic, glass, yard trimmings, etc.)

Mixed Paper: Recovered paper not sorted into categories such as old magazines, old newspapers, old corrugated boxes, etc.

Mixed Plastic:
Recovered plastic unsorted by category.

Mobile Incinerator Systems: Hazardous waste incinerators that can be transported from one site to another.

Mobile Source:
Any non-stationary source of air pollution such as cars, trucks, motorcycles, buses, airplanes, and locomotives.

Modular Incinerator: A relatively small type of prefabricated solid waste combustion unit.

Moisture Content:
1.The amount of water lost from soil upon drying to a constant weight expressed as the weight per unit of dry soil or as the volume of water per unit bulk volume of the soil. For a fully saturated medium, moisture content indicates the porosity. 2. Water equivalent of snow on the ground; an indicator of snowmelt flood potential.

The smallest division of a compound that still retains or exhibits all the properties of the substance.

Molten Salt Reactor:
A thermal treatment unit that rapidly heats waste in a heat-conducting fluid bath of carbonate salt.

Monitoring: Periodic or continuous surveillance or testing to determine the level of compliance with statutory requirements and/or pollutant levels in various media or in humans, plants, and animals.

Monitoring Well:
1. A well used to obtain water quality samples or measure groundwater levels. 2. A well drilled at a hazardous waste management facility or Superfund site to collect ground-water samples for the purpose of physical, chemical, or biological analysis to determine the amounts, types, and distribution of contaminants in the groundwater beneath the site.

Monoclonal Antibodies (Also called MABs and MCAs):
1. Man-made (anthropogenic) clones of a molecule, produced in quantity for medical or research purposes. 2. Molecules of living organisms that selectively find and attach to other molecules to which their structure conforms exactly. This could also apply to equivalent activity by chemical molecules.

Monofill: A landfill intended for one type of waste only.

Lakes and reservoirs which are relatively deep, do not freeze over during winter, and undergo a single stratification and mixing cycle during the year (usually in the fall).

The only seller with control over market sales.

Monopsony: The only buyer with control over market purchases.

Montreal Protocol: Treaty, signed in 1987, governs stratospheric ozone protection and research, and the production and use of ozone-depleting substances. It provides for the end of production of ozone-depleting substances such as CFCS. Under the Protocol, various research groups continue to assess the ozone layer. The Multilateral Fund provides resources to developing nations to promote the transition to ozone-safe technologies.

Most Probable Number: An estimate of microbial density per unit volume of the water sample, based on probability theory.

Muck Soils:
Earth made from decaying plant materials.

Mudballs: Round material that forms in filters and gradually increases in size when not removed by backwashing.

Mulch: A layer of material (wood chips, straw, leaves, etc.) placed around plants to hold moisture, prevent weed growth, and enrich or sterilize the soil.

Multiple Use: Use of land for more than one purpose; e.g., grazing of livestock, watershed and wildlife protection, recreation, and timber production. Also applies to use of bodies of water for recreational purposes, fishing, and water supply.

Municipal Discharge:
Discharge of effluent from waste water treatment plants which receive waste water from households, commercial establishments, and industries in the coastal drainage basin. Combined sewer/separate storm overflows are included in this category.

Municipal Sewage: Wastes (mostly liquid) originating from a community; may be composed of domestic wastewaters and/or industrial discharges.

Municipal Sludge: Semi-liquid residue remaining from the treatment of municipal water and wastewater.

Municipal Solid Waste: Common garbage or trash generated by industries, businesses, institutions, and homes.

Municipal Solid Waste (MSW):
All solid waste generated in an area except industrial and agricultural wastes, typically from residences, commercial or retail establishments. Sometimes includes construction and demolition debris and other special wastes that may enter the municipal waste stream. The EPA (1998c) defined municipal solid waste as "a subset of solid waste and as durable goods (e.g., appliances, tyres, batteries), non-durable goods (e.g., newspapers, books, magazines), containers and packaging, food wastes, yard trimmings, and miscellaneous organic wastes from residential, commercial and industrial non-process sources.

Municipal Solid Waste Collection:
The process of picking up wastes from residences, businesses, or a collection point, loading them into a vehicle, and transporting them to a processing, transfer, or disposal site.

Municipal Solid Waste Management (MSWM): Planning and implementation of systems to handle MSW.

Municipal Waste: Household and other waste collected by municipalities. Its great diversity and the leeway left to municipalities to collect or not certain types of waste explains the lack of comprehensive figures in this area.

Municipal Waste Combustor: Combustion facility that uses MSW as its primary, i.e., at least 70%, fuel source.

Municipal Waste Flue Gas Treatment:
The residue from the treatment of municipal waste incineration flue gasses is a solid residue collected after chemically treating flue gas to reduce pollution. The treatment is based on neutralization combined with filtration. The target pollutants are acid gasses and particulate matter, plus heavy metals, nitrogen oxides, and dioxins, which are treated by supplementary processes. The neutralizing reagents can be injected dry in the form of powder (lime or sodium bicarbonate), by semi-wet means (pulverized milk of lime), or by wet means in a soda washing column. These processes generate residual products, mainly comprised of fly ash. Flue gas treatment residue is stabilized before being stored in authorized landfills. These processes are used to treat over 98% of municipal waste incineration flue gas.

Municipalization: The process by which a municipal entity assumes responsibility for supplying utility service to its constituents. In supplying electricity, the municipality may generate and distribute the power or purchase wholesale power from other generators and distribute it.

Municipal Utility: A provider of utility services owned and operated by a municipal government.

Mutagen/Mutagenicity: An agent that causes a permanent genetic change in a cell other than that which occurs during normal growth. Mutagenicity is the capacity of a chemical or physical agent to cause such permanent changes.