GLOSSARY - Bioaugmentation for Groundwater Remediation - page 368

possesses both a polar-charged region, which attracts water molecules, and a non-charged and
non-polar area, which attracts non-polar oils and fats.

Long-term monitoring (LTM) ‐ Monitoring conducted after a remedial measure achieves its
objectives, to ensure continued protection and performance.

Lysogen ‐ Refers to a lysogenic phage. Bacteriophages reproduce by two methods, referred to
as the lytic and lysogenic cycles. In the lysogenic cycle, the phage can exist in a dormant state (a
prophage) within its host bacterium, in which its DNA is integrated into the host's genome.
Lysogenic phages, therefore, can be used to introduce foreign DNA into bacteria.

Mass balance ‐ An accounting of the total inputs and outputs to a system. For dissolved
plumes, it refers to a quantitative estimation of the mass loading to a dissolved plume and the
mass attenuation capacity within the affected subsurface environment.

Mass discharge ‐ The rate of mass flow across an entire plume at a given location. Also
referred to as “total mass flux” or “integrated mass flux.” Expressed in units of mass per time
(e.g., grams per day [g/day]), mass discharge essentially integrates several individual mass flux
measurements (expressed as mass/area/time, e.g., grams per square meter per day [g/m 2 /day]).

Mass flux ‐ The rate of mass flow across a unit area (typically measured in grams per square
meter per day [g/m 2 /day]). Typically calculated by integrating measured groundwater
contaminant concentrations across a transect. Often used interchangeably with mass
discharge or mass loading (expressed in grams per day [g/day]) to describe the mass
emanating from a source zone or the mass passing a given transect across the plume.

Maximum contaminant level (MCL) ‐ Standards set by the U.S. Environmental Protection
Agency (USEPA) for drinking water quality that provides for a legal threshold limit on the
amount of a hazardous substance that is allowed in drinking water under the Safe Drinking
Water Act. The limit is usually expressed as a concentration in milligrams or micrograms per
liter of water.

Messenger RNA (mRNA) ‐ A molecule of RNA that serves as a template for protein
synthesis. mRNA is transcribed from a gene and then translated by ribosomes in order to
manufacture a protein. The sequence of a strand of mRNA is based on the sequence of a
complementary strand of DNA.

Metabolite ‐ The intermediates and products of metabolism.

Metabolomics ‐ The measurement of metabolites and their levels. Used to understand
metabolic pathways and the levels of different intermediates.

Metagenomics ‐ The study of metagenomes (i.e., the genetic material that can be recovered
directly from environmental samples). Also referred to as environmental genomics,
ecogenomics, or community genomics, metagenomics allows research on organisms that are
not easily cultured in a laboratory as well as studies of organisms in their natural environment.

Methane monooxygenase ‐ Enzyme capable of oxidizing the C-H bond in methane, as well as
other alkanes. Found in both soluble (sMMO) and particulate forms (pMMO) in methanotrophs
(bacteria capable of growth on methane). Also capable of TCE degradation.