436MYCOTOXIN: A toxin produced by a fungus.
N
NaOCl: Is the molecular formula of Sodium hypochlorite.
NaOH: Is the molecular formula of Sodium hydroxide.
NASCENT: Coming into existence; emerging.
NASCENT: Coming into existence; emerging.
NATURAL GRAVEL PACK (Naturally packed): Refers to a well that has no gravel pack installed
but is simply allowed to develop a filter pack composed of the aquifer particles itself. Usually
coarse grained and hard rock aquifers are naturally packed.
NEAT: Conditions with a liquid reagent or gas performed with no added solvent or co-solvent.
NEUTRINO: A particle that can travel at speeds close to the speed of light and are created as a
result of radioactive decay.
NEUTRON: A neutral unit or subatomic particle that has no net charge.
NH3: The molecular formula of Ammonia.
NH4+: The molecular formula of the Ammonium ion.
NITRATES: A dissolved form of nitrogen found in fertilizers and sewage by-products that may
leach into groundwater and other water sources. Nitrates may also occur naturally in some
waters. Over time, nitrates can accumulate in aquifers and contaminate groundwater.
NITROGEN AND PHOSPHORUS: Pairs of elements and major plant nutrients that cause algae
to grow.
NITROGEN: Nitrogen is a nonmetal, with an electronegativity of 3.0. It has five electrons in its
outer shell and is therefore trivalent in most compounds. The triple bond in molecular nitrogen
(N2) is one of the strongest in nature. The resulting difficulty of converting (N2) into other
compounds, and the ease (and associated high energy release) of converting nitrogen
compounds into elemental N2, have dominated the role of nitrogen in both nature and human
economic activities.
NO3-: The molecular formula of the Nitrate ion.
NO3-: The molecular formula of the Nitrate ion.
NOBLE GASES: Group 18 elements, those whose outer electron shell is filled.
NON-CARBONATE HARDNESS: The portion of the total hardness in excess of the alkalinity.
NON-CARBONATE IONS: Water contains non-carbonate ions if it cannot be softened to a
desired level through the use of lime only.
NON-METAL: An element which is not metallic.
NON-POINT SOURCE POLLUTION: Air pollution may leave contaminants on highway surfaces.
This non-point source pollution adversely impacts reservoir water and groundwater quality.
NON-TRANSIENT, NON-COMMUNITY WATER SYSTEM: A water system which supplies water
to 25 or more of the same people at least six months per year in places other than their
residences. Some examples are schools, factories, office buildings, and hospitals which have
their own water systems.
NORMALITY: It is the number of equivalent weights of solute per liter of solution. Normality
highlights the chemical nature of salts: in solution, salts dissociate into distinct reactive species
(ions such as H+, Fe3+, or Cl-). Normality accounts for any discrepancy between the
concentrations of the various ionic species in a solution. For example, in a salt such as MgCl2,
there are two moles of Cl- for every mole of Mg2+, so the concentration of Cl- as well as of Mg2+
is said to be 2 N (read: "two normal"). Further examples are given below. A normal is one gram
equivalent of a solute per liter of solution. The definition of a gram equivalent varies depending on
the type of chemical reaction that is discussed - it can refer to acids, bases, redox species, and
ions that will precipitate. It is critical to note that normality measures a single ion which takes part
in an overall solute. For example, one could determine the normality of hydroxide or sodium in an
aqueous solution of sodium hydroxide, but the normality of sodium hydroxide itself has no
meaning. Nevertheless it is often used to describe solutions of acids or bases, in those cases it is
implied that the normality refers to the H+ or OH- ion. For example, 2 Normal sulfuric acid
(H2SO4), means that the normality of H+ ions is 2, or that the molarity of the sulfuric acid is 1.
Similarly for 1 Molar H3PO4 the normality is 3 as it contains three H+ ions.
NTNCWS: Non-transient non-community water system.