448under normal conditions can be considered volatile by this EPA definition. The term may refer
both to well characterized organic compounds and to mixtures of variable composition.
VOLT: One joule of work per coulomb - the unit of electrical potential transferred.
VOLTAGE: Voltage (sometimes also called electric or electrical tension) is the difference of
electrical potential between two points of an electrical or electronic circuit, expressed in volts. It
measures the potential energy of an electric field to cause an electric current in an electrical
conductor. Depending on the difference of electrical potential it is called extra low voltage, low
voltage, high voltage or extra high voltage. Specifically Voltage is equal to energy per unit charge.
VOLTIMETER: Instrument that measures the cell potential.
VOLUMETERIC ANALYSIS: See titration.
VULNERABILITY ASSESSMENT: An evaluation of drinking water source quality and its
vulnerability to contamination by pathogens and toxic chemicals.
VULNERABILITY ASSESSMENT: An evaluation of drinking water source quality and its
vulnerability to contamination by pathogens and toxic chemicals.
W
WAIVERS: Monitoring waivers for nitrate and nitrite are prohibited.
WATER H2O: A chemical substance, a major part of cells and Earth, and covalently bonded.
WATER PURVEYOR: The individuals or organization responsible to help provide, supply, and
furnish quality water to a community.
WATER QUALITY CRITERIA: Comprised of both numeric and narrative criteria. Numeric criteria
are scientifically derived ambient concentrations developed by EPA or States for various
pollutants of concern to protect human health and aquatic life. Narrative criteria are statements
that describe the desired water quality goal.
WATER QUALITY STANDARD: A statute or regulation that consists of the beneficial designated
use or uses of a waterbody, the numeric and narrative water quality criteria that are necessary to
protect the use or uses of that particular waterbody, and an antidegradation statement.
WATER QUALITY: The 4 broad categories of water quality are: Physical, chemical, biological,
radiological. Pathogens are disease causing organisms such as bacteria and viruses. A positive
bacteriological sample indicates the presence of bacteriological contamination. Source water
monitoring for lead and copper be performed when a public water system exceeds an action level
for lead of copper.
WATER VAPOR: A characteristic that is unique to water vapor in the atmosphere is that water
does not contain any salts.
WATERBORNE DISEASE: A disease, caused by a virus, bacterium, protozoan, or other
microorganism, capable of being transmitted by water (e.g., typhoid fever, cholera, amoebic
dysentery, gastroenteritis).
WATERSHED: An area that drains all of its water to a particular water course or body of water.
The land area from which water drains into a stream, river, or reservoir.
WAVE FUNCTION: A function describing the electron's position in a three-dimensional space.
Weathered: The existence of rock or formation in a chemically or physically broken down or
decomposed state. Weathered material is in an unstable state.
WHOLE EFFLUENT TOXICITY: The total toxic effect of an effluent measured directly with a
toxicity test.
WORK: The amount of force over distance and is in terms of joules (energy).
X
X-RAY: Form of ionizing, electromagnetic radiation, between gamma and UV rays.
X-RAY DIFFRACTION: A method for establishing structures of crystalline solids using singe
wavelength X-rays and looking at diffraction pattern.
X-RAY PHOTOELECTRON SPECTROSCOPY: A spectroscopic technique to measure
composition of a material.
Y
YIELD: The amount of product produced during a chemical reaction.
Z