79Water Quality Key Words.......................
2,4-D: A chlorinated phenoxy compound, functions as a systemic herbicide and is used to control
many types of broadleaf weeds. There are many forms or derivatives (esters, amines, salts) of 2,4-
D and these vary in solubility and volatility. Unless otherwise specified, this document will refer to
the acid form of 2,4-D. This compound is used in cultivated agriculture and in pasture and rangeland
applications, forest management, home and garden situations and for the control of aquatic
vegetation. 2,4-D was a major component (about 50%) of the product Agent Orange used
extensively throughout Vietnam. However most of the problems associated with the use of Agent
Orange were associated with a contaminant (dioxin) in the 2,4,5-T component of the defoliant. The
association of 2,4-D with Agent Orange has prompted a vast amount of study on the herbicide.
ANTIMONY: A chemical element with the symbol Sb (Latin: stibium, meaning "mark") and atomic
number 51. A metalloid, antimony has four allotropic forms. The stable form of antimony is a blue-
white metalloid. Yellow and black antimony are unstable non-metals. Antimony is used in flame-
proofing, paints, ceramics, enamels, a wide variety of alloys, electronics, and rubber.
ASBESTOS: A mineral fiber that has been used commonly in a variety of building construction
materials for insulation and as a fire-retardant. EPA and CPSC have banned several asbestos
products. Manufacturers have also voluntarily limited uses of asbestos. Today, asbestos is most
commonly found in older homes, in pipe and furnace insulation materials, asbestos shingles,
millboard, textured paints and other coating materials, and floor tiles.
BARIUM: A chemical element. It has the symbol Ba, and atomic number 56. Barium is a soft
silvery metallic alkaline earth metal. It is never found in nature in its pure form due to its reactivity
with air. Its oxide is historically known as baryta but it reacts with water and carbon dioxide and is
not found as a mineral. The most common naturally occurring minerals are the very insoluble
barium sulfate, BaSO4 (barite), and barium carbonate, BaCO3 (witherite). Benitoite is a rare gem
containing barium.
BERYLLIUM: A chemical element with the symbol Be and atomic number 4. A bivalent element,
beryllium is a steel grey, strong, light-weight yet brittle alkaline earth metal. It is primarily used as a
hardening agent in alloys, most notably beryllium copper. Commercial use of beryllium metal
presents technical challenges due to the toxicity (especially by inhalation) of beryllium-containing
dusts.
BROMATE: An inorganic anion, bromate is tasteless and colorless, with a low volatility. As a
moderately strong oxidant, bromate is reactive. BrO3- is a bromine-based oxoanion. A bromate is
a chemical compound that contains this ion. Examples of bromates include sodium bromate,
(NaBrO3), and potassium bromate, (KBrO3).
CADMIUM: A chemical element with the symbol Cd and atomic number 48. A relatively abundant,
soft, bluish-white, transition metal, cadmium is known to cause cancer and occurs with zinc ores.
Cadmium is used largely in batteries and pigments, for example in plastic products.
CHLORITE: The chlorite ion is ClO2−. A chlorite (compound) is a compound that contains this
group, with chlorine in oxidation state +3. Chlorites are also known as salts of chlorous acid.
CHROMIUM: A chemical element which has the symbol Cr and atomic number 24. It is a steel-
gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless,
tasteless, and malleable.