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_chrominimum _
By: chris
Chris Nicholatos 11/29/99 Mr. Cicero Block-D Chromium Chromium
is a metal found in natural deposits as ores containing other elements.
Chromium is a steel-gray, hard metal that is very brittle. It is classified as
a heavy metal. After its refined from the ore chromite its compounds are used
in leather tanning and manufacturing of chromic acid, pigments, and
corrosion-resistant chrome products. The greatest use of chromium is in metal
alloys such as magnetic tapes, paint pigments, cement, paper, and stainless
steel. It is also used as an ingrediant in drilling mud, which is used to
drill oil wells. Humans do need a certain amount of trivalent chromium to
maintain good health. Although, in other forms, chromium can be toxic for
humans. Workers in chromium products facilities have increased risks of cancer
of the lungs and nose. In 1974, Congess passes the Safe Drinking Water Act.
This act required EPA to determine safe levels of chemicals in drinking water
which might cauase health problems. These levels are called Maximum
Contaminant Level Goals or MCLGs'. The MCLG for chromium is 0.1 parts per
million or PPMs'. At this level there is no potential for health problems.
This and all other standards for water quality are called National Primary
Drinking Water Gegulations. All public water supplies must abide by these
regulations. Short-term effects can include, but are not limited to, skin
irritation or ulceration. This occurs when a person is exposed to chromium at
levels that exceed MCL standards for a relatively short period of time.
Long-term effects can include, but are not limited to, damage to liver,
kidneys, circulatory and nerve tissue, and skin irratation. This occurs when a
person is exposed to chromium at level above MCL standards over a lifetime.
Production of chromium contaminated water was about 250,000 tons in 1992.
Chromium occurs mostly as chrome iron ore and is widley found in soils and
plants, it is rare in natural water. The two largest sources of chromium
emissions in the atmosphere are fom the chemical manufacturing industry and
combustion of natural gas, oil, and coal. From 1987 to 1993, according to the
Toxic Release Inventory, chromium compound released to land and water totaled
nearly 200 million pounds. The releases were primarily from industrial organic
chemical industries. The largest releases occurred in Texas and North
Carolina. The largest direct release to water occurred in Georgia and
Pennsylvania. When released to land, chromium compounds bind to soil are not
likely to migrate to ground water. They are very persistant in water as
sediments. There is a high potential for accumulation of chromuim in aquatic
life. Now, EPA monitors your drinking water supply. They take samples and
analyze the water to make sure the chromium levels do not exceed MCL standards
of 0.1 ppm. If the levels are exceeded the officials must take steps to reduce
the contamination. Some steps that have been approved by the EPA for the
removal of chromium are: Coagulation/Filtration, Ion Exchange, Reverse
Osmosis, Lime Softening. Also, when chromium levels exceed health standards
EPA must notify the general public by newspaper, radio, television, or other
means. Currently Texas has the highest rate of toxins released into water and
land. In closing Massachusettes in general is not in any serious danger of
contamination by chromium. Only industrialzed cities and cities with nuclear
power plants and facilities. But since are current status is good in that
department we should do everything in our power to keep it that way.
Word Count: 579
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