Civil Engineering Reference
In-Depth Information
Barium
Sources
In surface and ground waters, naturally occurring barium may be present
in trace amounts through contact with barium-containing rocks. The most common
ores are the sulfate (barite) and the carbonate (witherite). Barium is found in lime-
stones, sandstones, and occasionally in soils. Barium is stable in dry air, but readily
oxidized by humid air or water. The normally low solubility of barium sulfate increases
in the presence of chloride and other anions.
Industrial release of barium occurs from oil and gas drilling muds, smelting of
copper, coal-fired power plants, jet fuels, auto paints, and manufacture of vehicle parts.
Occurrence
By its chemical nature, barium is unlikely to be found in raw water as
a barium ion. In seawater, it is recorded at 6.2
g / L. Barium is usually found in higher
concentrations in groundwater than in surface supplies. Maximum expected level to
be found in community water supplies is 1 mg / L, although the drinking water of many
communities in Illinois, Kentucky, Pennsylvania, and New Mexico can contain barium
at concentrations of 7 to 10 mg / L.
There are limited survey data on the occurrence of barium in drinking water. Most
supplies contain less than 200
g / L of barium. The average concentration of barium
in U.S. drinking water is 28.6
g / L (1977 data). The drinking water of many com-
munities in Illinois, Kentucky, Pennsylvania, and New Mexico contains concentrations
of barium that may be 10 times higher than the drinking water standard. The source
of these supplies is usually well water. Currently, 60 ground water supplies and 1
surface water supply exceeds 1000
g/L.
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Health Effects
Barium is very toxic when its soluble salts are ingested. The human
fatal dose of barium chloride is about 0.8 to 0.9 g, or about 550 to 600 mg of barium.
The human digestive system is permeable to barium, which is transferred to the blood
plasma. Acute barium poisoning exerts a strong, prolonged stimulant action on all
muscles, including cardiac and smooth muscle of the gastrointestinal tract and bladder.
In small chronic doses, barium may cause an increase in blood pressure and hyper-
tension. Barium does not accumulate in bones, muscles, kidneys, or other tissues. EPA
has not classified the carcinogenicity of barium (Group D) because of inadequate
evidence.
Beryllium
Sources
Beryllium is a member of the alkaline earth metals. It is found in many
minerals, and is mostly produced by reducing beryllium fluoride with magnesium
metal. Certain fossil fuels contain beryllium compounds, perhaps accounting for its
presence in some community air samples. It is primarily used as a metal and alloy in
nuclear reactors and aerospace applications, and as an alloy and oxide in electrical
equipment.
Occurrence
Beryllium is not common in drinking water due to the insolubility of
its oxides and hydroxides at the normal pH range. It has been reported to occur in
U.S. drinking water at 0.01 to 0.7 mg / L.
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Groundwater surveyed between 1962 and
1967 had a 5.4 percent detection frequency, with a maximum concentration of
