Civil Engineering Reference
In-Depth Information
Thallium
Sources
Thallium is found in the rare minerals crooksite, lorandite, and hutchin-
sonite. It is also found in minute quantities in pyrites, from which it is recovered while
producing sulfuric acid. Thallium is also obtained from the smelting of lead and zinc
ores. Thallium has been used in photocells as an infrared detector (in thallium bromide-
iodide crystals), in glass manufacturing, in the electronics industry, as an alloy, and in
pharmaceutical products to treat skin infections. Thallium oxide, in the presence of
water, forms hydroxide.
Occurrence
Limited data are available on thallium occurrence. It is found at con-
centrations of 1 to 88
g / L in rivers draining metal mining areas.
Health Effects
Thallium is a suspected carcinogen to humans and affects the kid-
neys, the liver, and the brain.
Vanadium
Sources
Vanadium is not common in drinking water, although it may occur locally
near residue piles from milling and mining operations. Particularly useful in nuclear
production, it is also used as an alloy (vanadium steel or ferrovanadium), in glass
manufacturing and photography.
Occurrence
A survey of raw waters had a 3.4 percent detection frequency with a
maximum concentration of 300
g / L and a mean of 40
g / L. Finished waters sur-
veyed demonstrated comparable results.
3
Another finished water survey of the 100
largest cities in the United States recorded a median value of less than 4.3 and a high
concentration of 70
g/L.
Health Effects
Health effects may be summarized as follows:
2
Absorption in the human body is extremely low.
•
Requirements in human nutrition have not been proven, but it has been suggested
as a protective against atherosclerosis.
•
Acute vanadium toxicity is primarily respiratory.
•
There is no evidence of chronic oral toxicity.
•
Vanadium in drinking water may be significant when considering the total diet due to
the small contribution of vanadium in food. If vanadium is proven as a beneficial
nutritional trace element, the daily contribution in drinking water may be considered
beneficial.
Zinc
Sources
Zinc commonly occurs in source waters and may be added to finished water
through corrosion of metal pipes. Many zinc salts are highly soluble in water; others
are not (carbonate, oxide, sulfide). Zinc is typically detected only in traces in natural
