Tungsten compounds
are considered somewhat more toxic than
those of molybdenum. However,
industrially, this element does not constitute
an important health hazard. Exposure is
related chefly to the dust arising from the
crushing and milling of the two chief ores of
tungsten, namely, scheelite and wolframite.
The feeding of 2,5, and 10% of dlet as
tungsten metal over a period of 70 days has
shown no marked effect upon the growth of
rats, as measured in terms of gain in weight.
Sodium tungstate (Na2WO4), the most
soluble salt, is moderately toxic by ingestion.
Large overdoses cause central nervous
system dlsturbances, diarrhea, respiratory
filure, and death in experimental animals.
Ammonium-p-tungstate has been found to
be much less toxic to rats upon ingestion
than either tungstic oxide or sodium
tungstate. Tungsten carbide (WC) is
chronically toxic to humans by inhalation
although the effect may be due to
contamination by cobalt. Heavy exposure to
the dust or the ingestion of large amounts of
the soluble compounds produces changes in
body weight, behavior, blood cells,
cholinesterase activity, and sperm in
experimental animals. See also specific
compounds.
