Wolframsäure, Dinatrium-Salz

TERRESTRIAL FATE: Tungsten compounds in soils are in the form of tungstate (i.e., WO4-2) and other tungsten polyanions(1). There are no reports of tungsten organic complexes(1). The sorption coefficient for tungsten increases with decreasing pH(2). It ranges from 100-50,000 at about pH 5, 10-6,000 at about pH 6.5, and 5-90 at between pH 8-9(2). These sorption coefficients values suggest that tungsten compounds will have moderate to no mobility in soils(SRC). Tungsten compounds will exist as ions or insoluble solids in the environment(3) and therefore volatilization from moist soil surfaces will not be an important fate process(SRC). Tungsten compounds are also will not volatilize from dry soil surfaces based upon their ionic character and low vapor pressures(SRC).

AQUATIC FATE: Tungsten in natural waters is in the form of tungstate (i.e., WO4-2) and other tungsten polyanions(1). There are no reports of tungsten organic complexes(1). The sorption coefficient for tungsten increases with decreasing pH(2). It ranges from 100-50,000 at about pH 5, 10-6,000 at about pH 6.5, and 5-90 between pH 8-9(2). These sorption coefficients values suggest that tungsten compounds will adsorb to suspended solids and sediment(SRC). Tungsten compounds will exist as ions or insoluble solids in the environment(3) and therefore volatilization from water surfaces will not be an important fate process(SRC).

ATMOSPHERIC FATE: Most tungsten compounds have low pressures at 25 °C and are expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase tungsten compounds may be removed from the air by wet and dry deposition. (SRC)

The range of tungsten concns in plants ranged from <0.001-100 mg/kg (dry wt)(1). The mean concn of tungsten in agricultural plants from Iowa was 0.18 mg/kg (samples = 22; range, 0-0.35 mg/kg)(2). Tree leaves from New Zealand contained tungsten at a mean concns of 2.2 to 3.5 mg/kg (range, 0.1-13 mg/kg)(2).

The sorption coefficient for tungsten increases with decreasing pH(1). The sorption coefficient ranges from 100-50,000 at about pH 5, 10-6,000 at about pH 6.5, and 5-90 at between pH 8-9(1). The sorption behavior of tungsten is due to changes in the surface charge of the soil as the contact solution becomes more acidic or alkaline(1). These sorption coefficients suggest that tungsten compounds are expected to have moderate to no mobility in soil under normal environmental conditions(SRC).

The production and use of tungsten compounds as cutting tools, abrasion resistant surfaces, and forming tools (e.g., tungsten carbide); filaments (e.g., tungsten metal and alloys); catalysts (e.g., tungsten oxides, sulfides, and heteropoly complexes); thin films (e.g., tungsten disulfide); and dyes and pigments (e.g., organic tungsten)(1) may result in the release of tungsten to the environment through various waste streams(SRC). Tungsten may be released to soil as a contaminate in phosphate fertilizers and manure(2,3). Only small concns of tungsten have been released into the atmosphere primarily by industrial emissions and nuclear fall-out(4).

The range of tungsten concns in surface soils was from 0.68-2.7 mg/kg(1). Agricultural soils from New Zealand had mean concns of tungsten ranging from 1.9 to 21.4 mg/kg(2). The mean tungsten concn in Iowa agricultural soils was 0.89 mg/kg (range, 0-2 mg/kg)(2).

Tungsten compounds are expected to exist as ions or insoluble solids in the environment(1) and therefore volatilization from moist soil and water surfaces is not expected to be an important fate process(SRC). Tungsten compounds are not expected to volatilize from dry soil surfaces based upon their ionic character and low vapor pressures(SRC).

...YOUNG RATS WERE FED FOR...70 DAYS...SODIUM TUNGSTATE EQUIV TO 2% W... MARKEDLY TOXIC, CAUSING INITIAL WT LOSS...DEATHS OF ALL ANIMALS...WITHIN 10 DAYS. IN DIETS HAVING EQUIV 0.5% W...DEATH IN 3/4 RATS.

SODIUM TUNGSTATE ANTAGONIZES THE NORMAL METABOLIC ACTION OF MOLYBDATE IN ITS ROLE AS METAL CARRIER FOR XANTHINE DEHYDROGENASE. ...SODIUM TUNGSTATE ADDED TO DIET INHIBITED THE INTESTINAL DEPOSITION OF XANTHINE OXIDASE IN RAT & REDUCED...XANTHINE DEHYDROGENASE & MOLYBDENUM CONCN IN LIVER OF CHICKEN.

...SODIUM TUNGSTATE /FED/ TO GOATS & COWS...SHOWED REDN IN XANTHINE OXIDASE SECRETED IN MILK... POSTULATED THAT TUNGSTATE CAN PREFERENTIALLY OCCUPY ENZYME SITES NORMALLY OCCUPIED BY MOLYBDATE.

SOL SODIUM TUNGSTATE...INJECTED SC IN...RATS... VERY YOUNG RATS (30 DAYS OLD) SURVIVED A DOSE THAT PROVED LETHAL TO OLD RATS.

For more Non-Human Toxicity Excerpts (Complete) data for SODIUM TUNGSTATE (7 total), please visit the HSDB record page.

Tungsten exists in several oxidation states, 0, 2+, 3+, 4+, 5+, and 6+(1,2). The most stable is 6+ with the lower states being relatively unstable(2). Tungsten exist as ions in combination with one or more elements, e.g., oxygen(1). Tungsten in natural waters is in the form of tungstate (i.e., WO4- 2) and other tungsten polyanions(3). There are no reports of tungsten organic complexes(3). Bivalent tungsten exists only as halogen compounds(1). Tungsten has a strong tendency to form complexes exemplified by a large series of heteropoly acids formed with oxides of phosphorus, arsenic, vanadium, and silicon, among others (e.g., phosphotungstic acid)(2). In addition, compounds of tungsten exist in which tungsten occurs in more than one valence state(2). Tungsten forms a series of oxyhalides (e.g., WOCl4, WO2Cl2, and WOBr4)(2).