Tungsten in Washington State surface waters.

At high concentrations, tungsten can be toxic to humans, animals, and the environment, though little is known about natural, aqueous tungsten in surface waters. To improve understanding and develop a model predicting tungsten concentrations, we collected water and sediment from 77 water bodies in 20 watersheds in Washington State, USA. We found aqueous tungsten concentrations spanning two orders of magnitude (10.3 ng L-1 - 2.05 µg L-1) with average tungsten concentrations in both water and sediments more than two-fold higher in watersheds with tungsten-bearing underlying rock types (average: 0.217 µg L-1, 0.669 mg kg-1; range: 0.010-2.05 µg L-1, 0.0713-4.691 mg kg-1 for surface waters and sediments, respectively) than in watersheds without such underlying geology (average: 0.068 µg L-1, 0.352 mg kg-1; range: 0.010-0.211 µg L-1, 0.0349-2.399 mg kg-1 for surface waters and sediments, respectively). Aqueous concentrations of tungsten significantly correlated with beryllium (Be) and copper (Cu) (R2 = 0.31, 0.41, respectively) and a multiple linear regression model using Be and Cu explained 65% of the variance in measured aqueous tungsten concentrations. Applying this model to existing Be and Cu data from 19 sites across the Pacific Northwest resulted in predicted tungsten concentrations ranging from 0.116 to 0.458 µg L-1. These predicted concentrations along with our measured concentrations indicate none of these sites were close to the drinking water standard for tungsten set by the former Soviet Union-the only country so far to set limits for tungsten in drinking water (50 µg L-1).

Uncertainty of inductively coupled plasma mass spectrometry based measurements: an application to the analysis of urinary barium, cesium, antimony and tungsten.

The wide use of barium (Ba), cesium (Cs), antimony (Sb) and tungsten (W) in many industrial and agricultural fields causes the increased release of these metals into the environment, laying the basis for health risk. To assess the exposure for the general population, the development of adequate and reliable analytical techniques becomes compulsory. This study refers to the quantification of urinary Ba, Cs, Sb and W levels by both quadrupole (Q) and sector field (SF) inductively coupled plasma mass spectrometry (ICP-MS). The two procedures were compared for their performances and their measurement uncertainties. The limits of detection were (Q and SF) 23.0 and 5.21 ng L(-1) for Ba; 21.1 and 7.52 ng L(-1) for Cs; 1.09 and 0.43 ng L(-1) for Sb; and 0.36 and 0.49 ng L(-1) for W. The trueness was better than 93.3% and the precision less than 12% for both techniques. Relative expanded uncertainties of the analytical procedures, at the median levels found in the general population, were below 5% for all the elements with both ICP-MS techniques. The uncertainties related to the calibration and repeatability were the parameters most influencing the final analytical performance. The urinary median values observed in healthy subjects from central Italy were 1146, 4301, 60.8 and 48.5 ng L(-1) for Ba, Cs, Sb and W, respectively.