Tungsten Content of Soils, Plants, and Sewage Sludges in Iowa
Information on the W content in environmental matrices is desired. Because of the antagonistic effect of W on Mo nutrition of plants and microorganisms, this study was conducted to assess the concentration of W in soils, plant materials, and sewage sludges in Iowa. Results showed that the total W in 18 soils ranged from 0 to 2 mg kg−1, with mean and median values of 0.89 and 0.88 mg kg−1, respectively. The corresponding values for 22 plant materials ranged from 0 to 0.35 mg kg−1, with mean and median values of 0.18 and 0.17 mg kg−1. Analysis of 44 sewage sludge samples from different wastewater-treatment plants in Iowa showed that the concentration of this element varied from 0.5 to 62 mg kg−1, with mean and median values of 4.3 and 2.2 mg kg−1, respectively.
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