Changes in uranium and thorium contents in topsoil after long‐term phosphorus fertilizer application

Abstract

Archived soil samples from the beginning and end of three long‐term field trials conducted in central France were analysed for total uranium (U) and thorium (Th) contents to evaluate the effect of 15–30 yr of phosphorus (P) fertilizer treatments on the accumulation of these elements in the topsoil. For comparison, the soil samples were also analysed for total P. Three treatments were compared: no P application (P0), 26 kg P/ha/yr (P26) and 52 kg P/ha/yr (P52). Significant effects of P fertilizer were observed on U content and, to a lesser extent, on Th content as a result of the P52 treatment at two of the field trials. This effect was demonstrated both in the analyses at the end of the field trials [P52–P0: +0.25 and +0.44 mg U/kg soil, +0.58 (not significant) and +1.03 mg Th/kg soil] and when considering the changes in U and Th contents between the beginning and the end of the field trials (end–start: +0.18 and +034 mg U/kg soil, +0.35 and +0.45 mg Th/kg soil). The P fertilizer effect was also supported by the correlations of U and Th with total levels of P in the soil. However, in one of the three trials, no significant accumulation of U or Th because of fertilizer could be seen, suggesting either that less U and Th were applied using a different P fertilizer and/or that soil heterogeneity masked significant effects.

Arabidopsis thaliana plants challenged with uranium reveal new insights into iron and phosphate homeostasis

“…The most contaminating industries are U mining and milling, metal mining and smelting, and the phosphate industry (Vandenhove, ). Agricultural phosphate fertilization also accounts for a major source of U dissemination (Schipper et al ., ; Wetterlind et al ., ). In its soluble form, U may be taken up by plants and can therefore contaminate the food chain (Neves et al ., ).…”

Uranium in groundwater — Fertilizers versus geogenic sources

“…Phosphate fertilizers contain different levels of radioisotopes and have long been identified as a possible source of uranium in the environment (e.g. Barišić et al, 1992;Guimond and Windham, 1975;Guimond and Hardin, 1989;Hamamo et al, 1995;Pfister et al, 1976;Wetterlind et al, 2012;Zielinski et al, 1997).…”

Uranium in agricultural soils and drinking water wells on the Swiss Plateau

“…For soils with high clay and organic-matter content, U is anticipated not to migrate substantially (Rogasik et al, 2008). Accordingly, several studies have shown that long-term fertilization with mineral based P-fertilizers leads to substantial accumulation of U in soils, particularly topsoil, compared to unfertilized soils (Bigalke et al, 2017;Jones, 1992;Rogasik et al, 2008;Schipper et al, 2011;Takeda et al, 2005Takeda et al, , 2006Taylor, 2007;Wetterlind et al, 2012;Yamaguchi et al, 2009;Zielinski et al, 2006). In accordance with these findings, a number of authors have pointed to regional variations in concentrations of U in drinking water generally related to bedrock composition, even if the direct relationship might be complicated by groundwater flow through different rock formations (CCME, 2011;Stalder et al, 2012).…”