Reduction of crop contamination by soil resuspension within the 30-km zone of the Chernobyl Nuclear Power Plant

A field experiment was conducted within the 30-km zone of the Chernobyl Nuclear Power Plant to analyze whether the application of mulching reduced resuspension of Cs-137 contaminated soil in oat (Avena sativa) crops. In 1993, we applied a mulch treatment at a dose of 200 g m(-2), and soil resuspension was measured by estimating soil loadings onto plant surfaces from Ti concentrations in plants. In 1994, two mulch doses were applied, 200 and 50 g m(-2), and we estimated the contribution of soil resuspension by using artificial resuspension collection devices (ARC). In the 1993 experiment between 4.6 and 34.4% of the plant's total Cs-137 contamination was attributed to external soil contamination. The mean amount of soil-derived Cs-137 attached to vegetation was 124.7 Bq kg(-1) plant in control plots and 53.7 Bq kg(-1) plant in mulched plots. In the 1994 experiment, covering the soil with a mulch layer decreased the radiocesium content in ARC by about 70%. Results obtained in these experiments suggest that soil resuspension was a significant mechanism for plant contamination and that mulching was effective in reducing that contamination.