Bly i jord och växter: Tillväxt och blyupptag
Sammanfattning: This study investigates how lead content and bioavailability in soil affects growth and root/shoot ratio in three commonly cultivated species: wheat (Triticum turgidum), clover (Trifolium) and radish (Raphanus sativus). The study investigates the levels at which soil lead content contribute to toxic effects in plants, and when it may pose a risk to consumers. In addition, lead accumulation and the suitability for phytoextraction of lead in soil is investigated for wheat and radish. The three crops were cultivated in soil collected from a disused shooting range outside Staffanstorp, Skåne, Sweden. To a control soil from a low-contaminated site of the shooting range, lead nitrate was added to increase lead content and bioavailability. Effects on growth and plant root/shoot ratios in this study occurred at a soil bioavailable lead content between 1100 and 2100 mg/kg. Negative effects on shoot growth were significant for radish at 2100 mg Pb/kg, while negative effects on root growth were significant for both radish and wheat. The root/shoot ratio was significantly affected for all three crops at 2100 mg/kg, redistributing biomass from roots to shoots. The accumulation of lead was about four times higher in radish than in wheat. Even at the lowest and least bioavailable lead concentrations in soil, lead content in wheat and radish was higher than the lead food safety limits for the respective groups of food. In some cases limits were exceeded more than a hundred times. Thus, no fruit or vegetables grown in shooting range soil should be consumed, nor should grass from shooting ranges be used as feeding for livestock. Radish accumulated lead to the highest extent, accumulating close to 700 mg/kg at the highest level of bioavailable lead in soil. Even though this is a high level, radish is not a suitable crop for large scale phytoextraction, as its biomass production is too low.
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