Assessment of soil Cr (Ⅲ) phytotoxicity using the chelating exchange resin extraction method

摘要

A chelating exchange resin, Chelex 100, was used to extract soil Cr (Ⅲ), and wheat seedling growth experiments were conducted to examine the phytotoxicity of Cr (Ⅲ)-spiked soils. The relationship between the amounts of resin-extractable Cr (Ⅲ) and the phytotoxicity of Cr (Ⅲ) was evaluated. Five agricultural soils with varying properties and Cr (Ⅲ) levels were tested. The results of the wheat seedling growth experiment showed that the dry weight and plant height of wheat grown in acid soils were affected by Cr (Ⅲ) addition. The level of Cr (Ⅲ) extracted from acidic soils by resins was higher than that from alkaline soils with the same level of added Cr (Ⅲ). The plant height of wheat seedlings grown in all tested soils was negatively correlated with the amount of soil resin-extractable Cr (Ⅲ), and the effective concentrations of resin-extractable Cr (Ⅲ) resulting in 10% and 50% growth inhibition (EC<,10> and EC <,50>) were 7 and 47mg· kg 1 respectively. These results suggest that the Chelex 100 resin extraction method is an appropriate method for assessing the phytotoxicity of soil Cr (Ⅲ).