Arsenic compounds in the leaves and roots of radish grown in three soils treated by dimethylarsinic acid

The effect of dimethylarsinic acid (DMA) on the growth of radish and the content of As compounds in roots and leaves of the radish were investigated. Radish was grown in pots in three soils (Fluvisols, Chernozems and Luvisols) amended with 20 mg As/kg of soil in form of DMA. Behavior and transformations of DMA in the soils differed depending on the individual soil type. In the first season, plants grew up at Luvisols only. In the second season the plants were able to grow at Luvisols and Chernozems, too. The roots and leaves of radish from Luvisols had DMA as the dominant arsenic compound present (~ 90% in the extract) in the first season. In the roots of the subsequently growing radish DMA accounted for 20% and arsenite for most of the total arsenic in the extract. In the leaves of the second-crop of radish DMA remained the dominant arsenic compound (~ 60% in the extract) with arsenate and arsenite for the remaining 40%. Roots and leaves of radish grown in Chernozems and Luvisols had a similar pattern of arsenic compounds. Soil properties significantly affected transformation of As species in the soils. At Fluvisols was the lowest As immobilization and about 98% was found as DMA after two years of experiments in the other two soils was higher As immobilization and DMA was recovered to inorganic As (V) - 31% in Luvisols and 78% in Chernozems.