Abstract
An incubation experiment was carried out to better understand the fate of As during the decomposition of As-rich Chinese brake fern (Pteris vittata L.) leaves and to assess As bioavailability in soil. Dried fern leaves with an As concentration of 1,150 +/- 14 microg/g were amended with unpolluted soil at 1 and 3%. After aging for one, three, and six months, germinated wheat was planted in the soil. After two months, wheat plants were harvested. Results showed that As concentration in shoots and roots significantly increased with increasing amounts of As-rich leaf additions in soil samples and decreased over the incubation time (p < 0.001). For treatments with 3% fern leaf incubation, the average of As concentration in shoots was 1.59 microg/g dry weight after one month of incubation, nearly 20-fold higher than that of the nonamended treatment; after six months of incubation, As concentration in shoots was 0.48 microg/g, almost 10-fold higher than the corresponding nonamended treatment. Based on a sequential extraction method, As showed a shift from weakly adsorbed fractions to more strongly adsorbed fractions during the incubation, hence resulting in less As bioavailability. Arsenic concentrations in shoots and roots could be well described with linear functions of As concentrations distributed in different fractions. In conclusion, aging effect should be considered during risk assessment of As in soil-plant systems where As is recycled by the plant.
Published Version
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