[Synergetic Control of Bioavailability of Pb, Cd and As in the Rice Paddy System by Combined Amendments].

This paper studied the effects of applying two combined amendments LST (limestone+meerschaum+titanium dioxide) and LSF (limestone+meerschaum+ferric sulfate) at different ratios of 0, 1, 2, 4, 8 and 16 g·kg on bioavailability Pb, Cd and As in paddy soil and bioaccumulation in rice plants through a pot experiment planting rice. The results indicated that: 1Compared with the control, applying LST and LSF could both significantly increase soil pH values (<0.05), and LST increased the soil pH values more. 2Applying combined amendments LST and LSF with the amount of 1-16 g·kg decreased exchangeable contents of soil Pb, Cd and As significantly by 16.8%-88.3%, 22.4%-73.7%, 2.25%-43.8%, and 20.2%-86.9%, 20.7%-51.2%, 18.0%-55.1%, respectively. LST and LSF significantly decreased contents of Pb, Cd and As of rice root, shoot, husk and brown rice. When the applying amount of LST and LSF was 16 g·kg, the contents of Pb, Cd and As in brown rice decreased by 50.7%, 64.7%, 34.1%, and 40.7%, 40.7%, 36.2%, respectively. 3The ability of rice organs transferring Pb and As was husk>rice straw>root, and that transferring Cd was husk >root >rice straw. The ability to transfer Pb, Cd and As from rice straw to brown rice was Cd >As >Pb. 4After applying LST and LSF, a significant positive relationship was observed between contents of Pb, Cd and As in brown rice and exchangeable contents of these elements in soil. Between contents of Pb, Cd and As in brown rice and soil pH values, there was a significant negative correlation.