Influence of chelating agents on plant uptake of 51Cr, 210Pb and 210Po Original

Plant uptake of radio-labelled ionic and EDTA-, EDDHA- and DTPA-chelated chromium, lead and polonium was examined in nutrient solution and in an Ultisol and a Vertisol. Nutrient culture studies revealed a marked enhancement in uptake and translocation of chelated 51Cr in beans (Phaseolus vulgaris L.); 51Cr-DTPA was most effective followed by 51Cr-EDTA and 51Cr-EDDHA. No significant differences were observed between chelated 210Pb complexes and 210Pb(N03)2. However, 210Po-DTPA and 210Po-EDDHA significantly increased the shoot uptake of 210Po in comparison to 210Po(NO3)4. A two fold increase in transport index for 51Cr and 210Po was observed with chelates compared to ionic forms. Results from soil-plant studies indicated 51Cr uptake by maize (Zea mays L.) plants, one to two orders of magnitude higher from both the Vertisol and the Ultisol, when 51Cr was added as 51Cr-EDTA compared to ionic forms. The DTPA complexes of 210Pb and 210Po did not contribute significantly to plant uptake of 210Pb in both soil types and of 210Po in Ultisol. In contrast, 210Po uptake was significantly enhanced from 210Po-DTPA compared to ionic 210Po(NO3)4 in the Vertisol.