Plant uptake of radio-labelled ionic and EDTA-, EDDHA- and DTPA-chelat
ed chromium, lead and polonium was examined in nutrient solution and i
n an Ultisol and a Vertisol. Nutrient culture studies revealed a marke
d enhancement in uptake and translocation of chelated Cr-51 in beans (
Phaseolus vulgaris L.); Cr-51-DTPA was most effective followed by Cr-5
1-EDTA and Cr-51-EDDHA. No significant differences were observed betwe
en chelated Pb-210 complexes and Pb-210(NO3)(2). However, Po-210-DTPA
and Po-210-EDDHA significantly increased the shoot uptake of Po-210 in
comparison to Po-210(NO3)(4). A two fold increase in transport index
for Cr-51 and Po-210 was observed with chelates compared to ionic form
s. Results from soil-plant studies indicated Cr-51 uptake by maize (Ze
a mays L.) plants, one to two orders of magnitude higher from both the
Vertisol and the Ultisol, when Cr-51 was added as Cr-51-EDTA compared
to ionic forms. The DTPA complexes of Pb-210 and Po-210 did not contr
ibute significantly to plant uptake of Pb-210 in both soil types and o
f Po-210 in Ultisol. In contrast, Po-210 uptake was significantly enha
nced from Po-210-DTPA compared to ionic Po-210(NO3)(4) in the Vertisol
.