ENAA studies of chromium uptake by Arthrobacter oxydans

To study chromium uptake by Arthrobacter oxydans [Cr(VI)-reducing bacteria isolated from Columbia basalt rocks, USA] the instrumental epithermal neutron activation analysis (ENAA) was applied. It was established that chromate accumulation is dose-dependent and it is most intensive in the interval of Cr(VI) concentrations (10-50 mg/l). At lower concentrations of Cr(VI) (up to 50 mg/l) the most intensive formation of Cr(V) was found using ESR method. Besides, it was established that reduction from Cr(VI) to Cr(V) is a faster process than the uptake of Cr(VI). According to ENAA measurements, in contrast to Cr(VI), Cr(III) is not accumulated in Arthrobacter oxydanscells up to concentrations of 200 mg/l. Using epithermal neutron activation analysis the background levels of 17 major, minor and trace elements were determined in Arthrobacter oxydans.