The dose-dependent formation of Cr(III) complexes and uptake of chromium by Arthrobacter oxydans — a Gram-positive bacterium from contaminated Columbian basalt rocks (USA) — were studied along with the testing under aerobic
conditions of two bacterial strains of Arthrobacter genera isolated from the polluted basalts from the Republic of Georgia. Instrumental neutron activation analysis (INAA) was
used to track the accumulation of chromium in the bacterial cells. To monitor and identify Cr(III) complexes in these bacteria,
electron spin resonance (ESR) spectrometry was employed.