The present study was designed to explore the relationship between radioactivity at Al-Rohban soil in Al-Najaf Governorate, located 30 km away from Najaf city center, and its microbial content. The radiological survey was conducted by γ–ray spectrometry, using purity Germanium (HPGe) detector. A selected surface soil layer (10 cm depth, 50 and 100 m expansion) was tested. The physical analyses were conducted in the Ministry of Environment, Center for Prevention of Radiation. The results showed that the estimated concentrations of Bi-214, Ra-226, Ac-228, Th-232, K-40 and Cs-137 were 47.93, 81.87, 5.03, 1.63, 126.3 and 3.5 Bq/Kg, respectively. Isotopes average concentrations were equivalent to the lowest specified International Atomic Energy standards. As related to the analysis of bacterial content in the soil sample, the total cell count (in cells per gram of soil) in the different areas studied (R1, R2, R3 and R4) had values of 70000, 200, 60000 and 300 cell/gm., respectively. The statistical analysis of these results revealed no relationship between radioactivity and microorganisms existence.
