In La Pampa,Argentina, soil bioremediation is one of the most widely used methods for the elimination of oil residues. Oil was treated with bacteria to degrade its organic compounds deposited in the soil. However, crude oil contains several transition elements, which can be accumulated in the soil after the bioremediation process is finished. For this reason, this paper discusses the determination of transition elements in bioremediated soils - including the concentration of Co, Cr, Cu, Fe,Mn,Mo, Ni, and Ti to evaluate its contribution to environmental impact in bioremediation zones from La Pampa, Argentina. The determinations of metals were carried out by inductively coupled plasma optical emission spectroscopy (ICP-OES) in soil samples proceeding from a remediation zone in the southwest of La Pampa. Testing samples without oil from the same zone were analyzed to determine the basal levels of elements. Results showthat oil has a contribution of transition elements and can be accumulated by repeated use of soil along time, which can produce an important environmental impact in the soil for futures uses, due to the fact it can lixiviate and contaminate the Colorado River.