The most widespread source of pollution in Russia is the oil pollution. It occurs at all stages of oil production, transportation and processing. Outflows, proceeding during decades result to formation of oil secondary deposits. In a near-surface zone, oil pollution becomes especially chemically active and reacts with geological environment, that results in the anomalies of various geophysical methods: SP, IP, GPR and resistivity. The oil pollution is an unusual object due to its ability to oxidation and mobility. The pollution causes processes, occurring with the speed, differed from natural geological processes. Changes of rock properties, caused by oil pollution are inconsistent. A priory, for example, the oil is an isolator, but frequently it causes anomalies of lowered resistivity. For engineering and environmental studies with electrical methods in urban areas (including pollution studies) the main problem is the influence of geological noise. Upper part of cross-section includes many near-surface inhomogeneities (NSI), caused with artificial ground, asphalt cover, trenches, cables, tubes, etc. These inhomogeneities create strong distortions and influence like "the broken glass", preventing from clear seeing deep objects. NSI distorting influence can be canceled by the application of total electric sounding (TES) technology, developed in MSU. In TES technology we apply two-sided pole-dipole array with step of distance growth equal to step between VES sites along profile. NSI creates distortions of four different types (fig.1C), when movable (single or dipole) element crosses the NSI, or unmovable (single or dipole) element is placed in NSI limits (fig.1B). Some distortions of sounding curves are conformable (fig.1C, 1-2), whereas others are non-conformable (fig. 1C, 3-4). On apparent resistivity cross-section distortions display as vertical and inclined strip zones (fig.2,3). For different types of array (Pole-dipole, polepole, Schlumberger, Wenner, dipole-dipole, etc.) distortions are different (fig.3). For several NSI (fig.3, 3) interference of distortions appears. We developed software for canceling such distortions. The algorithm of median polishing was offered by J.W.Tukey (1981), and after modification made by E.V.Pervago was applied for processing of Total Electrical Sounding (TES) data. The algorithm's operation is based on regularity of distortion effects and it allows to cancel effectively these effects on apparent resistivity pseudocross-section. J.W.Tukey described processing algorithm for data, given in the table as following: at the first step-counting and subtracting median value for each column; at the second stepcounting and subtracting median value for every row. Then the 1st and 2nd steps repeat several times.
