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In this paper, we report some new findings obtained by in situ radiotracer and voltammetric studies of the simultaneous adsorption of HSO4-/SO42-ions labelled with 35S, and Cr-containing species labelled with 5]Cr on a gold electrode in the course of dichromate reduction in 1 mol dm -3 C104-supporting electrolyte at various pH values (pH = 0 and pH = 2.0). Special attention is paid to show a modified version of the in situ radiotracer "foil" method, as well as to present a detection and calculation procedure elaborated for the quantitative evaluation of the surface excess of radiolabelled Cr species via measurement of the intensity of low energy X-rays (E = 4.90 keV) emitted by 51Cr. From our experimental results it can be stated that: (i) the electroreduction of Cr(VI) particles presumably proceeds via ace (chemical-electron-transfer) mechanism to yield a gold surface covered with intermediate surface adlayer containing Cr(VI) species and added anions (HSO4-/SO42-, C104-); (ii) the extent and mechanism of adlayer formation are affected by the solution pH values; Off) the maximum surface excess of Cr-containing species (FpH=O = 1.2 x 10 -9 mol cm-2; FpH=2. 0 = 1.6 x 10 -9 mol cm-2), as well as the molar ratio between the Cr species and HSO4-/SO42-ions (mpli= 0 = 6 at E = 0.8 V; mpH=2.0 = 2 at E = 0.05 V) attest that the coverage of the gold surface with intermediate complexes does not exceed one monolayer.