Using iterative 2δ‐technique and 4δ‐outlier test for evaluating the geochemical background concentrations of trace elements in topsoil at Cao Bang province, Vietnam

This study investigated the geochemical background values for seven trace elements in topsoil samples collected from highland areas within Cao Bang province, Vietnam. Total concentrations of these elements were determined, revealing the following order of mean concentration: Zn > Cr > Pb > Cu > As > Ni > Co. The background values were calculated using two different methods including iterative 2δ‐technique and 4δ‐outlier test. The 4δ‐outlier test yielded the following background concentrations (dry weight) for the seven elements: As (24.41 ± 12.42 mg kg−1), Co (15.64 ± 10.57 mg kg−1), Cr (49.31 ± 33.41 mg kg−1), Cu (29.77 ± 27.14 mg kg−1), Ni (22.52 ± 13.33 mg kg−1), Pb (38.06 ± 31.48 mg kg−1), Zn (71.79 61.09 mg kg−1). The 2δ‐technique, on the other hand, resulted in the following background concentrations (dry weight) for the same elements: As (8.41 ± 8.57 mg kg−1), Co (5.06 ± 4.31 mg kg−1), Cr (26.72 ± 26.20 mg kg−1), Cu (25.31 ± 24.81 mg kg−1), Ni (8.02 ± 7.83 mg kg−1), Pb (28.12 ± 27.58 mg kg−1), Zn (51.91 ± 49.44 mg kg−1). These results provide valuable baseline data for future environmental assessments and monitoring programs in the region. They also highlight the potential impact of human activities, such as mining, on the geochemical landscape of highland areas.