Geochemical baseline and distribution of cobalt, manganese, and vanadium in the Liao River Watershed sediments of China

The quantitative contamination assessment of toxic elements in sediments is a challenge due to the lack of their geochemical background or baseline levels and sediment heterogeneity. Eighty-eight sediment samples were collected in the Liao River Watershed (LRW) and analyzed for Co, Mn, V, Sc, Fe, Al, and sediment properties. The average background levels, geochemical baseline levels (GBL), and geochemical baseline functions of Co, Mn, and V in the sediments were obtained using statistical and geochemical methodologies. The concentrations of Co, Mn, and V were 0.86 to 23.40, 105.9 to 1771.6, and 6.47 to 153.30 mg/kg, respectively. The average background levels and GBLs were 7.2 and 14.4 mg/kg for Co, 422 and 762 mg/kg for Mn, and 35.4 and 59.0 mg/kg for V. The linear correlation of Co, Mn, and V with particle-size proxy elements (normalizers) Sc, Fe, and Al was statistically significant with probability (p-value) <0.001 level, showing that Fe, Al, and Sc can be used as particle-size proxy elements to develop the GBFs of Co, Mn, and V. The spatial distribution of the sampling sites with the concentrations of Co, Mn, and V either outlied or greater than GBLs may be related to industry and mine distribution, showing the impact of human activities on the contents of Co, Mn, and V in the LRW sediments. The procedure in the study can be used to estimate GBLs and construct GBFs of toxic elements in other watershed sediments on the world in order to manage sediment quality.