Different partitioning behaviors of molybdenum and tungsten in a sediment-water system under various redox conditions

On the other hand, at all the depths, W formed oxygen-coordinated species in the sediment. The subtle change of Kd for W with depth suggested that H2S did not affect the W adsorption in our samples. Hence, the Mo/W ratio in the sediments increased with the development of reducing conditions and vice versa in the coexistent porewater. Speciation analysis revealed that the high stability of oxygen-coordinated species of W was responsible for the variations of the Mo/W ratio under various redox conditions.