Arsenic speciation related to arsenic origine and geochemical conditions of the groundwater samples

摘要

The species distribution of arsenic in groundwater is controlled by the geochemical conditions in particular the redox environment. Water samples characterized in the study originated from four locations and five different input sources. The redox conditions varied from oxic to sul-fidic. Measurements indicate -as was expected- that the As(Ⅲ))/As(Ⅴ)-species distribution is closely related to the redox environment. But results also clearly reveal a dependence on the As input species, as thermodynamic equilibria were mostly not achieved. An oxidation path of As(Ⅲ) and a reduction path of As(Ⅴ) can be distinguished assuming that reaction partners limit the kinetics.