Colloids fractionation and characterization of arsenic (As) and dissolved organic matter (DOM) in surface water around a closed arsenic mine.

The speciation and mobility of arsenic (As) in waters are largely influenced by the colloids; however, the impacts of colloids with different molecular weights (MWs) in water fractions remain largely unknown. Herein, the surface water was fractionated into three colloidal fractions and truly dissolved fraction via cross-flow ultrafiltration. Total As (As(T)) presented mainly as As(V) and existed primarily in the truly dissolved fraction.