The stability of scorodite is highly dependent on pH and redox conditions
As release is ≤ 3% (11.3 mg L− 1) upon Fe reduction by hydroquinone at pH 4–8
Amorphous FeHAsO4·xH2O was the major secondary mineral produced
As(V) in scorodite was not reduced to As(III) by hydroquinone at pH 4–9