DATABASE wateq4f.dat
SOLUTION_SPECIES
 H2AsO4- = HAsO4-2 + H+; log_k -6.76
 H2AsO4- + 3H+ + 2e- = H3AsO3 + H2O; log_k 21.14
 H3AsO3 = H2AsO3- + H+; log_k -9.23
SOLUTION 1
 pH 6.76; pe 0.43
 As 1e-3 # 75 ug As/L
END