As discussed in a subsequent publication (8), As was
present in the leachate in the As(III) oxidation state.
Therefore, if the concentration of As in the leachate decreases
significantly by the formation of an insoluble compound
containing As and Ca, this must be a compound containing
As(III). Since no values were found in the literature regarding
the solubility product KS of any Ca-As(III) compound, it was
investigated experimentally (8) as to which insoluble compound
could be formed in an aqueous solution containing
Ca and As(III). The solubility product KS of this compound
was determined. In aqueous solutions, As(III) occurs in