E$)$ In anoxic conditions $($e$.$g$.E_H=-0\mathrm{.}3V$ and $pH=8)$ trace metals form very insoluble sulfides.

Would it make sense to treat water to anoxic conditions to eliminate dissolved $Hg?$

What is the balance of sulfates$/$sulfides species?

Make a Pourbaix diagram for sulfate$/$sulfide species.

What other minerals can precipitate? $($Hint: use the concentration of sulfides computed

in the previous step, recompile the matrix using $S^{2-}$ and without $e^{-}$and check for

precipitation $Hg+S$ minerals$)$