Mercury: THE Gunns Ltd pulp mill would use much more water than originally forecast if dry summers persist. Previously Gunns has said that the 26,000 megalitres a year would be just over 1 per cent of the annual flow through the Trevallyn power station. However, in dry months the pulp mill allocation would comprise up to 45 per cent of daily summer flows in the South Esk basin. The substantial share of available water would occur if the Hydro was forced to reduce water releases …