The effect of Kraft pulp mill effluents on the growth of Zalerion maritimum

Abstract

Growth of the marine fungus Zalerion maritimum was measured in Kraft pulp mill effluents. The effluents used were caustic effluent, acidic effluent, and acidic effluent adjusted to pH 8. The effluent and the seawater control flasks were supplemented, in some instances, with basal nutrients. Two concentrations of effluent, 50% (50% effluent, 50% seawater) and 100%, were used.When basal nutrients were added, dry weight was significantly greater (95% probability level) in 100% caustic effluent than in 50% caustic effluent or seawater alone. Without basal nutrients, growth was lower in 100% caustic effluent than in seawater or 50% effluent. This suggests that growth of Z. maritimum would not be stimulated by Kraft effluent under field conditions.Unlike the caustic effluent, the acidic effluent inhibited growth of Z. maritimum. With added nutrients, growth was lower in 50% and 100% acidic effluent than in seawater. When the acidic effluent solutions were adjusted to pH 8, growth was lower than in the seawater medium.