ABSTRACT
Laboratory and field studies conducted over the past several decades have confirmed earlier findings that pulp and paper mill effluents which have been well treated in conventional biological treatment processes in general do not constitute adverse aquatic life or human health impacts. Nonetheless, questions continue to arise regarding the effects of various components of bleached mill effluents on aquatic and human health. To address these concerns, the concentrations of chlorinated phenolic compounds in waters impacted by bleached kraft mills were examined relative to aquatic life and human health water quality protection values. Water quality protection values were assembled, discharge rates of chlorinated phenolics were estimated, and low flow stream conditions were determined. These data were combined to calculate frequency distribution plots of in-stream concentrations for each of the compounds downstream of each mill. The plots were used to determine whether differences exist in exceedance of water quality protection values for any of the compounds of concern under baseline conditions and under either of two currently proposed technology options. Results indicate that a minority of mills show some exceedances of water quality protection values under baseline conditions, but that no facilities will produce exceedances after implementation of either complete chlorine dioxide substitution or this option plus oxygen delignification.
