Survey of Pulp and Paper Mill Effluents for Their Potential to Affect Fish Reproduction

摘要

The objectives of this survey were to determine the potential of pulp and paper mill effluents to affect fish reproduction and to provide preliminary leads regarding factors that may be responsible for such effects. Six mills were selected for study: two bleached kraft, two thermomechanical pulp (TMP), and two using more than one pulping process (multiprocess). Effluents from these mills were assessed by a short-term laboratory test using adult fathead minnows (Pimephales promelas) exposed for 28 d. Fish exposed to effluent concentrations of 2% and 20% v/v were compared to controls. Endpoints included egg production, gonad size, secondary sexual characteristics, levels of vitellogenin in males, and steroid hormones in both males and females. Effluent-related effects were seen only at the 20% concentration. Egg production was affected by effluent from only one of the six mills, a multiprocess mill, while vitellogenin induction was evident in males exposed to effluent from three of the six mills. The reduced egg production at the multiprocess mill occurred at a time when the effluent did not meet the regulatory toxicity limit in Canada, which requires 50% survival of rainbow trout for 96 h in full strength effluent. The vitellogenin effect did not appear to be related to a particular pulping or biotreatment process. Overall, the results from these tests indicated that, with one exception, effluents from the mills in this study had minimal effects on the reproductive capacity offish in short-term laboratory tests.