It’s Of(fish)cial: Pulp Mill Effluent Can Alter Reproductive Cycles of Ontario Fish

Abstract

Pulp and paper mills are of economic importance in Canada, however their effluent waste is being channeled into water bodies and causing a variety of negative effects in aquatic ecosystems. Pulp mill effluents are chemical compounds which are oxygen consuming, persistent, and toxic, and have the capacity to mimic physiological compounds. A review of current literature on pulp mill effluent reveals that these chemicals can mimic the reproductive hormones of fish, thereby having effects on local fish reproductive cycles. These reproductive alterations include decreased steroidogenesis, reduced gonad size, and altered expression of secondary sex characteristics that together can affect the health of wild fish populations. However, there has been considerable variation found in the effects of pulp mill effluent based on chemical composition of the pollutants, and the sex, species, and exposure duration of the affected fish. Biotreatment has been considered as a viable option for reducing the impact of effluent on fish reproduction. We suggest that alterations in reproductive cycles can have downstream effects through trophic cascades which in turn may have widespread effects on community structure. Future research should include analysis of long term consequences on multiple species in affected ecosystems, as well as further study on the use of biotreatment to reduce the impact of effluent.