Review of Reproductive-Endocrine Effects of a New Zealand Pulp and Paper Mill Effluent

摘要

A combination of long-term mesocosm, short-term laboratory, and in-vitro bioassays was used to assess the reproductive and reproductive-endocrine effects of a mixed bleached kraft/thermomechanical pulp and paper mill effluent over a period of four years. Initial results showed masculinization of female mosquitofish in short-term bioassays, the reduction of ovary and ovarian follicle size in female rainbow trout, and the binding of components in effluent extracts to the goldfish androgen receptor. Observed effects in the in-vivo bioassays occurred at concentrations of 10 to 15% (v/v), similar to the concentration of effluent in the receiving environment. The effects on trout ovaries only occurred when trout exposure was initiated prior to the onset of gonadal maturation. Reproductive effects in trout were correlated with steroid-hormone concentrations in trout plasma. Out of four separate experiments, vitellogenin induction was only observed on one occasion. Induction of MFO enzymes in rainbow trout has diminished to the point of being nondetectable. Mosquitofish effects were eliminated by filtration of the effluent. In contrast, androgen receptor binding occurred in both filter and filtrate extracts. Subsequent to these experiments, further experimentation has shown the disappearance of both in-vivo reproductive effects that were previously observed. The mill has undergone changes during this period and shows incremental improvements in effluent quality. Thus, the exact reasons for the disappearance of effects cannot be easily determined.