Environmental impacts of pulp and paper wastewater: evidence for a reduction in environmental effects at north American pulp mills since 1992

In the early 1990s, a variety of responses were reported in fish populations living downstream of bleached kraft pulp mills. This included delayed sexual maturity, smaller gonads, changes in fecundity, and a depression in secondary sexual characteristics. The changes in fish reproductive development were also associated with alterations in the endocrine mechanisms controlling the production of the sex steroid hormones. The early studies were …