Utilization of diversity indices in evaluating the effect of a paper mill effluent on bottom fauna

The bottom fauna of the Lower Sabine river, Tex, were studied over a period of 3 years, before and after effluent was discharged from a black-liquor pulp mill, and above and below the outfall. Results, tabulated for the individual species and species diversity index, indicate a small number of species and a large number of individuals at each sampling point, but the reduced diversity is attributable to natural environmental stresses rather than the paper mill effluent. However, the discharge must be controlled carefully, avoiding periods of low stream flow and imposing high effluent standards to protect nearby Sabine lake, a shallow estuary, where unchanged material could settle and accumulate on the bottom, with detrimental effects.