Sensory evaluation of fish exposed to pulp and paper mill effluent: a case study of methods used for environmental effects monitoring

The federal Environmental Effects Monitoring (EEM) program, as a component of the Fisheries Act; Pulp and Paper Effluent Regulations, requires sensory evaluation at Canadian pulp and paper mills where there have been historical complaints of fish tainting or reduced fishing efforts and there is no potential health hazard. Sensory evaluation tests were conducted at three mills in British Columbia. Each test component yielded considerable variability. Nevertheless, there was a high degree of similarity between the mills for the tainting results. Significant tainting of two fish species occurred within three hours and at exposure concentrations less than 0.08% (v/v) effluent at one location. Adult and juvenile fish appear to be attracted to and reside in effluent plumes immediately downstream of the outfall at some mills. Tertiary treated effluent discharged from one mill continued to taint resident fish. Sensory evaluation may be the most sensitive monitoring tool available to assess and integrate effluent exposure with the usability of valuable sports, recreation, commercial and native fisheries resources. A proposal to focus EEM cycle 2 programs to evaluate the use of these fisheries resources is presented.