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, a requirement 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 were similarities in the results as defined by difference test methods, while the results of preference and acceptance test were less clear. Tainting, or taste impairment, occurred at one of three mills. Significant tainting of two fish species occurred within three hours and at exposure concentrations less than 0.08% (v/v) unbleached kraft effluent. Adult and juvenile fish appear to be attracted to and reside in effluent plumes immediately downstream of the outfall at some mills. 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.