7 UNCERTAINTIES

In reviewing the scientific information for this report, a number of uncertainties and attendant needs were identified. These are quite general and address the following:

More information is needed on the types of substances produced in ECF and TCF bleaching processes. These needs are particularly directed at non-chlorinated substances and their biological activity.

Future studies of the environmental consequences of modifications to pulp mill technology must be made in a much more systematic manner so that the biological implications of these changes can be assessed in the absence of experimental confounding.

Future monitoring of the effects of pulp mill effluents on organisms in the receiving environment must be made with a clearer understanding of the ecological significance of these changes.

More efficient monitoring of the influences of changes in raw materials, the process technology used, and wastewater treatment is required.