Using caged bivalves to characterize exposure and effects associated with pulp and paper mill effluents

Routine environmental effects monitoring (EEM) should include field bioassays with caged bivalves -- chemical exposure is characterized by measuring the concentration of chemicals in tissues and biological effects are characterized by measuring growth. This field bioassay combines the experimental control of laboratory bioassays with the environmental realism of field monitoring. Transplanting caged bivalves in the immediate vicinity of discharges ensures maximum exposure; if bioavailable chemicals are present in the effluent they will be accumulated within the tissues, and if the concentrations are sufficiently high to be deleterious, the effect of the exposure can be quantified. The transplant methodology described herein can be used to identify the following: (1) site-specific differences; (2) short-term and long-term trends; (3) temporal and spatial variability; (4) source identification; and (5) exposure-dose-response relationships. These results will help answer one of the most commonly asked questions asked by industry, government, and the public: “Are conditions getting better, worse, or staying the same?” Further, using the bivalve transplant approach as part of an integrated program will help reduce uncertainties associated with more traditional approaches like fish monitoring, laboratory bioassays and benthic community assessments.