TA8 Field-Based Effects Measures
A105 & A106
8:00 AM - 12:00 PM, Tuesday
() The need for risk assessment-based field experiments to characterize exposure and effects under environmentally realistic conditions.
Salazar, M1, Salazar, S1, 1 Applied Biomonitoring, Kirkland, WA, USA
ABSTRACT- In response to difficulties in characterizing exposure and effects in many environments, some monitoring and assessment programs have emphasized either exposure-based or effects-based approaches using indigenous populations. We believe that integrated field experiments with caged organisms, bioaccumulation (tissue chemistry), and biomarkers can be used to effectively complement laboratory studies and overcome the inherent weaknesses associated with typical laboratory and field studies. Furthermore, the ecological risk assessment framework should be adequate to characterize exposure and effects without emphasizing either exposure- or effects-based monitoring. This paper reviews the use of field experiments with caged bivalves as an evolving technique in risk assessment to assess chronic exposure and toxicity. The caged bivalve approach has become more feasible, practical, and routine as a result of experience and expertise gained in a number of developing paradigms including 1) ecological risk assessment, 2) tissue residue effects approaches, and 3) bivalve biomarkers. The ecological risk assessment paradigm ensures equal emphasis on the importance of characterizing both exposure and effects. Tissue residue effects approaches have facilitated the utility of tissue chemistry data from laboratory and field studies. Bivalve biomarkers have helped characterize and understand the biochemical processes linking exposure and effects. The paper also critically evaluates the use of field-based exposure and effects measures in the hazard and risk assessment process of aquatic ecosystems. The working premise is that risk assessment-based monitoring is more meaningful than either exposure- or effects-based monitoring. Theoretical and empirical evidence will be used to support this premise and examples will be provided to highlight the shortcomings of relying on indigenous organisms, unrealistic laboratory exposures, and relying on only half of the risk assessment paradigm.
Key words: field experiments, risk assessment, exposure, effects