Ecotoxicological indicators of water quality: Using multi-response indicators to assess the health of aquatic ecosystems

Abstract

As sensitive and ecologically relevant measures of environmental conditions, bioindicators can be used to assess the health of aquatic ecosystems which may be compromised by a variety of environmental stressors such as contaminants, sediments, nutrients, and varying temperature, salinity, and hydrologic regimes. The bioindicators approach is a proven bioassessment method that uses responses of key (sentinel) aquatic organisms both as integrators of stress effects and as sensitive response (early-warning) indicators of environmental health. This integrated approach involves measuring a suite of selected biological and ecological responses at several levels of biological organization from the biomolecular and biochemical to the community levels. When properly designed and applied in field situations, bioindicator studies can help identify causal mechanisms between environmental stressors and population and community-level effects, and serve as a basis for which the effectiveness of remedial actions on the health of aquatic organisms can be evaluated. Rapidly-responding sensitive biomarkers, such as biomolecular and biochemical responses, and slower-response ecologically relevant bioindicators, such as population and community responses, can be included in field bioassessment programs to provide measurement endpoints for use in environmental compliance, regulatory decision-making, and ecological risk assessments. This bioindicators approach should be particularly relevant in helping to identify and diagnose sources of stressors in environments impacted by multiple stressors. To demonstrate use of bioindicators in addressing water quality issues, spatial and temporal patters in various biological responses are related to spatial and temporal patterns of contaminants in two aquatic systems compromised by different stressors.