Aquatic Pollution and Coastal Management

Unit 11 : Monitoring and control of pollution

11.7.Assessment Methodology
When the pollutant type is known or well understood, certain indicators are more effectively used or are less expensive. When stressors are not known and/or less is known about species tolerance levels, multiple level assessment and more intensive and expensive studies that may include toxicity tests may be necessary . Multiple level assessment involves the monitoring of indicators and behavioral changes of organisms. Indicators must display a biochemical, genetic, morphological, or physiological change. Behavioral indices are determined by particular species, populations dynamics, or community changes.
Community level biomonitoring provides information on the magnitude and ecological effects of the stressor on the system. Cause and effect relationships are difficult to establish and a few definitely exist, because possible confounding factors are often present . Using indicators at different organizational levels (for example, individuals, species, community, ecosystem) may be more reliable.
Biomonitoring measures may be used at different, but related, levels of analysis