Earthworm biomarkers in ecological risk assessment

Area of Science:

• Ecotoxicology
• Environmental Science
• Soil Ecology

Background:

• Earthworms are key organisms in terrestrial ecotoxicology, widely used in standardized toxicity tests for metal pollution assessment.
• Existing reviews highlight the need to enhance the understanding and application of earthworm biomarkers in ecological risk assessment (ERA).
• Current research on earthworm biomarkers primarily focuses on metal contaminants, with limited data on responses to organic pollutants.

Purpose of the Study:

• To review recent information on widely studied earthworm biomarkers.
• To explore the potential of earthworm biomarkers in standardized toxicity tests for contaminated soil risk assessment.
• To summarize field studies and suggest future research directions for earthworm biomarker application.

Main Methods:

• Literature review of recent information on earthworm biomarkers.
• Summary of field studies categorized by retrospective ERA approaches (biological surveys, lab tests, simulated studies, in situ bioassays).
• Identification of research gaps and recommendations for future studies.

Main Results:

• Earthworm biomarkers are predominantly used for metal pollution assessment, with less data available for organic contaminants.
• Earthworm biomarkers show potential for estimating bioavailable fractions and sublethal effects in contaminated soils.
• Field studies using earthworm biomarkers are scarce and categorized into four main approaches.

Conclusions:

• Standardization of earthworm biomarker assays and development of operating guidelines are crucial for regulatory application.
• Linking molecular/physiological biomarkers to ecologically relevant behavioral changes is essential for their ecotoxicological validation.
• Development and field validation of biomarkers for organic pollutants are necessary, alongside assessing their role in environmental remediation and ERA.