Passive sampling methods for contaminated sediments: risk assessment and management

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Risk Assessment

Background:

• Contaminated sediment sites pose ecological and human health risks.
• Traditional methods using total contaminant concentrations (Ctotal) often overestimate bioavailability.
• Freely dissolved contaminant concentrations (Cfree) offer a more accurate measure of bioavailability.

Purpose of the Study:

• To detail the application of passive sampling methods (PSMs) in contaminated sediment risk management.
• To demonstrate how PSMs, by measuring Cfree, enhance site investigation and decision-making.
• To highlight the benefits of incorporating PSMs into study designs for improved exposure estimation.

Main Methods:

• Utilizing activity-based passive sampling methods (PSMs) to determine freely dissolved contaminant concentrations (Cfree).
• Designing studies to address challenges in representative sampling with passive sampling devices (PSDs).
• Applying PSM data for quantifying trends, identifying sources, calibrating models, and supporting weight-of-evidence frameworks.

Main Results:

• Cfree measured by PSMs is a superior predictor of bioavailability for key risk assessment endpoints compared to Ctotal.
• PSMs increase certainty in site investigation and management processes.
• Challenges in representative sampling with PSMs can be overcome through careful study design.

Conclusions:

• PSMs and Cfree measurements should be integrated into contaminated sediment investigations for better bioavailability assessment.
• PSM data aids in delineating management zones, monitoring remedies, and evaluating risk reduction.
• Broader adoption of PSMs requires addressing research and communication needs.