Managing long-term polycyclic aromatic hydrocarbon contaminated soils: a risk-based approach

Area of Science:

• Environmental Chemistry
• Soil Science
• Ecotoxicology

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants found in contaminated soils, posing significant risks to human and ecological health.
• Traditional remediation efforts targeting background levels have shown limited success, particularly for high molecular weight PAHs.
• Recent shifts in soil remediation strategies emphasize risk-based prioritization for managing contaminated sites.

Purpose of the Study:

• To review the fate and availability of PAHs in contaminated soils.
• To highlight the relevance of these factors in the risk-based management of long-term contaminated soils.
• To provide guidance for site-specific risk-based management methods.

Main Methods:

• Review of existing literature on PAH fate, distribution, and bioavailability in soils.
• Discussion of factors influencing PAH phase distribution, including soil properties and ageing.
• Emphasis on bioavailability-based assessment integrating chemical analysis, toxicological assays, and nonexhaustive extraction techniques.

Main Results:

• The hydrophobicity of PAHs significantly influences their distribution in soil, affected by soil properties and ageing.
• Total PAH concentration does not directly correlate with exposure and environmental effects.
• Bioavailability-based assessments offer a more accurate approach for risk evaluation in contaminated soils.

Conclusions:

• A bioavailability-based assessment is a valuable tool for the risk-based remediation of PAH-contaminated soils.
• Understanding PAH fate and availability is key to effective long-term management strategies.
• This review serves as a guide for implementing site-specific, risk-based management approaches for contaminated soils.