Selective supercritical fluid extraction to identify aged sediment-bound PCBs available for uptake by eel

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Analytical Chemistry

Background:

• Polychlorinated biphenyls (PCBs) are persistent organic pollutants found in sediments.
• Assessing the bioavailability of PCBs is crucial for understanding ecological risk.
• Traditional methods may not accurately reflect the fraction of PCBs available for uptake by organisms.

Purpose of the Study:

• To evaluate the effectiveness of selective supercritical fluid extraction (SFE) in removing bioavailable PCBs from contaminated sediment.
• To determine if SFE can be used to estimate PCB bioavailability.
• To assess the impact of SFE pre-treatment on PCB uptake by eels (Anguilla anguilla).

Main Methods:

• Sediment naturally contaminated with PCBs was partially extracted using selective SFE.
• Eels were cultured in tanks with either untreated or SFE-pre-extracted sediment.
• Biota-to-sediment accumulation factors (BSAFs) for eight PCB congeners were calculated and compared between the two systems.

Main Results:

• SFE significantly reduced the concentration of bioavailable PCBs in the sediment.
• Relative BSAF values for all eight PCB congeners were substantially lower in the pre-extracted sediment system.
• The reduction in BSAFs was consistent across different PCB congeners, regardless of chlorination degree or initial concentration.

Conclusions:

• Selective SFE is an effective method for removing bioavailable PCBs from sediments.
• SFE can be utilized as a feasible tool to estimate the bioavailability of PCBs in sediment matrices.
• This approach offers a more accurate assessment of ecological risk associated with PCB contamination.