Novel control and steady-state correction method for standard 28-day bioaccumulation tests using Nereis virens

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Marine Biology

Background:

• Assessing bioaccumulation potential of dredged material is crucial for aquatic placement.
• Standardized bioaccumulation tests require steady-state data for accurate interpretation.
• Control correction of initial contaminant residues is vital for bioassay validity.

Purpose of the Study:

• To evaluate the elimination kinetics of isotopically labeled polychlorinated biphenyls ((13)C-PCBs) in Nereis virens.
• To assess native PCB bioaccumulation from field-collected sediments using a novel approach.
• To determine the impact of contaminant elimination on biota-sediment accumulation factor (BSAF) calculations.

Main Methods:

• Application of a performance reference compound (PRC) approach with a pulse-chase experimental design.
• Simultaneous investigation of (13)C-PCB elimination and native PCB uptake in Nereis virens.
• Analysis of PCB bioaccumulation across three different sediment types.

Main Results:

• Over 90% elimination of most (13)C-PCBs within 28 days, except for (13)C-PCB209.
• Developed a predictive equation for PCB elimination rate constants based on log K(OW).
• Native PCB uptake was significant only in highly contaminated sediments, with BSAFs ranging from 1 to 3.

Conclusions:

• Rapid elimination of (13)C-PCBs suggests standard control corrections may underestimate bioavailable sediment residues.
• The PRC approach provides valuable insights into toxicokinetics and organism physiological performance.
• BSAFs peaked for PCB congeners with log K(OW) between 6.2 and 6.5.