Dietary exposure of Antarctic krill to p,p′-DDE: Uptake kinetics and toxicological sensitivity in a key polar species

This study evaluated the dietary uptake kinetics and sublethal toxicity of p,p′-dichlorodiphenyl dichloroethylene (p,p′-DDE) in Antarctic krill. The uptake rate constant (characterised by the seawater volume stripped of contaminant sorbed to algae) of 200 ± 0.32 mL g−1 wet weight h−1, average absorption efficiency of 86 ± 13% and very low elimination rate constant of 5 × 10−6 ± 0.0031 h−1 demonstrate the importance of feeding for p,p′-DDE bioaccumulation in Antarctic krill. Faecal egestion of unabsorbed p,p′-DDE of 8.1 ± 2.7% indicates that this pathway contributes considerably to p,p′-DDE sinking fluxes. A median internal effective concentration (IEC50) of 15 mmol/kg lipid weight for complete immobility indicates baseline toxicity and that Antarctic krill exhibit comparable toxicological sensitivity as temperate species under similar 10 d exposure conditions. These findings support the critical body residue approach and provide insight to the role of Antarctic krill in the biogeochemical cycling of p,p′-DDE in the Southern Ocean.

► Dietary uptake is important for accumulation of p,p′-DDE in Antarctic krill.
► 8.1% of ingested p,p′-DDE enters sinking fluxes via faecal egestion.
►  Limited elimination of absorbed p,p′-DDE enables transfer to higher trophic species.
► Tissue residues and temporal aspects of toxicity are important assessment factors.
► Overall, Antarctic krill are of similar toxicological sensitivity as temperate species.