Behavioural sensitivity of a key Southern Ocean species (Antarctic krill, Euphausia superba) to p,p′-DDE exposure

Persistent organic pollutants (POPs) have been frequently measured throughout the Southern Ocean food web for which little information is available to assess the potential risks of POP exposure. The current study evaluated the toxicological sensitivity of a key Southern Ocean species, Antarctic krill, to aqueous exposure of p,p′-dichlorodiphenyl dichloroethylene (p,p′-DDE). Behavioural endpoints were used as indicators of sublethal toxicity. Immediate behavioural responses (partial immobility and tail flicking) most likely reflect neurotoxicity, while the p,p′-DDE body residue causing a median level of sublethal toxicity in Antarctic krill following 96 h exposure (IEC50sublethal toxicity=3.9±0.21 mmol/kg lipid weight) is comparable to those known to cause sublethal narcosis in temperate aquatic species. Critical body residues (CBRs) were more reproducible across tests than effective seawater concentrations. These findings support the concept of the CBR approach, that effective tissue residues are comparable across species and geographical ranges despite differences in environmental factors.

► p,p′-DDE appears to act via multiple modes of toxic action in Antarctic krill.
► Behavioural and body residue analysis point to neurotoxicity and non-polar narcosis.
► 3.9 mmol p,p′-DDE/kg lipid weight induces median level narcosis in Antarctic krill.
► The measured internal sensitivity is comparable to temperate aquatic species.
► Support that critical body residues are comparable beyond species/climate boundaries.