Standardization of laboratory bioassays with Balanus amphitrite larvae for preliminary oil dispersants toxicological characterization

The Italian National regulations on oil-dispersants use (D.D. 23 December 2002) require for these products to pass several laboratory screenings before they can be applied in oil-spill clean-up. Although legislation recommend the use of the American mysid shrimp Americamysis bahia, for laboratory toxicity testing, there is growing interest in employing local marine crustacean species more representative than A. bahia, in quantifying the risk of significant harm to Mediterranean ecosystems. The aim of this study (in the framework of the National Project 'Taxa Project', supported by the Italian Ministry for the Environment and Territory) is to improve new specific bioassays for assessing acute or sublethal responses to oil dispersants using the larval stages of the sessile crustacean Balanus amphitrite. The bioassays were standardized using sodium dodecyl sulphate (SDS) as toxic reference compound. Results of acute toxicity (48 h LC50, 7.49 mg l-1) and behavioural tests (7 d EC50, 7.79 mg l-1) with barnacle larvae showed that their susceptibility to SDS could be comparable with that of A. bahia (96 h LC50; 6.6 mg l-1). Therefore, a B. amphitrite bioassay could be proposed to replace the A. bahia bioassay in a standardized toxicological screening of new products for oil-pollution remediation technologies in the Mediterranean Sea.