CHALLENGES IN EMERGING ENVIRONMENTAL CONTAMINANTS Could a harmonized tiered approach assess dispersant toxicity in Italy and France? Loredana Manfra 1,2 & Andrea Tornambè 1 & Julien Guyomarch 3 & Karine Duboscq 3 & Olga Faraponova 1 & Claudia Sebbio 1 Received: 23 April 2019 /Accepted: 12 September 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract In recent years, EU countries have recognized national policies to authorize dispersant use to mitigate the petroleum hydrocarbon contamination in case of unintentional oil spills at sea. A harmonization of dispersant approval procedures is needed because the application of different methodologies agrees on dissimilar toxic responses for the same dispersant in different European countries. Actually, different dispersant approval procedures are applied in France and Italy with one French mandatory toxicity test and three Italian bioassays accompanied with different criteria of toxicity classification. In this paper, a harmonized tiered approach is proposed to address the dispersant ecotoxicological assessment in these two nations. Our approach, applicable at the European level, introduces two mandatory tests (algal growth inhibition test and mortality test with crustaceans) and one discretionary test (fish mortality test), by reducing use of vertebrates as much as possible in accordance with humane principles and animal welfare. Keywords Oil spill management . Dispersants . Toxicity . Harmonized tiered approach Introduction Dispersants are chemical agents or biological products used to mitigate the petroleum hydrocarbon contamination in case of accidental oil spills at sea (Wise and Wise 2011). The use of dispersants favors the separation of oil from water, promoting the formation of dispersed oil drops. However, the dynamic environmental conditions (e.g., adequate depth and water ex- change) affect the dilution and dispersion processes of these substances. For this, differences between laboratory tests and field con- ditions need to be considered when dispersant adverse effects are assessed. Nevertheless, the most of dispersant studies did not evaluate these differences and interactions between oil and dispersant (Bejarano 2018). Some nations (as France, Norway, Spain, Italy, Greece, and the UK) have currently established procedures for dispersant testing for government approval (IMO/UNEP 2011), with the common objective of approving efficient and low toxic dis- persants. At European level, the harmonization of dispersant approval procedures is a discussed topic because diverse tox- icity testing procedures are used in different countries. For example in the UK, the toxicity of the oil/dispersant mixture has to be tested to approve the use of dispersants into the sea, while in other countries only the toxicity of dispersant alone (EMSA 2016). Furthermore, the methodologies of dispersant ecotoxicological evaluation and classification may be differ- ent at national and international levels. This process could be simplified with a more harmonized approach. In the framework of the RAMOGE Agreement, the approv- al and use of chemical dispersants as a response option to oil spills at sea is subject to diverging approaches between Italian and French delegations too. The RAMOGE Agreement rep- resents an instrument to co-ordinate joint actions to limit Loredana Manfra and Andrea Tornambè contributed equally to this work. Responsible editor: Philippe Garrigues * Loredana Manfra loredana.manfra@isprambiente.it 1 Institute for Environmental Protection and Research (ISPRA), Rome, Italy 2 Stazione Zoologica Anton Dohrn, Naples, Italy 3 Centre of Documentation, Research and Experimentation on Accidental Water Pollution (CEDRE), Brest, France Environmental Science and Pollution Research https://doi.org/10.1007/s11356-019-06535-7