Fighting oil spills at sea and toxicology of complex mixtures

Abstract

EPA as “moderately toxic” for two aquatic test species, the Gulf mysid Americamysis bahia and the inland silverside Menidia beryllina (US EPA 2010). In this journal, Zhang et al. (2013) have reported that the dispersant Corexit 9500A potentiated adverse effects of crude oil on the reproduction of the nematode Caenorhabditis elegans. Yet, the mode of action of such toxicity remained unknown. It was underlined that combination effects of chemical dispersant(s) with crude oil ingredients should be taken into account in possible future maritime cleanup applications. In this issue of Archives of Toxicology, the same group reports on its further investigations into the underlying mechanisms (Polli et al. 2014): The crude oil-dispersant mixture increased the number of apoptotic germ cells in treated C. elegans and led to changes in expression of a number of genes at the same time. These gene expression changes led to the conclusion that the germ cell apoptosis induced by the chemical mixture was CEP-1 dependent. Also, the anti-apoptotic ced-9/Bcl-2 was activated in response to the increase in cell death. With this first insight into the mode of action, the publication provides an invaluable methodological hint for further studies into the complexity of interactions, which finally leads to potentiation of this type of toxicity. The case is of highest practical relevance, within a field that is not sufficiently investigated.