Sperm cell toxicity test using sea urchin Paracentrotus lividus Lamarck (Echinodermata : Echinoidea): Sensitivity and discriminatory ability toward anionic and nonionic surfactants

A reliable sperm cell toxicity test procedure has been developed for the Me diterranean sea urchin Paracentrotus lividus. The sensitivity and discrimin atory ability of the test were investigated with regard to surfactants and their biotransformation products. Aromatic and aliphatic surfactants of ani onic (linear alkylbenzene sulfonates [LAS]) and nonionic (alcohol polyethox ylates [AE] and nonylphenol polyethoxylates [NPE]) types and their aerobic biodegradation products, i.e., sulfophenylcarboxylates (SPC), polyethylene glycols (PEG), carboxylated polyethylene glycols (PEGC), carboxylated AE (A EC), and nonylphenol (NP), were examined in order to elucidate the influenc e of their molecular structure on toxicity. Experimental results reveal tha t the sperm cell test showed good discriminatory ability among all tested c ompounds, median effective concentration (EC50) values differing by about f our orders of magnitude. The toxicity of anionic surfactants depends on the length of the alkyl chain and that of nonionic surfactants is due to their length and branching. Much lower toxicity was shown by aerobic biodegradat ion products in comparison with that of their parent compounds, with the ex ception of NP The obtained EC50s were comparable with available literature data and constitute new toxicity data regarding surfactants for sea urchins .