In situ evaluation of sediment toxicity in Guadalete Estuary (SW Spain) after exposure of caged Arenicola marina.

A 7 day in situ assay to assess sediment toxicity was carried out per replicate in two sites from Guadalete Estuary (Guad1 and Guad2) (South-West, Spain) using the polychaete Arenicola marina (n = 20) in benthic cages. After the exposure period, a battery of biomarkers were determined to asses the sediment toxicity. Five of them were exposure biomarkers [ethoxyresorufin O-deethylase (EROD), dibenzylfluorescein (DBF) dependant CytP450, gluthation reductase (GR), and gluthation-S-transferase (GST) activities] and one of them was an effect biomarker [lipid peroxidation (LPO)]. Toxicity due to metals bound to the sediment was found in Guad2. Metals provoke the inhibition of EROD, DBF, and GR and the induction of GST, which is showed to carry out antioxidative stress defense. Toxicity caused by metals and also PAH was detected in Guad1. The presence of these chemicals leads to GST induction in and presumably in consequence, to LPO inhibition. GST activity resulted to be the main protection mechanism against oxidative stress in Arenicola marina. We suggest further research in Guadalete Estuary focusing on the detection and toxicity assessment of pharmaceutical and personal care products.