SHORT RESEARCH AND DISCUSSION ARTICLE Biochemical effects of acetaminophen in aquatic species: edible clams Venerupis decussata and Venerupis philippinarum S. C. Antunes & Rosa Freitas & E. Figueira & Fernando Gonçalves & Bruno Nunes Received: 6 March 2013 / Accepted: 26 April 2013 / Published online: 14 June 2013 # Springer-Verlag Berlin Heidelberg 2013 Abstract Acetaminophen (paracetamol) is one of the most used pharmaceutical drugs, due to its antipyretic and anal- gesic properties that turn it into a primary choice in varied pathologies and conditions. However, and despite its mas- sive use, acetaminophen is not exempt of adverse effects, especially when administered in over dosage, which are related to the formation of toxic metabolites by oxidative pathways. It is thus possible to observe that toxicity caused by acetaminophen is usually mediated by reactive oxygen species and can result in multiple effects, ranging from protein denaturation to lipid peroxidation and DNA damage. The occurrence of acetaminophen has been reported in the aquatic environment, being important to address the poten- tial exertion of toxic effects on nontarget environmentally exposed organisms. The present study intended to charac- terize the effects of acute acetaminophen exposure on phys- iological traits (antioxidant defense, oxidative damage) of two species of bivalves, namely, the edible clams Venerupis decussata and Venerupis philippinarum. Results showed a significant increase in all oxidative stress biomarkers, evidencing the bioactivation of acetaminophen into a dele- terious prooxidant, triggering the onset of deleterious effects. Furthermore, strong interspecific differences were observed among responses of the two tested species, which was a major issue due to intrinsic ecological implications when one considers that both species share the same habitat. Keywords Clams . Acetaminophen . Oxidative stress . Lipid peroxidation . GST . GRed Introduction The occurrence of pharmaceutical drug residues in the wild, especially in the aquatic compartment, has re- ceived a great deal of attention from the scientific community during the last two decades (Winker et al. 2008). The number of publications coping with such presence and depicting the assessment of potential ef- fects of these compounds in exposed organisms has grown substantially and led to a compilation of a large amount of scientific data suggesting the possibility of exertion of toxic effects on exposed biota. The aquatic compartment is by far the most impacted, and a con- siderable number of articles show the presence of drugs in sewage effluents and wastewater in the proximity of sewage treatment plants, surface and groundwater, and also drinking water (Ganiyat 2008; Yang et al. 2008). In general terms, all pharmacotherapeutic classes have already been reported in the wild, but the most representative groups include antibiotics, anticonvulsants, antipyretics, cytostatic drugs, and hormones. The ways by which these compounds reach the aquatic environment are diverse and may occur by direct disposal of domestic surplus drugs, excretion in feces/urine after therapeutic use, and inadequate treatment of effluents from the manufacturing industry (Ganiyat 2008; Yang et al. 2008). Human therapeutics is not the only source of these compounds; the treatment and prophylaxis through the water in fish farms (aquaculture) (Brillas et al. 2005; Responsible editor: Philippe Garrigues S. C. Antunes Departamento de Biologia da Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal R. Freitas : E. Figueira : F. Gonçalves : B. Nunes Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro, Portugal S. C. Antunes : R. Freitas : E. Figueira : F. Gonçalves : B. Nunes (*) Centro de Estudos do Ambiente e do Mar (CESAM), Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal e-mail: nunes.b@ua.pt Environ Sci Pollut Res (2013) 20:6658–6666 DOI 10.1007/s11356-013-1784-9