title: Coping with seawater acidification and the emerging contaminant diclofenac at the larval stage: A tale from the clam Ruditapes philippinarum.
abstract: Seawater acidification could alter the susceptibility of marine organisms to emerging contaminants, such as pharmaceuticals. In this study, the combined effects of seawater acidification and the non-steroidal anti-inflammatory drug diclofenac on survival, growth and oxidative stress-related parameters (catalase activity and lipid peroxidation) in the larvae of the Manila clam Ruditapes philippinarum were investigated for the first time. An experimental flow-through system was set up to carry out a 96-h exposure of clam larvae. Two pH levels (pH 8.0, the control, and pH 7.8, the predicted pH by the end of this century) were tested with and without diclofenac (0.5 μg/L). After 4 days, mortality was dramatically higher under reduced pH, particularly in the presence of diclofenac (62% of the larvae dead). Shell morphology was negatively affected by both acidification and diclofenac from the first day of exposure. The percentage of abnormal larvae was always higher at pH 7.8 than in controls, peaking at 98% in the presence of diclofenac after 96 h. Instead, shell length, shell height or the ratio of these values were only negatively influenced by reduced pH throughout the whole experiment. After 96 h, catalase activity was significantly increased in all larvae kept at pH 7.8, whereas no significant difference in lipid peroxidation was found among the treatments. This study demonstrates a high susceptibility of R. philippinarum larvae to a slight reduction in seawater pH. Furthermore, the results obtained highlight that acidification enhances the sensitivity of clam larvae to environmentally relevant concentrations of diclofenac.
authors.affiliation: Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy. Electronic address: marco.munari@bio.unipd.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Munari
authors.affiliation: Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Chemello
authors.affiliation: Department of Developmental Psychology and Socialisation, University of Padova, Via Venezia, 8, 35131 Padova, Italy.
authors.forename: Livio
authors.initials: L
authors.lastname: Finos
authors.affiliation: Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Sezione di Oceanografia, Via A. Piccard 54, 34151 S. Croce (TS), Italy.
authors.forename: Gianmarco
authors.initials: G
authors.lastname: Ingrosso
authors.affiliation: Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Sezione di Oceanografia, Via A. Piccard 54, 34151 S. Croce (TS), Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Giani
authors.affiliation: Department of Biology, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Marin
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000187:drug effects*; D004008:Diclofenac / Q000032:analysis / Q000633:toxicity*; D004784:Environmental Monitoring / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007814:Larva / Q000187:drug effects; D012623:Seawater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D004008:Diclofenac
keywords: Bivalve; Growth; Larvae; Oxidative stress; Seawater acidification; Survival