Metal bioaccumulation, oxidative stress and antioxidant responses in oysters Crassostrea gasar transplanted to an estuary in southern Brazil Clarissa P. Ferreira a , Daína Lima b , Raphaella Paiva b , Juliano M. Vilke a , Jacó J. Mattos c , Eduardo A. Almeida e , Suelen C. Grott e , Thiago C. Alves e , Jacyara N. Corrêa f , Marianna B. Jorge f , Mariana Uczay d , Carla I.G. Vogel d , Carlos H.A.M. Gomes g , Afonso C.D. Bainy b , Karim H. Lüchmann h, ⁎ a Fishery Engineering Department, Santa Catarina State University, Laguna 88790-000, Brazil b Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry, Federal University of Santa Catarina, Florianópolis 88034-257, Brazil c Aquaculture Pathology Research Center, Federal University of Santa Catarina, Florianópolis 88034-257, Brazil d Animal and Food Production Department, Santa Catarina State University, Lages 88520-000, Brazil e Department of Natural Sciences, Regional University of Blumenau, Blumenau 89012-170, Brazil f Oceanography and Limnology Department, Federal University of Maranhão, São Luís 65080-805, Brazil g Laboratory of Marine Mollusks, Federal University of Santa Catarina, Florianópolis 88034-257, Brazil h Department of Scientific and Technological Education, Santa Catarina State University, Florianópolis 88035-001, Brazil HIGHLIGHTS • Oysters Crassostrea gasar were transplanted to an estuary impacted by anthropogenic activities. • Oysters bioaccumulated metals, espe- cially Al, Cd and Zn in gill and digestive gland. • A protective induction of antioxidant defense to deal with oxidative damage was revealed. • Gill and digestive gland react differently to cope with possible metal-induced stress. GRAPHICAL ABSTRACT abstract article info Article history: Received 22 December 2018 Received in revised form 7 May 2019 Accepted 24 May 2019 Available online 28 May 2019 Editor: Daniel Wunderlin The present study assessed the spatial and temporal variations on metal bioaccumulation and biochemical bio- marker responses in oysters Crassostrea gasar transplanted to two different sites (S1 and S2) at the Laguna Estu- arine System (LES), southern Brazil, over a 45-days period. A multi-biomarker approach was used, including the evaluation of lipid peroxidation (MDA) levels, and antioxidant defense enzymes (CAT, GPx, GR and G6PDH) and phase II biotransformation enzyme (GST) in the gills and digestive gland of oysters in combination with the quan- tification of Al, Cd, Cu, Pb, Fe, Ni and Zn in both tissues. The exposed oysters bioaccumulated metals, especially Al, Cd and Zn in gills and digestive gland, with most prominent biomarker responses in the gills. Results showed that GPx, GR and G6PDH enzymes offered an increased and coordinated response possibly against metal (Zn, Ni, Cd and Cu) contamination in gills. GST was inversely correlated to Cd levels, being its activity significantly lowered over the 45-d exposure periods at S2. On contrary, in digestive gland GST was slightly positively correlated to Cd, revealing a compensatory mechanism between tissues to protect oysters' cells against oxidative damages, since MDA levels also decreased. CAT also appeared to be involved in the cellular protection against oxidative stress, Keywords: Oysters Metal Biochemical biomarkers Estuarine pollution Science of the Total Environment 685 (2019) 332–344 ⁎ Corresponding author. E-mail address: karim.luchmann@udesc.br (K.H. Lüchmann). https://doi.org/10.1016/j.scitotenv.2019.05.384 0048-9697/© 2019 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv