title: Clams sensitivity towards As and Hg: A comprehensive assessment of native and exotic species.
abstract: To assess the environmental impact of As and Hg, bioindicator organisms such as bivalves have been used. Nevertheless, few studies have assessed the impacts of As and Hg in Ruditapes decussatus and Ruditapes philippinarum, which are native and exotic species in Europe, respectively. The main goal of the present study was to assess elements' partitioning and detoxification strategies of R. decussatus and R. philippinarum. Both clams showed a higher capacity to bioconcentrate Hg (BCF 2.29-7.49), when compared to As (0.59-1.09). Furthermore, As accumulation in both species was similar in the soluble and insoluble fractions, while in both species the majority of Hg was found in the insoluble fraction. Clams exposed to As showed different detoxification strategies, since R. decussatus had higher ability to enhance antioxidant enzymes and metallothioneins in order to reduce toxicity, and R.philippinarum increased glutathione S-transferase Ω activity, that catalyzes monomethyl arsenate reduction, the rate-limiting reaction in arsenic biotransformation. When exposed to Hg, R. decussatus presented, higher synthesis of antioxidant enzymes and lower LPO, being able to better tolerate Hg than the exotic species R. philippinarum. Thus under relevant levels of As and Hg contamination our work evidenced the higher ability of R. decussatus to survive and inhabit coastal environments not heavily contaminated by Hg and As.
authors.affiliation: Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro, Portugal; CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Cátia
authors.initials: C
authors.lastname: Velez
authors.affiliation: Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro, Portugal; CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Rosa
authors.initials: R
authors.lastname: Freitas
authors.affiliation: Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Rua dos Bragas 289, 450-123 Porto, Portugal.
authors.forename: Sara C
authors.initials: SC
authors.lastname: Antunes
authors.affiliation: Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro, Portugal; CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Amadeu M V M
authors.initials: AM
authors.lastname: Soares
authors.affiliation: Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro, Portugal; CESAM - Centro de Estudos do Ambiente e do Mar, Universidade de Aveiro, 3810-193 Aveiro, Portugal. Electronic address: efigueira@ua.pt.
authors.forename: Etelvina
authors.initials: E
authors.lastname: Figueira
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001151:Arsenic / Q000378:metabolism / Q000633:toxicity*; D049872:Bivalvia / Q000187:drug effects* / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D004787:Environmental Pollution / Q000009:adverse effects*; D005060:Europe; D005982:Glutathione Transferase / Q000378:metabolism; D008628:Mercury / Q000378:metabolism / Q000633:toxicity*; D008668:Metallothionein / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D014874:Water Pollutants, Chemical; D008668:Metallothionein; D002374:Catalase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D008628:Mercury; D001151:Arsenic
keywords: Arsenic; Biochemical mechanisms; Bivalves; Detoxification strategies; Mercury