Trace elemental characterization of fish species and their Portuguese coastal systems

• Autor(a) principal: Carneiro, José Rui Ferreira Picoto
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/15451
• topic: Estuários; Metais; Composição multi-elementar; Peixe; Músculo; Fígado; Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais

Estuaries are subjected to multiple anthropogenic stressors, among them enhanced inputs of potentially toxic trace metals. These are commonly derived from human activities, including mining, sewage discharge or fossil fuel burning, displaying high persistence in estuaries and affecting ecosystem health. In this study, multi-elemental concentrations of metals in fish tissues and water from major Portuguese estuaries were determined via Total X-ray Fluorescence Spectroscopy, to assess temporal and spatial variability patterns, which could be linked to environmental contamination, fish species ecology and origin of collection. Temporal changes in muscle and spatiotemporal variations in water elemental composition were assessed in the Mondego estuary and for juvenile Platichthys flesus. A multi-taxa and -estuary approach to metal distribution in muscle and liver tissues, and in water, was used to assess spatial variability of trace elements and our ability to accurately determine estuary of origin and inter-species differences. Target species included Diplodus vulgaris, D. bellottii, D. sargus, Platichthys flesus, Solea senegalensis, S. solea, Dicentrarchus labrax, Sparus aurata and Halobatrachus didactylus, collected from four Portuguese estuaries (Douro, Tejo, Sado and Mira). Results show that metal concentrations in Mondego water and P. flesus muscle were generally low, albeit some juveniles had metal loads above food safety thresholds. Multivariate statistical analysis, using canonical ordination methods (CAP), was only able to discern temporal variability of metal signatures in fish. However univariate analysis showed explicit relationships between abiotic factors (salinity and pH) and metals (e.g. Na, Cr, Mn, Sr, Cd and Hg) along the estuarine gradient. CAP analysis of muscle and liver elemental composition evidenced differences between tissues, with higher discretion capability in liver samples. Estuary elemental signatures were separated with a higher accuracy than species, which highlights environmental conditioning and underpins the potential of multi-elemental signatures to identify the estuary of origin and fish species.