Interdecadal variations of the mercury content in Scomber colias in Canary Islands

Environmental Factors Influencing Metal Concentrations in Scomber colias Along the Canary Islands

A total of 140 specimens of Scomber colias were collected from the Canary archipelago waters during the first semester of 2021, with 20 samples from each of the seven main islands. After analyzing the concentrations of metals (Al, Zn, Cd, Pb, Fe, and Cu) with ICP-OES, significant variations were observed among islands, with specimens from Tenerife and Gran Canaria containing higher levels of Al, Cd, and Pb, while those from Lanzarote and Fuerteventura had elevated levels of Zn, Fe, and Cu. These differences are probably related to greater anthropogenic activity around Tenerife and Gran Canaria coasts, leading to higher pollution levels, and the influence of Saharan dust and African upwelling on Lanzarote and Fuerteventura, enriching the waters with nutrients. Specific management strategies to mitigate marine pollution and continuous monitoring are crucial to safeguard marine ecosystems and to ensure food security.

Metal content in Sardina pilchardus during the period 2014-2022 in the Canary Islands (Atlantic EC, Spain)

The contamination present in an organism varies depending on biological and oceanographic conditions, so monitoring the same species is of great importance to understand the state of the ecosystem. Fifteen specimens in Sardina pilchardus between 12 and 15 cm in total length were collected during the second half of January of each of the study years (2014, 2016, 2018, 2020 and 2022). Samples were analyzed with Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) to measure metals (Al, Cd, Cu, Fe, Li, Ni, Pb and Zn) in mg/Kg. There was a progressive decrease in Pb content over the period, with the highest concentration being obtained in 2014 (0.086 ± 0.065 mg/kg). Locally important oceanic-atmospheric events may occur in the study period that strongly impact the tissue composition of marine organisms. In this case, discontinuous trends were evident in some of the metal concentrations analyzed in the muscle of European sardine in the Canary Islands.