Mercury, cadmium, and lead content in demersal sharks from the Macaronesian islands.

The overexploitation of shark and ray fishing as well as anthropogenic pollution in the sea has led to a large decline in their population, and because sharks occupy a high trophic position in the ecosystem, they could have high concentrations of heavy metals such as Hg, Pb, and Cd. This study is based on seven species of demersal sharks which were caught in the Macaronesian archipelagos (Tenerife, Gran Canaria, and the Azores Archipelago). Hg and Pb concentrations were found in the present study to be below those reported in other comparative studies, with the highest reported values of Hg and Pb being 281,738 µg/kg for Pb in Deania profundorum (Smith & Radcliffe, 1912) and 264,30 µg/kg for Hg in Centrophorus uyato, Rafinesque, 1810. As for Cd, the values found here are higher than those in the literature, the highest reported concentration being 120.36 µg/kg in Centrophorus squamosus (Bonnaterre, 1788).

Influence of the submarine volcanic eruption off El Hierro (Canary Islands) on the mesopelagic cephalopod's metal content.

This work investigates whether a submarine volcanic eruption off El Hierro (Canary Islands) in October 2011 influenced the metal contents of two deep water cephalopod species: Abraliopsis morisii and Pyroteuthis margaritifera. This was assessed by comparing metal contents in specimens collected off the island of El Hierro and in the neighbouring islands of La Palma and Tenerife during an experimental deep water fishing trip. The concentration of 20 heavy metals was analyzed in 180 specimens of A. morisii and P. margaritifera collected around the three islands to test for inter-island differences for each species and metal. While both species showed geographical differences in metal concentrations, the main finding was that A. morisii could be a bioindicator species for metals such as Li, Sr and Ca.

Content of lead and cadmium in barred hogfish, Bodianus scrofa, island grouper, Mycteroperca fusca, and Portuguese dogfish, Centroscymnus coelolepis, from Canary Islands, Spain.

Concentration of lead and cadmium has been analyzed in Bodianus scrofa and Mycteroperca fusca captured in the Canary Islands coast. Concentration of Pb ranged from 2.53 to 306.40 and 4.97 to 792.00 microg kg(-1) respectively, while that of Cd ranged from 1.75 to 1854.50 and 6.78 to 656.00 microg kg(-1). The same metals have been analyzed in muscles, liver and skin of Centroscymnus coelolepis from Canary Islands, with contents of Pb and Cd ranged between 24.18-96.12 microg kg(-1) and 32.00-3266.58 microg kg(-1) respectively, and in the Azores Archipelago, with concentrations of Pb and Cd ranged as follow: 18.41-38.99 microg kg(-1) and 5.23-4179.87 microg kg(-1) respectively. Percentage of contribution of both metals to the PTWIs, has also been calculated for both fishes.

Content of trace metals (iron, zinc, manganese, chromium, copper, nickel) in canned variegated scallops (Chlamys varia).

This article presents the results obtained through a study of the concentration of trace metals (iron, zinc, manganese, chromium, copper, nickel) in some conserves of variegated scallops (Chlamys varia, Bivalvia, Mollusca). A total of 300 samples of seven different commercial brands (named A, B, D, H, J, L and M) and one processing type, 'scallop sauce', were analysed. Samples were collected weekly in a large shopping centre in Santa Cruz de Tenerife during a 12-month period. Variegated scallops have considerable concentrations of zinc, cupper and manganese, so that their dietary intake constitutes an important source of these metals. However, they have low concentrations of chrome and nickel, and the levels of iron are similar to those found in other bivalve molluscs.

Lead and cadmium levels in coastal benthic algae (seaweeds) of Tenerife, Canary Islands.

Lead and cadmium levels of some species of brown-algae (Phaeophyta) from the mesolittoral (intertidal area) of the Island of Tenerife (central-eastern Atlantic) were determined by Atomic Absorption Spectrometry. The quality control was carried out using a standard "CRM 279 Ulva lactuca". The mean, minimum and maximum concentrations were 11.21, 2.090 and 81.795 microg/g/dw; and 1.13, 0.190 and 5.130 microg/g/dw for lead and cadmium, respectively. The fact that samples registering the highest cadmium concentrations were the same as those which showed the highest lead level corresponding to a sampling station nearby an urban water outlet could be relevant.