International audience | Sediment cores from the central Algerian coast were collected to investigate the distribution, sources and risk oftrace metals. The local geochemical background of metals was defined from the core S collected in an uncontaminatedarea of the coast. The anthropogenic inputs in Algiers Bay elevated Ag, Cd, Pb and Zn concentrationsas their maximum were 3.1, 3, 2.1 and 1.8 times the background values, respectively. Meanwhile, increasedcontents of Arsenic (up to 21.1 mg/kg) were detected in all sites. Correlations and PCA suggest that lithogenicsources controlled metal deposition, while most sediment arsenic was agriculture-derived. Organic matter actedas a sink or source for some trace metals. According to EFs, the study area showed slight to moderate enrichmentwith respect to Ag, As, Pb, Cd, Zn and Cu, whereas they remained uncontaminated with Cr, V, Co and Ni. Thisstudy provides a needed baseline for future environmental investigations.

International audience | Chemical pollution is a major threat to marine ecosystems, and top predators such as most shark species are extremely vulnerable to being exposed and accumulating contaminants such as metals and persistent organic pollutants (POPs). This work aimed to study the degree, composition, and the sources of contamination in the blue shark (Prionace glauca) inhabiting the Northeast Atlantic, as well as the potential risk faced by human consumers. A total of 60 sharks were sampled in situ aboard fishing vessels, and the concentrations of a set of metals and POPs were analysed in various tissues and complemented with stable isotope analyses. High levels of contaminants were found in most sharks sampled. The concentrations of most metals were higher in the muscle when compared with the liver. Regarding the dangers to consumers posed by the concentrations of arsenic (As), mercury (Hg), and lead (Pb), over 75% of the sharks presented muscle concentrations of at least one contaminant above the legal limits for human consumption, and a risk assessment determined that consumption of meat of these sharks exceeding 0.07 Kg per week could potentially expose human consumers to dangerous amounts of methylmercury (MeHg). Additionally, the assessment of single contaminants may lead to an underestimation of the risk for the human health. Finally, the overall accumulation of contaminants seems to be mostly influenced by the sharks' geographical distribution, rather than sex, size, or trophic level of their prey. ☆ This paper has been recommended for acceptance by Christian Sonne.