Trace metal distribution in pelagic fish species from the north-west African coast (Morocco)

Abstract

In the current study, ten elements contents (Fe, Zn, Mn, Cu, Cr, Co, Ni, Cd, Pb and Hg) have been measured in muscle and liver of four pelagic fish species (Engraulis encrasicolus, Sardina pilchardus, Scomber japonicus and Trachurus trachurus) from the north-west African coast (South Atlantic Moroccan coast), collected during summer and autumn seasons (July and December 2013, respectively). Significant differences in metal contents were found between the different species (p \ 0.05). Metals levels were also much higher in liver than those recorded in muscle tissues. The concentrations of Fe, Zn, Cd, Co, Cu and Pb were significantly higher in mackerel liver (p \ 0.05).While, in muscle, anchovy presents a higher content of Mn, Cu, Cr, Ni and Pb. A high level of cadmium was recorded in liver of the different species which can be attributed to an anthropogenic source (phosphate industry) and to natural sources (upwelling activities). The main concentration of toxic elements (Cd, Pb and Hg) recorded in the four edible muscles of pelagic fish species, under study, were below the established values by the European Commission Regulations and show that their effect on the consumers health can be considered as negligible.

Mercury, Lead, and Cadmium in the Muscles of Five Fish Species from the Mechraâ-Hammadi Dam in Morocco and Health Risks for Their Consumers

“…Unlike Cd, Hg preferentially accumulates in muscles due to their affinity for the sulfhydryl groups of proteins [ 49 ]. Therefore, there is an evidence for Hg bioaccumulation and biomagnification; however, evidence for Cd biomagnifications is inconsistent [ 2 ].…”

“…The aquatic ecosystems are continuously exposed to certain pollutants that are accompanied by increasing degradation of their quality [ 1 ]; this has a negative impact on the water quality and aquatic life of our ecosystems. The pollutants that could pose a threat to our aquatic ecosystems in general and fish fauna in particular are trace metals [ 2 ]. These elements are very dangerous because of their very high toxicity even at low concentrations, their prolonged persistence in the environment, and their tendencies to bioaccumulation in aquatic organisms because they are not biodegradable, and as a result, they concentrate large quantities in their tissues [ 3 – 5 ].…”

Metal Contamination of Ethmalosis (Ethmalosa fimbriata Bowdich, 1825) In the Bietri Bay (Ebrie Lagoon, Côte D'Ivoire).

“…This order of accumulation is similar to that reported by Copat et al 28 in the pelagic fish muscle (anchovy, mackerel, horse mackerel) from the Mediterranean Sea (Zn˃ Mn˃Ni˃ Cr˃ Pb˃ Cd). On the other hand, different results have been reported by Diop et al 29 in the muscle of Sardinella aurita and Solea senegalensis along the Senegalese coast (Fe˃Zn˃ Cu˃As˃ Se˃ Mn˃ Cd˃ Cr˃ V˃ Ni˃ Pb), and by Afandi et al 30 in the pelagic fish muscle from the northwestern African coast (.Fe˃Zn˃ Cu˃Mn ˃ Ni˃ Cr˃ Cd˃ Hg˃ Pb-Co). This difference in metal accumulation can be explained by many factors, corresponding to the physico-chemical characteristics of aquatic biotopes and their natural or anthropogenic variations, influencing the bioavailability of metals, via chemical speciation reactions and their transfer behavior and their bioaccumulation, in relation to adaptive responses to the main physiological functions (respiration, osmoregulation, nutrition) [31][32][33] .…”

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“…Naturally, we find the effects of upwelling that ascends nutrients and elements from the lower layers of the ocean, sandstorms from deserts that enrich the ocean, etc. (Afandi et al, 2018;Lozano-Bilbao et al, 2019b, 2020dRuilian et al, 2008;Qing et al, 2015).…”