Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul Seasonal variations of heavy metals content in mussels (Mytilus galloprovincialis) from Cala Iris offshore (Northern Morocco) Ghizlane Azizi a , Mostafa Layachi b , Mustapha Akodad a , David R. Yáñez-Ruiz c , Antonio Ignacio Martín-García c , Mourad Baghour a , Abdelhakim Mesfioui b , Ali Skalli a , Abdelmajid Moumen a, ⁎ a OLMAN-RL, Faculté Pluridisciplinaire de Nador (FPN), Université Mohammed 1er, B.P: 300, Selouane, 62700, Nador, Morocco b Centre Régional de l'INRH-Nador, 13 Boulevard Zerktouni BP: 493, Nador, Morocco c Departamento de Fisiología y Bioquímica de la Nutrición Animal, Camino del Jueves s/n, Armilla 18100, EEZ, CSIC, Granada, Spain ARTICLE INFO Keywords: Cala Iris offshore Mussel farming Mytilus galloprovincialis Heavy metal Sentinel organisms Seasonal variation ABSTRACT Heavy metal concentrations of Cd, Cr, Cu, Fe, Ni, Zn, Co, and Pb were investigated in soft tissues of Mytilus galloprovincialis coming from an aquaculture farm in Cala Iris sea of AlHoceima. Mytilus galloprovincialis were collected monthly during the period January to December 2016. The seasonal variations were affected sig- nificantly the concentrations of metals (Cd, Fe and Cr) in M. galloprovincialis. The highest heavy metal con- centrations were recorded in winter (0.89 mg/kg, 673.2 and 3.330 mg/kg; for Cd, Fe and Cr, respectively) and the lowest values were founded in summer for Cd (0.646 mg/kg), and in autumn for Fe (340.1 mg/kg) and Cr (1.959 mg/kg). A significant effect of seasons on metal concentrations can be attributed to a number of biological and environmental inter-related factors. Data from this study may provide information on the use of M. gallo- provincialis as a bioindicator for heavy metals pollution in the Cala Iris Sea. 1. Introduction Numerous anthropogenic pressures such as chemical pollution by heavy metals that are generated from the industrial, agricultural and urban development are transported through rivers or by air and finally accumulate in seas where they mainly affect coastal areas. The impacts of these substances on the environment are multifaceted; their toxic actions may directly or indirectly affect individuals, populations and ecosystems. The synergy phenomena are possible and they have com- plicated effects triggering (Wang and Rainbow, 2008; Zhang et al., 2014; Gillis et al., 2017). Chemical pollutants as heavy metals on the aquatic life are still poorly known. This situation led to the diversifi- cations of the approaches that allow understanding the state of pollu- tion of aquatic environments. Monitoring the coastal environment has arisen from the need to protect human health and living marine resources. During the past few decades, various biomonitoring strategies have been developed to monitor and evaluate the antagonistic impact of these compounds on marine ecosystems (Davies and Vethaak, 2012; Rodrigues et al., 2015). The Monitoring programs use a great number of bioindicators known as “sentinel organisms” to detect temporal and spatial variation of chemical pollutants and to contribute to the knowledge of trends in marine contamination (Pisanelli et al., 2009; Andral et al., 2011; Pinto et al., 2015; Chakraborty et al., 2016; Azizi et al., 2017). The Mussel Watch (Goldberg, 1975) is the oldest biomonitoring program in progress worldwide. It has been successfully developed in many countries (Boening, 1999; Monirith et al., 2003; Farrington et al., 2016; Robinson et al., 2017). In the Mediterranean area, scientists (Rouane-Hacene et al., 2015; Belivermiş et al., 2016; Azizi et al., 2017) suggested to use Mytilus galloprovincialis, as bioindicator, in order to evaluate the status of chemical contamination. Mytilus galloprovincialis are widely considered as one of the most suitable sentinels and biolo- gical indicators of pollution, due to their sedentary nature, wide geo- graphical distribution, capacity for accumulating contaminants, ease of sampling, and are remarkably tolerant to chemical pollution. At the same time, they have shown sensitive and measurable biological re- sponses when they are exposed to stressful conditions (Attig et al., 2014; Banni et al., 2014; Sericano et al., 2014). This paper study the effect of seasonal variations on heavy metals (Cd, Cr, Cu, Fe, Ni, Zn, Co, and Pb) concentrations in Mytilus gallopro- vincialis from Cala Iris of Al Hoceima region in Northern Morocco, and to investigate if Mytilus galloprovincialis concentrations are within the https://doi.org/10.1016/j.marpolbul.2018.06.052 Received 14 March 2018; Received in revised form 17 June 2018; Accepted 18 June 2018 ⁎ Corresponding author. E-mail address: abelm127@hotmail.com (A. Moumen). Marine Pollution Bulletin 137 (2018) 688–694 0025-326X/ © 2018 Elsevier Ltd. All rights reserved. T