Metallic Contamination of the Muscles of Three Fish Species from the Moulouya River (Lower Moulouya, Eastern Morocco)

Abstract

This study introduces a spatiotemporal evaluation of the metallic contamination with three trace metals (mercury, lead, and cadmium) in the muscles of three fish species (Lepomis macrochirus, Barbus callensis, and Barbus nasus), of which the samples were taken from three stations in the Moulouya River: the confluence of the Moulouya River and the Sebra River (station 1), the neighbourhood of the farms in the region of Aklim downstream from confluence of Lakhmis river (station 2), and the level of ancient bridge of Ras El Ma-Moulouya (station 3), during the period from July 2017 to May 2018. The results have allowed us to highlight rather high contents of lead and mercury in the fish muscles, mainly in station 1, which receives domestic and industrial discharges. The contents of cadmium in all fish species in different stations are very low. Moreover, all concentrations assessed in different fish species do not exceed the maximum limit recommended by European Community (EC) Commission Regulation No. 1881/2006.

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

“…The lower concentration of Cd in muscle observed in this study suggests that muscle tissue is not an active site for the Cd accumulation process. In the scientific literature, similar values were recorded in the muscles of L. macrochirus , B. callensis , and B. nasus from the Moulouya River to Morocco [ 26 ], in the muscles of L. graellsii , R. rutilus , and L. gibbosus in the station 1 from the Llobergat River to Spain [ 27 ], and in C. carpio of Kasumigaura Lake in Japan [ 6 ]. While, low concentrations of Cd were found in the muscles of B. barbus , and L. cephalus from the Shahid Rajaei Dam in northern Iran [ 28 ], in the muscles of ten species caught at Šalek Lake in Slovenia [ 29 ], in fish B. barbatula , S. cephalus , and B. barbus from the Sûre River in Luxembourg [ 30 ], in three species from the Vaal Dam in South Africa [ 31 ], and in the muscles of T. nilotica from the High Dam Lake in Egypt [ 32 ].…”

“…These levels detected in this study are all lower the European Community (regulation (EC) N° 1881/2006) for the Pb in fish flesh, which is in the order of 0.3 mg/kg of wet weight for muscle meat of fish [ 25 ]. The comparison with the data available in the literature indicated that similar concentrations of Pb were detected in the muscles of L. kimberleyensis from Vaal Dam to South Africa [ 36 ], in L. macrochirus , B. callensis , and B. nasus captured at the Moulouya River to Morocco [ 26 ], in the muscles of L. graellsii , R. rutilus , and L. gibbosus in the station 1 from the Llobergat River to Spain [ 27 ], and in G. holbrooki from Fouarat Lake and Sebou Estuary in Morocco [ 37 ]. However, low concentrations of Pb were found by Rashed et al [ 32 ], Wariaghli et al [ 38 ], Alam et al [ 6 ], Boscher et al [ 30 ], Plessl et al [ 31 ], and Petkovšek et al [ 29 ].…”

“…Comparing the results of our study with previous studies, we found that the study of Boscher et al [ 30 ] presented similar results in fish B. barbatula , S. cephalus , and B. barbus captured at the Sûre River in Luxembourg, while this metal is not detected in the muscles of six species belong to the Atatürk Dam studied by Karadede et al [ 45 ]. Other studies show low levels of Hg in fish muscles, such as the study of Petkovšek et al [ 29 ] on ten species caught at Šalek Lake in Slovenia, the study of Mahjoub et al [ 26 ] on L. macrochirus , B. callensis , and B. nasus captured at the Moulouya River in Morocco, the work of Mol et al [ 46 ] on eight species of the Atatürk Dam in Turkey, and the study of Plessl et al [ 31 ] on three species from the Vaal Dam in South Africa. On the contrary, some studies have shown high levels of Hg exceeding the recommended regulatory limits, such as the study of Dharampal et al [ 47 ] on M. salmoides from the Sipsey River in the USA, the study of Scerbo et al [ 48 ] on species of A. anguilla , L. cephalus cabeda , and C. toxostoma captured at the Cecina River in Italy, and the work of Shakeri et al [ 28 ] on B. barbus from the Shahid Rajaei Dam in northern Iran ( Table 10 ).…”

“…Higher values were obtained during summer season than during winter season, and this may be due to the increase in the volume of water in the dam by the supply of storm water, induced their dilutions in winter. Moreover, the very high temperatures in the summer could also lead to higher metabolic rates, which could induce an increase in fish food activity, and this in turn increases the concentration of metals in fish [ 26 , 55 , 56 ]. This result agrees well with some studies [ 26 , 56 , 57 ].…”

Metales pesados en truchas arcoíris (Oncorhynchus mykiss) de crianza intensiva de la zona noroeste del lago Titicaca

“…A nivel general, los niveles de metales pesados encontrados en los músculos de la trucha arcoíris están por debajo de los niveles máximos permisibles (WHO/FAO, 2015; FSANZ, 2013; MHPRC, 2013; OMS, 2016; Memet et al, 2017; European Commission, 2008), lo cual es un aspecto favorable, puesto que aún no constituye problema para la salud pública, pudiéndose consumir sin mucha preocupación (Mahjoub et al, 2020). El comparativo entre ambas zonas evidencia algunas variaciones (p<0.05) en el contenido de los metales pesados, lo cual puede ser indicador de la diferencia en el contenido de estos contaminantes en los cuerpos de agua; Cuadro 2.…”