Journal of Environmental Solutions Volume 2 (Issue 1) (2013): 1-8 Journal of Environmental Solutions Averroes Publisher METALLIC CONTAMINATION OF THE OCCIDENTAL MEDITERRANEAN COASTS OF MOROCCO (COASTAL FRINGE “KABILA - OUED LAOU”), USING Callista chione KHANNOUS SOUMAYA1; BOUZID SAIDA1; BENOMAR MOSTAPHA2; ER-RAIOUI HASSAN 1* 1Geosciences and Environment team - Department of Earth Sciences - Faculty of Sciences and techniques, Tangier, Morocco 2 Laboratory of Chemical Micropollutants, National Institute of Halieutic Research, Tangier, Morocco * Corresponding author. Er-raioui Hassan E-mail: [email protected] Tel: +212 5 39 39 39 54 A B S T R A C T Keywords: In order to study the metallic contamination of the western Mediterranean coasts of Morocco, bivalve samples metallic contamination (Callista chione) were collected during the pluvial period from five sites (Kabila, Cabo Negro, Oued Malleh, Oued Occidental Moroccan Mediterrane- Laou and Oued Laou River's mouth) and were analyzed for 6 elements (Zn, Ni, Cu, Pb, Cr and Cd) by ACP-AES. an coasts The average of metallic concentrations found (62.52 mg/kg for Zn, 16.23 mg/kg for Ni, 5.57 mg/kg for Cu, 2.21 Callista chione mg/kg for Pb, 1.50 mg/kg for Cr and 0.28 mg/kg for Cd) are far away from being considered as negligible even though industrial and harbor activities are less developed in this region compared to industrial countries. The concentrations show significant spatial variations. It seems that these variations are related to urban dis- missals from close agglomerations and from the washing of the geological formations of the back-country. I. INTRODUCTION The intensity of human activities in areas surrounding enclosed seas and semi-enclosed seas, such as the Mediterranean Sea, has always had a significant environmental impact resulting in coastal and marine degradation. Today, the coast of large industrial con- centrations shows the most disturbing marine forms of degradation. However, the Mediterranean coast which represents 1 % of the surface of the global ocean is a vast inland sea (Burns & Saliot, 1986). It is a fragile and vulnerable ecosystem and also corresponds to a semi-enclosed sea where the waters are renewed slowly (15 years for deep water) (Hopkins, 1978). The waterflow is greatly hampered by the Strait of Gibraltar. Such a closure worsens the impact of a rapidly expanding population. The Mediterranean coast of Morocco, economically rich, ecologically fragile, is an exceptional place for marine life by the multitude of animal and plant species that breed there. With its 512 km of coastline, it is characterized by a significant marine biodiversity, including a large amount of specific species (Belcaid, 2010). The areas at most risk are undoubtedly those located near to the Strait of Gibraltar where North and South meet and where major cities make up the Moroccan coast. The ports of Tangier, M'diq (Tetouan) and Nador with industrial releases are other sources of pollution, as well as those emissions in fishing areas. The areas receive a significant amount of both industrial and urban waste; in addition to that generated by tourism and maritime activities (Er-Raioui et al., 2012). There are many sources of water pollution and they are an ongoing problem in Morocco, which manifests particularly in irrigated perimeters and areas of economic activity. Among the causes of water pollution, are included industrial units, mainly concentrated in and around cities, and among these industries, some are recognized pollutants. Two types of industries can be distinguished: (1) those whose discharges are essentially organic and (2) those whose discharges contain toxic elements. Emissions correspond to ordinary organic substances, organic products of synthesis, hydrocarbons, minerals, heavy met- als, polychlorinated biphenyls (PCBs), chlorides, sulphates, cyanides, and arsenic salts. In summary, table 1 sums up some examples of industrial and agricultural sources which may introduce metals in the environment (Othmer, 1995). Table 1. Industrial and agricultural sources of metals in the environment. Uses Metals Batteries and other electrical appliances Cd, Hg, Pb, Zn, Mn, Ni, Pigments and paints Ti, Cd, Hg, Pb, Zn, Mn, Sn, Cr, Al, As, Cu, Fe Alloys and solders Cd, As, Pb, Zn, Mn, Sn, Ni, Cu Biocides (pesticides, herbicides, curators) As, Hg, Pb, Cu, Sn, Zn, Mn Catalyst agents Ni, Hg, Pb, Cu, Sn Glass As, Sn, Mn Fertilizers Cd, Hg, Pb, Al, As, Cr, Cu, Mn, Ni, Zn Plastics Cd, Sn, Pb Dental and cosmetic products Sn, Hg Textiles Cr, Fe, Al Refineries Ni, V, Pb, Fe, Mn, Zn Fuels Ni, Hg, Cu, Fe, Mn, Pb, Cd 1 Khannous et al. The coast of Tetouan (occidental Mediterranean), which is the subject of this study, is experiencing urbanization and rapid industri- alization, as well as important port and tourist activity. Domestic pollution is the main source of contamination in the area. First, the wastewater is discharged without any treatment, neither in the rivers that flow into the coastline (Oued Martil, Oued Smir and Oued Laou) nor directly into the sea. The second source of pollution comes from industrial units in the region, mainly from the industrial area of Martil. The volume of wastewater released at the coastline in question is more than 50 000 m3/day; draining more than 21.5 t/d oxidizable matter, and more than 83.85 t/d of suspended solids. These waters are also responsible for metal emission (Zn, Cu, Cd, Cr, Ni and Pb). The load is heavy in lead, cadmium, chromium and nickel, which show high concentrations in some places (Er-Raioui et al., 2012). Trace metal elements (TME) are one of the main chemicals that cause degradation of the water quality. Indeed, the contamination of the coastal ecosystem by these elements is a major problem in environmental toxicology. Unlike organic pollutants, some TME are practically not a subject of biodegradation. They can accumulate then in the food chain to reach toxic levels (Cumont, 1984) and generate critical, even dangerous situations (Serghini et al., 2001). In natural aquatic ecosystems, metals are found at low concentrations, typically in nanograms or micrograms per liter. However, in recent decades, the presence of trace metal concentrations above natural charges has become a serious problem due to the rapid population growth, the increased urbanization and the expansion of industrial activities. Regarding the toxicity of metals, it is necessary to distinguish between the essential and non-essential elements. A metal is consid- ered essential if the disease symptoms appear when its concentration decreases or is absent and disappears when it is added. It also requires that the symptoms are associated with a biochemical defect (Förstner & Wittmann, 1979). However, an essential element can be toxic when present in excessive concentrations. According to these criteria, 17 metals are considered essential, including four (Na, K, Ca and Mg) which are present in large quantities (>1 mmol.kg-1 fresh weight), while the other thirteen (As, Cr, Co, Cu, Fe, Mn, Mo, Ni, Se, Si, Sn, V and Zn) are present in trace (from 0.001 to 1 mmol.g-1 fresh weight) or ultra-trace (<1 μmol.kg-1 fresh weight) amounts (Mason & Jenkins, 1995). Non-essential metals have, unlike the essential ones, no biological role currently known. This is the case for Hg, Ag, Cd and Pb (Mason & Jenkins, 1995). They are considered harmful when they are present in the environment and cause deleterious biological effects at very low concentrations. To assess the state of metallic contamination at the coast of Tetouan for public health and protection of aquaculture areas, this pre- liminary study was carried out for some metals (Zn, Cu, Cd, Cr, Ni and Pb), primarily by use of a quality monitoring network of coastal waters using bivalve molluscs. These are used as indicators of metal pollution because of their great accumulation power. Often, it is possible to detect the presence of trace metals in molluscs, even when their concentrations in water are very low, highly variable or difficult to determine by routine chemical analysis (Mazlani et al., 1994). Molluscs have the capacity to accumulate contaminants directly from the environment (BCF) or by other means (e.g. food) to levels well above the level of contamination of the physical environment (water, sediment). Therefore, bio accumulative species are used frequently in monitoring networks (biomonitoring) for the quality of the marine environment (Amiard et al., 1998). In addition, the region has large reserves of shellfish, represented mainly by species such as Acanthocardia Tuberculata, Callista Chione, Venus and Galina Donax Trunculus. Clams represent the most sought bivalves in wide geographical distribution (Shafee, 1999). In addition, the monitoring of coastal metal contamination by bivalve organisms is a common practice in many monitoring programs around the world. For example, one famous site program called "Mussel Watch", which is the oldest continuous monitoring program of contaminants in coastal waters of the United States, uses bivalve tissues as indicators of several parameters including organic and inorganic contaminants, and trace metals in particular. In France, the National Network of Observation marine environmental quality (RNO) uses bivalve organisms to evaluate the safety of the French coast. II. MATERIALS AND METHODS II.1. Study area The studied area is localized in the Northwest of Morocco at the western part of the Mediterranean Sea. It corresponds to the fringe between Kabila and Oued Laou (figure 1). From a geological point of view, the western Mediterranean coasts are bordered on both sides by alpine chains known as Rifo-Betic- Kabyle, consisting of Paleozoic detritic lands, not or slightly metamorphosed, and generally having a clay, sandy and marly nature. The area is also made up of pleated and metamorphosed ultrabasic lands, essentially formed by peridotites, kinzigites, gneiss and micaschists (Michard et al., 2006 and Suter, 1980).