HEAVY METALS ASSESSMENT IN THREE FISH SPECIES: BOOPS BOOPS, SARDINA PILCHARDUS AND TRACHURUS TRACHURUS FROM NORTH-EAST OF MOROCCO.

Zineb Feddal 1 and Mustapha Aksissou 2 . 1. Laboratory of Environment, Biodiversity and Ecology, Faculty of Sciences, BP. 2121 M'HannechII, 93030 Tetouan, Morocco. 2. Laboratory of Environment, Biodiversity and Ecology, Faculty of Sciences, BP. 2121 M'HannechII, 93030 Tetouan, Morocco. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

Several pollutants are discharged daily and end up rapidly in the marine environment, which represent the ultimate repository of all anthropogenic emissions. Among these pollutants, the heavy metals are considered the most harmful for the aquatic environment due to their capacity to accumulate in marine organisms (Harte et al., 1991; h r r rt 1998 The accumulation of heavy metals in these living matters may subsequently affect the quality of the environment and deteriorate the ecological imbalance.  In the present work, levels of several metals (Cd, As, Zn, Cr, Cu, Ni, Pb, Mn and Fe) in the muscle tissue of some commercial fish from the Moroccan Mediterranean coast were determined. Three fish species Boops boops, Sardina pilchardus, Trachurus trachurus have been analyzed for heavy metals contents. These metals were selected based on their importance in the field of monitoring of the quality of marine environment. The aim of this work is to evaluate the current environmental status of the coast, and to compare the metals content in muscles against the recommended maximum permissible limit to assess the quality of fish and the health risk for human.  Measurements of the basic biological parameters:-Fishes were first identified, and then the total lengths (cm) and the body-wet weights (g) of each fish specimens were measured. The detailed information is listed in Analytical procedure:-Fishes are dissected, the muscles tissues were removed and dried in an oven at 60°C during 24h. Then each dried fish tissue was grounded to obtain a very fine powder. Heavy metal analysis was carried out by wavelength dispersive x-ray Fluorescence (WD-XRF) at the technical unit support to scientific research (UATRS) of the National Centre of Scientific Researches and Techniques (CNRST) in Rabat, Morocco.

Data analysis:-
The data of this study were statically analyzed. A One-way analysis of variance (ANOVA) was used to determine th sig ifi t iff r s i t l l v ls o g sp i s. t tisti l sig ifi w s fi s p≤0.05.

Results and Discussion:-
The port of M'diq is considered one of the important ports located in the Mediterranean cost and it is one of the main source of fishes in this area. The Figure 2 shows the importance annual production of the selected species in this harbor. Data provided by national fisheries office (ONP)   This study was held to investigate heavy metal concentrations in muscles of three commercially important fish species in North-East of Morocco because the concentration of heavy metals in commercial fish available in this region was rarely investigated. Although it is well known that fish muscle is not an active tissue in accumulating heavy metals (Bahnasawy et al., 2009) the present study concerned with the heavy metal concentrations in the fish muscles because it is the most consumed portion by the Morrocan people. Furthermore, it was documented that some fish in polluted regions may accumulate substantial amounts of metals in their tissues, which sometimes exceeded the maximum acceptable levels (Kalay et al., 1999).
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, table 1 sums up some examples of industrial and agricultural sources which may introduce metals in the environment (Othmer, 1995). According to USEPA2000 the Recommended mean of As is 1.2 µg/g, our result was slightly higher than the concentration allowed by USEP2000 and Turkish guideline The higher mean was found for Magnesium and Nickel; in our study was 52.1µg/g in Sardina pilchardus and Ni 2.62 µg/g Boobps Boops after rainy season. There is no information about maximum permissible limits for Magnesium and Nickel in fish tissues except for Turkish Food Codex (2004) they set 20µg/g as maximum limit for magnesium in fish tissues and 0.4 by FAO ( FAO/WHO, 1983) Our main interest was investigate the heavy metals Cd, As, Zn, Cr, Cu, Ni, Pb, Mn and Fe but after rainy season samples showed other different metals trace as Ti, Zr, Bp, Y, Sr et Ac. These trace metal showed so low concentration, which are represented in table 5; this could be attributed to the heavy rainfall during these seasons, which increases the metal content of water, by washing down the wastes.

Conclusion:-
The pollution of the marine environment has become a global problem and the need to investigate the safety of marine products become a necessity in any country.
Metal concentrations in the three studied fish species were within the same range or below the limits proposed for fish by various international standards and guidelines such as EU , FAO/WHO, and Turkish guidelines except for magnesium found in muscles of sardina pilchardus was high that limit set by Turkish Food Codex.
The examined fish were safe for human consumption at least with regard to residual levels of cadmium, copper, manganese, nickel, lead and zinc but a continuous monitoring of heavy metals in commercial fish in North-East of Morocco as well as other Moroccan regions is necessary to insure the prescribed worldwide limit. Reference:-