Heavy Metals in Some Fish Species and Bivalves from the Mediterranean Coast of Egypt

Abstract

Biota samples were collected seasonally during three consecutive years from the Egyptian costal region along the Mediterranean Sea for analysis of Zn, Cu, Cd, Pb and Hg. In addition to bivalve Donax, seven commercially important species of fish were examined to provide a comprehensive assessment for the concentrations of these metals in the Mediterranean coastal region of Egypt. Despite of the presence of several land-based sources of contamination, particularly at El-Mex Bay and El-Maadiya, the results showed very weak increase in the concentration of copper, lead and mercury revealing no accumulation of these metals in the biological material, even in non-migrant bivalve species such as Donax. However, an increase in the concentration of zinc and cadmium in fish tissues was measured from 1993 to 1995. Regardless of the fish species, no significant differences were observed in concentrations of most metals between different locations and from season to season. Regarding concentrations of most metals, no interspecies differences could be also measured in either fish tissues or in bivalve Donax. The study indicated that the concentration of these heavy metals were well below the documented toxic levels for human consumption and represent baseline levels against which possible future heavy-metal contamination can be measured.

Evaluation of Different Anthropogenic Effluents Impacts on the Water Quality Using Principal Component Analysis: A Case Study of Abu-Qir Bay-Alexandria-Egypt

“…It may also become highly toxic when concentrations exceed levels that are physiologically required, it has become the major biocide added in antifouling paints as a consequence of the prohibition of paints based on tributyl tin (TBT), it is used in small amounts as fertilizers in some soils deficient in this element. Cu is also used as an algaecide and fungicides [54,55], its concentrations are often elevated in harbors, which usually are located at estuaries, and the sources of copper to the aquatic environment are both natural, such as weathering of rock, minerals, anthropogenic, waste water discharges as a consequence of agricultural and industrial activity [3,15,56]. Table 2 and Figure 3, show concentrations of total dissolved copper in Abu-Qir drain waste water and Abu-Qir Bay seawater.…”

“…Significant positive correlation between dissolved copper concentrations and pH values were found (Table 3). Diffusion and deposition of copper from the bulk water into sediment, the adsorption of copper by humic materials, the chelation of copper by other artificial compounds deposited on the bottom sediment [15,52,53,56], and low DO (0.16 mg/l) are additional important factors. A significant positive correlation between dissolved copper concentrations and DO values were observed (Table 3).…”

“…PCA revealed a significant positive correlation between the pH and dissolved copper concentrations ( Table 3). The release of copper from sediments to overlying water [3,15,56], as well as the high DO (9.42 mg/l) are important factors. Concentrations of copper found to increase by increasing the DO which is strongly supported by PCA (Table 3 & Figure 4).…”

“…The growing increase in Egyptian population, as well as urbanization expansion; lead to a corresponding increase in industrial, agriculture, urban effluents that discharged into the aquatic environment of Egypt [8][9][10][11][12][13][14][15], leading to water quality deterioration. Poor quality water can lead to water borne diseases as well as death of aquatic life [16][17][18][19][20][21][22].…”

Nutrient Fluxes and Sediments Composition in El Mex Bay and Surround Drains, Alexandria, Egypt

“…Although these releases were significantly reduced during recent decades because of regulations, contaminants accumulated in the sediments over time [8]- [19]. These sediments now constitute a potential source of contaminants for the water column that could alter the water quality and threaten aquatic organisms [20]- [30]. Understanding the processes controlling the dynamics of contaminants in the sediment, improving our knowledge of the environmental risk induced by contaminated sediments and appropriately orientating the action of politics and managers, is thus a challenge for the next decades [31].…”