Determination of Heavy Metals Contamination in Fish Flesh and Water from the Red Sea Coast of Sudan

Abstract

The objective of this study was to determine the concentrations of some heavy metals (Hg, Pb, Zn, Cu, Ni, As and Se) in fish flesh and water from the Sudanese Coast of the Red Sea.Water samples were collected, during summer 2009, from twelve to eighteen stations on the Sudanese coast of Portsudan and Suakin. Twelve fish samples were collected from fish market of Suakin and Portsudan during summer 2010. Levels of heavy metals, mercury (Hg), Lead (Pb), Zinc (Zn), Copper (Cu), Nickel (Ni), Arsenic (As), and Selenium (Se), were determined in coastal water and fish flesh from twelve different stations in Portsudan and Suakin. The concentration ranges of heavy metals in water determined were: 1.588 – 40.08, 0.025 – 0.439, 0.227 – 4.99, 1.327 – 9.157, 0.377 – 3.950 and 0.0109 – 2.947 μg/l for Hg, Pb, Zn, Ni, Cu, As, and Se in Portsudan, respectively and 3.021 – 32.252, 0.115 – 0.439, 0.557 – 4.99, 1.327 – 1.123, 0.6 – 3.950 and 0.0109 – 0.715, 0μg/l for the above metals in Suakin, respectively. Two methods were used for mercury determination in fish flesh and sea waters UV/VIS spectrometric method and cold vapor atomic absorption spectrometry (CVAAS). Selenium and arsenic were determined by hydride generation atomic absorption spectrophotometry (HGAAS). Lead, Zinc, Copper and Nickel were determined either by. Flame atomic absorption spectrometry (FAAS) or graphite furnace atomic absorption spectrometry (GFAAS). The corresponding concentration values in fish flesh were 0.0016 – 0.036, 0.0003 – 0.0019, 0.2 – 0.49, 0.08 – 0.13 and 0.09 – 0.38μg/g for Hg, Pb, Zn, Ni, Cu, in Portsudan, respectively and 0.0038 – 0.032, 0.0003 – 0.002, 0.202 – 0.496, 0.082 – 0.126 and 0.091 – 0.378μg/g for Hg, Pb, Zn, Ni, Cu, in Suakin, respectively. The highest accumulated metals were Zn and Cu in both Portsudan and Suakin fish flesh samples, while the lowest, were Pb and Hg, in both Portsudan and Suakin. Both highest and lowest concentrations of Ni were recorded in Portsudan, but Suakin recoded also the same lowest concentration. Generally, concentrations of all metals in water and fish flesh were recorded at Portsudan city, while the lowest concentrations were recorded at Suakin city. Sewage and wastes discharged from the city, oil refiners and power station, in addition to waiting transit ships at Portsudan coast may be the main sources of metal pollution in Portsudan City.