Heavy metal concentration in two freshwater fishes from Wadi Hanifah (Riyadh,Saudi Arabia) and evaluation of possible health hazard to consumers

The contamination of heavy metals,such as chromium (cr),iron (fe),cobalt (co),nickel (ni),zinc (zn),cadmium (cd) and lead (pb) were evaluated in the water and tissues of african catfish clarias gariepinus and sabaki tilapia oreochromis spilurus from wadi hanifah,riyadh. the samples were collected from three sampling sites (namar,al-masani and al-hair) of wadi valley of central saudi arabia during may-june 2013. the water and fish samples collected from al-masani,nearby a vehicle mechanical industrial area,were found to be more contaminated by cr,fe,zn and pb than those of other sampling sites. the high concentrations of fe were detected in all the water and fish samples,followed by zn,pb,cr,co,ni and cd. however,none of the detected hm (heavy metals) concentrations were exceeded the permissible limits set by the different authorities. the estimated daily intake was found to be below the provisional tolerable daily intake (ptdi),established by the fao and who,indicating that there was no carcinogenic risk for humans. copyright 2015 zoological society of pakistan.