Health risk assessment of heavy metals in three invertebrate species collected along Alexandria Coast, Egypt

The distribution of eight heavy metals (Fe, Mn, Cu, Zn, Cr, Ni, Pb and Cd) in three species namely Pinctada radiata, Brachidontes pharaonis and Holothuria polii was determined seasonally from seven stations along Alexandria Coast, Mediterranean Sea, Egypt. Relatively the highest annual averages for each of the eight investigated metals during the period of the current study were found in Pinctada radiata. On the other hand, the lowest averages were found in Holothuria polii for Fe, Zn, Pb, Cr, Cu, Ni, and Cd, and in Brachidontes pharaonis for Mn (3.405 μg/g wet weight). In addition, the metal pollution assessment in mussels revealed that the total target hazard quotients were decreased in the order of Brachidontes pharaonis (0.198) > Holothuria polii (0.080) > Pinctada radiata (0.051). The target hazard quotients (THQs) values for each of the individual metal (Mn, Cu, Zn, Cr, Pb and Cd) in the investigated species were found much smaller than one, indicating that there is no human risk from their consumption.