Investigation of heavy metal accumulation in water, sediment and some fish in Ilisu reservoir region of Tigris river

In the present study, it was tried to determine heavy metal such as Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb concentrations in water, sediment, and liver, gill and muscle tissues of Cyprinion macrostomum (Heckel, 1843), Chondrostoma regium (Heckel, 1843), Capoeta trutta (Heckel, 1843) samples taken seasonally from various localities in Ilısu Dam Lake Region of Tigris River. The heavy metals in water and fish samples were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), whereas the sediment samples were analyzed by Atomic Absorption Spectroscopy (AAS). Considering seasonal heavy metal concentrations in water, they found to be the highest in Ilısu (except Cr and Ni) and in Batman Dam (except Cr) in the summer, while in they are at the highest level in the winter Hasankeyf (except Cr). The most encountered heavy metal in water samples from all localities was Fe, while the least encountered one was Cd. Heavy metal concentrations in Tigris River sediments were found as Fe > Mn > Cr > Ni > Zn > Cu > Co in Ilısu Dam and Hasankeyf, whereas in Batman Dam, they were in the order of Fe > Mn > Ni > Cr > Zn > Cu > Co, and the highest heavy metal accumulation was found in Ilısu Dam. Seasonal metal accumulation in the sediments was determined as spring in Ilısu Dam, autumn in Hasankeyf, while it was higher in the winter in Batman. It was found that heavy metal accumulation in liver, gill and muscle tissues of C.macrostomum, C. regium and C. trutta samples caught in different regions varies depending on the localities and in general heavy metal accumulation in Ilısu Dam samples was higher than that of Hasankeyf and Batman samples, and that in Batman samples was lower than the others. The highest metal accumulation in C. macrostomum, C. regium and C. trutta'da was in metabolically active organs such as liver and gill, while the lowest one was in muscle tissues. When the seasonal variation of the fish samples which we worked was examined, it was determined that in the muscle of C. macrostomum in spring Cr, Cu and Zn showed significant increase in Hasankeyf region, in Batman Dam Fe showed considerable increase in summer as well (p<0,05), but, although average heavy metal concentrations in muscle tissue of Ilısu Dam samples was high in spring, statistically there wasn't any significant difference (p>0,05). When the muscle tissue of C.regium was examined, it was determined that in Ilısu Dam Fe, Co, Ni and Pb and in Hasankeyf Cr, Cu and Zn in spring, in Batman Dam Cr, Ni and Cu accumulation in autumn and winter showed a significant increase (p<0,05). When the seasonal variation of C. trutta was examined, it was recorded that in Ilısu Dam Ni and in Hasankeyf Cr, Mn, Cu, Zn and Cd in spring and summer showed a significant increase, in Batman Dam the heavy metal concenrations (except Cu and Ni) showed an increase in autumn and winter (p<0,05). In conclusion, it can be said that heavy metal accumulation in liver, gill and muscle tissues of C. macrostomum, C. regium and C. trutta, which live in Ilısu Dam Lake Region of Tigris River, consumed as food stuff by the people living there and have an economic importancefor the region is in agreement with the values suggested as acceptable by WHO FAO, EC and Turkish Food Codex proper for human comsumption and has no risk for human.