Assessment of heavy metal pollution in Heshkaro stream of Duhok city, Iraq

Heavy metals pose serious risks on human health, environment and aquatic systems. They are taken into human body through ingestion, water consumption, inhalation and skin absorption. The occurrence of heavy metals in aquatic systems can last for long time and can be a real source of risk to human health. Since Iraqi government has long been under political and internal conflicts, clashes and even wars, they were not able to deal with environmental issues for a long time. Thus, the present study was conducted to assess the heavy metal pollution of Heshkaro stream in Duhok city of Northern Iraq and the impacts of various urban and industrial activities on the stream water quality. Water samples were taken from six different locations along the Heshkaro River starting from the beginning of Duhok city and extending until Mosul Lake. Samplings were performed between February and August 2017. Heavy metal (Al, Cr, Cu, Fe, Co, Pb, Mn, Ni, Zn and Cd) concentrations were measured spectrometrically. The spatial and temporal variations were also monitored for all sampling sites and the results were compared with the Iraqi standards set for water quality. The majority of samples tested for Al (0.062-1.2 mg/L), Cr (0.0-0.173 mg/L), Mn (0.011-0.253 mg/L) and in a less degree Pb (0.0-0.0274 mg/L) were above the Iraqi standards for almost throughout the entire study period. Most of the samples tested for Fe (0.0032-2.2 mg/L), Ni (0.0-0.14 mg/L), Zn (0.051-0.92 mg/L), Cu (0.0-0.06 mg/L), Co (0.00002-0.00233 mg/L) and Cd (0.0-0.0064 mg/L) were within the acceptable ranges in almost all sites. Among all sampling sites, Site 6, which was taken from Mosul Lake, had the highest water quality as compared to Iraqi standards. (C) 2019 Elsevier Ltd. All rights reserved.