Assessment of some heavy metals in water and sediments using bio-concentration method of al-ma’ail river in al-kahla’a district, maysan, southern iraq

Abstract

Al-Ma'ail river is one of the small Iraqi rivers, as it extends over a distance of approximately 47 km. Al-Ma'ail river is located next to Halfaya oil field, which is the main source of pollution to Al-Ma’ail river, consequently, the environmental quality of Al-Ma'ail river is under great pressure from a variety of human activities. Although water is commonly used as an indicator of contamination by heavy metals, sediments are considered as water important in assessing the environmental situation. In this study, water and sediment samples were analyzed to assess the pollution status of heavy metals in Al-Ma'ail river, with the aim of determining its ability to sustain aquatic life. Samples were taken from five sites along Al-Ma'ail river between the branch area of Al-Ma'ail river from the Al-Kahla river (which also branches from Tigris River upon its exit from Amara City), until Al-Ma'ail river reaches pond of Umm Al-Na'aj (marshland). Ten Water and five sediment samples were collected in August 2020. Samples were analyzed for eight heavy metals: As, Cd, Cr, Cu, Pb, V, Ni and Zn, using AAS techniques. As for the water samples, all the concentrations were over the standards (except Zn which was within the limits in all samples), While Cu concentration in (samples SW1 to SW7) are within the standards (except SW8 and SW9 are close U.S.EPA and within WHO). Concentrations of heavy metals in sediments were over the limits in all samples. The bio-concentration values of heavy metals were calculated and all metal rates were found within the acceptable range for the U.S. EPA, except for vanadium, which was higher than the permissible limit and was a bio-accumulative and considered as an indicator of oil pollution. The results indicate the presence of long-term contamination of the eight selected heavy metals in the river sediments which may be of concern to the health of the aquatic ecosystem.