Assessment of water quality in Khreisan River from Baquba city, Diyala (Iraq) by using algae as a Bioindicator

The current study conducted at nine sampling stations across the section of Khreisan River passing through Baquba city which is located in Iraq-Diyala in order to assessment the quality of water at this section of river by using of the most pollution tolerant genera and species for four groups of algae and employing of Palmer’s and Nygaard’s biotic indices as well as analytical of water samples for Dissolved Solids, Suspended Solids and Volatile Solids. The water samples were collected monthly from selected sampling stations for a period of 6 months starting from November 2014 to April 2015. According to Palmer’s biotic indices, Dominance of Chlorella, Scenedesmus, Oscillatoria, Navicula, Nitzschia and Euglena particularly with a total score greater than 20 for algal species Pollution Index at sampling stations (S3 and S1) which are located in Old Baquba's region and sampling station (S7) which is located in Buhriz's region considered to be indicate a confirmed high organic pollution. A probable high organic pollution induced in both of sampling stations (S8, S5 and S6) which are located in Buhriz's region due to frequently of Nitzschiapalea and Oscillatorialimosa and the dominance of Chlamydomonas spp., Navicula spp., which were caused a relatively high total score less than 20 for algal genera Pollution Index. According to Nygaard’s biotic indices, Eutrophic nature indicated from water sampling stations (S3 and S7) which are represented respectively (before river entry in popular Baquba's market and at beginning river entry in popular Buhriz's market), Meso-eutrophic nature indicated from water sampling stations (S1,S4 and S5), while the remaining sampling stations indicated Mesotrophic nature. Meso-eutrophic nature was obtained only by Chlorophycean at water sampling station (S3) and it wasn't recorded by the remaining groups of algae In the current study. Bacillariophycean wasn't recorded Olig-mesotrophic or Ultra-oligotrophic nature at any sampling stations. Chlorophycean wasn't recorded Oligotrophic and Ultra-oligotrophic nature at any sampling stations. Old Baquba's region recorded increase values of Total Volatile Solids (T.V.S.) in water sampling stations (S3) approximately (1.8)% followed by (S1) about (1.7)%, This was associated with decreased values of Total Dissolved Solids (T.D.S.) about (528 and 652) ppm and Total Suspended Solids (T.S.S.) about (114 and 163) ppm at sampling stations respectively (S3 and S1). Buhriz's region recorded increase value of (T.V.S.) in water sampling station (S7) approximately (1.7)% and this was associated with decreased value of (T.D.S.) about (572)ppm and (T.S.S.) about (130) ppm at the same sampling station. Uncoated by concrete and the zigzag path may effect on the flow rate of Khreisan River as well as high population density in some regions which is reflect directly on pollution levels due to decrease of dissolved oxygen and increased sedimentation rates as well as low solubility of pollutants, Perhaps this explains the high levels of organic pollution in those sampling stations across that section of river.