Quantity and quality of surfactants in sediment of Tigris River, Baghdad, Iraq

Detergents (surfactants) are one of the environmental risks that cause adverse effects on aquatic ecosystems. Due to less attention on their effects in Iraqi aquatic ecosystems, concentrations of surfactants in sediment were determined to assess their potential risks in Tigris River. Four sites were selected to collect sediment samples from February 2017 to February 2018. Anionic (AS) and nonionic surfactants (NS) were extracted from sediment by ultrasonic device and their concentrations were measured by using colorimetric determination Photo lab S12 and high-performance liquid chromatography. In addition, multiple physicochemical parameters were also measured. Results showed that both AS and NS were detectable in all sites for all months with slight variations, suggesting high washing activities that release directly to the river, causing surfactants to adsorb and accumulate in the sediment for a long time before degradation by microbial communities. High NS concentrations were recorded in the dry season for May 2017 at Al-Dora Bridge, suggesting that the NS, especially their degradation products (nonylphenol), were widespread pollutants compared with AS in the dry season. We recommend that these compounds must be monitored and further investigated in order to determine their effects on fish and other aquatic organisms.