Emergent Contaminants in Freshwater Ecosystem: A case study from Turkey

The current study evaluated certain emerging contaminants in the Susurluk sub-basin, which is under significant anthropogenic pollution pressure. Polychlorinated Biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorine insecticides, and microplastics were investigated from both surface and sediment samples collected in dry and wet seasons. In the Kocaçay river reaching the Marmara Sea, γ-HCH and β-HCH were detected in the dry season. Dieldrin was also observed in very high concentrations in river sediments during the dry season. Nilüfer stream is a significant waterway close to industrial and urban areas resulting in pollution of high concentrations of PCBs, DDT, and its metabolites. Sediment samples contained higher contaminants: DDT and metabolites in the sediment from almost all stations. According to the Hazard quotient coefficient, all detected pollutants were found to be >1, indicating a high risk in the river system. Fiber was the dominant microplastic. The water quality of Nilüfer Stream was poor/bad in quality both in dry and wet seasons, while Kocaçay River was moderate and poor/bad quality in dry and wet seasons, respectively. The findings of bacterial growth augmented and worsened water quality in the river basin with coliforms dominating, as assessed at the genus/species level and were very abundant.