Biodegradation of micropollutants in Ergene river during a dry season

Abstract

In recent years, there have been an increase in consumption and production of micropollutants, such as surfactants, flame retardants, pharmaceuticals, personal care products, gasoline additives and their degradation products, biocides, pesticides and their degradation products and various endocrine disrupting compounds, which have resulted in their accumulation in influent and treated both groundwaters and surface waters. Yet, their removal efficiency in biological systems is highly unsteady, and it is still unclear how operational and environmental parameters change. Today, Ergene River is one of the most important examples of this phenomena in Turkey. Thus, determining source of micropollutants in Ergene River and their fates is required. In this study, 29 sampling points were determined and about 100 mL of filtered samples were transferred into 250 mL amber glass Erlenmeyer Flasks. Each flask was spiked with acetaminophen at 10 μg/L as a biodegradable reference substrate. Acetaminophen is known as an easily biodegradable compound; therefore, its degradation shows a control of biological activity. Also, same procedure was applied for autoclaved sample as a control flask. All flasks were incubated at room temperature between 20-25oC and agitated at 100 rpm. Micropollutants were monitored for 30 days in the samples taken aseptically from each flask using AB SCIEX QTrap 4500 LC-MSn system. Forty-seven micropollutants such as; oxybenzone, N-benzyldimethylamine, nonylphenol diethoxylate were biodegraded at least in one sampling point and their half-lives and biodegradation rate constants were calculated. On the other hand, 17 micropollutants such as hexa(methoxymethyl)melamine, quinoxyfen were not degraded at none of the sampling points.