engleski

Presence of nanoparticles in water and their impact on human health

Discharge of silver nanoparticles (AgNP) from textiles and cosmetics, todays major application areas for metallic AgNP, into wastewater and than into the groundwater is inevitable. Transformation in wastewater treatment plants (WWTPs) will determine the impact of AgNP on aquatic and terrestrial environments. This study aimed to determine the behavior of AgNP in the sludge at the WWTP by adressing the effect of silver nanoparticles with three different capping agents AgNPs on biodegradation of laundry-relevant surfactants by activated sludge microorganisms (ASMs). Prior to the inductively coupled plasma mass spectrometry (ICP-MS) measurements, AgNP suspensions were digested with nitric acid (HNO3) in closed-vessels. Total silver concentrations in AgNPs colloidal suspensions were determined in acidified solutions (10% HNO3) using an Agilent Technologies 7500cx ICP- MS. In order to determine the effect of AgNP on biodegradation of laundry-relevant surfactants sodium dodecyl sulphate (SDS) and dodecylammonium chloride (DDACl), we employed standardized method for water quality HRN-EN- ISO-10707:2000. Additionally, we evaluated the inhibitory effect of AgNPs on the growth of activated sludge microorganisms (ASMs) according to a standardized method for water quality HRN-EN-ISO-15522:1999. The stability of the AgNPs was shown to depend on the charge and concentration of the adsorbed surfactants. Results showed that AgNPs were toxic to ASMs at very high concentration (>50 mg/L). However, biodegradability of SDS, DDACl and commercial laundry detergent were inhibited by more than 5% and 20% in the presence of 0.1 and 1 mg/L AgNP, respectively. It can be concluded that AgNP discharged to the wastewater stream will influence overall biodegradability of organic matter at various degrees in the sewer system. It is important as it may influence the subsequent transport of AgNPs through different chemical transients and thus their potential bioavailability and toxicity.

nanoparticles ; water ; human health

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