Identification and Quantification of a Wide Variety of Inorganic Nanoparticles in Municipal Wastewater

Abstract

Increasing use of inorganic nanoparticles in consumer products and industrial processes has resulted in greater presence of these nanoparticles in wastewater, and it is important to understand the occurrence and characteristics of this material in wastewater. The objectives of this research were to further develop and improve techniques to identify, quantify, and characterize these inorganic nanoparticles, and investigate their presence in wastewater from a large community with diverse wastewater sources. Single-particle inductively coupled plasma mass spectrometry (spICP-MS) was utilized, along with other nanoparticle characterization techniques. Wastewater samples were collected over monthly time intervals from a local wastewater treatment facility. Extraction and concentration protocols were developed to prepare samples for analysis using ICP-MS, scanning electron microscopy (SEM), dynamic light scattering (DLS), and atomic force microscopy (AFM). Results indicated the presence of detectable quantities of a wide range of inorganic nanoparticles in wastewater samples, with significant variability over time. As treated municipal wastewater is frequently discharged to the environment, the findings of this research are of importance to those determining environmental impacts.