Fast Multielement Quantification of Nanoparticles in Wastewater and Sludge Using Single-Particle ICP-MS

Abstract

Quantitatively monitoring the presence of engineered, natural, or incidental nanoparticles (NPs) is essential to understand their potential environmental and ecotoxicological implications. In particular, a significant number of NPs may travel through wastewater treatment plants (WWTPs), as a conduit to their release to the environment, either in treated effluent or in wastewater sludge (biosolids). Here we developed a fast and simple protocol for full quantitative multielement analysis of metallic or metal-containing NPs in wastewater and sludge samples via single-particle ICP-MS. We employed centrifugation to separate NPs from wastewater sludge, with high recoveries (>84%) for Au and Ag NPs, which have rather high densities (19.3 and 10.5 g cm–3, respectively). In wastewater samples, particle mass concentrations ranged from <1 ng/L for Cd-based NPs to almost 100 μg/L for Mg particles. Particles from most elements detected in wastewater were <100 nm in size, although TiO2 in raw wastewater was around 250 nm in size, and Mg was >1500 nm in size, well beyond the nanoscale. The efficiency of removal of NPs throughout the WWTP was significantly dependent on the type of metal-containing particles and the influent concentration.

Incidence of metal-based nanoparticles in the conventional wastewater treatment process

“…NPs extracted from the waste activated sludge and anaerobic sludge using centrifugation (3800 g, 10 min and 20 °C) represent around the 65% of NP present in these matrices based on previous studies ( Huang et al, 2020 ). Moreover, the concentrations in the sludges may not reflect internalized or tightly-adsorbed NPs in the flocs ( Polesel et al, 2018 ;Tuoriniemi et al, 2017 ), which must be considered in our results.…”

“…35) to avoid deposit build-up in the sampler and skimmer cones ( Tuoriniemi et al, 2017 ). Sludge samples were processed to extract metal-containing NPs according to our previous study ( Huang et al, 2020 ). Briefly, samples of waste sludge and anaerobic sludge were ultrasonicated 20 min at 280 W and a frequency of 40 kHz.…”

Influence of wastewater type in the effects caused by titanium dioxide nanoparticles in the removal of macronutrients by activated sludge

“…Water streams have been identi ed as the main transport media of NP S in the environment due to the connection between treated e uents and water bodies (Brar et al 2010;Kunhikrishnan et al 2015). Some studies have reported the presence of TiO 2 NPs in wastewater streams (Kiser et al 2009;Tuoriniemi et al 2012), even in the sludge of the bioreactors applied for wastewater treatment (Polesel et al 2018;Huang et al 2020;Cervantes-Avilés and Keller 2021). Hence, the interaction between these NPs and microorganisms may damage the performance of the wastewater treatment process.…”

Nanosafety: An Evolving Concept to Bring the Safest Possible Nanomaterials to Society and Environment

“…Previous studies stated that the waste treatment of those products containing large amounts of carbon-based nanomaterials could be eliminated during incineration and in the WWTPs, whereas a persistent potential was observed for nanomaterials containing metals and metal oxides [ 260 ]. In addition, some efforts focusing on the detection and characterization of nanomaterials in waste streams have been made [ 261 , 262 ], but more studies are needed to elucidate the potential risk of waste management treatments.…”