Anthropogenic Release and Distribution of Titanium Dioxide Particles in a River Downstream of a Nanomaterial Manufacturer Industrial Site

Danielle L Slomberg,Andrea Campos,Olivier Aguerre-Chariol,Bernard Angeletti,Daniel Borschneck,Mélanie Auffan,Jérôme Rose,Nelly Guéniche

doi:10.3389/fenvs.2020.00076

Abstract

Several industries manufacture and process large quantities of engineered nanomaterials, thus increasing the potential for their environmental release during waste management and disposal. Herein, we quantified the release and spatial distribution of titanium dioxide nanomaterials (TiO2 NMs) emitted from an industrial waste stream that flows into a nearby river. Two sampling campaigns were carried out on the river in fall 2017 and spring 2018 at selected sites upstream and downstream of the Industrial Effluent and an urban wastewater treatment plant (WWTP). Significant Ti accumulation was detected in the sediments at the Industrial Effluent and WWTP sites for both fall and spring samples, with measured Ti concentrations of 75–193 mg Ti/kg reaching 21–55× that of the local background upstream. X-ray diffraction analysis confirmed the anatase and rutile mineralogy of the inputs. River surface waters were filtered on-site to distinguish between particulate (>0.20 μm), colloidal (0.02–0.20 μm), and dissolved and/or small nanoparticulate (NP) ( 0.20 μm), and that the particles sediment rapidly near the emission source and accumulate in the sediment.

Highlights

As advances in nanotechnology research and development continue, engineered nanomaterials are being increasingly manufactured for incorporation into consumer products destined for cosmetic, textile, coating, and plastic applications (Piccinno et al, 2012; Vance et al, 2015)
When the river water Ca2+ concentration was increased to 3 mM, the decrease in TiO2 NM homo-aggregate size was no longer observed in the presence of Suwannee River fulvic acid (SRFA) and the addition of illite resulted in hetero-aggregation, favoring NM sedimentation
Concentrations of 124.6 ± 12.6 and 75.1 ± 7.9 mg Ti/kg sediment were measured at the Industrial Effluent site, while 144.5 ± 4.6 and 193.6 ± 25.8 mg Ti/kg sediment were detected at the wastewater treatment plant (WWTP) site for October 2017 and March 2018, respectively

Summary

Introduction

As advances in nanotechnology research and development continue, engineered nanomaterials are being increasingly manufactured for incorporation into consumer products destined for cosmetic, textile, coating, and plastic applications (Piccinno et al, 2012; Vance et al, 2015). Besides the physicochemical characteristics of the TiO2 NMs themselves and the pH of the aqueous environment, the presence of dissolved ions, suspended particulate matter (SPM), and natural organic matter (NOM) can significantly influence NM stability through processes such as aggregation and sedimentation or dispersion and transport (Loosli et al, 2013; Labille et al, 2015; Slomberg et al, 2019). The addition of SRFA (5–10 mg/L) slightly enhanced TiO2 NM dispersion and decreased the overall TiO2 aggregate size, and in the presence of illite (25 mg/L) no secondary hetero-aggregation was observed. When the river water Ca2+ concentration was increased to 3 mM, the decrease in TiO2 NM homo-aggregate size was no longer observed in the presence of SRFA and the addition of illite resulted in hetero-aggregation, favoring NM sedimentation

Methods

Results

Conclusion