Investigating the Impact of Manufacturing Processes on the Ecotoxicity of Carbon Nanofibers: A Multi–Aquatic Species Comparison

Abstract

Manufactured nanomaterial production is outpacing the ability to investigate environmental hazard using current regulatory paradigms, causing a backlog of materials requiring testing. To ameliorate this issue, regulatory bodies have proposed integrating safety into the production of novel nanomaterials, allowing for hazards to be identified early in development rather than aftermarket release. In addition, there is a growing interest in short‐term ecotoxicity testing to rapidly identify environmental hazards. In this sense, the present study investigated 3 carbon nanofibers (CNFs), created with different production methods, using short‐term in vitro and in vivo exposures on fish cell lines, mussel hemocytes, crustacea, and algae. The present study investigated if differences in ecotoxicity hazard between the CNFs could be identified and, if so, which product could be considered less hazardous. A major challenge in assessing the potential hazards posed by manufactured nanomaterials is standardizing the preparation for testing. Standardized operating protocols have been proposed using protein to facilitate the preparation of stable stock suspension, which is not environmentally representative. As such, the study also assessed the potential impacts these standardized protocols (with or without the use of protein) could have on the interpretation of environmental hazard. The results demonstrated that there were clear differences between the 3 CNFs and that the dispersion protocol influenced the interpretation of hazard, demonstrating a need for caution when interpreting ecotoxicity in a regulatory context. Environ Toxicol Chem 2019;38:2314–2325. © 2019 SETAC.

Applicability of OECD TG 201, 202, 203 for the aquatic toxicity testing and assessment of 2D Graphene material nanoforms to meet regulatory needs

“…Other critical issues that were identified by some of the authors are: (i) graphene material hetero-aggregation with algae and precipitation out of the water column (Marković et al, 2020); (ii) shading effects of the test dispersions on growth and/or nutrient depletion due to adsorption to graphene materials (Malina et al, 2019); and (iii) interferences with fluorescent readouts at high test material concentrations (Barrick et al, 2019;Malina et al, 2019;Marković et al, 2020). These three points are discussed herein.…”

“…32 and 84 mg/L, for -COOH and -NH 2 functionalised G, respectively) (Zhang et al, 2018). The graphene nanofiber tested (GANF®) and nanofibers produced through superheating (GANFg) and a scaled up production process of GANF® (GATam) had EC 50 72h values of 3.09, 8.48, and 2.12 mg/ L, respectively (Barrick et al, 2019). This influence of production process on effects was also evidenced in the case of different production methods used for GO with EC 50 values of 0.5, 14 and 10 mg/L according to the distinct production methods used (Hoffman, Hummers, and Tour, respectively) (Malina et al, 2019).…”

“…Organic acids have been used as natural dispersants to increase the concentration maintenance time of GO dispersions but this also leads to mitigation of toxic effects (Zhao et al, 2019) (EC 50 66.60 to 242.78 mg/L) (Castro et al, 2018). The incorporation of bovine serum albumin (BSA) as a dispersant also appeared to interfere with algal growth (Barrick et al, 2019). Therefore, careful consideration towards the use of dispersants is needed when applying TG 201 to graphene materials.…”

Toxicity of Carbon, Silicon, and Metal-Based Nanoparticles to Sea Urchin Strongylocentrotus intermedius

“…Moreover, it was reported that NPs can enter the environment during their manufacturing, utilization, and disposal [ 16 ]. A large and growing body of literature has investigated the aquatic toxicity of carbon nanotubes [ 17 , 18 ], carbon nanofibers [ 19 ], silicon NPs [ 20 ], and metal-based NPs [ 21 , 22 ] in different model organisms. However, it is still difficult to understand the mechanisms of toxicity and behavior of different types of nanomaterials in aquatic systems.…”

The toxic influence and biodegradation of carbon nanofibers in freshwater invertebrates of the families Gammaridae, Ephemerellidae, and Chironomidae

“…It should be noted that with an increasing annual production of CNFs, the risks of their harmful influence to the environment and human health is rising. Many research works have been devoted to studying of environmental toxicity of different nanomaterials including CNF [ [8] , [9] , [10] , [11] , [12] ]. However, the toxic properties of CNF are still not fully understood.…”