Testing the bioaccumulation potential of manufactured nanomaterials in the freshwater amphipod Hyalella azteca

Sebastian Kuehr,R Kaegi,D Maletzki,C Schlechtriem

doi:10.1016/j.chemosphere.2020.127961

Abstract

Standardized experimental approaches for the quantification of the bioaccumulation potential of nanomaterials in general and in (benthic) invertebrates in particular are currently lacking. We examined the suitability of the benthic freshwater amphipod Hyalella azteca for the examination of the bioaccumulation potential of nanomaterials. A flow-through test system that allows the generation of bioconcentration and biomagnification factors was applied. The feasibility of the system was confirmed in a 2-lab comparison study. By carrying out bioconcentration and biomagnification studies with gold, titanium dioxide and silver nanoparticles as well as dissolved silver (AgNO3) we were able to assess the bioaccumulation potential of different types of nanomaterials and their exposure pathways. For this, the animals were examined for their total metal body burden using inductively coupled mass spectroscopy (ICP-MS) and for the presence of nanoparticulate burdens using single-particle ICP-MS. The role of released ions was highlighted as being very important for the bioavailability and bioaccumulation of metals from nanoparticles for both examined uptake paths examined (bioconcentration and biomagnification). In 2018 a tiered testing strategy for engineered nanomaterials was proposed by Handy et al. that may allow a waiver of bioaccumulation fish studies using inter alia invertebrates. Data gained in studies carried out with invertebrates like the developed Hyalella azteca test may be included in this proposed tiered testing strategy.

Highlights

Due to the high production volume of NMs, they are subject to bioaccumulation assessment as required by the European Chemicals Registration REACH, the Japanese Chemical Substance Control Act “Kashinho” or others, e.g. the Turkish REACH like law KKDIK (Kaydi, Degerlendirilmesi, I_zni, Kisitlanmasi) (Ministry of Environment and Urbanization MoEU of Turkey, 2017), the High Production Volume Challenge Program of the USA (USEPA, 2014), or Toxic Chemicals Control Act of Korea (Korea Ministry of Government Legislation, 1997)
In this study we investigated the bioaccumulation of different NMs including AgNPs (NM 300 K), titanium dioxide nanoparticles (NM 105; TiO2NPs), and AuNPs in H. azteca following aqueous and dietary exposure
The filter feeding process of the test species only allows the determination of bioaccumulation factors (BAF) values which represent a less specific endpoint that is less accepted from the regulatory point of view compared to the commonly used bioconcentration factor (BCF) values

Summary

Introduction

Nanomaterials (NMs) are present in nearly every sector of the industry and, due to their broad range of properties (Yang et al, 2003; Hainfeld et al, 2006; Maier and Korting, 2005; Martin et al, 2015; Rahman et al, 2011; Rodrigues et al, 2017; DeLoid et al, 2018; Piccinno et al, 2012), can be found in various consumer products such as textiles, medicine, cosmetics, printer toners, car tires and even agri-foods. The BCF is commonly determined by fish-flow-through tests according to OECD test guideline 305 (Organization for Economic Co-operation and Development OECD, 2012). The establishment of suitable experimental conditions for determining the bioaccumulation potential of NMs or NPs is difficult (Aschberger et al, 2011; Hankin et al, 2011). As shown by Zeumer et al (2020), the bioavailability and accumulation of such NPs exposed to fish during a flow-through bioconcentration study according to OECD guideline 305, seem to depend on the bioaccumulation of the released ions rather than on the uptake of the used NPs (Organisation for Economic Cooperation and Development OECD, 2012; Zeumer et al, 2020). Considering the tendency of NMs to aggregate and sediment, benthic organisms may represent a worst case scenario for bioaccumulation testing as compared to fish. A standardized experimental approach to quantify bioaccumulation of NMs in invertebrates in general and benthic species in particular is still missing (Petersen et al, 2019)

Methods

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Discussion

Conclusion