Multispecies toxicity test for silver nanoparticles to derive hazardous concentration based on species sensitivity distribution for the protection of aquatic ecosystems

Abstract

With increasing concerns about the release of silver nanoparticles (AgNPs) into the environment and the risks they pose to ecological and human health, a number of studies of AgNP toxicity to aquatic organisms have been conducted. USEPA and EU JRC have published risk assessment reports for AgNPs. However, most previous studies have focused on the adverse effects of AgNPs on individual species. Hazardous concentration (HC) of AgNPs for protection of aquatic ecosystems that are based on species sensitivity distributions (SSDs) have not yet been derived because sufficient data have not been available. In this study, we conducted multispecies toxicity tests, including acute assays using eight species from five different taxonomic groups (bacteria, algae, flagellates, crustaceans and fish) and chronic assays using six species from four different taxonomic groups (algae, flagellates, crustaceans and fish). Using the results of these assays, we used a SSD approach to derive an AgNP aquatic HC5 (Hazard concentrations at the 5% species) of 0.614 μg/L. To our knowledge, this is the first report of a proposed HC of AgNPs for the protection of aquatic ecosystems that is based on SSDs and uses chronic toxicity data.

The Toxicity of Nonaged and Aged Coated Silver Nanoparticles to Freshwater Alga Raphidocelis subcapitata

“…Silver NPs are used in a wide variety of products including medical and personal care products, food containers, textiles, paints, and disinfectants (Reidy et al 2013;Keller et al 2014;Caballero-Guzman and Nowack 2016;Mackevica et al 2016;McClements and Xiao 2017). Migration of AgNPs from these products into the aquatic environment after use may pose toxicity risks to organisms (Matzke et al 2014;Kwak et al 2016). However, their impacts on ecosystems and human health are not fully evaluated (Kwok et al 2016;Selck et al 2016).…”

The Toxicity of Silver Nanoparticles (AgNPs) to Three Freshwater Invertebrates With Different Life Strategies: Hydra vulgaris, Daphnia carinata, and Paratya australiensis

“…There are several methodologies which are employed by regulatory bodies in different countries to derive HC 5 values and we chose the species sensitivity distribution (SSD) approach. Since we only had acute toxicity test results, the USEPA protocol was adopted since it supports using acute toxicity values (Kwak et al, 2016). To predict more accurate HC 5 values, toxicity values of sufficient species should be available representing a comprehensive ecosystem.…”

“…Besides, there is no commensurate investment in environmental safety research while we invest heavily in the development of new nanotechnologies (Miller and Wickson, 2015). There are several known and unknown hurdles in evaluating the toxicity of NPs (Fabrega et al, 2011;Kumar et al, 2017) and the reported recommendation values for the protection of aquatic species in the literature vary greatly (USEPA, 1985(USEPA, , 2012Fabrega et al, 2011;Gubbins et al, 2011;CCME, 2015;Kwak et al, 2016). Multispecies toxicity studies which include different trophic levels or species with different life strategies are scarce.…”

“…Multispecies toxicity studies which include different trophic levels or species with different life strategies are scarce. Previous studies using more than one species showed that the toxicity of both Ag + ions and AgNPs significantly differed based on the test species (Ribeiro et al, 2014;Kwak et al, 2016). Therefore, it is important to develop a species sensitivity distribution (SSD) which can be used to estimate the potentially affected fraction of species and to set up threshold concentrations (Garner et al, 2015;Belanger et al, 2017).…”

“…Several studies have focused on deriving hazardous concentration values based on SSD Adam et al, 2015;Garner et al, 2015;Nam et al, 2015). Kwak et al (2016) and Chen et al (2018) have studied SSDs of AgNPs and suggested hazardous concentration values (HC 5 ) in the range of 1.1-31.73 µg L −1 at which 95% of species are not harmed in the aquatic environments. The objectives of the present study were to examine the toxicity of organic (tyrosine)-coated AgNPs (tyr-AgNP) and Ag + ions to three freshwater invertebrates at different trophic levels: the cnidarian Hydra vulgaris, the daphnid Daphnia carinata, and the freshwater shrimp Paratya australiensis and to compare species sensitivity and the influence of culture media on the toxicity of AgNPs.…”