Toxicity and Accumulation of Cu and ZnO Nanoparticles in Daphnia magna

Abstract

There is increasing recognition that the wide use of nanoparticles, such as Cu (CuNPs) and ZnO nanoparticles (ZnONPs), may pose risks to the environment. Currently there is insufficient insight in the contribution of metal-based nanoparticles and their dissolved ions to the overall toxicity and accumulation. To fill in this gap, we combined the fate assessment of CuNPs and ZnONPs in aquatic test media with the assessment of toxicity and accumulation of ions and particles present in the suspensions. It was found that at the LC50 level of Daphnia magna exposed to the nanoparticle suspensions, the relative contributions of ions released from CuNPs and ZnONPs to toxicity were around 26% and 31%, respectively, indicating that particles rather than the dissolved ions were the major source of toxicity. It was additionally found that at the low exposure concentrations of CuNPs and ZnONPs (below 0.05 and 0.5 mg/L, respectively) the dissolved ions were predominantly accumulated, whereas at the high exposure concentrations (above 0.1 mg/L and 1 mg/L, respectively), particles rather than the released ions played a dominant role in the accumulation process. Our results thus suggest that consideration on the contribution of dissolved ions to nanoparticle toxicity needs to be interpreted with care.

Thermal evolution offsets the elevated toxicity of a contaminant under warming: A resurrection study in Daphnia magna

“…Whether the nanoparticles or the dissolved ions are responsible for the toxicity depends on the concentration of the nanoparticle suspensions. In our experiment, the exposure concentration was very low and the toxic effects under lower concentrations are commonly attributed to the dissolved ions (Li, Lin, & Zhu, 2013; Mos et al., 2017), and this was explicitly demonstrated by Xiao, Vijver, Chen, and Peijnenburg (2015). Also, the small difference in temperature (4°C) has been shown to have limited influence on dissolution rates of nZnO (Mos et al., 2017).…”

Rethinking Stability of Silver Sulfide Nanoparticles (Ag2S-NPs) in the Aquatic Environment: Photoinduced Transformation of Ag2S-NPs in the Presence of Fe(III)

“…18 In brief, at each time interval (0, 4,8,18,28,48,72, and 96 h), 4 mL of aqueous sample was taken from each quartz glass bottle. Every 4 mL of solution was then divided into two subsamples: one group of subsamples (1 mL) was characterized by DLS and TEM or HRTEM−EDX.…”

Evaluation of nano-specific toxicity of zinc oxide, copper oxide, and silver nanoparticles through toxic ratio

“…Cytotoxicity contributed from released ions and particle parts was calculated employing the following equation Eq. 2, as descried before (Wang et al 2012a;Xiao et al 2015):…”

“…The nanotoxicological responses of metal (oxide) NPs have been associated with many toxic mechanisms (Bondarenko et al 2013;Golbamaki et al 2015;Magdolenova et al 2014;Wang et al 2012b), e.g., ROS, cell membrane permeability, DNA damage, and mechanical damage. Overall, toxic effects are derived from particles, metallic ions, or both (Bondarenko et al 2013;Magdolenova et al 2014;Wang et al 2012a;Xiao et al 2015).…”

“…For example, the OECD Working Party on Manufactured Nanomaterials (WPMN) was established to promote international cooperation in guiding the human health and environmental safety aspects of manufactured nanomaterials. A number of OECD test guidelines traditionally used for non-nano chemicals have been used to assess the risks of NMs (Heinlaan et al 2008;Xiao et al 2015). These methods provide valuable NMs hazard and toxicity data.…”