Biotic and Abiotic Interactions in Freshwater Mesocosms Determine Fate and Toxicity of CuO Nanoparticles

Abstract

Transformation, dissolution, and sorption of copper oxide nanoparticles (CuO-NP) play an important role in freshwater ecosystems. We present the first mesocosm experiment on the fate of CuO-NP and the dynamics of the zooplankton community over a period of 12 months. Increasingly low (0.08−0.28 mg Cu L −1 ) and high (0.99−2.99 mg Cu L −1 ) concentrations of CuO-NP and CuSO 4 (0.10− 0.34 mg Cu L −1 ) were tested in a multiple dosing scenario. At the high applied concentration (CuO-NP_H) CuO-NP aggregated and sank onto the sediment layer, where we recovered 63% of Cu applied. For the low concentration (CuO-NP_L) only 41% of applied copper could be recovered in the sediment. In the water column, the percentage of initially applied Cu recovered was on average 3-fold higher for CuO-NP_L than for CuO-NP_H. Zooplankton abundance was substantially compromised in the treatments CuSO 4 (p < 0.001) and CuO-NP_L (p < 0.001). Community analysis indicated that Cladocera were most affected (b k = −0.49), followed by Nematocera (b k = −0.32). The abundance of Cladocera over time and of Dixidae in summer was significantly reduced in the treatment CuO-NP_L (p < 0.001; p < 0.05) compared to the Control. Our results indicate a higher potential for negative impacts on the freshwater community when lower concentrations of CuO-NP (<0.1 mg Cu L −1 ) enter the ecosystem.

Remediation of Metal Oxide Nanotoxicity with a Functional Amyloid

“…The identified cell death mechanisms induced by metal oxide nanoparticles are consistent with previous findings, [ 72 , 73 , 74 ] and are associated with microenvironmental changes owing to nanoparticle dissolution. [ 58 , 75 , 76 , 77 ] Therefore, based on the generally well‐established concept of metal‐promoted toxicity of ZnO and CuO nanoparticles, the sequestration of solubilized metal ions could serve as an effective strategy to mitigate the toxicities caused by metal oxide nanoparticles. To confirm this, HUVECs were exposed to increasing concentrations of CuCl 2 (0, 200, and 400 µ m ) and ZnCl 2 (0, 200, 400, and 500 µ m ) in the presence and absence of the bLg amyloid (5 mg mL −1 ), and their cell viabilities (%) were evaluated upon incubation for 24 h (Figures S7 and S8 , Supporting Information).…”