Accumulation and toxicity of metal oxide nanoparticles in a soft-sediment estuarine amphipod

• Published in: Aquatic toxicology Vol. 142-143; pp. 441 - 446
• Main Authors: Hanna, Shannon K., Miller, Robert J., Zhou, Dongxu, Keller, Arturo A., Lenihan, Hunter S.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.10.2013
• Subjects: Amphipoda; Amphipoda - drug effects; Amphipoda - metabolism; Amphipods; Animals; bioassays; Copper; Copper - toxicity; exposure pathways; Geologic Sediments - chemistry; marine sediments; Metal Nanoparticles - analysis; Metal Nanoparticles - toxicity; mortality; Nanomaterials; Nanoparticles; Nickel; Nickel - toxicity; pollutants; Seawater - chemistry; toxicity; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - metabolism; Water Pollutants, Chemical - toxicity; Zinc; zinc oxide; Zinc Oxide - toxicity; Nanoparticles; Nanomaterials; Nickel; Copper; Amphipods; Zinc
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/j.aquatox.2013.09.019

•ZnO nanoparticles dissolve within days while CuO and NiO nanoparticles take months.•ZnO and CuO nanoparticles are toxic to amphipods at similar concentrations.•NiO nanoparticles are not toxic to amphipods up to 2000μgg−1.•Metal concentration in amphipods increased with nanoparticle exposure, making trophic transfer possible.•ZnO toxicity is due mainly to dissolved Zn while CuO toxicity is due to particulate CuO. Estuarine and marine sediments are a probable end point for many engineered nanoparticles (ENPs) due to enhanced aggregation and sedimentation in marine waters, as well as uptake and deposition by suspension-feeding organisms on the seafloor. Benthic infaunal organisms living in sediments encounter relatively high concentrations of pollutants and may also suffer toxic effects of ENPs. We tested whether three heavily used metal oxide ENPs, zinc oxide (ZnO), copper oxide (CuO), and nickel oxide (NiO) were toxic to an estuarine amphipod, Leptocheirus plumulosus. We used results from 10-day laboratory bioassays to estimate potential demographic impacts of ENP exposure. We also evaluated fate and transport pathways of the ENPs in the experiments to elucidate routes of uptake and exposure. Dissolved Zn was found in sediment pore water and overlying water samples at 10 fold the concentrations of Cu or Ni, a pattern indicative of the relatively high dissolution rate of ZnO ENPs compared with CuO and NiO ENPs. Accumulation of metals in amphipod tissues increased with exposure concentrations for all three ENPs, suggesting possible exposure pathways to higher taxa. Amphipods accumulated ≤600μg Zn and Cug−1 and 1000μgNig−1. Amphipod mortality increased with ZnO and CuO concentrations, but showed no significant increase with NiO to concentrations as high as 2000μgg−1. The median lethal concentration in sediment (LC50) of ZnO was 763μgg−1 and 868μgg−1 for CuO ENPs. Our results indicate that ZnO and CuO ENPs, but not NiO ENPs, are toxic to L. plumulosus and that ZnO toxicity primarily results from Zn ion exposure while CuO toxicity is due to nanoparticle exposure.