Chronic toxicity of ZnO nanoparticles, non-nano ZnO and ZnCl2 to Folsomia candida (Collembola) in relation to bioavailability in soil

• Published in: Environmental pollution (1987) 2011-10, Vol.159 (10), p.2713-2719
• Main Authors: Kool, Pauline L., Ortiz, Maria Diez, van Gestel, Cornelis A.M.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Arthropods - drug effects; Bioavailability; Biological and medical sciences; Candida; Chlorides - analysis; Chlorides - toxicity; Chronic toxicity; Collembola; Constants; Ecotoxicology, biological effects of pollution; Folsomia; Folsomia candida; Fundamental and applied biological sciences. Psychology; Insecta; Invertebrates; Metal Nanoparticles - analysis; Metal Nanoparticles - toxicity; Nanoparticles; Particle Size; Pollution abatement; Reproduction - drug effects; Soil; Soil (material); Soil - chemistry; Soil Pollutants - analysis; Soil Pollutants - toxicity; Springtail; Toxicity; Toxicity Tests, Chronic; Zinc; Zinc Compounds - analysis; Zinc Compounds - toxicity; Zinc oxide; Zinc Oxide - analysis; Zinc Oxide - toxicity; Zinc oxide nanoparticles
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2011.05.021

The chronic toxicity of zinc oxide nanoparticles (ZnO-NP) to Folsomia candida was determined in natural soil. To unravel the contribution of particle size and free zinc to NP toxicity, non-nano ZnO and ZnCl2 were also tested. Zinc concentrations in pore water increased with increasing soil concentrations, with Freundlich sorption constants Kf of 61.7, 106 and 96.4 l/kg (n = 1.50, 1.34 and 0.42) for ZnO-NP, non-nano ZnO and ZnCl2 respectively. Survival of F. candida was not affected by ZnO-NP and non-nano ZnO at concentrations up to 6400 mg Zn/kg d.w. Reproduction was dose-dependently reduced with 28-d EC50s of 1964, 1591 and 298 mg Zn/kg d.w. for ZnO-NP, non-nano ZnO and ZnCl2, respectively. The difference in EC50s based on measured pore water concentrations was small (7.94–16.8 mg Zn/l). We conclude that zinc ions released from NP determine the observed toxic effects rather than ZnO particle size. ► ZnO nanoparticles and non-nano ZnO were equally toxic to Folsomia candida in soil. ► Pore water from soil spiked with ZnO nanoparticles showed saturation with zinc suggesting aggregation. ► Pore water based EC50 values for ZnO nanoparticles and ZnCl2 were similar. ► ZnO nanoparticle toxicity in soil was most probably due to Zn dissolution from the nanoparticles. ZnO nanoparticle toxicity to springtails in soil can be explained from Zn dissolution but not from particle size.