Trophic transfer and transformation of CeO2 nanoparticles along a terrestrial food chain: influence of exposure routes

Research output: Contribution to journalArticle

Authors

  • Yuhui Ma
  • Jie Yang
  • Xiao He
  • Yayun Ding
  • Junzhe Zhang
  • Guohua Wang
  • Changjian Xie
  • Wenhe Luo
  • Jing Zhang
  • Lirong Zheng
  • Zhifang Chai
  • Yuliang Zhao
  • Zhiyong Zhang

Abstract

The trophic transfer and transformation of CeO2 nanoparticles (NPs) through a simulated terrestrial food chain were investigated using a radiotracer technique and X-ray absorption near edge structure (XANES). Radioactive 141CeO2 NPs were applied to head lettuce (Lactuca sativa), treated via root exposure in its potting soil (5.5 or 11 mg/plant) for 30 days or foliar exposure (7.2 mg/plant, with half of the leaves treated and the other half not) for 7 days. Subsequently, two groups of land snails (Achatina fulica) were exposed to 141Ce via either a direct (i.e., feeding on the lettuce leaves with 141Ce-contaminated surfaces) or an indirect/trophic (i.e., feeding on the lettuce leaves with systemically distributed 141Ce) route. To evaluate the influence of exposure routes, the Ce contents of the lettuce, snail tissues, and feces were determined by radioactivity measurements. The results show that both assimilation efficiencies (AEs) and food ingestion rates of Ce are greater for the trophic (indirect) exposure. The low AEs indicate that the CeO2 NPs ingested by snails were mostly excreted subsequently, and those that remained in the body were mainly concentrated in the digestive gland. XANES analysis shows that >85% of Ce was reduced to Ce(III) in the digestive gland under direct exposure, whereas Ce in the rest of the food chain (including feces) was largely in its original oxidized (IV) state. This study suggests that CeO2 NPs present in the environment may be taken up by producers and transferred to consumers along food chains and trophic transfer may affect food safety.

Details

Original languageEnglish
Pages (from-to)7921-7927
Number of pages7
JournalEnvironmental Science & Technology
Volume52
Issue number14
Early online date21 Jun 2018
Publication statusPublished - 17 Jul 2018