title: A novel approach reveals that zinc oxide nanoparticles are bioavailable and toxic after dietary exposures.
abstract: If engineered nanomaterials are released into the environment, some are likely to end up associated with the food of animals due to aggregation and sorption processes. However, few studies have considered dietary exposure of nanomaterials. Here we show that zinc (Zn) from isotopically modified (67)ZnO particles is efficiently assimilated by freshwater snails when ingested with food. The (67)Zn from nano-sized (67)ZnO appears as bioavailable as (67)Zn internalized by diatoms. Apparent agglomeration of the zinc oxide (ZnO) particles did not reduce bioavailability, nor preclude toxicity. In the diet, ZnO nanoparticles damage digestion: snails ate less, defecated less and inefficiently processed the ingested food when exposed to high concentrations of ZnO. It was not clear whether the toxicity was due to the high Zn dose achieved with nanoparticles or to the ZnO nanoparticles themselves. Further study of exposure from nanoparticles in food would greatly benefit assessment of ecological and human health risks.
authors.affiliation: U.S. Geological Survey, Menlo Park, California 94025, USA. mcroteau@usgs.gov
authors.forename: Marie-Noële
authors.initials: MN
authors.lastname: Croteau
authors.forename: Agnieszka D
authors.initials: AD
authors.lastname: Dybowska
authors.forename: Samuel N
authors.initials: SN
authors.lastname: Luoma
authors.forename: Eugenia
authors.initials: E
authors.lastname: Valsami-Jones
mesh_terms: D000818:Animals; D004032:Diet; D023381:Endpoint Determination; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis* / Q000706:statistics & numerical data; D004785:Environmental Pollutants / Q000378:metabolism* / Q000633:toxicity; D005504:Food Analysis; D008195:Lymnaea / Q000187:drug effects / Q000378:metabolism; D053768:Metal Nanoparticles / Q000633:toxicity*; D015032:Zinc / Q000378:metabolism* / Q000633:toxicity
chemical_list: D004785:Environmental Pollutants; D015032:Zinc