The trophic transfer of engineered nanoparticles from soil through terrestrial food chains is being evaluated. Cerium oxide and lanthanum oxide bulk and nanoparticles (NP) were added to soil (0-1000 mg/kg) with zucchini or lettuce plants, respectively. Additionally, studies have been initiated in which lettuce was added to soil 0 or 70 d after amendment with copper oxide NP, bulk particles or ions (0-400 mg/kg). The plant Ce, La and Cu accumulation was determined by ICP-MS and leaves were fed to crickets or darkling beetles for 14 days. Crickets were then fed to secondary consumers; wolf spiders, mantids or lizards for 7 or 14 days. The Ce, La and Cu accumulation in the primary/secondary consumers and cricket/lizard feces were also measured. Results from the Ce experiment showed that zucchini Ce content was significantly greater with the NP exposure. The flowers, leaves, stems, and roots of bulk-exposed plants contained 93.3, 707, 331, and 119,000 ng/g, respectively; nanoceria-exposed plants contained 153, 1510, 479 and 567,000 ng/g, respectively.  Crickets fed bulk and NP-exposed leaves contained 15 and 34 ng/g, respectively. Spiders consuming bulk-exposed crickets had non-detectable Ce but NP-fed spiders contained Ce at 4.9 ng/g. Upon lanthanum exposure, lettuce mass was reduced across all treatments but there was no difference in lettuce, cricket, or mantid La content based on particle size. Although the CuO experiment is ongoing, preliminary results from pigment content/production showed no significant effects in lettuce from the two soils (0 or 70-d weathered Cu) upon Cu exposure. Interestingly, expression levels of several target genes involved in Cu transport suggest that the mechanisms involved in CuO NPs accumulation are differentially regulated as compared to ionic Cu.  Additional results focused on accumulation of Cu in plant, crickets and lizard tissues will also be presented.<br/>

Trophic transfer of engineered nanoparticles in terrestrial food chains

251st National Meeting (2016)

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