Trophic Transfer of Au Nanoparticles from Soil along a Simulated Terrestrial Food Chain.

Abstract

To determine if nanoparticles (NPs) could be transferred from soil media to invertebrates and then to secondary consumers, we examined the trophic transfer of Au NPs along a simulated terrestrial food chain. Earthworms (Eisenia fetida) were exposed to Au NPs in artificial soil media and fed to juvenile bullfrogs (Rana catesbeina). Earthworm Au concentrations were continuously monitored so that the cumulative dose to bullfrogs could be accurately estimated throughout the experiment. We exposed a second group of bullfrogs to equivalent doses of Au NPs by oral gavage to compare the bioavailability of NPs through direct exposure to trophic exposure. We observed accumulation of Au in liver, kidney, spleen, muscle, stomach, and intestine in both treatment groups. Tissue concentrations decreased on average of approximately 100-fold with each trophic-step. The total assimilated dose averaged only 0.09% of the administered dose for direct exposure (oral gavage), but 0.12% for the trophic exposure. The results suggest that manufactured NPs present in soil may be taken up into food chains and transferred to higher order consumers. They also suggest that Au NPs may be more bioavailable through trophic exposure than direct exposure and that trophic transfer may influence the biodistribution of particles once absorbed.

Bioavailability, Toxicity, and Fate of Manufactured Nanomaterials in Terrestrial Ecosystems

“…Bioaccumulation efficiency (bioaccumulation factor ¼ 0.16) was much lower for dietary consumption of surface-contaminated plant material than for consumption of plant material within which MNMs had been accumulated via root uptake. Similarly, Unrine et al (2012) investigated trophic transfer of tannic acid Au MNMs from earthworms to bullfrogs and compared transfer efficiency of this pathway with direct gut gavage exposure in the presence of control worms. As was the case with the hornworms, bioaccumulation efficiency in the bullfrogs was higher via ingestion of the earthworms than by gut gavage.…”

Toxicity-based toxicokinetic/toxicodynamic assessment of bioaccumulation and nanotoxicity of zerovalent iron nanoparticles in <em>Caenorhabditis elegans</em>

“…[60][61][62][63] However, several NPs with conflicting results have been reported to have no biomagnification effects in food chains. [64][65][66][67] Tangaa et al 68 and Unrine et al 69 suggested that the discrepancies among BMFs could be due to both abiotic (eg, environmental parameters) and biotic (eg, organism physiology and life-history traits, foodweb structure, and analyses of whole-body vs single-organ concentration) that affect the efficiency of trophic transfer.…”

Review of Applications and Environmental Fate of Gold Nanoparticles

“…GNP transfer in the terrestrial trophic chain from tobacco (Nicotiana Tabacum L. cv Xanthi) to the tobacco hornworm Manduca sexta was studied and biomagnification was noted [48]. Likewise, GNP transfer and accumulation in the terrestrial trophic chain from the earthworm Eisenia fetida to the bullfrog Rana catesbeina was also studied and noted similar results of biomagnification along with accumulation in liver, kidney, spleen, muscle, stomach and intestines [49].…”