Toxicokinetics and Particle Number-Based Trophic Transfer of a Metallic Nanoparticle Mixture in a Terrestrial Food Chain

Abstract

Herein, we investigated to which extent metallic nanoparticles (MNPs) affect the trophic transfer of other coexisting MNPs from lettuce to terrestrial snails and the associated tissue-specific distribution using toxicokinetic (TK) modeling and single-particle inductively coupled plasma mass spectrometry. During a period of 22 days, snails were fed with lettuce leaves that were root exposed to AgNO 3 (0.05 mg/L), AgNPs (0.75 mg/L), TiO 2 NPs (200 mg/L), and a mixture of AgNPs and TiO 2 NPs (equivalent doses as for single NPs). The uptake rate constants (k u ) were 0.08 and 0.11 kg leaves/kg snail/d for Ag and 1.63 and 1.79 kg leaves/kg snail/d for Ti in snails fed with NPs single-and mixture-exposed lettuce, respectively. The elimination rate constants (k e ) of Ag in snails exposed to single AgNPs and mixed AgNPs were comparable to the corresponding k u , while the k e for Ti were lower than the corresponding k u . As a result, single TiO 2 NP treatments as well as exposure to mixtures containing TiO 2 NPs induced significant biomagnification from lettuce to snails with kinetic trophic transfer factors (TTF k ) of 7.99 and 6.46. The TTF k of Ag in the single AgNPs treatment (1.15 kg leaves/kg snail) was significantly greater than the TTF k in the mixture treatment (0.85 kg leaves/kg snail), while the fraction of Ag remaining in the body of snails after AgNPs exposure (36%) was lower than the Ag fraction remaining after mixture exposure (50%). These results indicated that the presence of TiO 2 NPs inhibited the trophic transfer of AgNPs from lettuce to snails but enhanced the retention of AgNPs in snails. Biomagnification of AgNPs from lettuce to snails was observed in an AgNPs single treatment using AgNPs number as the dose metric, which was reflected by the particle number-based TTFs of AgNPs in snails (1.67, i.e., higher than 1). The size distribution of AgNPs was shifted across the lettuce-snail food chain. By making use of particle-specific measurements and fitting TK processes, this research provides important implications for potential risks associated with the trophic transfer of MNP mixtures.

In Vitro Toxicity and Modeling Reveal Nanoplastic Effects on Marine Bivalves

“…The decision to reduce the cell culture time to 4 h, as opposed to maintaining the same duration as the proliferation experiments (120 h), was primarily influenced by the observable decrease in the survival probability and viability of the hemocytes with prolonged coculture time (Figures b and S5c). Our pilot studies, in conjunction with prior research, have consistently recommended that incubation times for freshly isolated hemocytes should not exceed 5 h to ensure result accuracy. , …”

“…Our pilot studies, in conjunction with prior research, have consistently recommended that incubation times for freshly isolated hemocytes should not exceed 5 h to ensure result accuracy. 28,49 Notably, pronounced dark/light spots were evident in the hemocytes exposed to NPs, even at the lowest concentration (Figure 3c). Examination through Confocal Laser Scanning Microscopy (CLSM) and TEM images confirmed that these spots corresponded to agglomerates of NPs (Figures 3d and S 5d).…”