Trophic Transfer and Toxicity of (Mixtures of) Ag and TiO₂ Nanoparticles in the Lettuce–Terrestrial Snail Food Chain

Abstract

The increasing application of biosolids and agrochemicals containing silver nanoparticles (AgNPs) and titanium dioxide nanoparticles (TiO 2 NPs) results in their inevitable accumulation in soil, with unknown implications along terrestrial food chains. Here, the trophic transfer of single NPs and a mixture of AgNPs and TiO 2 NPs from lettuce to snails and their associated impacts on snails were investigated. Both AgNPs and TiO 2 NPs were transferred from lettuce to snails with trophic transfer factors (defined as the ratio of the Ag/Ti concentration in snail tissues to the Ag/Ti concentration in lettuce leaves) of 0.2–1.1 for Ag and 3.8–47 for Ti. Moreover, the majority of Ag captured by snails in the AgNP-containing treatments was excreted via feces, whereas more than 70% of Ti was distributed in the digestive gland of snails in the TiO 2 NP-containing treatments. Additionally, AgNP-containing treatments significantly inhibited the activity of snails, while TiO 2 NP-containing treatments significantly reduced feces excretion of snails. Furthermore, the concurrent application of AgNPs and TiO 2 NPs did not affect the biomagnification and distribution patterns of Ag and Ti in snails, whereas their co-existence exhibited more severe inhibition of the growth and activity of snails than in the case of applying AgNPs or TiO 2 NPs alone. This highlights the possibility of nanoparticle transfer to organisms of higher trophic levels via food chains and the associated risks to ecosystem health.

Biological effects of AgNPs on crop plants: environmental implications and agricultural applications

“…22 Previous reports have shown that Ag can accumulate in edible tissues of leafy vegetables either via root exposure or foliar exposure. For example, Wu et al 32 reported that Ag can be taken up by hydroponically cultivated lettuce ( L. sativa L.). By using inductively coupled plasma-mass spectrometry (ICP-MS), Ag (1 mg kg −1 ) was detected in the leaves of lettuce exposed to 0.75 mg L −1 AgNPs, which can be further transferred to lettuce's consumer snails.…”

TiO2 Nanoparticles and Their Effects on Eukaryotic Cells: A Double-Edged Sword

“…The environmental impact of this nanoparticulate metal oxide should not be underestimated, not only because it can have an adverse effect on single organisms and their ecosystem functioning, but also because its potential bioaccumulation, biomagnification and transfer through the food chain may very well, in the end, impact multiple species [ 20 , 66 , 68 , 69 ]. The complex interconnectivity between different trophic levels within and, indeed, between different ecosystems means that next to none are immune to TiO 2 contamination.…”

“…The impact of TiO 2 is not limited only to aquatic vegetation and its toxic effects have also been explored in terrestrial plants, where accumulation/uptake appears to occur via their root system in a concentration dependent manner [ 13 , 69 , 92 ]. Although detrimental effects of TiO 2 should always be of concern (e.g., [ 73 ]), it is apparent that TiO 2 can induce some changes that could be considered beneficial, such as an increase in chlorophyll content and connected plant weight/growth, at least at lower concentrations [ 13 , 14 , 15 , 16 , 105 ], which is particularly interesting in agriculture.…”

Effects of Trophic Level and Land Use on the Variation of Animal Antibiotic Resistome in the Soil Food Web

“…27 In soil ecosystems, animals form a complex food web through predator−prey relationships. 28 Many contaminants (e.g., heavy metals 29 and nanoparticles 30 ) have been found to transmit through the soil food chain and affect the health of organisms at high trophic levels. In terms of ARGs, microcosm experiments have shown that ARGs from pig manure can be transmitted through the food chain into the microbiomes of high-trophic animals.…”