The uptake, bioaccumulation, biotransformation, and risks of nanomaterials (NMs) for food crops are still not well understood. Very few NMs and plant species have been studied, mainly at the very early growth stages of the plants. Most of the studies, except one with multiwalled carbon nanotubes performed on the model plant Arabidopsis thaliana and another with ZnO nanoparticles (NPs) on ryegrass, reported the effect of NMs on seed germination or 15-day-old seedlings. Very few references describe the biotransformation of NMs in food crops, and the possible transmission of the NMs to the next generation of plants exposed to NMs is unknown. The possible biomagnification of NPs in the food chain is also unknown.

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Interaction of nanoparticles with edible plants and their possible implications in the food chain

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Assessing the Impact

Magnetic nanoparticles: essential factors for sustainable environmental applications.

Nanotechnology: The new perspective in precision agriculture.

Review on nano zerovalent iron (nZVI): From synthesis to environmental applications

The potential environmental toxicity of zero-valent iron nanoparticles (nZVI) and three types of nanosilver differing in average particle size from 1 to 20 nm was evaluated using seed germination tests with ryegrass, barley, and flax exposed to 0-5000 mg L(-1) nZVI or 0-100 mg L(-1) Ag. For nZVI, germination tests were conducted both in water and in two contrasting soils to test the impact of assumed differences in bioavailability of nanoparticles. Inhibitory effects were observed in aqueous suspensions at 250 mg L(-1) for nZVI and 10 mg L(-1) for Ag. Reduction in shoot growth was a more sensitive endpoint than germination percentage. Complete inhibition of germination was observed at 1000-2000 mg L(-1) for nZVI. For Ag, complete inhibition was not achieved. The presence of soil had a modest influence on toxicity, and inhibitory effects were observed at 300 mg nZVI L(-1) water in soil (equivalent to 1000 mg nZVI kg(-1) soil). Complete inhibition was observed at 750 and 1500 mg L(-1) in sandy soil for flax and ryegrass, respectively, while for barley 13% germination still occurred at 1500 mg L(-1) . In clay soil, inhibition was less pronounced. Our results indicate that nZVI at low concentrations can be used without detrimental effects on plants and thus be suitable for combined remediation where plants are involved. Silver nanoparticles inhibited seed germination at lower concentrations, but showed no clear size-dependent effects, and never completely impeded germination. Thus, seed germination tests seem less suited for estimation of environmental impact of

Impact of Fe and Ag nanoparticles on seed germination and differences in bioavailability during exposure in aqueous suspension and soil

Ecotoxicological effects on earthworms of fresh and aged nano-sized zero-valent iron (nZVI) in soil.

DDT degradation efficiency and ecotoxicological effects of two types of nano-sized zero-valent iron (nZVI) in water and soil.

Nanoscale zero-valent iron particles (nZVI), with sizes smaller than 100 nm, are promising for environmental remediation of polluted water, soil and sediments. nZVI particles have high potential for migration in the environment and are likely to interact not only with pollutant chemicals but also with living organisms. For these reasons, an environmental concern is rising with respect to unintended effects that need to be weighed against the benefits of remediation. The nZVI particles have a tendency to release electrons and Fe(2+). The Fe(2+) can convert less reactive hydrogen peroxide to more reactive oxygen species, particularly hydroxyl radicals, via the Fenton reaction. Hydroxyl radicals show strong biochemical activity and can react directly with membrane lipids, proteins and DNA. Reactive oxygen species are normally scavenged by antioxidants and various enzymes; however, elevated concentrations of ROS in microbial cells can result in oxidative stress. Cells under severe oxidative stress show various dysfunctions of membrane lipids, proteins and DNA. This review focuses on the processes resulting in oxidative stress and on up-to-date studies of nZVI-induced intracellular changes leading to such stress in microorganisms.

https://www.jstage.jst.go.jp/article/jsme2/26/4/26_ME11126/_pdf

Yehia S. El-Temsah

Papers

Impact of Fe and Ag nanoparticles on seed germination and differences in bioavailability during exposure in aqueous suspension and soil

Ecotoxicological effects on earthworms of fresh and aged nano-sized zero-valent iron (nZVI) in soil.

DDT degradation efficiency and ecotoxicological effects of two types of nano-sized zero-valent iron (nZVI) in water and soil.

Oxidative Stress Induced in Microorganisms by Zero-valent Iron Nanoparticles

Effects of nano-sized zero-valent iron (nZVI) on DDT degradation in soil and its toxicity to collembola and ostracods.