Trophic transfer of nanomaterials and their effects on high-trophic-level predators

Nanotechnology offers great opportunities for numerous sectors in society. One important challenge in sustainable nanotechnology is the potential of trophic transfer of nanomaterials (NMs), which may lead to unintentional impacts on environmental and human health. Here, we highlight the key advances that have been made in recent 15 years with respect to trophic transfer of heterogeneous NMs, including metal-based NMs, carbon-based NMs and nanoplastics, across various aquatic and terrestrial food chains. Particle number-based trophic transfer factors (TTFs), rather than the variable mass-based TTFs, capture the particle-specific transfer, for which NMs exhibit dynamic and complex biotransformation (e.g., dissolution, sulfidation, reduction, and corona formation). Trophic transfer of NMs has toxicological significance to predators at molecular (e.g., increased oxidative stress and modified metabolites), physiological (e.g., feeding inhibition) and population (e.g., reproduction inhibition) levels. However, linking NM exposure and toxicity remains a challenge, partly due to the dynamic biotransformation along the food chain. Although NMs have been used to increase crop yield in agriculture, they can exert detrimental impacts on crop yield and modify crop quality, depending on NMs type, exposure dose, and crop species, with unknown consequences to human health via crop consumption. Given this information, we describe the challenges and opportunities in understanding the significance of NMs trophic transfer to develop more sustainable, effective and safer nanotechnology.