Nanoplastics: Methods, Exposure and Effects on Domestic, Farm and Wild Animals

Nanoplastics (NPs) are synthetic polymer particles ranging in size from 1 nm to 1 μm that have been identified as a major concern for ecosystems and organisms due to their plethora of negative effects. The aim of this review is to provide a comprehensive overview of the knowledge relating to exposure and effects of NPs in domestic (i.e., farm and companion animals) and wild animals, a topic that is to date, still in its infancy. The exposure routes for these animals are several; from contaminated food and water, inhalation, dermal contact as well as through grooming, and specifically for pets, release from toys/training devices, alongside with the chronic inhalation by living in the same environment as their human owners. Regarding the toxicity, several studies highlighted that in farm animals, NPs can disrupt gut microbiota and intestinal permeability, as well as cause reproductive and neurotoxic effects. Moreover, given the role of farm animals in the food chain sector, the potential accumulation of NPs and their associated chemicals in animal tissues poses a significant threat to food safety. Aquatic and terrestrial wildlife (both invertebrates and vertebrates) experience a broad spectrum of negative effects including oxidative stress, neurotoxicity, immune response deficits, as well as reproductive and behavioral alteration, while up to now no information is available regarding the negative effect on pets. Although the analysis of the current literature demonstrates the undeniable threat posed by NPs, the existing technical limitations in detection indicate that significant knowledge gaps remain. Methodological and technological advancements are therefore necessary to more accurately assess and elucidate the risks NPs pose to these organisms.