Threats of Nano-material Contamination in Agroecosystem: What We Know and What We Need to Know

Abstract

The use of nanomaterials has integrated in day to day human life. The application of nanomaterials is widespread in the range of sectors. Nanomaterials possess peculiar physical, chemical and biological properties in contrast to macro- and micro-particles of the same precursor material primarily due to their unique nanoscale dimensions. Nanomaterials are naturally present in the environment but can also be incidental and engineered for specific purposes. With their sub-micron size, they can free float in the air and may easily penetrate the animal or plant cells with potential to cause range of unidentified effects. The lesser known and many unknown potential hazards raised the concerns regarding nanomaterials and flagged them as “emerging contaminants”. In agriculture, nanomaterials can be used as nano-pesticides, nano-fertilizers, nano-fungicides or as catalytic substances for plant germination and plant growth. They can also be used as biomarkers/sensors for plant pathogen detection. Toxic effects to the components of agro-ecosystem, including plants and soil microbes, have been documented with nanomaterials used in agriculture. However, the studies of the systemic effects of altered reactivity of nanomaterials on plants, humans and microbes are still in infancy. Cellular DNA damage, biochemical dysfunction, heavy metal release from metallic nanomaterials, generation of reactive oxygen species etc. are some of the reported toxicities associated with the use of nanomaterials. The present chapter deals with the various sources and routes of introduction of exposure to nanomaterials into agro-ecosystem, their fate and potential bearings to environment and human health in near future. Numerous factors, such as plant species, growth conditions, physico-chemical properties of nanomaterials, abiotic and biotic conditions are the elements which decide the interactions and fate of nanomaterials in agro-ecosystem. Furthermore, use of non-biodegradable inorganic chemicals like metals, ceramic, silica, metal oxides etc., is also a matter of grave concern. The nanomaterials induced adverse impacts on plants, animal and human lives are being unraveled and yet to be explored in full. Distinction between natural and engineered nanoparticles is the foremost challenge for the detection of nanomaterials in the environment. The end recipient, duration of activity in the environment, reactions with target and non-target entities, are some of the pressing concerns associated with the use of nanomaterials. Intense research efforts are required to address crucial issues associated with nanomaterials, for example; toxicity levels compared to their microsized counterparts or their transformation in the environment, to unveil their ultimate fate in ecosystem which may help in devise interventional management plans.