Fate and Transport of Metal-Based Nano-Agriproducts in the Environment

Ekta, . (2022) Fate and Transport of Metal-Based Nano-Agriproducts in the Environment. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Ekta (17RS066)) 17RS066_DES.pdf - Submitted Version Restricted to Repository staff only Download (9MB)

Abstract

Continuously increasing population leads to an exponential increase in the global food demand requiring high crop yield and agricultural security. In this direction, nano-agriproducts (NAPs) show promising results in the laboratory environment ranging from nano pesticides to nano fertilizers. Based on high target efficacy and enhanced crop yield, the scientific community and industries are looking towards their commercialization. These NAPs can be inorganic metal-based nanoparticles (MNPs), organic formulations, emulsions, polymeric nanocarriers, etc. Due to their size in the nano range and high reactivity, their behavior can drastically vary in the natural environment, impacting their target efficacy and leading to long-range transport. Apart from MNPs used as agriproduct, their utilization in various industrial sectors pose a high risk of their release in the soil and aqueous environment. Soils are complex matrices containing clays and organic matter that interact with MNPs and influence their aggregation and subsurface transport. Moreover, wide variations in soil pore water chemistry and physicochemical parameters of different water bodies further decide the stability and transport of MNPs in freshwater and subsurface environment. In addition, MNPs and metal-based nanocarriers can have high interaction with other prevailing and emerging environmental contaminants, impacting their overall reactivity and toxicity. These scientific gaps emphasize the crucial need to develop a deep understanding of the fate and transport of MNPs in complex matrices before their commercialization. The thesis revolves around the discussed scientific gaps and addresses stability, fate, and transport of MNPs in complex soil and aqueous environment, including colloid-aided transport of MNPs and metal nanocarriers interaction with the emerging contaminant, i.e., nanoplastic debris. Concisely the thesis combines five broad objectives to understand the fate of MNPs in the environment. Starting from understanding the aqueous stability of MNPs as a function of interfering ions, carbonates, clays, and dissolved organic matter followed by their interaction and retention behavior in different agricultural soils, i.e., alluvial, black, laterite, and red soils. Further, we move towards understanding the transport of MNPs in saturated porous media under the influence of soil pore water and other varying environmental parameters, including nanoplastic debris as an emerging contaminant. Finally, as the last objective of the work, we explored a new research dimension and looked at the interaction of metal-based nanocarriers with nanoplastic debris. Overall, the present study has compiled the possible fate of MNPs in the aquatic and the terrestrial environment with respect to abiotic environmental components. The study may provide baseline data while preparing the safety protocol for the release of MNPs in the environment.

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