Microscopic characterization of bioaccumulated aluminium nanoparticles in simplified food chain of aquatic ecosystem

In the present context, the bioaccumulation of aluminium nanoparticles (AlNPs) in Elodea canadensis (a perennial aquatic plant), Melanopsis praemorsa (freshwater snail), and cercaria and sporocyst of some molluscs (infected with Cercaria agstaphensis 25 larvae) was studied using light microscope and transmission electron microscope. Further, the bioaccumulation of AlNPs in the simplified food chain components (plant, mollusc, and trematoda) was observed in electronograms using linear scanning of the level of gray intensity (grey value) of unstained ultra-thin sections. Results depicted that AlNPs were accumulated in the cell wall and intercellular spaces of E. canadensis leaf, cytoplasm of M. praemorsa's digestive glands (passing through by microvilli of epithelium cells), and parenchyma (wall tissue) as well as internal organs of the cercaria. In addition, the pathomorphological changes due to AlNPs in plant, mollusk, and parasite were also studied at the histological and ultrastructural level which showed thinning of the tunica propria of the digestive glands, irregularity of digestive glands, and formation of edema. Ultra-thin incisions made from the digestive glands infected with sporocysts containing cercariae showed that AlNPs passed through the wall of the sporocyst (capsule) into the parenchyma of the cercaria (wall tissue), and then accumulated in the internal organs of the cercaria. In a nutshell, this study revealed the adverse effect of AlNPs accumulation in plant, mollusk, and trematoda which emphasized to minimize the leakage of toxic nanoparticles contaminants in freshwater and marine environments.