Risk assessment of potential toxicity induced by bio and synthetic plastic microspheres in Lates calcarifer

Abstract

Plastic pollution is a serious issue in the aquatic environments. This concerning issue of negative impacts of synthetic plastic debris particles in the aquatic ecosystem give rise to the bioplastic materials. These bioplastics are synthesized from biological organisms, retaining same structural and functional ability as synthetic plastics. However, their degradability and toxicity in natural environment is still unknown. So, in this study we have focused on to elucidate the toxicity caused by Bacillus subtilis synthesized biopolymer - polyhydroxybutyrate (PHB) microspheres and compare their effects with synthetic plastic. The effect of Synthetic plastic (Polystyrene microspheres) and bioplastic (PHB microspheres) were studied on acute exposure to in-vitro and in-vivo model of Lates calcarifer. PHB microspheres were characterized and confirmed using Flurospectrophotometer, Fourier-Transform infrared spectroscopy (FTIR), Particle size analyzer (PSA), Zeta potential and Scanning electron Microscope (SEM). Histopathology assessment for in-vivo model and MTT assay for in-vitro model were performed. The results of fish exposed to 0.5 μg/ml and 1 μg/ml of both microspheres have shown significant necrosis and alteration in muscle, gill and heart tissues. The increased cytotoxicity observed in spleen cell line of Lates calcarifer on exposure to 0.5 μg and 1 μg of both microspheres. Bioplastics are needs specific times for degradation into the aquatic environment. In these results suggest, that even bioplastic have the risk of inducing toxicity similar to the synthetic plastic.

Keywords: Cytotoxicity; Histopathology; Microplastics; Polyhydroxybutyrate; Polystyrene.