Microplastic pollution of the Amansea axis of Ezu River with emphasis on its spatial concentrations within the aquatic ecosystem

Abstract

Microplastic pollution is adversely impacting the Amansea section of Ezu River in Anambra State, adversely affecting local aquatic life. This study examined microplastic pollution in the Amansea section of Ezu River, Anambra State. Water and fish samples (Xenomystus nigri, Malapterurus electricus, and Pelteobagrus fulvidraco) were collected from three sections of the river: upstream, midstream, and downstream. The physicochemical parameters of water: temperature, pH, TDS, EC, DO, alkalinity, and TSS, were measured using standard water analysis techniques, while microplastics were extracted and identified using Fourier transform infrared spectroscopy (FTIR). Statistical analysis revealed the highest microplastic levels at the upstream section of Ezu River (0.23 ± 0.12), with lower levels at the midstream and downstream sections (0.14 ± 0.16). The fish X. nigri had the highest microplastic load in gills (0.53 ± 0.08) and tissues (0.7 ± 0.04). Different microplastic types prevailed across locations and fish species: upstream water and M. electricus gills contained mostly polyvinyl alcohol, X. nigri gills predominantly had alginic acid sodium salt powder, and P. fulvidraco gills and fish tissues featured polyvinyl alcohol and polyacrylamide carboxyl, respectively. Neoprene was notably present in X. nigri tissues. Fish samples (0.41 ± 0.19) were more polluted than water samples (0.17 ± 0.15). These findings highlight the presence of microplastic pollutants in the Ezu River and its potential impact on aquatic organisms. Hence, implementing strict regulations on plastic waste management, raising public awareness, and promoting sustainable practices, continued monitoring and research are recommended as essential and effective mitigation measures.