Analysis of macro-and microplastics in the water, soil/sediment in riverine, riverbanks and irrigated farms in Arusha Tanzania

Abstract

Microplastics and macroplastics have been reported in different urban rivers and agricultural soil across the globe. However, the interlink between them has not been previously assessed therefore, the present study evaluated the relationship between macro-and microplastics in the water columns and sediments in riverine, riverbanks, and soils from irrigated farms in Arusha, Tanzania. Detached pieces from macroplastics and suspected particles of microplastics from the samples were analyzed using the total attenuated reflectance - Fourier transform Infrared spectroscopy, where statistical analysis showed that the number of microplastics in the sediments was higher than in the water columns and that in irrigated farms than in the riverine by a magnitude of 4. Besides, the numbers of microplastics and macroplastics in the irrigation farms were exponentially-related while the macroplastics from the riverbanks had an inverse relationship with the rivers’ profile elevation. Polyethylene was the dominating macroplastic in the riverbanks and irrigated farms with a 100% frequency of occurrence while polystyrene was abundant in all samples of microplastics. However, the irrigated farms adjacent to canals had a greater number of microplastics and macroplastics. In generally, the findings showed a similar trend of plastic distribution in urban rivers and irrigated farms, suggesting an interaction between them.