The macro-debris pollution in the shorelines of Lake Tana: First report on abundance, assessment, constituents, and potential sources

Highlights: • The shore of Lake Tana was polluted with different types of solid waste. • Overpopulated and tourist-based areas of shorelines were the most polluted region. • Plastics were found as the most abundant type of macro-debris. • PE, PET, and HDPE were the most frequent plastic polymer types. • Improper disposal of land-based wastes by shoreline users is the main sources. Macro-debris monitoring in the shores of freshwater systems is critical to estimate the macro-and micro-plastic pollution levels for the subsequent investigation of ecological pollution. The study aims to report the composition of macro debris and their distribution on the shore of Lake Tana, Ethiopia, as a first baseline document. The distribution of litter surveys was conducted at seven different town/village shorelines of Lake Tana. The debris was categorized, and its constituent, abundance, and accumulation rates were computed. The findings showed that the mean accumulation rates of Lake Tana debris ranged between 4.9 ± 3.9 and 30.5 ± 20.2 items m⁻¹ day⁻¹ in counts and between 0.32 ± 0.21 and 0.04 ± 0.09 ± 0.03 g m⁻¹ day⁻¹ in mean weight. Also, the plastic polymers were identified as PET, PE, and HDPE. The litter categories abundance is different in different sampling locations. Plastics as packaging materials were extensively distributed in surveyed areas. A significant quantity of litter are local products and a locally feasible solid waste management system can be used to eradicate outflow into Lake Tana and can reduce pollution.