Anthropogenic litter pollution in selected African transboundary and Great Rift Valley lakes

Litter pollution is a growing problem affecting almost all the world’s oceans, lakes, and rivers. Comprehensive beach and floating litter surveys were carried out in select African Great Lakes (Lake Victoria and Lake Turkana) and two Great Rift Valley lakes (Lake Naivasha and Lake Baringo) using the standing stock method to determine the abundance, composition, distribution and potential sources of plastic litter. A total of 11,977 macrolitter items were collected, translating to a mean density of 2.890 ± 1.90 items/m². Lake Naivasha had the most polluted beaches with a mean macrolitter density of 3.707 ± 1.975 items/m² followed by Lake Victoria (3.375 ± 1.825 items/m²), Lake Baringo (2.156 ± 1.324 items/m²) and Lake Turkana (1.732 ± 2.276 items/m²). Plastic was the most dominant litter category (2.269 ± 1.503 items/m², 78.9 %), with LDPE being the most abundant type of packaging (69.5 %). Of all the litter items collected, 23.7 % had visible branding. Of the branded items, 97 % originated from local manufacturers, with food product packaging accounting for a majority (71.6 %) of the branded items. The mean density of mesolitter items on beaches was higher in Lake Victoria (53.48 ± 41.32 items/m²) compared to Lake Turkana (7.56 ± 5.85 items/m²) with glass being the most abundant litter category (70.5 %). A total of 125 litter items were retrieved during floating surveys translating to a mean density of 13,041 items/km². The study concludes that litter pollution in these lakes is of local origin and recommends enforcement of extended producer responsibility to prevent litter leakage into the environment.