Spatial macro-plastics assessments to enhance awareness on microplastics sources, potential exposures in freshwater ecosystems and circularity in sustainable management of plastic pollution

Plastics waste management is a major challenge in the environment, due to its persistence and ease of transportation and transfer into soils, air, waterways, reservoirs, rivers and lakes, where fragmentation into micro and nanoplastics occurs. Again, evidence on the potential uptake and transfer of micro and nano plastics into biological tissues is growing. However, less information and data is documented on the characteristics of plastic litter in the different inland lakes, dams, reservoirs and major rivers within the Lake Victoria basin. A six beaches survey was conducted at pre-selected sites along the shoreline of Lake Victoria (Kenya) to assess the abundances of plastic litter in order to understand level of occurrences, distribution and potential sources. Sampling was conducted at Marenga, Dunga, Litare, Sindo and Sori-Karungu beach sites. The solid wastes were collected by hand-picking, sorted, weighed and categorized as particles/items per area. The total amount of macro-litter items decreased from 1071 (Dunga), 681 (Sori-Karungu), 548 (Usenge), 528 (Sindo), 418 (Marenga) and 414 items (Litare beach) respectively. The residential and landing sites recorded much higher amounts of total macro-litter. The macro-litter density ranged from 72 (Litare market area) to 449 (Dunga landing area) items per 100 m2. Plastic macro-litter was the dominant category in terms composition of the solid wastes. Plastic litter category was significantly associated with paper/cardboard (p < 0.01) and Sub-County population density (p<0.05). Fragments or remains of disused and discarded fishing ropes and nets were identified. The landward areas revealed similar socio-economic activities, mainly dominated by commercial and residential structures, restaurants and open air markets, whereas the lakeward zone was mainly used for boating activities. We recommend extended surveys to cover more beaches and develop suitable methods for inland lakes beach litter monitoring as they differ when compared to long stretches of marine beaches, with significant tidal influences.