Assessing Plastic Pollution in Kenyan Mangroves: Distribution, Sources, and Social Impact in Gazi Bay

The increase in global production of plastics has led to widespread environmental pollution, with mangrove ecosystems becoming significant traps for both macro- and microplastics. This study investigated plastic pollution in the mangrove forest of Gazi Bay, Kenya, focusing on the spatial distribution, types and sources of plastic debris. Macroplastic and large microplastic (LMPs; 1–5 mm) samples were collected from different zones in the mangroves and adjacent beach areas. The average concentration of plastic debris on the forest floor was 0.79 ± 0.35 items m−2, with an additional 0.17 ± 0.04 items tree−1 entangled in the trees. Fishing-related plastics, such as ropes and fishnets, were prevalent in the seaward zones, while domestic waste was more common in the landward zones. LMPs were primarily concentrated in the landward zone and beach areas. Landward transects showed the highest average concentrations (1.25 ± 0.66 LMPs kg−1 dry sand), while the beach zone had the largest proportion of polluted samples, with 25.93% of replicates containing LMPs. A social survey in Gazi village revealed ongoing waste management challenges, with 55% of residents admitting to littering despite Kenya’s 2017 ban to reduce the use of single-use plastics. While the ban has had some positive effects, compliance remains difficult due to economic constraints and limited waste management. Respondents expressed willingness to reduce plastic use, indicating that policy enforcement must be combined with community-driven solutions. The findings emphasise the need for integrated waste management strategies, public engagement and improved infrastructure to mitigate plastic pollution in Kenyan mangrove ecosystems.