Microplastic pollution has been recognized as a global threat in marine environments and a danger to prey, predators and humans. Yet there have been limited studies in the Western Indian Ocean (WIO) and along the Kenyan coast making it difficult to estimate the extent of such pollution. This is the first study on microplastics (MPs) in the surface waters within creeks (Tudor, Port-Reitz and Mida creeks) in Kenya. Sampling was done in January/ February and September 2018 to collect microplastics from surface water. Neuston nets of 500 μm (large) and 250 μm (medium) size were towed for ten minutes and 50 litres of seawater sieved through a 20 μm net (small) in three replicates. The samples were digested in 10 % Potassium Hydroxide, sieved, and then filtered with cellulose nitrate membrane microfilters. Concentrations of total microplastics, different shapes and colours were established under a microscope. High concentrations of small size (20-250 μm) MPs were encountered and Tudor and Port Reitz had higher concentrations compared to Mida Creek. The study provides data on microplastic concentrations within the creeks and recommends focussing on small size microplastics for monitoring purposes, which due to their high concentrations can be hazardous to organisms.

Whereas the Western Indian Ocean (WIO) has been reported to be polluted with microplastics (MPs). Documented information on the specific polymeric composition of these particles in seawater and sediments along the Kenya coast is insufficient. This study assessed the abundance and types of microplastic polymers in the region. Microplastics were sampled from surface water using 500µm neuston nets and from the sediments using a 3.6 cm-diameter corer. Fourier Transform Infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC) and Nuclear Magnetic Resonance (NMR) were used to identify the MPs polymer types. Four polymer types were identified of which, high-density polyethene was the most abundant at 38.3%, followed by polypropylene (34.6%), low-density polyethene (27.1 %), and medium density polyethene (17.1%). The results demonstrate the extent of exposure to microplastics of the region's ecosystems and provide the impetus for proper policy briefs regarding the management and disposal of plastic waste, protect and save oceans rich in biodiversity for sustainable development.

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