Detection and Chemical Composition of Polysynthetic Plastic Materials Along the Coastline of Zanzibar, Tanzania

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The State University of Zanzibar



Polysynthentic polymers (plastics) pollutants are of growing global concern due to its detection and accumulation in diversified ecological systems. In particular, the anthropogenic contamination through persistent forms of microplastics poses unforeseeable risks for aquatic environments such as oceans, lakes and rivers. This study aimed to assess the status (distribution and chemical composition) of microplastics particles around the beach sediment in coastal systems of Zanzibar. The sample collection was conducted between February 2016 and July 2016 along the coastline of Zanzibar Island. The study used volume reduced sampling method for collected samples. The study also applied both field and laboratory techniques to identify and quantify microplastic along the Zanzibar coasts. Specifically, the study analyzed abundance, distribution (spatial and temporal), size, shape, colour and chemical composition. The microplastics were extracted from sediment by density separation, morphology of micro particles categorized through visual inspection under stereoscopic and dissecting microscope. The identification was done by Fourier-Transform Infrared-Spectroscopy (4500 Series Portable FTIR). Automatic surface chemical mapping and reference to an infrared library data base was used to identify the compositional spectra of plastics particles. Results of this study revealed that microplastics were widely distributed along the coasts with a total abundance composed of 34.36±4.6 particles/kg. Higher concentrations founded in West region during the wet season. A total of nine polymer types were identified from the sediments i.e polypropylene (PP), polyvinyl chloride (PVC), polyester (PES), polyethylene terephthalate (PET), polystyrene(PS), polyethylene(PE), acrylnitrile butadiene-styrene (ABS), low density polyethylene (LDPE) and cellulose. The mostabundant (>50%) found polysynthetic materials were polypropylene and polyvinylchloride whilst the dominant (~53.8%) size range was between 1 - 5mm. The possible main sources of the identified polymers were from thermoplastic products like fishing gears, plastic bottles, food containers, textiles, pipes, bags, and cigarette butt. The results provide current status and baseline data of polysynthetic polymers in marine and coastal environments of Zanzibar, which support management strategies of plastics debris in the ecosystems and allied resources.


Current status and chemical composition of microplastics particles around the beach sediment in coastal area of Zanzibar, Amount of microplastics in intertidal sandy beaches environments.