Microplastic Occurrence and Distribution in the Water, Sediment and Fish of the Pra Estuary, Ghana

Abstract

ABSTRACT The study investigated the occurrence and distribution of microplastics in the water, sediment and fishes from the Pra estuary. Samples were collected using a manta trawl and Ekman grab within sixteen sampling points of 1km apart. Microplastics (MPs) were categorized into shapes, colour, size and polymer types using a stereomicroscope and ATR-FTIR spectrometer. A total of 12 species, Gobionellus occidentalis, Ethmalosa fimbriata, Chrysichthys nigrodigitalus, Elops lacerta, Mugil bananesis, Cynoglossus senegalensis, Galeoides decadactylus, Sarotherodon melanotheron, Apsilus fuscus, Pseudotolithus senegalensis Callinectis aminicola, and Penaeus penaeus were identified to accumulate microplastics. Occurrence of MPs in the gastrointestinal tract exceeded that of the gills. Microplastics were present in the vesical tissues of all the shellfishes sampled. The overall mean (± s.d) density of microplastics in the surface water and sediment were 196,259.84 ± 60168.72 items.km-2 and 116.44 ± 11.31 items.kg-1d.w respectively. The occurrence of microplastics was significantly higher at S-N (a tributary passing the Anlo community) along the Pra estuary. Temporally, microplastic abundance was observed to increase during the early raining season (April) compared to the other months. Further, the flow velocity had a significant influence on microplastic distribution in the water column. Transparent and black fibres, less than 0.5 mm were found to dominate the surface water, sediment and fish. Polyethylene and Polypropylene were found to be the most occurring polymer type in the Pra estuary. Hence, there is the need for proper plastic waste management strategies to reduce the amount of plastics waste entering into the aquatic environment