Occurrence Of Microplastics In Water, Sediment, Cultured And Wild Fish In The Lower Volta Basin Of Ghana

Abstract

Despite the recent surge in microplastic research in Ghana, there is limited information on MPs in the Lower Volta Basin- an important freshwater resource that provides fish for human consumption. This study aims to fill in knowledge gaps by providing baseline information on MPs sampled from cultured and wild fish species, river water and sediment from Asikuma Labolabo, Kpong, and Sogakope Agodormi along the Lower Volta Basin, during the wet and dry seasons. The fish species analysed included Oreochromis niloticus from aquaculture farms and 12 local species- Chrysichthys nigrodigitatus, Chrysicthys auratus, Tilapia guineensis, Tilapia zilli, Mormyrus spp, Synodontis vellifer, Synodontis schall, Parachanna obscura, Auchenoglanis occidentalis, Brycinus brevis and Malapterurus electricus sampled from the wild. The overall percentage abundance of MPs in both cultured and wild sites, for both seasons, was highest in Asikuma Labolabo (47 %), followed by Kpong (33 %), and Sogakope Agodormi (20 %); there were significant differences in MP abundance obtained from the three sampling sites/locations (p < 0.05). The total microplastic concentration obtained in fish [wet =1586 MP items/fish, dry = 1114 MP items/fish] in the wet season was higher than for the dry season. Mean microplastic concentrations was higher in sediment (97.50 ± 78.78 MP items/g sediment) in comparison to water (11.10 ± 10.61 MP items/L water). All three different brands of fish feed used at various aquaculture farms, for fish production, recorded mean levels of MPs (Afeed = 25.00 + 13.57 items/g, Bfeed = 15.67 ± 6.15 items/g, and Cfeed = 6.67 ± 3.85 items/g). Within the matrices of the Lower Volta Basin, fibres were the dominant MP type identified.