Assessment of microplastic accumulation in aquatic insects of different feeding guilds collected from wastewater in Sohag Governorate, Egypt

Context Microplastic (MP) contamination is a strong candidate to be one of the most important environmental problems worldwide. Microplastics have been detected in many freshwater organisms because of increasing plastic contamination within aquatic ecosystems. However, the correlation between MPs in organisms and their surrounding environments still needs further study. Aim This is the first study assessing the accumulation of MPs in aquatic fauna from water and sediment by bioaccumulation equations in one of the wastewater basins in Sohag Governorate, Egypt. Methods Four common freshwater insect families representing different feeding guilds were employed to detect MP contamination. Key results The collector–gatherers (Chironomidae and Hydrophilidae) recorded the highest MP load per gram wet weight, the highest bioaccumulation factor (BCF), and the biota-sediment accumulation factor (BSAF), whereas predators (Aeshnidae) recorded the lowest values. In both sediment and water, polyester fibres were the most common type of MP, followed by fragments (polyethylene and polypropylene). However, only polyester fibres were found in the different insect taxa. The blue colour was the predominant colour in the water, sediment and insect fauna. The mean length of fibres in the different insects was a little smaller than those in the surrounding environment. Conclusion The present study suggests that MP ingestion by aquatic insects is not necessarily associated with environmental pollution levels, because other factors such as feeding strategies and habitats may play an important role in MP ingestion. Implications The presence of MPs in the insects (lower trophic levels) gives a possibility of inter trophic-level transfer through predation. As a result, higher trophic-level studies in different feeding groups should be conducted to detect the potential risk of MPs on different freshwater fauna.