Effects of Microplastics on Aquatic Animals: A Case Study on Daphnia

Plastic is one of the most significant technological products of the twentieth century. Its environmental impact includes the release and accumulation of toxins and contaminants, as well as endocrine disruption in aquatic organisms. Microplastics, in particular, are increasingly present in freshwater ecosystems; however, their specific effects on small aquatic organisms, such as Daphnia, remain poorly understood. In this study, various types of virgin plastics (HDPE, LDPE, LLDPE, PA6, PA6.6, PVC (rigid and flexible), PP, PS, TPU) were obtained from Hi-Tech Polymer Products in Ludhiana. These plastics were ground into small particles and measured using a micrometer, yielding a mean particle size of 0.398 µm. The chemical structures of the microplastics were identified using FTIR spectroscopy. The Daphnia culture was maintained in 1000 ml glass beakers. Microplastic particles and small elongated fibres, approximately 300 µm in size, were introduced into the aquatic environment to evaluate ingestion and toxicity. The findings revealed that Daphnia ingested long synthetic fibres and that exposure to microplastics negatively affected their normal biological functions. Mortality increased with both exposure time and microplastic concentration. This study contributes to the understanding of microplastic toxicity in freshwater ecosystems and emphasizes the vulnerability of Daphnia to plastic pollution.