Understanding the microplastic pollution impact on Chironomus sancticaroli larvae development and emergence

Abstract

Plastic materials are increasingly present in our lives. It is estimated that more than 360 million tonnes of plastics are produced annually worldwide. Particularly, single-use plastics represent an important segment in plastic production. In this context, plastic contamination, and consequently microplastic release, has become a growing concern for aquatic ecosystems. In this study, we investigated the effects of exposure to polyethylene terephthalate (PET) microplastics (<32 μm) on Chironomus sancticaroli larvae. The larvae were exposed to different concentrations of PET particles (0 (control group), 500, and 5,000 particles.kg−1 of dry sediment) for 10 days. Our results demonstrated that C. sancticaroli larvae displayed PET microplastics in their digestive tracts, and the ingestion increased with increasing PET concentrations. Plastic particles in the digestive tract can reduce the energy obtained by larvae feeding and, consequently, impair their development. The adult emergence rate displayed a significant decrease observed at the highest PET concentration compared with the control group. These findings reinforce existing concerns that microplastics, at concentrations currently found in the natural freshwater environments, can impact the development of benthic macroinvertebrates and, consequently, result in an unbalance in the freshwater ecosystems.