Potential use of morphological deformities in Chironomus (Diptera: Chironomidae) as a bioindicator of heavy metals pollution in North-East Algeria

Human activities have led to profound changes in aquatic environments and degradation at several levels. Preserving the quality of aquatic environments, their good functioning, and the species that are dependent on them has become a crucial element. In order to monitor the overall health of aquatic ecosystems, it is necessary to develop early indicators of environmental quality. In this work, we have tried to evaluate whether the analysis of morphological deformities affecting Chironomidae larvae could tell us about the state of degradation of water courses that are subjected to different discharges. To do this, water, sediment, and larvae of Chironomidae were sampled in dry weather in August–September of 2017 at three sites located in the North-East of Algeria. The heavy metals in the three compartments as well as the deformities affecting the mentum and mandibles of Chironomus were analyzed. The results showed a metal contamination especially in sediments; the highest values were found in Meboujda River and Seybouse River. The three sites have high deformities incidences, more than 33%, which suggests the presence of toxic stress. This study reflected the relationship between heavy metal concentrations in water, sediments, and deformities larval mouthparts (mentum and mandibles) in Chironomus. The use of deformities in Chironomus sp. can serve as an effective tool for bioassessment of freshwater ecosystems.