Head capsule observations in chironomid larvae and contaminant levels in a moderately contaminated small karstic stream, Jura Mountains, eastern France

Specifically, mouthparts deformities in chironomid larvae are considered as indicators of environmental stress (e.g. caused by water pollution). In this study, a total of 50 chironomid larvae from a small karstic stream were examined for cephalic/mouthpart deformities.

Five years earlier, toxicological analysis were performed on stream sediment and bryophyta and revealed a significative pollution (trace metals, pesticides and as well organic contamination). The highest contaminant concentration was 59 (+/- 11.8) mg/kg for Zn in bryophyta and 960 µg/kg for fluoranthene in sediment. According SEQ-Eau (French System of Evaluating Water Quality), this pollution is sufficient to cause adverse effects on aquatic biota.