Larvae of Hydropsyche angustipennis (Trichoptera, Hydropsychidae) as indicators of stream contamination by heavy metals in Lódz agglomeration.

A biomonitoring technique was employed to assess metal contamination of several degraded urban streams in the Lódz agglomeration. Presence of heavy metals (Zn, Cu, Fe, Cd, Pb, Cr, was determined in whole bodies of Hydropsyche angustipennis larvae. Larvae of H. angustipennis were the only caddisflies living in most of  investigated streams. These metals as well as other environmental variables were investigated in sediments or free waters of urban streams and in a stretch of a similar size of the Grabia River (reference site), outside the city but still in the vicinity of the Lódz agglomeration. The results of our research demonstrated different levels of contamination of urban streams as well as a correlation between environmental and larval tissue concentrations of heavy metals. Significant differences among sites were observed for metal concentrations in H. angustipennis larval bodies and larval responses to metals were time specific. The highest concentration of heavy metals was observed during the spring months. Differences were evident among various heavy metal levels in the bodies of larvae collected from different streams and at different sampling stations in the same stream.

Assessment of water quality in urban streams based on larvae of Hydropsyche angustipennis (Insecta, Trichoptera).

Hydropsyche angustipennis (Insecta, Trichoptera) larvae were used as indicators of stream contamination in the city of Lódz, Poland. The larvae of H. angustipennis were present at 9 sampling sites established for this study. Significant differences between the sampling sites were noted for environmental parameters as well as concentration of chemicals in water and biodiversity of aquatic invertebrates. Statistical analyses showed significant correlations between quantity and quality of water pollutants and density of H. angustipennis larvae, concentration of metals in larval bodies, and the appearance of morphological anomalies in tracheal gills and anal papillae. In comparison to literature data, the level of contaminants in water, including heavy metals, for each of the studied streams of Lódz was surprisingly low while concentration of these metals in the whole bodies of H. angustipennis larvae was very high. Some of the heavy metals present in the water might be identified only after conducting analyses of their concentration in the larval bodies. Therefore, long life cycle of H. angustipennis and heavy metal tolerance with a possibility of their accumulation in the larval bodies may constitute a support to traditional chemical assessment of water quality or traditional biomonitoring.