Multi-level ecotoxicity assay on the aquatic midge, Chironomus tentans (Diptera, Chironomidae) exposed to octachlorostyrene

Octachlorostyrene (OCS) is a ubiquitously distributed compound, of which, ecotoxicological property is little known. To investigate the ecotoxicity of OCS, short- and long-term experiments were conducted under controlled laboratory conditions, using the aquatic midge, Chironomus tentans, as a biological model system. Ecophysiological responses using organism/population level endpoints, such as growth, reproduction and development, were investigated. Moreover, oxidative stress-related parameters and the expression of heat shock protein and hemoglobin gene were also investigated as potential biomarkers for OCS exposure. Significant disturbance in male/female adult ratio and on oviposition by chronic exposure to OCS suggests that this compound may have serious consequences on Chironomus population by affecting reproduction. To elucidate the mechanism of these speculated phenomena, direct experimental demonstrations on the relationships between observed ecotoxicological response and upstream-induced molecular/biochemical events may be needed.