Acute and chronic exposure to diesel exhaust particles impairs the survival and development of the freshwater midge Chironomus riparius

Diesel-powered vehicles contribute significantly to pollution through emission of fine particulate matter in the form of diesel exhaust particles (DEP). Significant amounts of DEP are introduced into freshwater bodies via road runoff after precipitation. These particles ultimately sink to the bottom of lakes and rivers and interact with macrobenthic invertebrates through ingestion or contact with the organisms' body surface, possibly leading to adverse effects. To date, little is known about whether DEP can have negative effects on benthic invertebrate species. We therefore exposed individuals of Chironomus riparius, a representative of the most abundant macroinvertebrate group and link in freshwater food webs, to DEP and examined their effects after acute, semi-chronic, and life-cycle exposure. DEP significantly affected the development and growth after sublethal 10-day exposure. The emergence ratio, development, and oviposition behaviour of C. riparius were significantly impaired after exposure to environmentally relevant DEP concentrations over a life cycle. We determined an LC₅₀ of 85.3 mg/l for C. riparius exposed to DEP after 48 h. These results provide insight into how DEP may contribute to biodiversity and biomass loss in freshwater habitats acting as an additional stressor to drivers such as habitat loss and climate change. SYNOPSIS: The effects of diesel exhaust particles (DEP) on aquatic invertebrates are mostly unknown. This study reports acute and chronic negative effects of DEP on the survival and development of Chironomus riparius.