Reference Sediment Selection in the Lower Mississippi Delta

摘要

Floodplain deposition has been a critical part in the evolution of Arkansas' Delta ecoregion, and because of its high potential for such events, this region is highly enriched and extremely fertile. Historically, water quality in the area has been the subject of scientific study, and as a result little has been published on the effects of underlying sediment with associated benthic communities. Sediment analysis is critical to many of the ongoing aquatic studies because of its significance as both a habitat for benthic organisms and a sink for contaminants. Seven rivers and one creek within the Delta ecoregion were examined for water chemistry, sediment characterization, and sediment toxicity to determine survival and growth of Chironomus tentans. Greatest midge growth occurred in sediment collected from Black River site A; additionally, those sediments were high in silt content ( > 80%) and supported high midge survival. The results of combined characterization and biological test methods indicated that the Black River (site A) was the sediment that met criteria set by the researchers and was suitable to use as a reference control sediment for future Delta toxicity testing.