BENTHIC MACROINVERTEBRATE ASSEMBLAGES AND SEDIMENT TOXICITY TESTING IN THE ELY CREEK WATERSHED RESTORATION PROJECT

摘要

The Ely Creek watershed in Lee County, Virginia, contains an abundance ofabandoned mined land (AML) seeps thatcontaminate the majority of the creek and itsconfluence into Big Stone Creek. Contaminatedsediments had high concentrations of iron(approx l0,000 mg/kg), aluminum (approx l,500mg/kg), magnesium (approx 400 mg/kg) andmanganese (approx l50 mg/kg). Copper and zincgenerally ranged from 3 to 20 mg/kg. Benthicmacroinvertebrates surveys at six of 20 sitessampled in the watershed yielded no macroinvertebrates, while eight others hadtotal abundances of 1 to 9 organisms. Fourreference sites contained >= 100 organisms andat least 14 different taxa. Laboratory, l0-day survival/impairment sediments tests withDaphnia magna did not support the field data.Mortality of 92 to 100 percent for D. magnaoccurred in samples collected from six sites.Daphnid reproduction was more sensitive thinlaboratory test organism survivorship;however, neither daphnid survivorship norreproduction were good predictors of taxarichness. Laboratory test concerns includedthe use of a reference diluent water rather thin site specific diluent water.