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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Ecotoxicology
MACROINVERTEBRATE BIOASSESSMENT OF A PENNSYLVANIA LIMESTONE STREAM INFLUENCED BY AN INDUSTRIAL DISCHARGE.
R.A. Connelly1, T.J. Layfield1, and S.Z. Tritsch2. 1EA Engineering, Science and Technology, Inc., Sparks, Maryland 21152, 2USFilter, State College, Pennsylvania 16801
The objective of this study was to compare the biological condition of the benthic community downstream of the confluence of a large limestone spring and an industrial discharge to determine if differences exist between the downstream spring creek stations and the reference stations. The principal contaminant of concern was lead, which was present in high levels in the sediment, but low levels in the water column. Kick net samples were collected from an upstream spring creek reference station, two nearby spring creek reference stations, and from stations downstream of the discharge. Seven metrics were selected which were considered to be most sensitive to changes in limestone macroinvertebrate communities based on studies in Pennsylvania. The results indicated that the upstream spring creek reference and the nearby reference stream stations were not suitable reference sites due to low scores, so the conclusions were based on a reference condition approach for Pennsylvania limestone streams. The station just downstream of the confluence of the spring creek and the industrial discharge was classified as moderately impaired and the upstream spring creek station was classified as severely impaired. The predominance of metal tolerant fauna below the discharge, specifically orthoclad midges, indicated a possible connection with the high lead levels in the sediment.
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