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Microbial enzyme activities (MEA’s) are measurements of microbial metabolism. These activities are dependent on the need for nutrients and respiration. This extended study evaluated four streams in the same watershed that had an approved fecal coliform Total Maximum Daily Load. Sediment and water samples were collected monthly for the first year of each specific stream study, and then quarterly to the end of 2006. Dehydrogenase, a measure of microbial respiration, along with acid phosphatase, alkaline phosphatase, galactosidase and glucosidase activities were measured using colorimetric assays. Biochemical oxygen demand (BOD) was determined using the standard 5-day test (BOD5). Nitrate and phosphate concentrations were measured using colorimetric procedures. Sediment MEA values were compared to the BOD, nitrate concentration and phosphate concentration in the overlying water. Seasonal means of each parameter were not significantly different (p5, nitrate concentration, and phosphate concentration). This suggests to us that MEA’s may be an alternative tool for water quality assessments.

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This document was originally published by the ETSU College of Public Health.