Environmental monitoring and assessment program: Current status of Virginian Province (US) estuaries

Monitoring of indicators of the ecological condition of bays, tidal rivers, and estuaries within the Virginian Biogeographic Province (Cape God, Massa chusetts to Cape Henry, Virginia) was conducted annually by the U.S. EPA's Environmental Monitoring and Assessment Program (EMAP) during the summer mo nths of 1990 to 1993. Data were collected at 425 probability-based stations within the Province. Indicators monitored included water quality (temperat ure, salinity, water clarity, and dissolved oxygen concentration), sediment contamination, sediment toxicity, benthic community structure, fish commun ity structure, and fish gross external pathology. Data were used to estimat e the current status of the ecological condition of Virginian Province estu arine resources, and provide a baseline for identifying possible future cha nges. Estimates, with 95% confidence limits, of the areal extent of impacte d resources within the Province are provided. Data are also presented by es tuarine class (large estuaries, small estuarine systems, and large tidal ri vers). Results show that, overall, approximately half of the estuarine wate rs of the Virginian Province can be classified as impacted based on multipl e indicators, with hypoxia being the major stressor.