Transport, fate and effects of energy-related pollutants: evaluation of surface and groundwaters. Third progress report

Identification of fresh waters throughout the United States which are sensitive to acidification by atmospheric deposition, and documenting the existance of long-term trends in water chemistry at particular sites, requires the establishment of a large data base of select water quality data. The Acidification Chemistry Information Database (ACID) consists of 1.75 x 10/sup 6/ water quality measurements made on 5.75 x 10/sup 5/ dates from 4.15 x 10/sup 4/ water sampling stations. Most of these data come from the EPA STORET system, which emphasizes down-stream sites. However, 157 sources of data not included in STORET have contributed information on sites which, for the most part, are located toward the headwaters. Considerable effort has gone into obtaining complete records for many stations, especially with respect to geographic variables. Work in FY 1982 emphasized acquisition of data, but some preliminary analyses were conducted to identify sites with decreased alkalinity. Applications of equations derived by Henrikson to predict alkalinity on the basis of existing Ca/sup + +/ and Mg/sup + +/ concentrations was found to be inappropriate until such time as edaphic information for each station is included in the database. Trend analyses, however, found 689 stations to have significantly decreasing alkalinity concentrations.more » Those trend stations are listed and mapped on a state-by-state basis. The analysis of trends is still considered to be preliminary as the quality of the specific data sets has not yet been verified. Data from ACID have been provided to 14 individuals contracting with EPA on regional aspects of acid deposition.« less