The South Florida Water Management District, the U.S. Environmental Protection Agency, and the USGS South Florida Ecosystems Initiative have organized an intensive study of surface water chemistry in Southern Florida. In 1994, several onsite-research locations were selected in the Water Conservation Areas of the South Florida Water Management District in conjunction with this multidisciplinary, multiagency research project. Surface water and marsh porewater water samples were collected and analyzed. Details of the onsite and laboratory procedures used in this investigation are described in other reports ( Aiken, 1992 ; Fishman and Friedman, 1985 ; Garbarino and Taylor, 1979 and 1980 ; Reddy and others, 1989 ; Skougstad and others, 1979 ; Wood, 1976 ). Sample preparation, analytical procedures, and laboratory quality-control protocols used by the U.S. Geological Survey laboratory are described by Cotlove and others (1958) , Fishman and Friedman (1985) , Garbarino and Taylor (1979; 1980) and Schroder and others (1980) . Field procedures and equipment were adapted from a trace metal protocol developmed by the U.S. Geological Survey National Research Program ( Taylor and others 1995 ).
This work has been done as part of the U.S. Geological Survey South Florida Ecosystems Initiative and was funded in part by the U.S. Environmental Protection Agency (through Grant IAG #DW14936802-01-0). The purpose of this report is to make available to the South Florida Ecosystem Research Community the results of our investigation of DOC concentration, nature, and distribution in a prompt and widely available manner. Further additions will be made to the data file as sample collection continues, and as laboratory analyses are completed.
The data file contains sample description, DOC concentration, and specific UV absorbance. Additional analytical data for samples collected at several sites in the Water Conservation Areas, the Everglades, South Florida, intended to be used by this project for chemical species modeling, are included.