The program PESTAN represents model for evaluating the one-dimensional vertical transport of organic pollutants through homogeneous soil to ground-water. It calculates organic movement based on a linear isotherm (S=K*C), first-order degradation, and longitudinal dispersion. The program requires the following input: solubility, recharge rate, sorption, saturated water content, degradation, characteristic curve coefficient, saturated hydraulic conductivity, bulk density, dispersion coefficient, minimum and maximum depth, and minimum and maximum time. Furthermore, a maximum of 10 applications of the active ingredient can be applied in a single calculation. For each application, the time of application in days prior to recharge (rain) need to be given. The program provides a table of characteristic curve coefficients. Calculated results include projected water content, pore water velocity, pollutant velocity, and length of pollutant slug. Furthermore, the program lists, for a total of 4 time periods and for each of 7 depths, the solution concentration, the solid concentration, and the total concentration.

The public domain PESTAN program is menu-driven; input files are prepared using the DOS text editor. The results are routed to a text file; output is also saved for graphical postprocessing using commercial line graph packages. PESTAN distribution includes source code, runtime version and example problem files. The documentation consists of installation instructions, theory and user's instructions.

SYSTEM REQUIREMENTS

Intel 80i86 based computer, at least 256 Kb free conventional RAM, DOS 3.1 or higher; math coprocessor optional.

Author: C. Enfield, V. Ravi, J. Johnson (USEPA/RSKERL-CSMoS).