A tracer study is done using a “conservative” material that passes through the system without significant adsorption or degradation. In most cases we use a lithium chloride salt or fluorescent dye. The presence and concentration of which can be readily measured using accurate lab procedures. Dosing is based upon generating a target initial concentration and them measuring concentrations at sampling points at set times for two theoretical residence times.
The sample data is then plotted to determine:
1. Time at first appearance
2. Peak concentration time
3. Peak concentration magnitude (amount of tracer)
4. Decrease in tracer concentration (time & pattern)