Tracer tests are a method commonly used in hydrogeology and environmental science to track the movement of fluids in underground environments such as aquifers or soil. Tracer tests involve introducing a known quantity of a tracer substance into a system and then monitoring its movement through the subsurface. This allows researchers to determine parameters such as flow rates, transport pathways, and dispersion characteristics of the fluid being studied. Tracer tests can be used to evaluate the efficiency of remediation techniques, understand groundwater flow patterns, and assess the impact of contaminants on water sources. Different types of tracers, such as dyes, isotopes, or fluorescent compounds, can be used depending on the specific research objectives. Overall, tracer tests are a valuable tool for studying and managing subsurface fluid movement in a variety of environmental and geologic settings.