Quality assurance/Quality control (

Quality assurance/Quality control (QA/QC) Approaches and procedures employed to ensure accurate and reliable results from environmental studies. A QA/QC plan includes field and laboratory protocols for sample collection and handling, and blanks, duplicates, and split samples in the laboratory.
Raoult's Law States that the vapor pressure of a solvent above a solution is equal to the product of the mole fraction of a solvent in the solution and the vapor pressure of the pure solvent.
Rate constant Proportionality constant for the rate of a chemical reaction.
Reactivity Hazardous property of a chemical owing to the chemical's high likelihood to react chemically with other substances in the environment.
Receptor (1) Person, organism, or material that is exposed to a contaminant. (2) Location on a cell wall or within a cell that binds to a chemical.
Receptor model Models used to determine pollutant sources (usually air pollution) that are based upon measurements of tracers taken in the ambient environment. Contrast with dispersion model.
Recharge Water that is added to an aquifer,- e.g., when rainfall percolates into the ground.
Reclaimed wastewater Treated wastewater used for beneficial purposes, such as irrigating certain plant life.
Record of Decision (ROD) Document that contains the selected remedial action to be taken at a site, based upon the results of the remedial investigation/ feasibility study.
Recycled water Water used more than once before returning to a hydrologic system.
Glossary of