Contaminated and Hazardous
Waste Site Management
Quadrature: That part of a periodic signal that is 90 degrees out of phase
with a reference signal. See also In-phase.
Assessment (QS): Those activities which assess the quality of data being gathered
in the site assessment. Examples include: analyzing replicate samples to define
Assurance (QA): Management of the data to ensure it meets the data quality objectives.
This includes steps to control data quality and to assess the data quality. It
commonly includes designing appropriate protocols, ensuring they are carried out,
and independently testing the data quality.
Control: Management of the collection and analysis of data to ensure it meets
the data quality objectives. Activities include following sampling protocols,
and routinely checking calibration of laboratory equipment.
Control Sample: A solution obtained from an outside source having known concentration
values to be used to verify the calibration standards.