Decoding QAQC For Water Quality Monitoring


Erik Host-Steen, product manager for the Hydrolab product line at Hach Company, explains Quality Assurance and Quality Control.

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The following is an excerpt from a Q&A with Water Online Radio. Click on the Radio Player above to hear the full interview.

Water Online Radio: What we are here to talk about today is the QAQC. What the heck is that?

Erik: It is a good question. QAQC stands for Quality Assurance and Quality Control, and, generally, it is a set of processes and procedures that are used to maximize the quality of water data, in this case, over time.

Quality assurance refers to planned and systematic processes that provide confidence in a measurement process’ ability to achieve its intended outcome. And then quality control activities, such as test and inspection, aim to find defects and specific elements of the measurement process.

What's neat is that QAQC is something that is not only found in water quality monitoring, but in many processes in everyday live. So for products sold by weight or volume, the devices that are used to measure these products have been tested and validated on a regular basis, for example.

When you go to have your gas tank filled at a filling station, those pumps need to be validated by government agencies to deliver the correct volume of fuel. And, similarly, grocers use certified scales to weight meat or fish that is sold by mass.

Probably the most intriguing aspect is that obtaining the absolute value or true value for any water quality measurement really isn't even possible. So a robust QAQC program is really critical to judge the quality of a measurement.

Water Online Radio: That last statement you made is a little bit disconcerting. Basically, what I am hearing you say is that getting an exact measurement is something that cannot be done?

Erik: That's true. With one fine example, the only measurement that you can make in life that is truly 100% percent accurate is a count. So if I were to say, how many table pencils are there on this table in front of us? You may be able to count physically three. And that is 100% sure, but anything that is not a count, has errors associated with the estimate.

Water Online Radio: Erik, if an individual wanted to begin implementing QAQC as part of their monitoring program, where do they start?