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Which laboratories can be used for the testing?

Please refer to our website for a list of ZDHC Accepted Laboratories for testing in accordance with the ZDHC Wastewater Guidelines: link.

How can I become a ZDHC accepted laboratory for the purpose of testing wastewater?

If you want to be registered as a ZDHC accepted laboratory, please contact ZDHC directly via the ZDHC website.

Can my laboratory apply to become ZDHC accepted for testing wastewater or ZDHC MRSL conformance, even if it cannot test 100% of MRSL or WWG parameters in-house?

Yes, because not all parameters need to be tested in-house. If you cannot test for a certain parameter, you can still apply to become a ZDHC Accepted Laboratory, as long as testing for that parameter is sub-contracted to an ISO Certified Laboratory that meets ZDHC standards.

How are Method Detection Limit (MDL) and Reporting Limit (RL) related?

The Method Detection Limit (MDL) is used to determine the Reporting Limit (RL). The RL should be 5-10 times higher than the MDL. This incorporates a safety factor which compensates for the varying sensitivity of equipment. The Reporting Limit (RL) is the value a laboratory should use in reports such as ClearStream Reports to indicate their Non Detected (ND) level.

What is the difference between Method Detection Limit (MDL) and Reporting Limit (RL)?

MDL – the Method Detection Limit is the concentration at which there is 99% confidence that a compound can be detected in a method blank sample. In other words – the value that can be detected on the day a MDL determination is made, which overcomes the background noise of the method used, and the sensitivity of the detector. A MDL determination is required for each instrument at every lab. Typically, the MDL is determined once a year.

RL – the Reporting Limit is 5-10 times higher than the MDL. This “safety factor” is applied to the MDL to compensate for varying “noise levels” of the method used and the varying sensitivity of detectors. In other words - it is likely that the MDL will not be the same on two different days. Therefore, the laboratory applies a safety factor to the MDL, based on their best judgement. This ensures that on any day, a Non Detected (ND) reported result is absolutely below the RL value.

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