We’ve received questions from area residents whose wells have been tested for per- and polyflouroalkyl substances (PFAS) by Rose & Westra/GZA, the Michigan Department of Environmental Quality (MDEQ), and other reputable lab services about how to interpret the results. MDEQ offers a fact sheet on this topic (click here), and we have asked our experts to provide some additional information for you. In this post you’ll find a sample well test report, along with a description of the relevant sections.
The most important information from your water testing report is in the middle section of the well report, and includes the analyte name, results, minimum reporting limit (MRL), and dilution, each of which is explained below.
Analyte Name: lists all of the PFAS compounds that were tested by the lab. The analytical labs use EPA’s modified method (EPA Method 537) to test for PFAS in your water, which provides results for 23 specific PFAS compounds.
The two PFAS compounds you should note are PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid). The results of PFOA and PFOS should be added together and compared to the EPA’s Lifetime Drinking Water Health Advisory Level of 70 ppt (see Result discussion, below).
Due to the pervasiveness of PFAS in a wide-range of manufacturing practices and consumer products, it is not surprising or uncommon to see trace levels of a range of other PFAS compounds in water samples.
Result: is the level of the specific PFAS compound detected in your water, listed in ng/L (which is the same thing as ppt).
PFOA and PFOS results should be added together and compared to EPA’s Drinking Water Lifetime Health Advisory Level of 70 ppt. Combined detections at or below 70 ppt are considered safe by EPA and MDHHS, and this level has a significant “safety buffer” built in, including assuming exposure for an entire lifetime, and that a pregnant or nursing woman could drink over 4 liters of water per day at 70 ppt PFOA/PFOS with no effect on developing babies and infants. For more information, please see our blog post on this topic.
None of the results from other PFAS compounds should be added together or compared to EPA’s Drinking Water Lifetime Health Advisory Level of 70 ppt. This value is only for PFOA and PFOS. In the sample well test report, then, the relevant number is 5.1 ppt of PFOA/PFOS.
ND means that the lab did not detect that PFAS compound in your water.
Additional letters like “U”, “E” or “J” may be present and are called “qualifiers”, which just means that the lab was unable to detect the PFAS, or the level was so low that it had to be estimated.
MRL: stands for Minimum Reporting Limit, which is the lowest level of that PFAS that the lab can reliably detect. These numbers may be different between different labs.
Dil.: stands for dilution. This is additional lab information that records whether the sample had to be diluted in order to reliably detect the PFAS chemical. A “1” means that the lab did not dilute the sample. Any higher number means that the same was diluted. This does NOT have any impact on how you interpret your results. The final result remains the same regardless of whether the sample was diluted or not.
We developed this blog as one way for you to hear directly from us and you’ll be hearing more from us in the coming days and weeks. West Michigan is our home and we’ve always acted responsibly and taken our obligations as part of this community personally – for over a hundred years, Wolverine has been not only a leader and contributor to this community, but we’ve also been your neighbor – that’s why we’ve taken the proactive steps we have so far and why we’re committed to seeing this through to the end. We hope you’ll follow this blog, learn about what we’re doing to make this right, and hear the other side of the story.
We Are Wolverine.