Even though GAC filters may seem inferior, a recent study (published in 2020) by Duke University found that cheap GAC dual-stage POU filters may be more effective at removing PFAS from residential water. Dual-stage filters and RO were able to remove, on average, more than 90% of PFAS from POU, while other GAC filters were less effective and had varied results.

The previously mentioned systems may not always remove all PFAS from water. In order to eliminate PFAS from a household’s water supply, a custom, comprehensive system of filters is required. The NHDES says that a water system containing the following has “proven to be effective at removing PFAS to non-detectable levels in New Hampshire and other New England states.”:

• Five-micron particulate filter for pre-filtering;
• Two GAC treatment vessels (two cubic feet each) in series with a test port installed after the lead treatment unit (the exact size and number of carbon vessels required depends on flow rate and flow volume associated with the home);
• Five-micron particulate filter for post-filtering;
• Totalizer meter;
• Ultra-violet treatment system and associated controllers if untreated water from the well exhibits bacteria contamination;

In my opinion, whether it is feasible to implement household PFAS mitigation systems all depends on cost. On Amazon, an RO POU system costs around $200, and various small household GAC systems cost $100 or more. The comprehensive filter system I mentioned earlier is difficult to price, but taking into account how household GAC filters can exceed $1000, the total price would be no lower than $2000. In addition to these PFAS treatment systems, there are water testing costs. Each lab test for a single water source will cost around $250. At the bare minimum, $500 dollars will be spent on testing, because a homeowner would need to know two things: whether their water contains detectable amounts of PFAS and whether the installed PFAS mitigation system was effective.

Sources:
NHDES website
Duke University PFAS study

The EPA has a large database of chemicals called DSSTox, which provides extensive chemical-related data on over 800,000 compounds. From DSSTox, EPA has applied structural filters to weed out all chemicals that generally cannot be classified as PFAS. From there, EPA applies “primary structural categories,” which divide the selected PFAS into specific categories depending on chemical structure. After that, each primary category is divided into secondary categories that classify PFAS based on length. In literature, the length of PFAS have shown to affect how long they spend in the human body, in addition to adverse health effects.

When the PFAS has been categorized by structure, the EPA then applies filters based on whether a specific chemical has toxicity data and is industrially prevalent. On its initial selection run, the EPA selected 24 PFAS candidates that were representative of the numerous PFAS categories.

I believe that the categorization of PFAS based on structure and toxicity is a step in the right direction. Currently, official EPA drinking water testing methods analyze for ~30 PFAS, which were picked based on their industrial prevalence. In selecting specific PFAS candidates, EPA testing methods can be improved to provide more information about all PFAS in a sample, not just a select few.

Furthermore, I think that systematically categorizing PFAS by a central authority has implications beyond sample testing. If this standard of PFAS grouping is established in academia, the health effects of PFAS can be more extensively studied. In addition, adopting standards by which PFAS can be categorized will prevent chemical companies from avoiding regulations by inventing new PFAS.

For more information, check out this link.

Today, having performed multiple sample collections, I would like to walk my readers through the process of collecting water samples for EPA Method 537 with photographs.

Before collecting any samples, please make sure you have the following from the laboratory analyzing your samples:

• Two sealed HDPE PFAS sample containers with TRIZMA preservative inside. Some laboratories may have fewer bottles, and may provide two more bottles. I will explain this in the procedure down below.

• Chain-of-custody form

• Powder-free nitrile gloves

• A cooler filled with ice

With these items gathered, we can now start preparing to take our sample.
Make sure:

• You are wearing powderless nitrile gloves
  • Do NOT use latex or vinyl gloves
• You have not handled any aerosolized perfumes, detergents, or insect repellents before sampling
• You have not touched any food packaging before sampling

Time to start the procedure!

1. Put gloves on. Label your sample bottles with your initials, time and date of collection, and sample name.

3. After three minutes, narrow the water flow down until you can see through it.

4. Open sample bottle and fill to its neck.

5. Close the cap, and shake a couple times to mix the preservative.

6. Depending on the laboratory, you may have more samples bottles to fill. Additionally, some laboratories may provide you a bottle filled with laboratory water and an empty bottle for the purpose of collecting a control sample. If you have extra sample bottles, repeat steps 4 and 5. If you have a laboratory water bottle, simply pour the water into the empty bottle and discard the now-empty bottle.

7. Place your sample bottles and control (if applicable) into your cooler.
   

8. Return your samples to the lab and you’re done!

I hope that this guide was helpful and instructive. If you have any questions, don’t hesitate to contact me at tomtomboy2011@gmail.com.

For more detailed instructions, visit this website.

I was appalled to find out that there were only 14 certified labs to which PFAS levels could be officially measured! [1] Of these 14 labs, only two are in MA state: Pace Analytical Laboratories and Alpha Analytical. When I contacted Alpha Analytica, it turns out that they would not be able to support me until next Spring, way outside of the timeline of my project. My next best bet was Pace Analytical Labs. The response I got from them was even more lackluster than Alpha Analytical’s: they simply didn’t respond.

My third option was to contact Absolute Resource Associates, who hooked me up with an arrangement to test water samples. However, another appalling part of the process was the price of using LC-MS (see previous posts). Alpha Analytical and Absolute Resources charge $250-280 (depending on method) per sample! For one run of samples, this is quite expensive!

For many researchers, these obstacles hinder scientific development. Studies require a lot of data, which in the case of PFAS is very expensive to obtain via official methods. In addition, the few labs that offer certified methods are often not available for testing because they are too overloaded with demand.

The issue of hard-to-access testing compounds current existing problems surrounding scientific research of PFAS, including public awareness and government action. Without sufficient scientific activism to back up activism, PFAS’ relative unchartedness allows chemical manufacturing companies to keep polluting and harming public health.

Sources
– MassDEP database

The analytical column essentially acts as a filter for the physical components of the liquid sample. Larger components will flow slower through the filter, getting stuck on the bits of the stationary phase, while smaller components will pass through faster. This allows the separated parts to sequentially exit the chromatography system and allows them to be individually analyzed and counted.

The flow of the solvent is important in maintaining the proper separation of components in the analytical column. The separation of components allows different parts of a solution to be measured accurately by mass spectrometry.




Sources
https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Supplemental_Modules_(Analytical_Chemistry)/Instrumental_Analysis/Chromatography/Chromatographic_Columns

http://hiq.linde-gas.com/en/analytical_methods/liquid_chromatography/high_performance_liquid_chromatography.html

https://static1.squarespace.com/static/54d9087ce4b058d3cfb44d78/t/58efcd7fb3db2bed6e7f0712/1492110732957/%2326+Expand+Your+Lab+with+the+Use+of+Mass+Spectrometry.pdf

LC-MS as an analytical method was developed over the course of the past 70 years. However, it requires lengthy training and uses hard-to-access lab equipment. Additionally, expensive solvents have to be consumed in running these tests. These limitations leave a demand for easy-access, fast screening methods for PFAS. To date, there have not been easy to access PFAS testing methods for homeowners; those that wish to get their water tested have to pay upwards of 80 dollars to send a water sample to a third party company.

Thus, a cheaper alternative is needed, not only for homeowner use, but for data collection to advance the field of PFAS knowledge. PFAS has lived in a dark age for the past 20 years, and it is time data is collected on these dangerous chemicals.

Sources

https://en.wikipedia.org/wiki/Liquid_chromatography%E2%80%93mass_spectrometry

Grebe, S., & Ravinder, S. (2011). LC-MS/MS in the Clinical Laboratory – Where to From Here? Reviews / Australian Association of Clinical Biochemists, 32(1), 5–31. https://www.researchgate.net/publication/50937180_LC-MSMS_in_the_clinical_laboratory-Where_to_from_here