By Dylan Ahearn
Herrera is currently conducting multiple projects which involve field sample collection for PFAS, 6PPDQ, and microplastics. The standard operating procedures for sampling these contaminants of emerging concern (CECs) are developing and sometimes in conflict with one another, so finding the right personal protective equipment (PPE) to wear in the field can be a challenge!
Choosing the Right Clothing
6PPDQ: 6PPD is an additive includes in nearly every consumer rubber compound. When sampling for 6PPDQ field staff should be aware that the soles of their shoes contain 6PPD. New shoes in particular will leach 6PPDQ, so field staff should avoid wearing new shoes or boots when sampling.
PFAS: PFAS (per- and polyfluoroalkyl substances) also know as “forever chemicals” are commonly used as a water proofing treatment, in fabric softeners, cosmetics, sharpie pens, blue ice, and food wrappers. Look for rain jackets explicitly labeled as PFAS-free or those that use alternative waterproofing technologies, such as waxed cotton or polyurethane coatings. All clothing should be well laundered and PFAS-free.
Microplastics: This is where things get tricky. Unless you are going with waxed-cotton, you will not be able to find a rain jacket that does not contain polyester. The best we can do is to find a PFAS-free rain jacket, wash it a few times to remove any potential PFAS, but not let it get too old, as all synthetic clothing will shed microplastics with age.
Additional Tips for Sample Collection
While proper clothing is vital, other precautions can further ensure the accuracy and integrity of stormwater samples:
- Minimize Contact: Never touch the inside of sample containers or lids with your hands or clothing.
- Use Disposable Gloves: Wear disposable powder-free nitrile gloves when handling samples to prevent contamination from skin oils or residues. Make sure to rinse cloves with lab grade DI water prior to collecting microplastics samples.
- Seal Containers Properly: Ensure sample containers are sealed tightly to prevent any external contamination during transport.
- Document Procedures: Keep detailed records of the sampling procedures, including the clothing worn, to track any potential sources of contamination.
Collecting stormwater samples for 6PPDQ, PFAS, and microplastics presents unique challenges, particularly when it comes to selecting and maintaining proper clothing. By choosing PFAS-free rain jackets, laundering clothing correctly, and adhering to additional sampling precautions, you can ensure the accuracy and integrity of your samples.
All these CECs have very low detection limits which compounds the issue of potential influence on sampling results from improper sample collection technique. Field blank collection is essential to assure that results are not biased by contamination from improper attire and sampling technique. Remember, attention to detail in your attire and procedures is key to obtaining reliable results for these critical environmental monitoring tasks.
