Pace® has been testing biota (plant and animal tissue) for various pollutants for years. Recently, we’ve seen an increasing number of requests to analyze PFAS levels in biota. Since this topic is relatively new for many in our PFAS-oriented audience, we recently conducted an online webinar to cover some basics. I’ll share highlights from that webinar in this post. It is also available in its entirety on demand:
Watch: Navigating the Complexities of Testing for PFAS in Plant and Animal Tissue
Why Test for PFAS in Biota?
This question was addressed during the Q&A portion of the webinar. As Jim Occhialini from Pace® shared, many of our projects revolve around the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). There is usually a risk assessment component associated with these projects, which can be focused on either human health or ecological risk. Here are three common scenarios:
Liability assessments for non-listed sites – If PFAS contamination is suspected, property owners may test groundwater and soil in anticipation of future liabilities, such as being designated a Superfund site and being held responsible for cleanup and remediation. If PFAS contamination is found, biota may be tested to evaluate the extent of the environmental contamination.
Initial investigations for listed properties – Before being designated a Superfund site, a property is added to the EPA’s Superfund National Priorities List. From there, an initial investigation is conducted to determine the extent of PFAS contamination. This may include testing orders for biota, especially if protected areas, such as wetlands, may be impacted.
Remediation – Testing can help inform remediation strategies by defining the extent of the contamination and determining which compounds are present. After remediation of a Superfund site, soil, water, and biota samples may be tested again to determine the efficacy of the remediation efforts and to monitor ongoing contamination control efforts.
There are many other reasons to test biota for PFAS. Biosolids, a byproduct of wastewater treatment, have been used for decades as an organic soil amendment. Unfortunately, wastewater treatment does not remove PFAS, so these biosolids have been found to contain PFAS. Soil samples are typically analyzed to identify the presence of PFAS, but biota analysis can determine whether crops and livestock, both meat and milk, have been impacted.
In addition, state Departments of Natural Resources frequently have fish tissues analyzed to ensure they do not pose a danger to those who may catch and consume local fish or shellfish. Deer and other game tissue are another frequently submitted sample type. Pace® also collaborates with several universities and other research facilities studying the impacts of PFAS in the environment.
Which Test Method is Used for Analyzing PFAS in Biota?
EPA Method 1633 was recently validated for multiple matrices. Non-potable water, e.g., wastewater and stormwater discharge, tends to get the most attention. However, this method was also validated for the analysis of 40 PFAS in solids, including biota.
If your preferred laboratory isn’t using EPA 1633, they’re likely using a modified method they developed before EPA 1633 was finalized. In the webinar, Jim covers some of the questions you might ask the laboratory as well as much more detail about how EPA 1633 is used to analyze biota samples.
How Should We Prep Our Samples for Analysis?
In the webinar, Jim spent considerable time covering the sample prep process for fish tissue. The same processes apply to other types of biota samples as well. In this post, I’ll touch on a few high-level questions we get asked and encourage you to watch the webinar for more specifics.
The first thing you need to determine is what you want analyzed. This may be the entire animal, a portion of the animal or specific organs. Most Pace® clients work with experts in the field of environmental sciences, either in-house or consulting firms, to determine what should be tested, but here are a couple of rules of thumb. If you are testing to protect public health, e.g., testing to determine whether fish caught in a specific body of water are safe to eat, then you would typically test the edible parts of the animal. If you are conducting a more expansive study, such as a toxicological impact investigation, then you might choose to test specific organs, such as the liver, where toxic compounds tend to build up faster.
Fish are among the most common species we get asked to analyze at Pace®. Section 8.4.2 of EPA 1633 provides basic instructions for sending whole fish samples to the laboratory:
If whole fish are collected, wrap the fish in aluminum foil...and maintain at or below 6°C from the time of collection until receipt at the laboratory, to a maximum of 24 hours...If a longer transport time is necessary, freeze the sample before shipping. Ideally, fish should be frozen upon collection and sent to the laboratory on dry ice.
Source: EPA 1633A
The rest of the sample prep, including homogenization, can be done by our technicians at a Pace® laboratory. This helps minimize the potential for external contamination. As importantly, we have the equipment and protocols necessary to handle even large specimens like a 50-pound striped bass.
However, as Jim mentioned in the webinar, we’re chemists, not biologists. If you want a portion of a larger animal tested, such as a specific organ of a deer or cow, it’s best to have the organ extracted by a biologist and then sent to us to ensure you get the tissues you need analyzed. Just remember to follow all other sampling guidelines to minimize the potential for contamination.
Read: Is PFAS Sampling Cross-Contamination Really an Issue?
Need More Information?
We’ve just scratched the surface in this post. Jim also conducted a non-PFAS specific webinar on sampling biota that you may find interesting if you’re considering a broader contamination study. I encourage you to reach out to us if you still have questions about the incredibly interesting but relatively new science of analyzing for PFAS in plant and animal tissue.
