Toxicology tests offer ‘more questions than answers’

The Martha’s Vineyard Commission Thursday night heard from various experts on the toxicology reports compiled by two environmental consulting firms — Tetra Tech and Horsley Witten. 

At the third development of regional impact (DRI) public hearing for the proposed Martha’s Vineyard Regional High School athletic field project, independent consultants from Tetra Tech and Horsley Witten went over the testing process, and dove into how the results were analyzed.

Ron Myrick, vice president and engineer at Tetra Tech, said the purpose of the toxicology project was to identify and analyze potential chemicals that could be found in the various synthetic turf components.

Myrick said the analysis compares existing risk-based values for soil and groundwater standards, established by the Massachusetts Department of Environmental Protection and the Environmental Protection Agency, to the concentration levels found in the turf components.

Myrick explained that because the lab he engaged with, Alpha Analyticals, would be analyzing materials that are not customarily used in laboratory analysis, they used methods designed to test for chemicals in soil and groundwater.

In order to determine any potential risks involved with direct contact, solid samples of each component were tested, including the plastic carpet, the engineered pine infill, the shock-absorbent pad, and the two bonding adhesives.

Myrick said he compared the values found in the infill to background soil data of virgin samples taken during a University of Vermont study.

A background value indicates the concentration amount of chemicals in natural soil without exposure to direct human influence.

One of the main toxicological areas of concern for the proposed project is related to per- and polyfluoroalkyl substances (PFAS) — a compound with emergent concerns that is ubiquitous in the world due to its extensive commercial value in fireproofing, waterproofing, and other functions.

It was used extensively in food packaging, and most recently was identified in aqueous film-forming foams (AFFF) at Martha’s Vineyard Airport used in fighting aircraft petroleum fires.

PFAS is a class of compounds that contains around 6,000 or more individual compounds. Currently, with existing laboratory methods, only around 40 of those PFAS can be identified, Myrick said. In Massachusetts, six PFAS compounds are listed as being the highest points of concern.

Apart from testing the solid materials directly, a leachate test was performed by exposing the materials to high pH levels. Through the process of oxidation, this test can transform certain PFAS compounds that are undetectable into forms of PFAS that can be identified and quantified in the lab, Myrick said. Those figures were then compared to existing groundwater standards.

“Now, you aren’t drinking what comes off the field; however, at least we have some data to compare it to,” Myrick said.

Although Myrick said the tests indicated some chemicals of concern were present, he said those were found in low concentrations that were consistent with background concentrations found in natural soil, or were “well below” the risk-based standards.

“However, the understanding of PFAS detection and risk are limited for the vast majority of PFAS compounds, and certainty in such an assessment is not possible at this time,” he said. “PFAS was hardly in our vocabulary three or four years ago — now it has become a big issue. There are still more questions than answers.”

Brian Massa, senior scientist at Horsley Witten, said his company applied the best available science, and looked at existing soil and groundwater standards for comparison. “Obviously, these materials are not soil, they are not groundwater, but these are the best available things for us to look at right now,” Massa said.

Through a synthetic precipitation leaching procedure, annual and unprecedented rainfall was simulated using a high pH water, to determine what PFAS might be created through chemical reactions in the environment.

“The methods that we used aren’t perfect, but they are informative. This is all cutting-edge stuff,” Massa said. “Some of the results are inconclusive, but I still think they are valuable.”

According to Massa, semi-volatile organic compounds, metals, and PFAS were detected in most of the samples, but he reiterated Myrick’s point that most of these values were at background level, or were below the comparison soil and groundwater standards.

A few levels exceeded existing comparison standards, including that of antimony, phenol, and PFAS precursors, which can degrade into PFAS through reactions with the environment.

Massa said phenol in the pine infill can be naturally occurring in pine trees, but that phenol could still potentially leach into underlying groundwater, although the detected levels were well below state standards.

In his conclusion, Massa said the field is safe to play on from a direct-contact perspective, but it is likely that PFAS compounds beyond the currently regulated group may exist. 

Overall, he said, the science “just isn’t there” for further testing, and said there is an uncertainty “due to testing limitations and understanding of how these compounds react in soil and groundwater.”

He recommended that if the synthetic surface is installed, that periodic PFAS testing be performed.

Laura Green, a toxicologist speaking for the school and paid for by a community funder, said all sports fields contain various chemicals, including metals, and potentially PFAS. Green said she wanted to look at the field project holistically, not just at the synthetic field, in order to get a better understanding of the big picture.

She said the study done at the University of Vermont (on which the comparison standards for the project are based) showed that PFAS were detected in all 66 of the samples taken from virgin soils found in green areas like state forest and parks.

Many of these PFAs substances, Green said, have been used for decades in the Western world, and you would be hard-pressed to find topsoil samples without the presence of PFAS.

“PFAS are in all of our bodies, they are in all the effluent from septic systems on the Vineyard,” she said.

She pointed out that the most concerning PFAS substance, perfluorooctanesulfonic acid (PFOS), and the one that bioaccumulates most in the human body, was not detected in the infill.

Green also stressed that the leachate test conducted on the turf materials uses water with a pH level about 10 times more acidic than the rainwater on Martha’s Vineyard. “It’s an extremely aggressive test,” she said. “It is a gross overestimate of what rainwater on the Island today would actually generate.”

Although various metals were present in small concentrations, Green directed the commission’s attention to the absence of lead in the turf infill, and the minute presence of lead in soil samples taken at the high school. She said lead is, for most toxicologists, the most important and concerning material in regards to public health.

“I have to conclude, as a toxicologist, that I can find no threat to the health of athletes or other people using or living near these fields — not through the existing grass and dirt fields, or the proposed synthetic field,” Green said.

She attempted to clarify a point on the high overall organic fluorine levels found in certain turf components, which Massa had said could indicate existing PFAS compounds that are not currently classified by the state or federal government. “Total organic fluorine has been misrepresented to you,” she said.

She continued to say that organic fluorine was found in the products because of a “completely inert” fluorinated copolymer that is used in production of the grass fibers. 

“This polymer is similar to what is used in medical-grade materials such as sutures, skin-wearable sensors, and is found in filaments used in fishing lines,” she explained. “It does not represent some mysterious PFAS compound that might be toxic; that is simply incorrect.”

In ending her presentation, Green said everything is toxic at a certain level, but that is why safety standards exist for these compounds.

“You do not and should not swallow 20 Tylenol all at once, but you can swallow two Tylenol and you are perfectly fine. It’s about the numbers,” she said.

Kristen Mello, a chemist and data analyst speaking on behalf of the Field Fund, said PFAS pile up in your blood, your organs, and your brain. They are resistant to degradation, and bioaccumulate — meaning organisms take them in faster than their body can process them.

She added that like mercury in certain fish species, PFAS bioaccumulate in the body, and concentrations increase as you move up the food chain.

When PFAS and other compounds react with environmental factors, Mello said, they can leach into groundwater and stormwater, and be absorbed by plants and animals. “Their addition to your stormwater and groundwater could disrupt your local ecosystem in ways that you have not yet considered,” she said.

Because available analytical standards don’t include the majority of PFAS compounds that are thought to exist, Mello said, scientists can test for only a fraction of the total PFAS that could potentially be in the materials. “The results tell us that the installation of this proposed artificial turf field system will place a point source of PFAS discharging into your irreplaceable freshwater sole-source aquifer. You aren’t going to be able to take this back out,” she said.

Additionally, she highlighted the fact that lab results are based on extractions from samples weighing less than half a pound each. In order to calculate the total amount of chemicals being potentially deposited in the aquifer, Mello said, you would have to multiply those results across the entire mass of the installation, including replacements for each component that would be required in the coming decades.

As the problem at the airport illustrated, Mello said, these compounds migrate through groundwater and surface water, and can spread for miles, potentially affecting plant and animal life.

And with so much uncertainty surrounding PFAS, Mello said, there is still a lot to consider: “That science is still unfolding. What if next year, the MassDEP adds more short-chain PFAS to the combined maximum contaminant level, and you find yourself in violation of state regulations after the fact?”