“The substances we studied in the CELSPAC-FireExpo project with firefighters are all around us, and the population is commonly exposed to them,” says environmental epidemiologist Nina Pálešová

Nina Pálešová is an environmental epidemiologist and a recent PhD graduate. She started at the Faculty of Science as a student of experimental biology, planning to focus primarily on microbiology. However, after learning about RECETOX in one of the lectures, she quickly changed her mind. She chose her thesis supervisor at the center, where she also completed her dissertation. In the interview, we explored how the young scientist transitioned from studying wastewater treatment to researching the impact of chemicals on the cardiovascular system of firefighters, what both topics have in common with her interest in the environment, and where everyone can come into contact with toxic substances.

Nina, what brought you to RECETOX?

During the first semester of my experimental biology studies as an undergraduate, various research directions at the Faculty of Science, Masaryk University, were presented. The RECETOX lecture impacted me so much that I quickly changed my plan and focused on ecotoxicology instead of microbiology. I remember the lecture was about a study on crayfish that couldn’t reproduce due to contraceptive residues in rivers. I’ve always been drawn to environmental protection, and when I found out there was a field based on biology and chemistry that also focused on environmental protection, I knew I wanted to continue there.

In your thesis, you focused on filtration technologies for wastewater treatment, but in your dissertation, you worked on epidemiological research. How did that shift happen?

The topic I chose for my thesis was very engaging, but when I decided to pursue a PhD, I felt a lot of energy that I wanted to use to broaden my horizons with a new topic. Associate Professor Pavel Čupr had a topic on studying chemical exposure at the population level and biomonitoring. During my master’s, it became clear that the technique of screening and measuring chemicals directly in human matrices, such as blood or urine, would be very appealing to me. The researcher looks inside the body, finding out what is where, what levels of substances we have in blood, urine, or even breast milk. I always found that very interesting.

Changing the focus of your research topic must have brought about a change in research methods as well. How was that for you?

It was also a leap, but a fairly smooth one. The change for me started at the level of population studies, where I had to work with statistics. Fortunately, during my master’s studies, I had some statistical courses, so I wasn’t completely unfamiliar with it; I just started using it practically. The rest were laboratory methods that I had already used in my thesis or learned about during my master’s studies.

Recetox: “The substances we studied in the CELSPAC-FireExpo project with firefighters are all around us, and the population is commonly exposed to them,” says environmental epidemiologist Nina Pálešová

Your dissertation eventually evolved into the CELSPAC-FireExpo project, which focused on the firefighter population. What was it about?

It is a population study in which we worked with more than a hundred firefighters primarily from the South Moravian Region. The aim was to assess the chemical exposure of firefighters during work or training. Everyone can imagine that firefighters are exposed to many chemicals, such as smoke. We were interested in four groups of substances that everyone is exposed to in smaller amounts and are suspected of having negative health effects. These were PFAS, sometimes known as forever chemicals, polycyclic aromatic hydrocarbons (PAHs), benzotriazoles, and toxic metals. Specifically, we were interested in how these substances could affect cardiovascular health. The incidence of cardiovascular diseases is higher among firefighters, and exposure to chemicals could play a role in this.

What can I imagine these groups of substances to be?

PFAS are used, for example, in firefighting foams as foaming agents and are also found in protective suits, where they protect firefighters from dirt, temperature, and other factors. PAHs are combustion by-products and are part of the aforementioned smoke. Firefighters wear masks during interventions, but they can inhale substances from residual smoke when searching through debris or even if they are just standing nearby after an intervention. PAHs also penetrate the body through the skin, for example, through soot. Benzotriazoles are relatively new to research and are found everywhere in the environment, whether in water, soil, or dust. Due to their chemical properties, they serve as anti-corrosion coatings and can be found in household appliances. They are also added to laundry detergents and dishwasher tablets or used as de-icing fluids in aviation or flame retardants. It has been found that they are present in our bodies in measurable concentrations, but it is not yet clear whether they have toxic effects, although their structure and models suggest such potential. Toxic metals are found in batteries and were historically part of pipe coatings or pesticides. This group of substances can also be released during combustion.

How did the research turn out?

Firefighters had elevated levels of PFAS, PAHs, and lead in their bodies. In case of benzotriazoles, we did not observe elevated levels among firefighters, however, we know that they can be excreted from the body very quickly.Elevated concentrations of PFAS and PAHs in firefighters were associated with increased bilirubin. Elevated lead levels were also associated with increased cholesterol. Both bilirubin and cholesterol are considered indicators of cardiovascular health. So, in simple terms, an increase in these markers indicates a higher future risk of developing cardiovascular disease. Thus, our hypothesis was confirmed.

Were the results of the project successfully implemented in practice, and were any measures adopted?

PFAS are being addressed at a global level, with legislative steps already underway. For other substances, various measures can be proposed specifically for firefighters to reduce exposure. These measures are relatively simple but not yet implemented in the fire service. The fire service addresses injuries, but there is no department or working group that deals with the effects of chemical exposure on health; firefighters are only briefly introduced to the topic during their initial training. It is necessary to deepen education and explain that even though substances are invisible, they still enter the body. The next step is to change procedures, such as introducing new decontamination processes after interventions. Foreign research indicates that even the environment of a fire station is somewhat contaminated and can affect the levels of substances in their bodies. Currently, it is often taken for granted that since this issue has not been addressed for thirty years and seemingly nothing has happened, there is no need to address it in the future. However, thanks to the project’s activities, the results were communicated not only at professional conferences but also with study participants. A working group called “Healthy Firefighter” was even established, which prepares websites, guides, and study materials for firefighters. We strive to have an impact on the entire community.

What is the significance of the project’s results for the broader society and the environment?

The substances we studied in the project are everywhere, and the general population is constantly exposed to them. This project focuses on a specific group of people, but it’s still the same pollutants. If our research shows that the health of the selected group may be at risk, these substances will receive more attention, which can lead to significant changes and improvements not only in the quality of life for firefighters but practically for all of us. Chemical substances migrate in the environment and almost always find their way back to humans. However, if we limit their use, we limit their migration and improve the quality of the environment for everyone. And I don’t mean just people! For example, the aforementioned firefighting foams not only endanger firefighters but, after use, can flow through the sewage system into the nearest river, further contributing to the contamination of river ecosystems and even reaching drinking water sources. We can imagine something similar for benzotriazoles, which are used in large quantities at airports as de-icing fluids. By highlighting the potentially toxic effects of these substances, we initiate a societal debate and create space for further research and possible new regulations.

You are surrounded by information about toxic substances every day. What do you personally avoid in your daily life?

My perception of the risks of toxic substances evolves, and at this point in my life, I accept it more and try not to stress unnecessarily. Within my means, I try to avoid what I think are sources and what doesn’t benefit the planet, such as unnecessary single-use packaging. In single-use paper food packaging, we can encounter the already mentioned PFAS because they effectively repel water and grease, increasing the durability of the paper. This can include microwave popcorn, pizza boxes, or fast-food packaging. While plastic packaging doesn’t contain PFAS, it does contain plasticizers that can leach into the surrounding environment. When something hot (and tasty) is placed in the container, there is potential for plasticizers or other additives (such as phthalates or bisphenols) to quickly transfer into the food. For this reason, I prefer glass food containers.

Do you plan to continue researching toxic substances?

I have just defended my dissertation and definitely plan to continue with the ongoing projects. Besides that, I might want to try something new, but I don’t have a specific idea yet. I enjoy science and believe I will continue to pursue it. I also believe that we will be able to utilize all the data from the CELSPAC-FireExpo study; we have collected a lot, and theoretically, we could also study the effect of substances on immunity. Ideally, we would continue with the same firefighters and collect samples and data from them every five years. That’s the dream; what the reality will be, we will see.