In 2000, Timothy Mousseau, a USC professor with a PhD in biology, began the first-ever research initiative studying the environmental outcomes of the Chernobyl disaster.
The disaster occurred 50 years ago after a reactor exploded near Pripyat, Ukraine, resulting in nuclear fallout. Years later, scientists wanted to observe the effects of the radiation in the natural setting.
“Most of our initial studies were looking for signs of adaptation and changes in the biology that might reflect coping with this kind of stress,” Mousseau said. “It’s turned into a much wider range of questions, but that’s how we got started.”
The team's first visit to Chernobyl was in 1999. In the early years of the project, Mousseau visited the site multiple times a year. In 2012, the group decided to establish their lab in a renovated house on-site where work is still being done today. Studies were slowed down a few years later due to COVID-19 and the Russian invasion but resumed in October 2022.
Mousseau has only been back to Ukraine a few times since then, but the team has been present multiple times a year to collect data.
Researchers have focused on taking ecological censuses of birds and insects to look at demographic effects, as well as conducting DNA sequencing and genotoxicity testing to look at any visible genetic damage. Mousseau said findings revealed noticeable differences and damage.
"I got into this field because of an interest in evolutionary biology," Mousseau said. "The big question was whether or not organisms living in this very stressful, kind of unique environment could evolve adaptations to tolerate this increased radiation level."
Originally, scientists wanted to look at the genetic effects of wildlife resulting from the radiation.
“We published a so-called meta-analysis of all the studies that we could find about 10 years ago ... and basically found that for studies of Chernobyl organisms ... we see vast amounts of genetic damage,” Mousseau said.
Mousseau said the goal of his research is gathering more insight on how biological systems, individuals and species respond to this kind of exposure. Though multiple laboratory studies have taken place regarding Chernobyl, the on-site environmental studies were lacking, he said.
While laboratory studies are important for manipulating variables experimentally, most science originally starts with observations of the natural world.
"What we study in Chernobyl should be useful, as we explore ways to defend ourselves from other sources of radiation," Mousseau said.
Andrea Bonisoli Alquati, an associate professor with a PhD in ecology at Cal Poly Pomona, began contributing to Mousseau’s research around 2007. Alquati has centered studies around organisms' relations with each other as well as the environment.
Alquati worked with Mousseau in his lab for a few years, starting around 2010.
“There are a number of consequences for specifically exposure to radiation in Chernobyl for the populations that live there,” Alquati
said. “That includes effects on their reproduction ... that means their parental behavior, as well as their mating. Also, it does affect many aspects of their physiology, sort of their functioning that ultimately result in these behavioral changes.”
An example is the native bird species of barn swallows, Strawkowski said. Barn swallows are known to come back year in and year out to the same place, making it easy to track any type of physical or behavioral change that may occur. Mousseau said that it was immediately clear that the birds in more radioactive areas were being impacted by stressful conditions. The biodiversity in these areas was noticeably lower, he said.
“Significant numbers of them showed morphological changes, asymmetries and patches of white feathers. A few of them even had tumors,” Mousseau said. “It was pretty clear that this wasn’t a healthy environment for those critters.”
Magdalena Stawkowski, a USC professor with a PhD in anthropology is Mousseau's colleague. Stawkowski has focused her research on the society and culture of those most affected by the radiation.
“It also displaced millions of people, millions of people. It created a population of what have been known or become known as ‘the children of Chernobyl,’" Stawkowski said.
Later studies showed signs of correlation between radiation exposure and thyroid cancer.
“We know for a fact that it impacted the rise of thyroid cancers, especially in children ... as a result of being exposed to Iodine 131,” Stawkowski said. “The effects were quite profound, and the effects still linger.”
Alquati said that the team’s findings are transformative in terms of radiation studies.
“He has restarted interest in Chernobyl as a place for doing biological research, a place for understanding the consequences of ionizing radiation exposure and also, more generally, for interpreting biological phenomena such as DNA damage, adaptation to radiation,” Alquati said.
With over 35 research expeditions to Chernobyl, the team has published over 90 scientific publications of their findings over the past two decades.
“I didn’t come into this trying to solve any particular problem,” Mousseau said. “I came in because it was an unexplored area of the natural world that very few people had really addressed in any reasonable way in a natural setting."