Turning Trash Into Treasure: How scientists are using peanut shells and rice husks to clean up toxic mercury in our environment
By Tyjaha Steele

In the wake of Hurricane Helene and the recent flooding across the Southeast, it is crucial to understand the environmental impact of such events. Flooding historically causes sediment disruption which spreads harmful contaminants like mercury. These events can allow for toxic levels of mercury to enter the food web, posing serious risks to wildlife and humans. Researchers at the University of Georgia’s Savannah River Ecology Laboratory (SREL) have developed a promising solution to remediate this issue using biochar, a carbonized byproduct of organic waste. When added to contaminated soil, biochar can reduce the harmful effects of mercury, especially in flooded areas.
Natural soil samples were collected for testing from the Phinizy Center for Water Sciences and Phinizy Swamp Nature Park in Augusta, Georgia. Mesocosms, enclosed environments designed to replicate natural ecosystem conditions, were used to simulate flooding conditions on a smaller scale. The soil sediment was then enriched with inorganic mercury, mercury that has been combined with other chemical elements, to mimic a pollution event before it was left to sit for 28 days.
Different types of biochar, either rice husk or peanut hull, unmodified or modified with sulfur, were added to the soil, and the mesocosms were flooded to observe the effects of water on the polluted soil.
“Peanut hull and rice husk were chosen due to their wide availability and established background research,” explains Xiaoyu Xu, an assistant research scientist at the University of Georgia’s Savannah River Ecology Laboratory and lead researcher for this study.
The soil then sat to adjust again for 28 days. Afterward, the soil’s chemical properties were measured to see how they changed, and samples were collected to see how much total mercury, labile mercury, and organic mercury (toxic methylmercury) remained. Researchers then reviewed how each type of biochar, applied at different application rates, affected the amount of mercury that became more toxic over time.
The measurements were repeated at 28-day intervals (56 and 84 days after biochar application) to monitor changes in its effectiveness over time and to determine the most efficient application method. Researchers discovered that sulfur-modified rice husks, applied between 56 and 84 days, worked best in stabilizing labile mercury in contaminated floodplains. Success was determined based on decreases in total mercury and labile mercury concentrations, and a reduction in methylmercury.
“Overall, we found that adding biochar reduced the amount of mercury that can easily move and react in the environment by bonding with smaller particles, making the mercury more stable and less harmful,” states Xu. “However, adding large amounts of sulfur-modified biochar unexpectedly increased the production of toxic methylmercury.”
The ability of biochar to stabilize mercury is especially critical as extreme weather events like Hurricane Helene highlight the risks associated with flooding. Heavy rainfall and floodwaters can redistribute harmful metals like mercury that are associated with health concerns in humans. The research findings suggest that using biochar could offer a sustainable and scalable solution for remediating contaminated sites. This method repurposes agricultural waste that would otherwise be discarded and reduces the mobility and toxicity of mercury. As a result, it lowers the risk of mercury entering the food chain and causing health issues.
More research is needed to understand how sulfur-modified biochar affects methylmercury levels over time. “This approach shows promise as an environmentally friendly and cost-effective way to use organic byproducts to tackle mercury contamination,” Xu adds.
The original article was published in the Journal of Environmental Quality by Brittany E. Jensen, Breanna Spencer, and Xiaoyu Xu.
A genetic clock can predict lifespan in mammals, UGA’s SREL research suggests
By Lauren Maynor

Do humans have a ticking clock within them that can determine their lifespan? The answer may surprise you.
A recent study conducted by Emily Bertucci-Richter, a genomics analyst at the University of Michigan and former graduate student at the University of Georgia’s Savannah River Ecology Lab, and Benjamin Parrott, associate professor at SREL, has provided fascinating new insights into the phenomenon of epigenetic drift, also known as “epigenetic disorder.” This biological process is like a countdown within an animal’s DNA, marking the passage of time and influencing its rate of aging.
“There are a lot of folks working on epigenetic aging as it relates to human health,” Parrott explains. “Age is a major risk factor for many human diseases including cancers, dementia, and Alzheimer’s.”
Epigenetic drift is a process in which changes happen to an animal’s DNA as it ages, affecting the aging process. This research sought to unravel the mysteries surrounding epigenetic drift and its possible contribution to the differences in maximum lifespan observed across various mammal species.
The researchers monitored how rats, mice, dogs, and baboons age and how chemical modifications to their DNA change over time. The study analyzed the dynamics of epigenetic drift accumulation with age across these four mammal species. They aimed to understand how it relates to maximum lifespan and whether CpG density, a specific DNA sequence, plays a role in buffering against epigenetic drift. Their findings hinted at the possible protective role of CpG density in mitigating the effects of age-associated epigenetic disorder.
“Our working model and hypothesis are that CpG density does play a role in buffering against epigenetic drift,” Parrott says. “Other researchers have found that the CpG density in certain regions of the genome is higher in longer-lived species when compared to species with shorter lifespans. For example, humans, chimps, and dogs have greater CpG density than mice and rats.”
The researchers found that all animals they studied experience epigenetic drift, but it happens faster in animals that have shorter lifespans. Their study suggests that there are other mechanisms, in addition to CpG density, that act to slow epigenetic drift.
Parrott adds, “Genes involved in repairing DNA damage might underlie some of the differences in the rate of epigenetic drift. For example, Sirtuin proteins are involved in DNA repair and some nice work from Dr. Vera Gorbunova’s lab has shown that Sirtuins in longer-lived species are more efficient at repairing breaks in DNA when compared to the same genes in shorter-lived species.”
These findings supported the researchers’ hypothesis that the rate of epigenetic drift explains maximum lifespan. The research conducted provided partial support for the hypothesis that CpG density buffers against epigenetic drift.
Their research findings have significant implications in aging research. By understanding the role of epigenetic drift in aging, scientists may be able to develop new ways to predict and potentially slow down the aging process.
“Our group is driven by basic curiosity,” Parrott says. “Why is it that some species live longer than others? What are the ecological and evolutionary dynamics that led to such wide variation in lifespans across the tree of life? These questions are a major inspiration for the work we do, and this study gets us just a bit closer to better understanding the answer.”
The original study, The rate of epigenetic drift scales with maximum lifespan across mammals, was completed by Emily Bertucci-Richter and Benjamin Parrott at SREL.
The Power of Progress: Head-starting and the Future of Mojave Desert Tortoise Conservation
Researchers from the University of Georgia’s Savannah River Ecology Laboratory in collaboration with the University of California, Davis, recently conducted a study in the Mojave National Preserve in San Bernardino County, California, to further investigate the effectiveness of head-starting as a conservation tool for the Mojave desert tortoise. This species is currently listed as “Threatened” under the federal Endangered Species Act due to significant threats from habitat destruction and over-exploitation and was listed as “Endangered” by the State of California.
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Kojima and Oswald awarded Fellowships
Laura Kojima, a master’s student at SREL and the Odum School of Ecology, is the recipient of a 2021 National Science Foundation Graduate Research fellowship. The fellowship will provide a stipend for up to three years and additional funds to directly support her research.
“Receiving this fellowship is a huge honor, especially as an underrepresented minority in STEM. The process of grant writing and conducting my own research was a completely new process for me, and to have the mentorship and accessibility to successfully do so is something I am very grateful for,” said Kojima.
Kojima’s research assesses levels of chemical contaminants in alligator tail muscle and exposure concerns associated with the public harvest and consumption of alligators that travel on and off contaminated areas.
Scott Oswald, a doctoral student at SREL and the Warnell School of Forestry and Natural Resources, was recently named a recipient of the 2020 Office of Science Graduate Student Research fellowship from the U.S. Department of Energy.
The award is given for outstanding accomplishments in academics and research that show the potential to make important contributions to the mission of the DOE Office of Science. The fellowship will allow Oswald to conduct research at the Oak Ridge National Laboratory in 2022.
Oswald’s research will work to improve how large ecosystem models represent sugar and starch dynamics to better predict how plants respond to future climates, and to develop a framework for those dynamics using ecological and evolutionary theory.
“This fellowship is a good opportunity to receive mentorship and guidance about developing the ability to make connections between my background in mathematical biology and experimental observations,” said Oswald.

Ecological Society of America elects Beasley 2019 Fellow
Aiken, S.C. – James C Beasley, associate professor at the University of Georgia’s Savannah River Ecology Laboratory and the Warnell School of Forestry and Natural Resources, has been named an Ecological Society of America Early Career Fellow for 2019. He is one of eight recently selected for the honor.
According to ESA’s recent press release announcing the honor, Beasley was elected for outstanding contributions internationally in the field of applied ecology through his research in invasive species ecology, carnivore ecology, scavenging ecology and wildlife population ecology in landscapes abandoned following nuclear accidents.
ESA also states the honor is given to members who within eight years of completing doctoral training have advanced ecological knowledge and applications and show promise of continuing to make outstanding contribution to a wide range of fields served by ESA. Individuals are elected to serve for five years.
Beasley received a doctoral degree in wildlife ecology from Purdue University. Prior to coming to UGA, he was a visiting assistant professor at Purdue. In 2018, he was chosen as the UGA’s Fred C Davison Early Career Scholar.
ESA established its fellows program in 2012 with the goal of honoring its members and supporting their competitiveness and advancement to leadership positions in the Society, at their institutions and in broader society. Additional information about ESA Fellows and Early Career Fellows can be found on the ESA Fellows page.
SREL mourns Michael H. Smith
The leadership and staff of SREL are deeply saddened by the death of Michael H. Smith, former and longest-serving director of SREL. Smith died on Nov. 15.
Big Mike, as he was affectionately known, earned an undergraduate degree from San Diego State University and a doctorate from the University of Florida. He served as director of SREL from 1973 to 1999, remaining as a professor of ecology at UGA until he retired in 2002.
Smith was recognized internationally as an expert in population genetics, ecology and radioactivity in the environment. His unique expertise evaluating the effects of radiation in the ecosystem led to his role as an adviser in response to the Chernobyl nuclear reactor accident.
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