(Press-News.org) The Environmental Protection Agency (EPA) largely remedies Superfund sites containing asbestos by capping them with soil to lock the buried toxin in place. But new research suggests that this may actually increase the likelihood of human exposure to the cancer-causing mineral.
"People have this idea that asbestos is all covered up and taken care of," said Jane Willenbring, who is an associate professor of geological sciences at Stanford University's School of Earth, Energy & Environmental Sciences (Stanford Earth). "But this is still a lingering legacy pollutant and might be dribbling out pollution, little by little."
Willenbring has published several studies about asbestos behavior and, most recently, turned her attention to the lack of information about how asbestos may move through the soils where it is stored. Through lab experiments with asbestos fibers, which were detailed in a paper published Jan. 27 in the Journal of Hazardous Materials Letters, she and colleagues determined that the soil's organic material actually enables the asbestos to move through the ground and potentially into nearby water supplies.
They found that dissolved organic matter changes the electric charge on asbestos particles and makes them less sticky, thereby enabling them to move faster through soil. The work disproves the prevailing theory that asbestos fibers cannot easily move through soil - an assumption that has been made in part because of the mineral's hair-like shape.
"It's surprising that even though these little fibers are so long, because their shortest diameter is small enough, they can wind their way through these soil pores," said Willenbring, who is senior author on the study.
Inhalation of asbestos increases the risk of developing lung disease and lung cancer, and exposure could occur through irrigation, taking showers, using humidifiers or other unfiltered sources that disperse water into the air.
A legacy pollutant
Asbestos is a naturally occurring mineral that mainly forms in the subsurface, at the boundary of Earth's oceanic and continental crusts. For much of the 20th century, it was revered as a miracle building material for its high heat capacity and insulation properties, and mining and production boomed worldwide. Following widespread evidence of its link to cancer, including a rare and aggressive form called mesothelioma, production of asbestos in the U.S. declined dramatically starting in the 1970s.
In addition to thinking that the shape of the fibers would inhibit transport, the scientific community has been influenced by a 1977 EPA report that minimized the threat of asbestos moving through soil. Since then, new findings about the role of colloids - microscopic particles that remain dispersed within solutions rather than settling to the bottom - have led researchers to challenge the assumption that asbestos stays fixed in soil.
"Now we can show that exactly the thing that they do, which is add manure or other organic sludge to the asbestos piles that creates the production of dissolved organic matter, is exactly what causes the liberation of asbestos," Willenbring said. "It's actually facilitating the transport of asbestos fibers."
In some ways, the team's breakthrough about asbestos is not surprising because it aligns so closely with recent findings about the transport of colloids in soil, Willenbring said. But she was stunned by the scale of the problem: Millions of people in the U.S. are living near thousands of sites contaminated with asbestos.
At least 16 Superfund sites contain asbestos and areas where the mineral naturally occurs can also pose a risk.
Improving remediation
As part of the lab experiments, Willenbring and her team sampled soil from the BoRit Superfund Site in Ambler, Pennsylvania before it was capped in 2008. The waste dump is located next to a reservoir, as well as a stream that feeds water to the city of Philadelphia.
However, there is a silver lining to the team's discovery.
"Not all types of dissolved organic matter have the same effect on asbestos mobility," said lead study author Sanjay Mohanty, an assistant professor at UCLA's Civil and Environmental Engineering who collaborated with Willenbring on the experiments. "Thus, by identifying the types that have the worst effect, the remediation design could exclude those organic amendments."
As part of the remediation strategy, some sites include vegetation planted on top of the soil to prevent erosion. Willenbring's ongoing research involves figuring out how fungal-vegetation associations may be able to extract iron and make the asbestos fibers less toxic to people.
"It's not just inflammation in the lungs that's a problem - there's a process by which iron contained in the asbestos fiber is actually responsible for causing DNA damage, which can lead to cancer or mesothelioma," Willenbring said.
INFORMATION:
The study was co-authored by a researcher from Midwestern University.
The research was supported by the University of Pennsylvania's SRP Center Grant (P42 ES027320), "Asbestos fate, exposure, remediation, and adverse health effects" from the National Institute of Environmental Health Sciences (NIEHS).
Sugar is not just something we eat. On the contrary. Sugar is one of the most naturally occurring molecules, and all cells in the body are covered by a thick layer of sugar that protects the cells from bacteria and virus attacks. In fact, close to 80 per cent of all viruses and bacteria bind to the sugars on the outside of our cells.
Sugar is such an important element that scientists refer to it as the third building block of life - after DNA and protein. And last autumn, a group of researchers found that the spike protein in corona virus needs a particular sugar to bind to our cells efficiently.
Now the same group of researchers have completed a new study that further digs into the cell receptors to which sugars and thus bacteria and virus ...
Researchers at Tokyo Medical and Dental University (TMDU) in a pioneering study identify clinical, genetic and histopathological characteristics that may help confirm the diagnosis when nephronophthisis occurs in adults
Tokyo, Japan - Nephronophthisis (NPH) is a kidney disease affecting mainly children. Now, for the first time, researchers at Tokyo Medical and Dental University (TMDU) have studied a number of adults with NPH and highlighted clinical, genetic and pathological characteristics that could help in confirming this challenging diagnosis.
NPH is inherited in an autosomal recessive pattern and, though rare, is the commonest genetic cause of kidney failure in children. The ...
It is 2,250 kilometers long, but only 355 kilometers wide at its widest point - on a world map, the Red Sea hardly resembles an ocean. But this is deceptive. A new, albeit still narrow, ocean basin is actually forming between Africa and the Arabian Peninsula. Exactly how young it is and whether it can really be compared with other young oceans in Earth's history has been a matter of dispute in the geosciences for decades. The problem is that the newly formed oceanic crust along the narrow, north-south aligned rift is widely buried under a thick blanket of salt and sediments. This complicates direct investigations.
In the international journal Nature Communications, scientists from GEOMAR Helmholtz Centre for Ocean Research Kiel, ...
Tsukuba, Japan - Blood vessels can be injured by the build-up of atherosclerosis and long-standing hypertension, among other conditions. As a consequence, blood vessels may undergo a process called remodeling, whereby their walls thicken and cause blockages (known as occlusion). In a new study, researchers from the University of Tsukuba discovered how cells marked by platelet-derived growth factor receptor alpha (PDGFRa+) residing predominantly in the most outer layer of blood vessels contribute to their remodeling.
Blood vessels comprise three layers, each of which fulfills a unique role ...
Single-molecule fluorescence detection (SMFD) is able to probe, one molecule at a time, dynamical processes that are crucial for understanding functional mechanisms in biosystems. Fluorescence in the Near-infrared (NIR) offers improved Signal to Noise Ratio (SNR) by reducing the scattering, absorption and autofluorescence from biological cellular or tissue samples, therefore, provides high imaging resolution with increased tissue penetration depth that are important for biomedical applications. However, most NIR-emitters suffer from low quantum yield, the weak NIR fluorescence signal makes the detection extremely difficult.
Plasmonic nanostructures are capable of converting localized electromagnetic energy into free radiation ...
Strawberry geranium (Saxifraga stolonifera) has been used in Japan as a herbal medicine to treat wounds and swelling, and continues to be an ingredient in food and cosmetics. Pharmacological studies have shown that extracts of strawberry geranium have antioxidant and antitumor activities. However, the anti-inflammatory effect of strawberry geranium on the skin had not been well characterized.
This study, first-authored by associate professor Takeshi Kawahara of the Institute of Agriculture, Shinshu University for a joint research project with Maruzen Pharmaceutical Co., ...
Dr. Sabrina Coninx from Ruhr-Universität Bochum and Dr. Peter Stilwell from McGill University, Canada, have investigated how philosophical approaches can be used to think in new ways about pain and its management. The researchers advocate not merely reducing chronic pain management to searching and treating underlying physical changes but instead adopting an approach that focuses on the person as a whole. Their work was published online in the journal "Synthese" on 15 April 2021.
It is not currently possible to treat chronic pain effectively in many cases. This has encouraged researchers from various disciplines to consider new approaches ...
A team led by Prof. GUO Guangcan and Prof. ZOU Changling from the University of Science and Technology of China of the Chinese Academy of Sciences realized efficient frequency conversion in microresonators via a degenerate sum-frequency process, and achieved cross-band frequency conversion and amplification of converted signal through observing the cascaded nonlinear optical effects inside the microresonator. The study was published in Physics Review Letters.
Coherent frequency conversion process has wide application in classical and quantum information fields such as communication, detection, ...
A new study conducted jointly by the University of Liege (Belgium) and the Ecole normale superieure - PSL (France) shows that heart brain interactions, measured using electroencephalography (EEG), provide a novel diagnostic avenue for patients with disorders of consciousness. This study is published in the Journal of Neuroscience.
Catherine Tallon-Baudry (ENS, CNRS) introduces : "The scientific community already knew that in healthy participants, the brain's response to heartbeats is related to perceptual, bodily and self-consciousness. We now show that we can obtain clinically meaningful information if we probe this interaction in ...
Networks offer a powerful way to visualize and analyze complex systems. However, depending on the size and complexity of the network, many visualizations are limited. Protein interactions in the human body constitute such a complex system that can hardly be visualized. Jörg Menche, Adjunct Principal Investigator at the CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Professor at the University of Vienna and research group leader at Max Perutz Labs (Uni Wien/MedUni), and his team developed an immersive virtual reality (VR) platform that solves ...
