(Press-News.org) URBANA -- A 150-foot-high garbage dump in Colombia, South America, may have new life as a public park. Researchers at the University of Illinois have demonstrated that bacteria found in the dump can be used to neutralize the contaminants in the soil.
Jerry Sims, a U of I associate professor of crop sciences and USDA-Agricultural Research Service research leader and Andres Gomez, a graduate student from Medellín, Colombia, have been working on a landfill called "El Morro" in the Moravia Hill neighborhood of Medellín, which served as the city dump from 1972 to 1984. In that period, thousands of people came to the city from the rural areas to escape diverse social problems. There was no housing or employment for them, so they made a living picking up trash from this dump and built their homes upon it.
"There are some frightening pictures of this site on the Internet," said Sims. "At one point, close to 50,000 people lived there. They grew vegetables on the contaminated soil and hand-pumped drinking water out of the garbage hill."
In recent years, the Colombian government decided to relocate the people to different neighborhoods with better conditions. Then they decided to see if it was possible to clean up the area and turn it into a park. Unfortunately, the most reliable solution -- digging up the garbage and treating it -- is not economically feasible in Colombia.
Another problem was that there were no records of exactly what was in the dump.
"Apparently, hydrocarbon compounds were one of the main sources of contamination," said Gomez. "Phenyls, chlorinated biphenyls, and all kinds of compounds that are sometimes very difficult to clean up."
Three professors from The National University of Colombia in Medellin -- Hernan Martinez, Gloria Cadavid-Restrepo and Claudia Moreno -- considered a microbial ecology approach. They designed an experiment to determine whether bioremediation, which uses biological agents such as bacteria or plants to remove or neutralize contaminants, could be used to clean the site.
Gomez, who was working on his master's thesis at the time, collaborated with them. He was charged with finding out if there were microorganisms living in the soil that could feed on the carbon in the most challenging contaminants.
This was not a trivial task. As Sims explained, "There are maybe 10,000 species of bacteria and a similar number of fungi in a gram of soil."
Gomez's work was further complicated by the fact that the material in the hill was loose and porous with air spaces and voids that resulted from dirt being thrown over layers of garbage. Because of the unusual physical structure and the contaminant levels, it was unclear if the indigenous bacterial community would be as complex, and thus as effective at bioremediation, as those normally found in soils.
Gomez analyzed bacteria at different depths in the hill down to 30 meters. He found microbial communities that appeared to have profiles typical of bacteria involved in bioremediation. The communities seemed to contain a robust set of many organisms that could be expected to weather environmental insults or manipulations.
Gomez then came to Sims's lab at the U of I on a grant from the American Society for Microbiology to perform stable isotope probing, a test to link diversity and function that he was not able to do in Colombia. Contaminants are labeled with a heavy isotope that serves as a tracer that can be detected in the end products of biodegradation.
His results confirmed that the bacterial communities had, in fact, been carrying out bioremediation functions. In collaboration with assistant professor of microbial ecology Tony Yannarell who assisted with the microbial diversity analysis, he determined that the organisms involved changed at every depth.
Based on these results, the Colombian government decided to go ahead with the bioremediation project using the indigenous organisms. One of the professors who worked on the pilot study is looking at ways to provide the microorganisms with extra nutrients to speed up the process. Another project takes a phytoremediation approach, which uses plants to absorb heavy metals.
###
END
Turbulent jet streams, regions where winds blow faster than in other places, churn east and west across Saturn. Scientists have been trying to understand for years the mechanism that drives these wavy structures in Saturn's atmosphere and the source from which the jets derive their energy.
In a new study appearing in the June edition of the journal Icarus, scientists used images collected over several years by NASA's Cassini spacecraft to discover that the heat from within the planet powers the jet streams. Condensation of water from Saturn's internal heating led to temperature ...
MADISON -- Ice samples pulled from nearly a mile below the surface of Greenland glaciers have long served as a historical thermometer, adding temperature data to studies of the local conditions up to the Northern Hemisphere's climate.
But the method -- comparing the ratio of oxygen isotopes buried as snow fell over millennia -- may not be such a straightforward indicator of air temperature.
"We don't believe the ice cores can be interpreted purely as a signal of temperature," says Anders Carlson, a University of Wisconsin–Madison geosciences professor. "You have to consider ...
Like a white blanket, Tropical Storm Debby's clouds covered the entire state of Florida in a NASA satellite image.
Two satellites have captured imagery that shows Tropical Storm Debby has thrown a large white blanket of clouds over the state of Florida, and it doesn't seem like that blanket is going to lift quickly as Debby moves slowly north.
NASA's Aqua satellite passed over Tropical Storm Debby and the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument onboard the satellite captured a visible image of the storm on Sunday, June 24 at 3:00 p.m. EDT. The ...
MEDFORD/SOMERVILLE, Mass. (June 25, 2012) – The twinkling of fireflies heralds summer romance for these magical insects. While courting on-the-wing, male fireflies attract females' attention with bioluminescent flashes.
But new research from biologists at Tufts University's School of Arts and Sciences, published online in Proceedings of the Royal Society - Biological Sciences, reveals that, after the lights go out, female fireflies prefer substance over flash. They seem to choose mates able to give them the largest "nuptial gift" (a high protein sperm package that helps ...
A team of UCLA researchers has created the most powerful high-performance nanoscale microwave oscillators in the world, a development that could lead to cheaper, more energy-efficient mobile communication devices that deliver much better signal quality.
Today's cell phones, WiFi–enabled tablets and other electronic gadgets all use microwave oscillators, tiny devices that generate the electrical signals used in communications. In a cell phone, for example, the transmitter and receiver circuits contain oscillators that produce radio-frequency signals, which are then converted ...
A classic study from more than 60 years ago suggesting that males are more promiscuous and females more choosy in selecting mates may, in fact, be wrong, say life scientists who are the first to repeat the historic experiment using the same methods as the original.
In 1948, English geneticist Angus John Bateman published a study showing that male fruit flies gain an evolutionary advantage from having multiple mates, while their female counterparts do not. Bateman's conclusions have informed and influenced an entire sub-field of evolutionary biology for decades.
"Bateman's ...
In the brains of humans and non-human primates, over 100 billion nerve cells build up complicated neural circuits and produce higher brain functions. When an attempt is made to perform gene therapy for neurological diseases like Parkinson's disease, it is necessary to specify a responsible neural circuit out of many complicated circuits. Until now, however, it was difficult to introduce a target gene into this particular circuit selectively. The collaborative research group consisting of Professor Masahiko TAKADA from Primate Research Institute, Kyoto University, Professor ...
PHILADELPHIA -- Researchers have long been interested in discovering the ways that human brains represent thoughts through a complex interplay of elec-trical signals. Recent improvements in brain recording and statistical methods have given researchers unprecedented insight into the physical processes under-lying thoughts. For example, researchers have begun to show that it is possible to use brain recordings to reconstruct aspects of an image or movie clip someone is viewing, a sound someone is hearing or even the text someone is reading.
A new study by University ...
Charlottesville, VA (June 26, 2012). Researchers at the University of Michigan have found that the Apple iPad 2 can interfere with settings of magnetically programmable shunt devices, which are often used to treat children with hydrocephalus. The iPad 2 contains magnets that can change valve settings in the shunt if the tablet computer is held too close to the valve (within 2 inches). Such a change may result in shunt malfunction until the problem is recognized and the valve adjusted to the proper setting. Patients and their caregivers should monitor use of the tablet computer ...
An investigation led by UCSF has found that the risk of female-to-male HIV transmission is increased three fold for women with bacterial vaginosis, a common disorder in which the normal balance of bacteria in the vagina is disrupted.
"Previous research has shown that bacterial vaginosis can increase a women's risk of becoming infected with HIV as much as sixty percent. Our study is the first to show that the risk of transmitting HIV is also elevated. Our findings point to the need for additional research to improve the diagnosis and treatment of bacterial vaginosis, ...
