Friday, June 3, 2016

NASA Satellite Finds Unreported Sources of Toxic Air Pollution


New research has detected smaller sulfur dioxide concentrations and sources around the world, including human-made sources such as medium-size power plants and oil-related activities.
Credits: EPA

Using a new satellite-based method, scientists at NASA, Environment and Climate Change Canada, and two universities have located 39 unreported and major human-made sources of toxic sulfur dioxide emissions.

A known health hazard and contributor to acid rain, sulfur dioxide (SO2) is one of six air pollutants regulated by the U.S. Environmental Protection Agency. Current, sulfur dioxide monitoring activities include the use of emission inventories that are derived from ground-based measurements and factors, such as fuel usage. The inventories are used to evaluate regulatory policies for air quality improvements and to anticipate future emission scenarios that may occur with economic and population growth.

But, to develop comprehensive and accurate inventories, industries, government agencies and scientists first must know the location of pollution sources.

"We now have an independent measurement of these emission sources that does not rely on what was known or thought known," said Chris McLinden, an atmospheric scientist with Environment and Climate Change Canada in Toronto and lead author of the study published this week in Nature Geosciences. "When you look at a satellite picture of sulfur dioxide, you end up with it appearing as hotspots -- bull's-eyes, in effect -- which makes the estimates of emissions easier."

The 39 unreported emission sources, found in the analysis of satellite data from 2005 to 2014, are clusters of coal-burning power plants, smelters, oil and gas operations found notably in the Middle East, but also in Mexico and parts of Russia. In addition, reported emissions from known sources in these regions were -- in some cases -- two to three times lower than satellite-based estimates.

Altogether, the unreported and underreported sources account for about 12 percent of all human-made emissions of sulfur dioxide -- a discrepancy that can have a large impact on regional air quality, said McLinden.

The research team also located 75 natural sources of sulfur dioxide -- non-erupting volcanoes slowly leaking the toxic gas throughout the year. While not necessarily unknown, many volcanoes are in remote locations and not monitored, so this satellite-based data set is the first to provide regular annual information on these passive volcanic emissions.

"Quantifying the sulfur dioxide bull's-eyes is a two-step process that would not have been possible without two innovations in working with the satellite data," said co-author Nickolay Krotkov, an atmospheric scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

First was an improvement in the computer processing that transforms raw satellite observations from the Dutch-Finnish Ozone Monitoring Instrument aboard NASA's Aura spacecraft into precise estimates of sulfur dioxide concentrations. Krotkov and his team now are able to more accurately detect smaller sulfur dioxide concentrations, including those emitted by human-made sources such as oil-related activities and medium-size power plants.

Being able to detect smaller concentrations led to the second innovation. McLinden and his colleagues used a new computer program to more precisely detect sulfur dioxide that had been dispersed and diluted by winds. They then used accurate estimates of wind strength and direction derived from a satellite data-driven model to trace the pollutant back to the location of the source, and also to estimate how much sulfur dioxide was emitted from the smoke stack.

"The unique advantage of satellite data is spatial coverage," said Bryan Duncan, an atmospheric scientist at Goddard. "This paper is the perfect demonstration of how new and improved satellite datasets, coupled with new and improved data analysis techniques, allow us to identify even smaller pollutant sources and to quantify these emissions over the globe."

The University of Maryland, College Park, and Dalhousie University in Halifax, Nova Scotia, contributed to this study.

For more information about, and access to, NASA's air quality data, visit:

http://so2.gsfc.nasa.gov/

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives, and safeguard our future. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.

For more information about NASA Earth science research, visit:

http://www.nasa.gov/earth

Tuesday, May 17, 2016

Chicken Coops, Sewage Treatment Plants are Hot Spots of Antibiotic Resistance

Study Surveyed Bacterial Ecosystems in Developing Countries


A new study surveyed ecosystems of bacteria and their capacity to resist antibiotics in low-resource communities, including Pampas de San Juan de Miraflores, a densely populated slum outside Lima, Peru. (Photo: Pablo Tsukayama

Antibiotic-resistant bacteria most often are associated with hospitals and other health-care settings, but a new study indicates that chicken coops and sewage treatment plants also are hot spots of antibiotic resistance. The new study surveyed ecosystems of bacteria and their capacity to resist antibiotics in low-resource communities, including Pampas de San Juan de Miraflores, a densely populated slum outside Lima, Peru.

Antibiotic-resistant bacteria most often are associated with hospitals and other health-care settings, but a new study indicates that chicken coops and sewage treatment plants also are hot spots of antibiotic resistance.

The research, led by a team at Washington University School of Medicine in St. Louis, is published May 12 in Nature.

The scientists surveyed bacteria and their capacity to resist antibiotics in a rural village in El Salvador and a densely populated slum on the outskirts of Lima, Peru. In both communities, the researchers identified areas ripe for bacteria to shuffle and share their resistance genes. These hot spots of potential resistance transmission included chicken coops in the rural village and a modern wastewater treatment plant outside Lima.

"Bacteria can do this weird thing that we can't -- exchange DNA directly between unrelated organisms," said senior author Gautam Dantas, PhD, an associate professor of pathology and immunology. "That means it's relatively easy for disease-causing bacteria that are treatable with antibiotics to become resistant to those antibiotics quickly. If these bacteria happen to come into contact with other microbes that carry resistance genes, those genes can pop over in one step. We estimate that such gene-transfer events are generally rare, but they are more likely to occur in these hot spots we identified."

While the study was done in developing parts of the world, Dantas suggested ways the data could be relevant for the U.S. and other industrialized countries. If the chicken coops of subsistence farmers are hot spots of resistance gene transfer, he speculated that bacteria present in industrial farming operations -- where chickens regularly receive antibiotics -- would see even more pressure to share resistance genes. Dantas expressed concern about such bacteria getting into the food system. Further, the wastewater treatment facility the investigators studied in Lima is a modern design that uses technologies typical of such facilities around the world, including those in the U.S., suggesting these plants may be hot spots of antibiotic resistance transmission regardless of their locations.

The study is the first to survey the landscape of bacteria and the genetics of their resistance across multiple aspects of an environment, including the people, their animals, the water supply, the surrounding soil, and samples from the sanitation facilities. While the densely populated slum surrounding Lima has a districtwide sewage system and modern wastewater treatment plant, the village in El Salvador has composting latrines.

Rural villagers who rely on subsistence farming, and residents of densely populated, low-income communities surrounding cities make up a majority of the global population; yet their microbiomes are largely unstudied. Most similar studies to date have focused on heavily industrialized populations in the United States and Europe and on rare and so-called pristine communities of people living a traditional hunter-gatherer lifestyle.

"Not only do the communities in our study serve as models for how most people live, they also represent areas of highest antibiotic use," Dantas said. "Access to these drugs is over-the-counter in many low-income countries. Since no prescription is required, we expect antibiotic use in these areas to be high, putting similarly high pressure on bacteria to develop resistance to these drugs."

In general, Dantas and his colleagues found that resistance genes are similar among bacteria living in similar environments, with more genetic similarity seen between bacteria in the human gut and animal guts than between the human gut and the soil, for example. In addition, the researchers also found that bacteria that are closely related to one another have similar resistance genes, which might be expected as bacteria pass their genes from one generation to the next.

"The general trends we found are consistent with our previous work," Dantas said. "We were not terribly surprised by the resistance genes that track with bacterial family trees. On the other hand, the genes we found that break the hereditary trend are quite worrisome. Genes that are the exceptions to the rule -- that are not similar to the surrounding DNA -- are the ones that are most likely to have undergone a gene-transfer event. And they are the resistance genes at highest risk of future transmission into unrelated bacteria."

Of the locations sampled in the study, resistance genes that are most likely to be mobile and able to jump from one bacterial strain to another were found in the highest numbers in the chicken coops of villagers in El Salvador and in the outgoing "gray" water from the sewage treatment plant outside Lima. Not suitable for drinking, most of this water is released into the Pacific Ocean, and some is used to irrigate city parks, the researchers said.

"Soils in the chicken coops we studied appear to be hot spots for the exchange of resistance genes," Dantas said. "This means disease-causing bacteria in chickens are at risk of sickening humans and transferring their resistance genes in the process. Our study demonstrates the importance of public health guidelines that advise keeping animals out of cooking spaces."

As for the wastewater treatment plant, Dantas called it the perfect storm for transmitting antibiotic resistance genes. Such facilities are excellent at removing bacteria that are well-known for causing disease and can be grown in a petri dish, such as E. coli. But that leaves room for other types of bacteria to grow and flourish.

"The system is not designed to do anything about environmental microbes that don't make people sick," Dantas said. "But some of these bacteria carry resistance genes that are known to cause problems in the clinic. We are inadvertently enriching this water with bacteria that carry resistance genes and then exposing people to these bacteria because the water is used to irrigate urban parks."

Dantas and his colleagues suspect that the antibiotic resistance they measured in microbes that survive the plant's treatment process is driven by the presence of over-the-counter antibiotics in the sewage being treated. The researchers measured antibiotic levels before and after treatment, and while most of these drug residues are removed during the process, the fact that they're present at the beginning favors the survival of bacteria that are resistant to them.

"All the antibiotics we detected in the pre-treated water were among the top 20 sold in Peru," Dantas said. "These findings have implications for public health, perhaps in designing future wastewater treatment plants and in making policy decisions about whether antibiotics should be available without a prescription."

________________________________________

Story Source:

The above post is reprinted from materials provided by Washington University School of Medicine. The original item was written by Julia Evangelou Strait. Note: Materials may be edited for content and length.

Friday, April 8, 2016

Report Shows How to Say Goodbye to Harmful Algal Blooms

Date: April 7, 2016

Source: Ohio State University

Summary: Harmful algal blooms dangerous to human health and the Lake Erie ecosystem--such as the one that shut down Toledo's water supply for two days in 2014--could become a problem of the past. Scientists have reported on approaches to reduce harmful algal blooms on Lake Erie.



Jay Martin, an ecological engineer with The Ohio State University, poses next to the Maumee River in Toledo, Ohio, in this 2015 photo.
Credit: Photo: Ken Chamberlain, CFAES.

Harmful algal blooms dangerous to human health and the Lake Erie ecosystem--such as the one that shut down Toledo's water supply for two days in 2014--could become a problem of the past.

A new report shows that if farmers apply agricultural best management practices (BMPs) on half the cropland in the Maumee River watershed, the amount of total phosphorus and dissolved reactive phosphorus leaving the watershed would drop by 40 percent in an average rainfall year -- the amount agreed to in the 2012 Great Lakes Water Quality Agreement between the U.S. and Canada.

Scientists believe that a drop of this magnitude would keep algal blooms at safe levels for people and the lake.

"With aggressive adoption of best management practices, it is possible to reduce harmful algal blooms to safe levels while maintaining agricultural productivity," said Jay Martin, ecological engineer in The Ohio State University's College of Food, Agricultural, and Environmental Sciences and co-author of the study.

The study, "Informing Lake Erie Agriculture Nutrient Management Via Scenario Evaluation," was a collaborative effort between the University of Michigan as the lead, The Nature Conservancy, Heidelberg University, LimnoTech, Texas A&M and Ohio State.

It reviewed 12 approaches to reducing total and dissolved reactive phosphorus and concluded that two of them would result in a 40 percent reduction on average.

"All 12 of the modeled scenarios produced results beneficial to phosphorus reduction," said Don Scavia, lead author of the study, environmental engineer and director of the University of Michigan's Graham Sustainability Institute.

Of the scenarios that reached the 40 percent threshold, one was an extreme approach unlikely to be implemented, Scavia said. That extreme approach showed that 1.5 million crop acres would need to be converted into grassland to meet the targets, if no additional BMPs were employed on agricultural lands.

On the other hand, "the most promising scenarios included widespread use of in-field and edge-of-field nutrient management practices, especially subsurface application of phosphorus fertilizers, expansion of cover crops and creation of buffer strips," he said.

The BMPs are practices farmers have successfully used for decades, said Martin, who also leads Ohio State's Field to Faucet water quality initiative. They include subsurface fertilizer application, cover crops, fertilizing according to soil tests and installing buffer strips to intercept runoff.

Solutions must be good for both water, farmers

"The BMP scenarios are more sustainable because they can sustain agricultural productivity while improving water quality," Martin said. "To move forward, it is most important to find solutions that both improve water quality and maintain economic returns for farmers."

In the most promising BMP scenario, about 1 percent of the land in the watershed, or about 30,000 acres, would need to be converted to buffer strips, and about half the farm acreage would need to have cover crops and subsurface phosphorus applications. Farmers in the watershed are already implementing some of these BMPs, and so are on the way to reaching the 50 percent adoption level that would be necessary, Scavia said. A scenario that included enhanced nutrient management on all the cropland was also effective in reaching this goal.

While the BMPs are familiar to farmers, "It's clear that broadening their use as much as needed will be a big lift," Martin said. "What will help is the additional $41 million that USDA announced it would invest in the Western Lake Erie Basin. This represents a significant investment that would help reach the 40 percent goal."

The U.S. Department of Agriculture's Natural Resources Conservation Service (NRCS) announced theinvestment March 28 at Maumee Bay State Park near Toledo. The dollars will be used to support farmer implementation of conservation practices.

Funding will help implement best practices

"This, along with other innovative efforts like water trusts, cost shares, drain fee incentives, and public-private partnerships that are already underway within the Lake Erie Basin and other parts of the Great Lakes, provide examples of how to make this happen," Martin said.

"The challenge is how to integrate and scale up these and other parts of the solution to treat the number of acres needed to see measureable improvements in water quality," he said.

The researchers chose the Maumee watershed because it has the most impact on the Western Lake Erie Basin, where most of the dangerous algal blooms occur. Information from the study could likely be applied to other agriculturally dominated watersheds with similar slopes, soil types, crop rotations and drainage, Scavia said, but current BMP use would need to be determined.

"The study's models provided the best available advice on both the scale and direction of change needed to meet the new load targets, and they suggested multiple pathways for it. But, as with all modeling of this sort, they may have under- or overestimated what is needed," Scavia said.

"The real test is to begin implementing the change, tracking implementation progress, measuring environmental outcomes, and adjusting both the models and the actions if needed," he said.

The report can be found online at: http://graham.umich.edu/media/pubs/InformingLakeErieAgricultureNutrientManagementviaScenarioEvaluation.pdf

Story Source: Ohio State University. "Report shows how to say goodbye to harmful algal blooms." ScienceDaily. ScienceDaily, 7 April 2016. .

Tuesday, March 22, 2016

Antibiotic Resistance: It's a Social Thing

Date: March 15, 2016
Source: University of York
Summary: Trace concentrations of antibiotic, such as those found in sewage outfalls, are enough to enable bacteria to keep antibiotic resistance, new research has found. The concentrations are much lower than previously anticipated, and help to explain why antibiotic resistance is so persistent in the environment.


Aerial view of sewage water treatment plant.
Credit: © josefkubes / Fotolia

Trace concentrations of antibiotic, such as those found in sewage outfalls, are enough to enable bacteria to keep antibiotic resistance, new research from the University of York has found. The concentrations are much lower than previously anticipated, and help to explain why antibiotic resistance is so persistent in the environment.

Antibiotic resistance can work in different ways. The research described the different mechanisms of resistance as either selfish or co-operative. A selfish drug resistance only benefits the individual cell with the resistance while a co-operative antibiotic resistance benefits both the resistant cell and surrounding cells whether they are resistant or not.

The researchers analysed a plasmid called RK2 in Escherichia coli, a bacterium which can cause infectious diarrhea. RK2 encodes both co-operative resistance to the antibiotic ampicillin and selfish resistance to another antibiotic, tetracycline. They found that selfish drug resistance is selected for at concentrations of antibiotic around 100-fold lower than would be expected -- equivalent to the residues of antibiotics found in contaminated sewage outfalls.

The study, which is published in Antimicrobial Agents and Chemotherapy (AAC), involved Professor Michael Brockhurst, Dr Jamie Wood and PhD student Michael Bottery in the Departments of Biology and Mathematics at York. The work was supported by the European Research Council under the EU's Seventh Framework Programme and the Wellcome Trust.

Dr Wood said: "The most common way bacteria become resistant to antibiotics is through horizontal gene transfer. Small bits of DNA, called plasmids, contain the resistance and can hop from one bacteria to another. Worse still, plasmids often contain more than one resistance."

Michael Bottery added: "There is a reservoir of antibiotic resistance out there which bacteria can pick and choose from. What we have found is some of that resistance can exist at much lower concentrations of antibiotic than previously understood."

Source: University of York. "Antibiotic resistance: it's a social thing." ScienceDaily. ScienceDaily, 15 March 2016. .

Friday, March 11, 2016

New Report: Attribution of Extreme Weather Events in the Context of Climate Change

A new report from the National Academies of Sciences, Engineering, and Medicine concludes it is now possible to estimate the influence of climate change on some types of extreme events. Confidence is strongest in attributing types of extreme events that are influenced by climate change through a well-understood physical mechanism, such as, the more frequent heat waves that are closely connected to human-caused global temperature increases, the report finds. Confidence is lower for other types of events, such as hurricanes, whose relationship to climate change is more complex and less understood at present. For any extreme event, the results of attribution studies hinge on how questions about the event’s causes are posed, and on the data, modeling approaches, and statistical tools chosen for the analysis. Read a 4-page summary of the report's findings and download the report for free.

Wednesday, January 6, 2016

More Environmentally-Friendly Concrete Made Using Sugar Cane Residue

Date: January 4, 2016
Source: Asociación RUVID
Summary: A new type of concrete has been developed that is cheaper and much less polluting to the environment. Researchers have swapped in sugar cane straw ash, a crop residue typically discarded as waste, as a substitute for Portland cement.

Researchers from the Universitat Politècnica de València (Polytechnic University of Valencia, UPV) and San Paolo State University (Unesp) have developed a new type of concrete that is cheaper and much less polluting to the environment. They have done so by swapping in sugar cane straw ash, a crop residue typically discarded as waste, as a substitute for Portland cement.

Currently pursued at laboratory scale only, the results of this work have been published in the Construction and Building Materials journal. They also form part of Brazilian student João Cláudio Bassan de Moraes's master's dissertation, directed by lecturer Mauro Tashima, who completed his PhD at the UPV and is currently lecturing at Unesp.

Talking to us about the project, Jordi Payá, researcher at the Concrete Science and Technology Institute (ICITECH) at the UPV, explains: "The harvester strips the cane, discarding the tops and leaves as waste. This is the raw material we work with, sugar cane straw." In total around 650 million tonnes of sugar cane are harvested in Brazil every year. Of this, between 15 and 20% corresponds to sugar straw, which is left on the field and either burned or left to decay naturally.

So far, the international research team has been able to obtain concrete using 30% less Portland cement, substituting it with the ashes obtained from burning the sugar cane straw.

"The cement itself is the most expensive and most polluting ingredient of concrete, which makes the benefits [of this new method] as much economic as environmental. We are also making use of a by-product that is currently unexploited, with all the benefits that this entails" (Payá).

Process

To burn the waste, UPV and Unesp researchers have designed a bespoke combustion burner, into which the raw material must be fed following a strict procedure. "Through this process we obtain ashes that are very reactive to the cement, a quality that is very important to the mechanical performance of the resulting concrete, to its resistance to compression, for instance" (Payá).

Work has focused primarily on the microstructural analysis of the concrete. "In the lab we analyse the chemical compounds of the ashes and of the compounds produced during the reaction with the cement, in order to assess their performance in the final product," explains Payá. Future work would include studying indicators related to the durability of mass and reinforced concrete.

The ICITECH research team also studies the use of other agricultural waste as a cement substitute, including the bamboo leaf.


Story Source: The above post is reprinted from materials provided by Asociación RUVID.

Thursday, December 17, 2015

Our Water Pipes Crawl with Millions of Bacteria

Date: December 16, 2015

Source: Lund University

Summary: Our drinking water is to a large extent purified by millions of "good bacteria" found in water pipes and purification plants, Swedish researchers have found. So far, the knowledge about them has been practically non-existent, but this new research is about to change that.


A glass of water contains millions of bacteria, say researchers.
Credit: © Andrey Kuzmin / Fotolia

Researchers from Lund University in Sweden have discovered that our drinking water is to a large extent purified by millions of "good bacteria" found in water pipes and purification plants. So far, the knowledge about them has been practically non-existent, but this new research is about to change that.

A glass of clean drinking water actually contains ten million bacteria! But that is as it should be -- clean tap water always contains harmless bacteria. These bacteria and other microbes grow in the drinking water treatment plant and on the inside of our water pipes, which can be seen in the form of a thin, sticky coating -- a so-called biofilm. All surfaces from the raw water intake to the tap are covered in this biofilm.

Findings by researchers in Applied Microbiology and Water Resources Engineering show that the diversity of species of bacteria in water pipes is huge, and that bacteria may play a larger role than previously thought. Among other things, the researchers suspect that a large part of water purification takes place in the pipes and not only in water purification plants.

"A previously completely unknown ecosystem has revealed itself to us. Formerly, you could hardly see any bacteria at all and now, thanks to techniques such as massive DNA sequencing and flow cytometry, we suddenly see eighty thousand bacteria per millilitre in drinking water," says researcher Catherine Paul enthusiastically.

"From having been in the dark with a flashlight, we are now in a brightly lit room, but it is only one room. How many different rooms are in the house is also an interesting question!" she continues.

The work of doctoral student Katharina Lührig, who works together with Catherine, professors Peter Rådström and Kenneth Persson, and colleagues Björn Canbäck and Tomas Johansson has been published in Microbes and Environments.

The results have led to lively discussions within the industry about the role of biofilms in drinking water.

At least a couple of thousand different species live in the water pipes. According to the researchers there is a connection between the composition of bacteria and water quality.

"We suspect there are 'good' bacteria that help purify the water and keep it safe -- similar to what happens in our bodies. Our intestines are full of bacteria, and most the time when we are healthy, they help us digest our food and fight illness, says Catherine Paul.

Although the research was conducted in southern Sweden, bacteria and biofilms are found all over the world, in plumbing, taps and water pipes. This knowledge will be very useful for countries when updating and improving their water pipe systems.

"The hope is that we eventually may be able to control the composition and quality of water in the water supply to steer the growth of 'good' bacteria that can help purify the water even more efficiently than today," says Catherine Paul.


Story Source:
The above post is reprinted from materials provided by Lund University.