Thursday, January 19, 2017

Wastewater Treatment Upgrades Result in Major Reduction of Intersex Fish

Date: January 10, 2017
Source: University of Waterloo
Summary: Upgrades to a wastewater treatment plant along Ontario's Grand River, led to a 70 per cent drop of fish that have both male and female characteristics within one year and a full recovery of the fish population within three years, according to researchers.


PhD candidate Patricija Marjan and Professor Mark Servos collect rainbow darter fish on the Grand River in Ontario.
Credit: University of Waterloo


Upgrades to a wastewater treatment plant along Ontario's Grand River led to a 70 per cent drop in fish that have both male and female characteristics within one year and a full recovery of the fish population within three years, according to researchers at the University of Waterloo.

The 10-year study, published in Environmental Science and Technology found that the microorganisms used to remove ammonia in the wastewater treatment process also reduced the levels of endocrine disrupters in the water, which caused the intersex occurrences in fish to dramatically decline.

"Having long-term data of the fish population, before and after the wastewater treatment upgrades makes this a truly unique study," said Mark Servos, Canada Research Chair in Water Quality Protection in Waterloo's Department of Biology. "The changes to Kitchener's wastewater treatment system have had a much larger positive impact then we had anticipated."

In 2007, Servos started tracking the number of intersex male rainbow darter fish in the Grand River. Intersex fish are a result of exposure to natural and synthetic hormones in the water, which cause male fish to grow eggs in their testes. At one point Servos noted the rate of intersex changes in the Grand River was one of the highest in the world.

In 2012, the Region of Waterloo upgraded the Kitchener Wastewater Treatment Plant and changed the aeration tank to reduce toxic ammonia. Within one year the proportion of intersex males dropped from 100 per cent in some areas to 29 per cent. By the end of three years, the numbers dropped below the upstream levels of less than 10 per cent.

"Rainbow darters are the Grand River's canary in the coal mine," said Servos, also a member of the Water Institute at Waterloo. "They're extremely sensitive to the concentration of estrogens and other hormone disrupters in the water. Still, we didn't expect them to recover so quickly."

Endocrine disruption in water systems is a worldwide phenomenon. Estrogen in birth control pills and other chemicals that mimic natural hormones are known to impact fish health in trace amounts as low as one part per trillion, far below what conventional wastewater treatment can typically remove.

"In Europe, water treatment engineers have been turning to extremely expensive tertiary treatments to meet regulatory standards," said Servos. "Kitchener's example shows what can be done with currently available technology."

The Grand River watershed in southern Ontario, is the largest watershed that drains into Lake Erie. The area has a growing population of nearly one million people.

Story Source:
University of Waterloo. "Wastewater treatment upgrades result in major reduction of intersex fish." ScienceDaily. ScienceDaily, 10 January 2017. http://www.sciencedaily.com/releases/2017/01/170110151418.htm.

Journal Reference:
Keegan A Hicks, Meghan LM Fuzzen, Emily K. McCann, Maricor J Arlos, Leslie M. Bragg, Sonya Kleywegt, Gerald R Tetreault, Mark E McMaster, Mark R. Servos. Reduction of intersex in a wild fish population in response to major municipal wastewater treatment plant upgrades. Environmental Science & Technology, 2016; DOI: 10.1021/acs.est.6b05370

Friday, December 9, 2016

Bacterial Mechanism Converts Nitrogen to Greenhouse Gas

Author: Blaine Friedlander
Source: Cornell Chronicle

Cornell researchers have discovered a biological mechanism that helps convert nitrogen-based fertilizer into nitrous oxide, an ozone-depleting greenhouse gas. The paper was published online Nov. 17 in the Proceedings of the National Academy of Sciences.

“The first key to plugging a leak is finding the leak,” said Kyle Lancaster, assistant professor of chemistry and chemical biology, and senior author on the research. “We now know the key to the leak and what’s leading to it. Nitrous oxide is becoming quite significant in the atmosphere, as there has been a 120 percent increase of nitrous oxide in our atmosphere since pre-industrial times.”

Lancaster, along with postdoctoral researcher Jonathan D. Caranto and chemistry doctoral candidate Avery C. Vilbert, showed that an enzyme made by the ammonia oxidizing bacterium Nitrosomonas europaea, cytochrome P460, produces nitrous oxide after the organism turns ammonia into an intermediate metabolite called hydroxylamine.

N. europaea and similar “ammonia-oxidizing bacteria” use hydroxylamine as their fuel source, but too much hydroxylamine can be harmful – and the resulting production of nitrous oxide is a chemical coping strategy.

Lancaster and his colleagues hypothesize that when ammonia-oxidizing bacteria are exposed to high levels of nitrogen compounds, such as in crop fields or wastewater treatment plants, then nitrous oxide production via cytochrome P460 will ramp up.

In the atmosphere, greenhouse gases are a soup of many species, and Lancaster explained that nitrous oxide has 300 times the potency of carbon dioxide. “That’s a staggering number,” he said. “Nitrous oxide is a really nasty agent to be releasing on a global scale.”

Lancaster added that nitrous oxide is photochemically reactive and can form free radicals – ozone-depleting agents – which aggravates the issue of blanketing Earth’s atmosphere with more gas and raising the globe’s temperature. “In addition to its role as a greenhouse gas cloak, it’s removing our protective shield,” Lancaster said.

The United States is among the world leaders in importing nitrogen fertilizer, according to the U.S. Department of Agriculture’s Economic Research Service. The Food and Agriculture Organization of the United Nations noted that the world’s nitrogen fertilizer demand was projected to be 116 million tons for this past agricultural season.

“For the world, I realize that we are trying to feed more people and that means more fertilizer – and that means more nitrous oxide,” said Lancaster, who noted that about 30 percent of nitrous oxide emissions come from agriculture and its accompanying land use.

To reduce the negative impact of nitrogen, farmers already use nitrification inhibitors.

Said Lancaster: “While it will be challenging to develop ways to stop this process, now we have pinpointed one biochemical step leading to nitrous oxide production. Future work may lead to inhibitors, molecules that can deactivate or neutralize this bacterial enzyme. Alternatively, we may just use this new information to develop better strategies for nitrogen management.”

The Department of Energy Office of Science and the National Institutes of Health supported the research.

Thursday, November 3, 2016

Fuel From Sewage is the Future -- And It's Closer Than You Think

Technology Converts Human Waste into Bio-Based Fuel

Date: November 2, 2016
Source: Pacific Northwest National Laboratory
Summary: It may sound like science fiction, but wastewater treatment plants across the United States may one day turn ordinary sewage into biocrude oil, thanks to new research. The technology, hydrothermal liquefaction, mimics the geological conditions Earth uses to create crude oil, using high pressure and temperature to achieve in minutes something that takes Mother Nature millions of years.



Biocrude oil, produced from wastewater treatment plant sludge, looks and performs virtually like fossil petroleum.
Credit: Courtesy of WE&RF


It may sound like science fiction, but wastewater treatment plants across the United States may one day turn ordinary sewage into biocrude oil, thanks to new research at the Department of Energy's Pacific Northwest National Laboratory.

The technology, hydrothermal liquefaction, mimics the geological conditions Earth uses to create crude oil, using high pressure and temperature to achieve in minutes something that takes Mother Nature millions of years. The resulting material is similar to petroleum pumped out of the ground, with a small amount of water and oxygen mixed in. This biocrude can then be refined using conventional petroleum refining operations.

Wastewater treatment plants across the U.S. treat approximately 34 billion gallons of sewage every day. That amount could produce the equivalent of up to approximately 30 million barrels of oil per year. PNNL estimates that a single person could generate two to three gallons of biocrude per year.

Sewage, or more specifically sewage sludge, has long been viewed as a poor ingredient for producing biofuel because it's too wet. The approach being studied by PNNL eliminates the need for drying required in a majority of current thermal technologies which historically has made wastewater to fuel conversion too energy intensive and expensive. HTL may also be used to make fuel from other types of wet organic feedstock, such as agricultural waste.

Using hydrothermal liquefaction, organic matter such as human waste can be broken down to simpler chemical compounds. The material is pressurized to 3,000 pounds per square inch -- nearly one hundred times that of a car tire. Pressurized sludge then goes into a reactor system operating at about 660 degrees Fahrenheit. The heat and pressure cause the cells of the waste material to break down into different fractions -- biocrude and an aqueous liquid phase.

"There is plenty of carbon in municipal waste water sludge and interestingly, there are also fats," said Corinne Drennan, who is responsible for bioenergy technologies research at PNNL. "The fats or lipids appear to facilitate the conversion of other materials in the wastewater such as toilet paper, keep the sludge moving through the reactor, and produce a very high quality biocrude that, when refined, yields fuels such as gasoline, diesel and jet fuels."

In addition to producing useful fuel, HTL could give local governments significant cost savings by virtually eliminating the need for sewage residuals processing, transport and disposal.

"The best thing about this process is how simple it is," said Drennan. "The reactor is literally a hot, pressurized tube. We've really accelerated hydrothermal conversion technology over the last six years to create a continuous, and scalable process which allows the use of wet wastes like sewage sludge."

An independent assessment for the Water Environment & Reuse Foundation calls HTL a highly disruptive technology that has potential for treating wastewater solids. WE&RF investigators noted the process has high carbon conversion efficiency with nearly 60 percent of available carbon in primary sludge becoming bio-crude. The report calls for further demonstration, which may soon be in the works.

PNNL has licensed its HTL technology to Utah-based Genifuel Corporation, which is now working with Metro Vancouver, a partnership of 23 local authorities in British Columbia, Canada, to build a demonstration plant.

"Metro Vancouver hopes to be the first wastewater treatment utility in North America to host hydrothermal liquefaction at one of its treatment plants," said Darrell Mussatto, chair of Metro Vancouver's Utilities Committee. "The pilot project will cost between $8 to $9 million (Canadian) with Metro Vancouver providing nearly one-half of the cost directly and the remaining balance subject to external funding."

Once funding is in place, Metro Vancouver plans to move to the design phase in 2017, followed by equipment fabrication, with start-up occurring in 2018.

"If this emerging technology is a success, a future production facility could lead the way for Metro Vancouver's wastewater operation to meet its sustainability objectives of zero net energy, zero odours and zero residuals," Mussatto added.

In addition to the biocrude, the liquid phase can be treated with a catalyst to create other fuels and chemical products. A small amount of solid material is also generated, which contains important nutrients. For example, early efforts have demonstrated the ability to recover phosphorus, which can replace phosphorus ore used in fertilizer production.

Story Source:

Materials provided by Pacific Northwest National Laboratory. Note: Content may be edited for style and length.
Pacific Northwest National Laboratory. "Fuel from sewage is the future -- and it's closer than you think: Technology converts human waste into bio-based fuel." ScienceDaily. ScienceDaily, 2 November 2016. www.sciencedaily.com/releases/2016/11/161102134504.htm

Tuesday, October 18, 2016

Fracking Wastewater is Mostly Brines, Not Human-Made Fracking Fluids

Date: October 17, 2016
Source: Duke University
Summary: Human-made chemical-laden fracking fluids make up less than 8 percent of wastewater being produced by fracked wells; more than 92% of it is naturally occurring brines, which carry their own risks but may have beneficial re-uses, say investigators.

Naturally occurring brines, not human-made fracking fluids, account for most of the wastewater coming from hydraulically fractured unconventional oil and gas wells, a new Duke University study finds.

"Much of the public fear about fracking has centered on the chemical-laden fracking fluids -- which are injected into wells at the start of production -- and the potential harm they could cause if they spill or are disposed of improperly into the environment," said Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment.

"Our new analysis, however, shows that these fluids only account for between 4 and 8 percent of wastewater being generated over the productive lifetime of fracked wells in the major U.S. unconventional oil and gas basins," Vengosh said. "Most of the fracking fluids injected into these wells do not return to the surface; they are retained in the shale deep underground.

"This means that the probability of having environmental impacts from the human-made chemicals in fracking fluids is low, unless a direct spill of the chemicals occurs before the actual fracking," he said.

More than 92 percent of the flowback and produced water -- or wastewater -- coming from the wells is derived from naturally occurring brines that are extracted along with the gas and oil.

These brines carry their own risks, Vengosh stressed. They contain varying levels of salts, heavy metals and naturally occurring radioactive elements, and their sheer volume makes disposing of them a challenge.

"But with proper treatment, they potentially could have beneficial reuses," he said, "especially out West, where our study shows most brines being produced by fracked wells are much less saline than those in the East. These Western brines, which are similar in salinity to sea water, could possibly be treated and re-used for agricultural irrigation or other useful purposes, especially in areas where freshwater is scarce and drought is persistent."

The Duke team published its findings Oct. 14 in the peer-reviewed journal Science of the Total Environment.

The researchers used three statistical techniques to quantify the volume of wastewater generated from unconventional oil and gas wells in six basins nationwide: the Bakken formation in North Dakota; the Marcellus formation in Pennsylvania; the Barnett and Eagle Ford formations in Texas; the Haynesville formation in Arkansas, Louisiana and East Texas; and the Niobrara field in Colorado and Wyoming.

Using multiple statistical techniques "helped us more accurately account for changes in each well's wastewater volume and salinity over time, and provide a more complete overview of the differences from region to region," said Andrew J. Kondash, a doctoral student in Vengosh's lab at Duke's Nicholas School, who led the study.

"This makes our findings much more useful, not just for scientists but for industry and regulatory agencies as well," he said.

Among other findings, the new study shows that the median volume of wastewater produced by an unconventional oil or gas well ranges from 1.7 to 14.3 million liters per year over the first five to 10 years of production. The volume of produced water coming from these wells declines over time, while its salinity increases.

"The salt levels rise much faster than the volume declines, resulting in a high volume of saline wastewater during the first six months of production," Vengosh said. After that, the volume of wastewater produced by a well typically drops, along with its hydrocarbon output.

Elizabeth Albright, assistant professor of the practice of environmental science and policy methods at the Nicholas School, co-authored the study with Kondash and Vengosh.

Story Source:

Materials provided by Duke University. Note: Content may be edited for style and length.

Duke University. "Fracking wastewater is mostly brines, not human-made fracking fluids." ScienceDaily. ScienceDaily, 17 October 2016. www.sciencedaily.com/releases/2016/10/161017150835.htm

Friday, October 14, 2016

Brewery Wastewater Transformed into Energy Storage

Date: October 7, 2016
Source: University of Colorado at Boulder
Summary: Engineers have developed an innovative bio-manufacturing process that uses a biological organism cultivated in brewery wastewater to create the carbon-based materials needed to make energy storage cells. This unique pairing of breweries and batteries could set up a win-win opportunity by reducing expensive wastewater treatment costs for beer makers while providing manufacturers with a more cost-effective means of creating renewable, naturally-derived fuel cell technologies.

CU Boulder engineers have developed an innovative bio-manufacturing process that uses a biological organism cultivated in brewery wastewater to create the carbon-based materials needed to make energy storage cells.

This unique pairing of breweries and batteries could set up a win-win opportunity by reducing expensive wastewater treatment costs for beer makers while providing manufacturers with a more cost-effective means of creating renewable, naturally-derived fuel cell technologies.

"Breweries use about seven barrels of water for every barrel of beer produced," said Tyler Huggins, a graduate student in CU Boulder's Department of Civil, Environmental and Architectural Engineering and lead author of the new study. "And they can't just dump it into the sewer because it requires extra filtration."

The process of converting biological materials, or biomass, such as timber into carbon-based battery electrodes is currently used in some energy industry sectors. But, naturally-occurring biomass is inherently limited by its short supply, impact during extraction and intrinsic chemical makeup, rendering it expensive and difficult to optimize.

However, the CU Boulder researchers utilize the unsurpassed efficiency of biological systems to produce sophisticated structures and unique chemistries by cultivating a fast-growing fungus, Neurospora crassa, in the sugar-rich wastewater produced by a similarly fast-growing Colorado industry: breweries.

"The wastewater is ideal for our fungus to flourish in, so we are happy to take it," said Huggins.

By cultivating their feedstock in wastewater, the researchers were able to better dictate the fungus's chemical and physical processes from the start. They thereby created one of the most efficient naturally-derived lithium-ion battery electrodes known to date while cleaning the wastewater in the process.

The findings were published recently in the American Chemical Society journal Applied Materials & Interfaces.

If the process were applied on a large scale, breweries could potentially reduce their municipal wastewater costs significantly while manufacturers would gain access to a cost-effective incubating medium for advanced battery technology components.

"The novelty of our process is changing the manufacturing process from top-down to bottom-up," said Zhiyong Jason Ren, an associate professor in CU Boulder's Department of Civil, Environmental and Architectural Engineering and a co-author of the new study. "We're biodesigning the materials right from the start."

Huggins and study co-author Justin Whiteley, also of CU Boulder, have filed a patent on the process and created Emergy, a Boulder-based company aimed at commercializing the technology.

"We see large potential for scaling because there's nothing required in this process that isn't already available," said Huggins.

The researchers have partnered with Avery Brewing in Boulder in order to explore a larger pilot program for the technology. Huggins and Whiteley recently competed in the finals of a U.S. Department of Energy-sponsored startup incubator competition at the Argonne National Laboratory in Chicago, Illinois.

The research was funded by the Office of Naval Research and came as a result of a unique cross-disciplinary collaboration between Ren's lab in CU Boulder's Department of Civil, Environmental and Architectural Engineering; Professor Se-Hee Lee's lab in CU Boulder's Department of Mechanical Engineering; and Justin Biffinger's lab at the Naval Research Laboratory in Washington, D.C.

"This research speaks to the spirit of entrepreneurship at CU Boulder," said Ren, who plans to continue experimenting with the mechanisms and properties of the fungus growth within the wastewater. "It's great to see students succeeding and creating what has the potential to be a transformative technology. Energy storage represents a big opportunity for the state of Colorado and beyond."

Story Source:
Materials provided by University of Colorado at Boulder. Note: Content may be edited for style and length.

University of Colorado at Boulder. "Brewery wastewater transformed into energy storage." ScienceDaily. ScienceDaily, 7 October 2016. www.sciencedaily.com/releases/2016/10/161007120518.htm.

Thursday, October 6, 2016

China's Forest Recovery Shows Hope for Mitigating Global Climate Change

Date: March 18, 2016
Source: Michigan State University
Summary: China's sweeping program to restore forests across the country is working. The vast destruction of China's forests, leveled after decades of logging, floods and conversion to farmland, has become a story of recovery, according to the first independent verification.


Much of the land in this Chinese community has been converted to forest from cropland through the government's Grain to Green program.
Credit: Michigan State University Center for Systems Integration and Sustainability

China's sweeping program to restore forests across the country is working.

The vast destruction of China's forests, leveled after decades of logging, floods and conversion to farmland, has become a story of recovery, according to the first independent verification published in today's Science Advances by Michigan State University (MSU) researchers.

"It is encouraging that China's forest has been recovering in the midst of its daunting environmental challenges such as severe air pollution and water shortages," said co-author Jianguo "Jack" Liu, Rachel Carson Chair in Sustainability and director of MSU's Center for Systems Integration and Sustainability (CSIS). "In today's telecoupled world, China is increasingly connected with other countries both socioeconomically and environmentally. Every victory must be measured holistically, or we aren't getting a true picture."

Forests are crucial to ensuring soil and water conservation and climate regulation. The fate of forests in the world's most populous nation has global consequences by virtue of the country's sheer magnitude and its rapid development.

Since the beginning of the 21st Century, China has implemented the largest forest conservation andRecovering forests, with deforested areas in the background in Wolong China restoration programs in the world, the Natural Forest Conservation Program (NFCP), which bans logging, and in some forested areas compensates residents for monitoring activities preventing illegal timber harvesting.

The MSU scientists used a unique combination of data, including the big-picture view of NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) annual Vegetation Continuous Fields tree cover product, along with high spatial resolution imagery available in Google Earth. Then they combined data at different scales to correlate the status of the forests with the implementation of the NFCP.

And, as the Chinese government has contended, the program is working and forests are recovering, with about 1.6 percent, or nearly 61,000 square miles, of China's territory seeing a significant gain in tree cover, while 0.38 percent, or 14,400 square miles, experienced significant loss.

"Our results are very positive for China," said author Andrés Viña of MSU-CSIS. "If you look at China in isolation, its program is working effectively and contributing to carbon sequestration in accordance to its agenda for climate change mitigation. But on the other hand, China is not in a vacuum."

In the future, it is important to quantify how much China's forest gain and improved carbon sequestration may be a loss for places like Madagascar, Vietnam and Indonesia. Those are among the countries that are chopping down their forests to sell products to China. And the global increase in greenhouse gases and loss of biodiversity may have just changed addresses.

Viña noted more research is needed to document the broader impacts of forest degradation and recovery around the world. He also noted that the voracious appetite for natural resources -- both timber and the agricultural products grown on converted forestland -- is not just China's issue.

"We are all part of the problem one way or another," he said. "We all buy products from China, and China has not changed their imports and exports of wood at all. What has changed is where timber is coming from."

Besides Viña and Liu, "Effects of conservation policy on China's forest recovery" was written by MSU associate professor William McConnell, and CSIS PhD students Hongbo Yang and Zhenci Xu.

The work was supported by the National Science Foundation and MSU AgBioResearch.

Story Source:
Materials provided by Michigan State University. Note: Content may be edited for style and length.

Journal Reference:
A. Vina, W. J. McConnell, H. Yang, Z. Xu, J. Liu. Effects of conservation policy on Chinas forest recovery. Science Advances, 2016; 2 (3): e1500965 DOI: 10.1126/sciadv.1500965

Michigan State University. "China's forest recovery shows hope for mitigating global climate change." ScienceDaily. ScienceDaily, 18 March 2016. www.sciencedaily.com/releases/2016/03/160318181617.htm.

Tuesday, August 9, 2016

Mechanisms On Why 'Green' Helps in Urban Life

Biological Mechanism for Health Benefits of Urban Greenery and on the Methodology to Expand Research Efforts

Date: August 2, 2016
Source: University of Oregon
Summary: New research finds that airborne bacterial communities differ from one urban park to the next but those of parking lots are alike -- and differ from those of parks in subtle but potentially important ways.


Gwynne Mhuireach, a doctoral student in landscape architecture at the University of Oregon, check out a data-collection site at a park in Eugene, Oregon. Part of her project showed that using inexpensive petri dishes to collect air samples works as well as more expensive methods.
Credit: University of Oregon

New research finds that airborne bacterial communities differ from one urban park to the next but those of parking lots are alike -- and differ from those of parks in subtle but potentially important ways.

At a glance, such findings seem intuitive. Parks often have different vegetation in them, and asphalt-covered parking lots are much the same -- barren asphalt bombarded by solar radiation as well as heavy metals and fuel from motor vehicles.

The importance, according to University of Oregon researchers, is that this pilot study describes not only the differences in microbial communities but also how far from a park the influence may extend.

Recent studies suggest that the composition of the bacterial communities may be important to human health -- and not in the ways you think, says Gwynne Mhuireach, a doctoral student in landscape architecture who led the new study that is online ahead of print in the journal Science of the Total Environment. There is a reason, she says, to believe that healthy air depends not just on the absence of bad things like pollutants, but the presence of good things such as bacteria with which humans have co-evolved.

"We're starting to build larger and more complex cities," Mhuireach said. "I am interested in ways to help maintain people's health and happiness as we do so. Some studies say that as we are building these denser cities we are losing green space. I am looking for mechanisms that explain why vegetation helps people and how we can design for it."

In the study, the researchers simultaneously collected six air samples over an eight-hour period at five parks and five parking lots in Eugene. The locations were free of tall trees that block air movement to constrain microbial differences due to air circulation -- another role vegetation may play. The idea, Mhuireach said, was to first discover whether vegetation was a significant source of microbes for nearby areas.

Microbial samples were gathered using three petri dishes and three vacuum-pump-driven units -- all placed 2 meters (6 feet) above the ground at each site. Researchers collected 5.8 million DNA sequences representing 16,633 operational taxonomic units from 40 unique bacterial phyla.

Subsequent DNA analyses found that Sphingomonas, commonly found in soil and on plant surfaces, accounted for one fourth of bacteria collected. Also abundant were Hymenobacter, Pedobacter, Agrobacterium and Rhodococcus, all soil-associated species. The samples were collected during the harvesting season of the grass-seed industry north of Eugene, when prevailing winds likely blew associated microbes into the sites, researchers noted.

Parking lots tended to be more similar to each other, with a prevalence of Acetobacteraceae, while parks had unique bacterial fingerprints likely reflecting vegetation types in and near each park.

The findings provide evidence of how differences in vegetation in an urban area influence airborne microbial communities at fine spatial scales, said co-author Bart Johnson, a professor of landscape architecture. The study, he said, provides a path to future studies that should help guide landscape design in cities where growing populations are driving denser living spaces.

While the specifics of how plant-associated microbes affect human health, and whether microbes contribute to the well-documented benefits of urban parks for people are unknown, the researchers suggest that "provisioning urban residents with green space within 400 meters (about 1,300 feet) of their homes" would make it more likely that they are exposed to the "park-like microbiome."

"There have been studies that compared the health of children who grow up on farms versus cities," Johnson said. "They've concluded that the lower incidence of allergies in children from farms was related to different microbial exposures, but there has been little work to examine whether there is enough microbial variation at the fine spatial scales of a park, a street or a block to potentially influence the health of children in cities.

"Do children and adults with greater exposure to vegetation receive increased health benefits because of the associated microbes? We don't know, but this study points to some promising new directions of inquiry," he said.

Equally important, the researchers documented that the simple use of petri dishes, a passive data-collection approach, successfully captured airborne microbial samples comparable to the more-expensive use of vacuum-powered equipment at the study sites.

"We just let air out of the sky settle into petri dishes and found that we can use this method in future projects because we found similar composition and diversity of microbes using both methods," Mhuireach said.

Mhuireach's research, Johnson said, creatively combines methodologies from biology, architecture and landscape architecture. It is reminiscent, he said, of Dr. John Snow's mapping of cholera outbreaks in the 1850s. Snow's work provided a scientific understanding of how the disease was spread by waterborne bacteria rather than by "bad vapors," and it coincided with the efforts of landscape architect Frederick Law Olmsted to incorporate nature into urban park designs to improve human well-being.

"Olmtead was dealing with invisible things -- then unknown -- that influenced people's health," Johnson said. "This new research is pointing to a biological mechanism behind Olmstead's ideas."

Mhuireach, who grew up on a farm, said she has been curious about health differences between people who grew up in rural and urban areas. She and her co-authors noted that while overall health has improved with technological progress and lifestyle changes, researchers have found that the shift away from childhood exposures to natural environments is associated with later-life inflammatory response problems such as allergies and asthma.

"As the research advances," she said, "we will be looking at vegetation around homes and neighborhoods where people live to start answering the big questions: Why does green space improve people's well-being? Are there physiological as well as psychological mechanisms? Are there beneficial microbes that we should be exposed to on a daily basis?"


Story Source:
University of Oregon. "Mechanisms on why 'green' helps in urban life: Biological mechanism for health benefits of urban greenery and on the methodology to expand research efforts." ScienceDaily. ScienceDaily, 2 August 2016. http://www.sciencedaily.com/releases/2016/08/160802133747.htm.