Sewer upgrade flushes West Nile virus vector from Atlanta stream

About 50 Emory students, mostly undergraduates, worked in the field to gather data for the stream monitoring project.

By Carol Clark

Just 10 years ago, a heavy rain in Atlanta could turn Tanyard Creek into a river of raw sewage. “You would sometimes see toilet paper hanging from low branches along its banks,” recalls Gonzalo Vazquez-Prokopec, a disease ecologist in Emory’s Department of Environmental Sciences.

Few fish or turtles were evident in the stream, which flows alongside expensive Buckhead real estate. But larvae from the Culex quinquefasciatus mosquito, the main vector of West Nile virus in Atlanta, thrived in the polluted waters.

Today, that scene is largely reversed, following the remediation by the city of Atlanta of a combined sewage overflow (CSO) facility connected to Tanyard Creek. A five-year study led by Emory researchers gathered the before-and-after data to prove it.

“This is the first study that shows how the construction of a deep storage tunnel for a CSO system not only improves stream health and water quality but reduces the mosquitoes that spread West Nile virus,” Vazquez-Prokopec says.

The journal Environmental Research published the study’s results, which could help guide interventions for cities across the country dealing with problems of aging sewage systems and burgeoning populations.

“Our data provide evidence for how a particular cost-saving technology can work to significantly reduce both pollution and disease vectors,” Vazquez-Prokopec says.

About 50 Emory students, mostly undergraduates, worked in the field to help gather the data for the project. “I now use the research in my ‘Urban Ecology and Development Class’ to introduce students to the levels of impairment that urban streams can suffer,” Vazquez-Prokopec says.

In addition to Vazquez-Prokopec, the study’s co-authors include Andrea Lund, Joseph McMillan, Shirin Jabbarzadeh and Uriel Kitron (all from Emory’s Department of Environmental Sciences); Rosmarie Kelly from the Georgia Department of Public Health; Daniel Mead from the University of Georgia; and Thomas Burkot from James Cook University in Australia.

Toilet paper hangs from the underbrush alongside Tanyard Creek, following a heavy rain in 2008.

Cities alter the natural environment in myriad ways, and one of the most obvious is water pollution. Sewage, chemicals and heavy metals wind up in creeks, streams and rivers.

More than a century ago, many cities in the United States combined their sewer lines from buildings with runoff from streets. When populations were smaller and fewer surfaces were paved, the sewage pipes were generally large enough to handle the combined flows, and the systems only rarely overflowed.

Today, however, many of the more than 700 cities across the country using CSO systems are facing an environmental crisis. During periods of heavy rain, the wastewater flows directly into natural waterways after only minimal chlorine treatment and sieving to remove large physical contaminants.

Congress had passed the Clean Water Act in 1972, calling for zero discharge of pollutants into fishable and swimmable waters by 1985. Atlanta was among the many cities that failed to achieve this goal even by the late 1990s. After heavy rains, federal water-quality monitoring stations along the Chattahoochee River have recorded as much as 20,000 colonies per liter of e-coli fecal chloroforms, essentially traces of human feces.

Under the pressure of lawsuits, and enforcement action by the U.S. Environmental Protection Agency, Atlanta began remediation efforts. The city eventually won an extension to 2027 to complete the system upgrades.

In June 2008, when Emory’s Department of Environmental Sciences began its water quality study, Tanyard Creek was one of the most polluted streams in the city. “Just one-quarter-inch of rain was enough to initiate a sewage overflow,” Vazquez-Prokopec says. “Tanyard Creek was subjected to more than 40 overflows per year, totaling about 150 million gallons of sewage.”

Gonzalo Vazquez-Prokopec shot this video of a sewer overflow after an Atlanta downpour:


Chemical analysis of water samples from the creek showed high levels of ammonia, nitrogen and phosphorus. Worms that thrive in this type of pollution were moving about Tanyard’s waters, but most of the fish the researchers encountered were dead. “Ammonia, in particular, is food for bacteria and algae, which had overgrown and depleted oxygen levels to the point that fish couldn’t breathe,” Vazquez-Prokopec explains.

The researchers also recorded the amount and types of mosquito larvae and pupae in the water. Culex mosquitos, which can carry the West Nile virus and transmit it between birds and other animals and humans, were teeming in the polluted waters. Cup-sized Tanyard Creek water samples typically had more than 1,000 Culex larvae and pupae, compared to almost none in samples from Peavine Creek. (Peavine, which flows through the Emory campus, is a healthy urban stream not subjected to CSOs, and was used as a control in the research.)

City of Atlanta graphic of deep storage tunnel

A new deep storage tunnel for the CSO facility connected to Tanyard Creek became operational in November of 2008. The tunnel was a less expensive fix than installing larger sewage pipes, and it is able to contain most of the CSOs coming from Midtown Atlanta. A total of 42 sewer discharges were recorded at the facility in 2008, none were recorded in 2009, and only one in 2011 and two in 2012. The total annual volume discharged from the CSO facility was reduced from 154 million gallons in 2008 to six million gallons in 2012.

The effects of the remediation effort were dramatic, Vazquez-Prokopec says. “From 2008 to 2009, it was like, ‘Boom!’”

The before-and-after data showed the water quality continued to improve through October of 2012 when the study was completed. “The ammonia and nitrate levels were down, and the oxygen levels went from really low to normal,” Vazquez-Prokopec says. “We’re seeing an urban stream as healthy as an urban stream can be, with wildlife coming back, including turtles, tadpoles, frogs and water snakes. And the main vector of West Nile virus is disappearing.”

A cup-sized dip of water from Tanyard Creek that previously contained hundreds of Culex mosquito larvae now may have 10 Culex larvae, Vazquez-Prokopec says.

Atlanta has about 40 different species of mosquitoes, he notes. The Culex is the main species that can carry the West Nile virus in the city, and it happens to prefer polluted waters, making the old CSO system and frequent heavy rains a perfect storm for an outbreak of the disease.

Rapid urban growth means rapid changes throughout an ecosystem, a fact that will increasingly present challenges to public health. “In 2007, the human world population shifted from primarily rural to more urban,” Vazquez-Prokopec says. “That’s a huge and important milestone in history. We have to understand that our own health is not separate from the health of the environment.”

Photos courtesy Gonzalo Vazquez-Prokopec

Related:
Sewage raises West Nile virus risk
Mosquito hunters invent better disease weapon

The economics of happiness

Shomu Banerjee has learned lessons in how to lead a contented life through encounters with all kinds of people, from an Indian road worker he sat next to on a bus to a Nobel Laureate in economics who was his graduate school advisor.

What can economics, "the dismal science,” teach us about happiness?

Plenty, says Shomu Banerjee. A senior lecturer and applied microeconomic theorist at Emory, Banerjee was a presenter for the university’s recent Good Life Speaker Series.

“Happiness is related to our perspective, the way we choose to look at things,” he said in his talk. “And the definition of economics in this day and age is the study of choice: How do people choose things, how do they make decisions.”

He recalled an experience he had while walking on the Emory campus, when he noticed a woman in her early 30s standing at a bus stop and crying. “She had tears flowing from her eyes and there were all these people standing around and nobody was saying anything to her,” Banerjee said. “I said, ‘Is there anything I can do for you?’ And she said, ‘No, it’s okay, thank you very much.’ And then she said, ‘You know, one day I’m going to look at this and laugh.’ So I said, ‘If you already know you’re going to look at this and laugh one day, why not start right now?’ And she did actually start laughing at that point.”

Once your basic needs are met, such as food, water and shelter, happiness becomes more about choice and perspective, and finding ways to create meaning in your everyday life, Banerjee said.

Banerjee, who was born in England, described his family as “pretty poor.” He grew up in Pakistan, Madagascar and Turkey, with occasional stints in India, before moving to the United States at 21.

The Crab Nebula is the remnant of a supernova recorded by Chinese astronomers in 1054, located 6,500 light years from Earth with a diameter of 11 light years. “It’s massive,” says Banerjee. “When you look at it, you realize how ephemeral our lives are and how we really shouldn’t agonize over the small, irrelevant things in life.”

“When I came to the United States, the thing that I wasn’t ready for was what a cold place this was in terms of relationships, relative to what I’d been exposed to,” he recalled.

Outside of primary relationships, he said, many people seem to consider their relationships as transactional, like the market environment that imbues so much of society. He urged students to go beyond the transactional and take the time to notice others and empathize with them.

Banerjee recalled a story from his college years in India. He had boarded a bus with no empty seats. He stood next to a seated man who was obviously a road worker. “Road workers worked with their hands and wore turbans to carry baskets of dirt. Their fingernails would be caked with mud,” Banerjee said. “Maybe this man saw the tired look on my face. He scoots up on his seat, makes a little space and says, ‘Sit down here.’”

The man had been sweating and was covered in grime from a day of labor in the hot sun. Banerjee hesitated. He politely declined the man’s offer to squeeze in next to him, giving the excuse that he didn’t want to crowd him.

“The man told me, ‘If there is space in your heart, then there is space here,’” Banerjee said. “Now this came from a man who is probably totally illiterate. I went into automatic mode and sat down. I wasn’t even thinking. This is what I mean by empathy. These things do make a difference in the quality of our lives, but we tend to forget how to relate to others.”

Watch the video of the talk by Shomu Banerjee:


Another key to happiness is choosing not to compare one’s self to others, Banerjee said. He told a story from his graduate school years: “I had a wonderful PhD advisor, Leonid Hurwicz, a Polish-American economist who won the Nobel Prize in 2007. He was Jewish, part of his family died in the Holocaust, but he never talked about those things, ever. Except this one time.”

When a faculty member came up for tenure, and Hurwicz was asked to rank the candidate next to other luminaries in the field, he told Banerjee: “How can I compare people, and say that this person is as good as A or not as good as B? I cannot do that. And more than that, I refuse to do it, because that was the kind of madness that the Nazis were engaged in.”

Banerjee encouraged students to choose to do things that they love, rather than search for direction by browsing the marketplace. “That’s appropriate for grocery shopping,” he said, “but for living I think it’s far more important to ask, ‘Who am I? What lights me up? What motivates me? Rather than just go from classroom to classroom or major to major, shopping.”

He also advised them to make a list of simple activities that nurture their spirits and to do these things from time to time. He recalled feeling overwhelmed when he was a graduate student working on his thesis, and how he would escape that feeling by sitting beneath a tree to feed the campus squirrels.

“The challenge was getting them to actually eat out of my hand,” he said. “For those 10 to 12 moments that I was trying to feed the squirrels, I was really enjoying this inter-species interaction. I was in the moment. I was not thinking about, ‘If I don’t get my thesis I’ll have to go back to India with my tail between my legs.’”

Banerjee still makes time for activities to nurture his spirit. “Last year, around Thanksgiving, my daughter and I climbed Stone Mountain early in the morning,” he said. “We went up in the dark and watched the sun rise. It kept me going for months. It really filled me with joy. I don’t know why. Maybe it connected me with my human ancestors who looked at the sun and didn’t know what it was and were totally amazed. But I was equally amazed in the 21st century. It’s the beginning of a day, so much promise, all those things that make me feel happy.”

Many students who come to him for advice do not have a strong calling, Banerjee said. One of the hardest decisions they have to make is what to do with themselves.

He offered a quote by the late Howard Thurman, an African-American civil rights leader, who said: “Don’t ask what the world needs. Ask what makes you come alive, and go do it. Because what the world needs is people who have come alive.”

Photo credits: Top, iStockphoto.com; center, NASA; bottom, Wikipedia

What smart animals are teaching scientists

“Up until a million years ago, the brainiest species were dolphins and whales,” says Lori Marino, an Emory neuroscientist who studies these marine mammals. “We are just a very recent kid on the block.”

Marino is featured in a new NOVA series called “Inside Animal Minds,” which is exploring what makes an animal smart.

“The six million dollar question is how dolphins and whales got such large brains,” says Marino, who is examining fossil skulls for clues about how complex cognition involved in cetaceans.

Research into many species is showing that animals may be more like us than we ever thought possible.

Other Emory scientists featured in the series include primatologist Frans de Waal and neuroscientist Gregory Berns, who is researching the minds of dogs through the use of fMRI. Emory graduate Brian Hare, who is exploring the canine brain through behavioral studies, is also part of the series.

Visit the NOVA site to see the complete series.

And check out the Spring 2014 issue of Emory Magazine, which is focused on what we can learn from animals.

Related:
Should killer whales be captive?
What is your dog thinking? Brain scans unleash canine secrets
Asian elephants are huggers, reassuring others in distress

Are you a thrill seeker or a chill seeker? Join a psychologist's survey

"I don't want people to think that sensation seeking is a psychological disorder at all, but it can be linked to or exacerbate certain situations," says psychologist Ken Carter.

By Elaine Justice, Emory News Center

Whether you're a thrill seeker, or someone who'd rather be safe than sorry, clinical psychologist Ken Carter is looking for you. Carter, professor of psychology at Emory's Oxford College, is casting a wide net in gathering research for an upcoming book project on "high sensation seeking" people.

He's looking for people to visit his website, buzz.drkencarter.com, where they can complete a brief survey showing how much of a "sensation seeker" they are. The survey is a modified version of a sensation seeking scale personality test developed in the 1960s by Marvin Zuckerman of the University of Delaware. Zuckerman says that sensation seeking is "a personality trait expressed in behavior as a tendency to seek varied, novel, complex and intense sensations and experiences and to take physical risks for the sake of having such experiences."

Know anyone like that? One of the things Carter noticed in some of his friends, his clients and some of his students, too, is that there seem to be certain people who tend to have more chaotic lives than others. "I didn't know how much of that they were creating themselves or whether they just happened into these situations," he says. "I thought about them as 'chaos junkies,' as people who loved a chaotic life, who feed off that chaos. The concept of sensation seeking seemed to explain what I was seeing."

While there are people who get their thrills from really high sensation seeking activities, "it doesn't have to be jumping off a building or sky diving," says Carter. He cites the example of fire fighters or police officers, who have fairly routine activities during long stretches, punctuated by very high sensation activities that are part of the job. The sensation seeking test shows an overall score as well as sub-scores in four areas: thrill and adventure seeking, experience seeking, dis-inhibition, and boredom susceptibility.

"Different people can be high or low on different parts of the overall concept," says Carter, "and the high sensation seeking person can look very different in different situations." Carter says he plans to use not only the sensation seeking test results but people's stories as well. "When I did a workshop on sensation seeking recently, people's eyes light up, because they either know someone like this, or they themselves are like this," he says.

A psychologist approached Carter after the workshop and said he was an introverted high sensation seeking person. "You'd think that introversion and high sensation seeking would be an oxymoron, but introversion has a lot to do with being in your head and recharging yourself by being alone," says Carter. "There are high sensation activities you can do alone, such as rock climbing, which an introvert would really enjoy."

Carter says one of the great things about using social media to gather research material is that it gives him the ability to test his ideas and find out what's interesting to audiences before publishing the final product. Those wishing to share their stories can do so on Carter's Facebook page, and can follow him (@drkencarter) on Twitter as well. "I'm looking forward to collecting people's stories and experiences," he says. "For instance, sensation seeking tends to decrease as we get older, so I'm curious to see how individuals who were high sensation seeking when they were younger change as they get older."

His book is intended for three audiences and purposes: as a compendium of research on sensation seeking for academics; as a resource for counselors and therapists; and as an information tool for the public. For therapists, more information on sensation seeking could help them help clients. "Some people may seem to have attention deficit hyperactivity disorder (ADHD) or be bipolar, but what it really may be is high sensation seeking, which requires a very different kind of intervention than a psychological disorder might."

"I don't want people to think that sensation seeking is a psychological disorder at all, but it can be linked to or exacerbate certain situations," says Carter. "I want to explain to people what this concept is, how them how it can manifest itself in different ways, but also help them get the most out of that awareness." For example, "some research indicates that people who are high sensation seeking have lower levels of stress and anxiety, that there's a protective factor for them," says Carter.

"You'd think they'd be more stressed out, but apparently they can tolerate a lot more chaos." While lower sensation seeking people may be more easily thrown off base, says Carter, "high sensation seeking people can more easily roll with the punches, so there are some great aspects of it, too."

Sky diving, anyone?

Related:
The math of rock climbing

Image by iStockphoto.com

The art and physics of falling fluid

Pouring layers of paint, of different colors, produces “the most magical fantasies and forms that the human mind can imagine,” wrote Mexican painter David Alfaro Siqueiros.

It turns out that Siqueiros and Jackson Pollock, two iconic artists of Abstract Expressionism, were also experimentalists of fluid mechanics.

“Physical analysis illuminates the ways that both artists used a natural effect – fluids falling under gravity – to produce their works,” writes Emory physicist Sidney Perkowitz, in a recent issue of Physics World.

The video above demonstrates that the patterns produced by Siqueiros, who described his technique as “accidental painting,” result from a Rayleigh-Taylor instability of a viscous gravity current.

You can read Perkowitz’s article in the April issue of Physics World.