Tracking Trouble in Paradise
Graduate students from the Tufts Water: Systems, Science, and Society (WSSS) program are researching the water issues facing the Bahamas.
The Bahamas, with its postcard-perfect clear blue Caribbean waters, has a problem that seems almost unimaginable. The country's main tourist draw—its lovely beaches—are virtually unmonitored for environmental contamination. Rainfall gets swept quickly into the coastal waters, along with all the pollutants typical of a growing urban center like the country's capital Nassau, situated on the main Bahamian island of New Providence.
Last spring, a group of Tufts graduate students who are part of the university's Water: Systems, Science, and Society (WSSS) program teamed up with biologists from the College of The Bahamas. Their goals: to make some initial measurements of Nassau harbor's water and sediment pollution and to give the Bahamas some recommendations for monitoring and improving the country's water quality. The experience was part of the WSSS research practicum, a required course that gives students firsthand practice in integrated water resources research.
For a country that reaps almost half of its gross domestic product from tourism, the Bahamas have a lot riding on their image of clean water and pristine beaches, which means answering a number of key questions:
How much water that flows across areas like parking lots, roadways, and roof tops picks up contaminants such as nitrogen, phosphorus, zinc, copper, and lead before making its way to the ocean? How does that affect Nassau harbor's water quality and marine life? Who is responsible for mitigating these effects?
Before the Tufts students arrived in the Bahamas, they learned that little had been done to determine what happens to Nassau's storm water (i.e., water that isn't naturally absorbed into the ground).
"That was really surprising," says Ali Akanda, a civil and environmental engineering graduate student. "There was almost nothing on storm water management in the Bahamas. We don't even have baseline data to compare our research to."
"Ours was the first report of its kind, which was kind of exciting to be a part of," says Katie Resnick, an urban and environmental policy and planning (UEP) graduate student. Resnick had visited the islands once before, but stayed on New Providence's neighbor, Paradise Island.
"When I was on vacation, we were only in the clean areas that are very well maintained and can be artificial," says Resnick. "I got more of a natural, more organic view when we went to areas that were more local, where the tourists don't always go."
And these are where the problems are.
"From the air, there's this lovely blue color to the water. But once you get to the main island, it's not. Nassau is pretty urbanized and not the pristine look you expect from a vacation place," adds Akanda.
"We really expected infrastructure to be pretty bad in terms of storm water management," says recent UEP graduate Josh Berkowitz, referring to the structures used to manage the storm water runoff as well as the government agencies responsible for overseeing their management. "The physical infrastructure—storm drains and outfalls—for the most part is poorly maintained and underinvested in and sometimes nonfunctional," he says. "The government agencies are under resourced and understaffed. Particularly, there are problems with coordination between different water management departments. So it wasn't exactly a shock but was nonetheless concerning."
At Surface Level
The Tufts team responsibilities were clear. Some graduate students would take sediment samples and assess water quality alongside their onsite collaborators from the College of The Bahamas. Others, led by UEP lecturer Rusty Russell, would ask questions of Bahamian agencies, both governmental and NGOs, to determine how storm water management was overseen and organized. And both graduate student groups would participate in a survey of how the land around the harbor was used. This "land-use survey" is the first step in understanding how pollutants—in addition to other pollution already present in Nassau harbor from cruise ships or fishing boats—might end up in the water.
Driven through the streets of Nassau on the back of a pickup truck or walking with clipboards in hand, the WSSS students made notes of what they saw. In particular, they were concerned about impervious surfaces, or "parking lots, roof tops, or roads that can carry pollutants as water runs over them instead of being absorbed into the ground," according to Katie Resnick.
Along with such development come human activities that create pollutants, such as fertilizer from lawn care or oil from gas stations and garages. One way to prevent or treat excess storm water run off before it reaches the harbor is to implement structural engineering strategies such as bioretention systems. Such structures would direct water from parking lots into grassy islands, which mimic ecosystems that naturally remove pollutants. Another simple technique would be to equip commercial or residential buildings with rooftop rain collection systems that would prevent relatively clean rain water from flowing unimpeded across dirty roadways.
"We recommend these strategies be examined because they are relatively inexpensive and are perhaps easily constructed retrofits appropriate for Nassau's existing development," says Paul Kirshen, director of the WSSS program and research professor in the civil and environmental engineering department.
In Nassau, the Tufts team found that commercial activities use about a third of the land, parking lots and roadways cover about a fourth, and residential and industrial activities come short of using another fourth. The more impervious surfaces an urban landscape has the more rainfall becomes storm water runoff that carries pollutants to the harbor.
Professor Paul Kirshen (second from left) meets with WSSS students to review the day's sampling activities.
Clear Sailing….For Now
The environment at the end of these drainage systems can tell the team a lot about how storm water moves pollutants into the harbor. From a boat in the harbor, students went snorkeling and diving to collect water, vegetation and sediment samples from the ocean floor. The boat team also tested water pH, salinity, temperature, and the amount of dissolved oxygen—all of which serve as measures of the overall health of the ecosystem.
The College of The Bahamas team, led by Kathleen Sullivan-Sealey, executive director of the Marine and Environmental Studies Institute, is currently analyzing these water and vegetation samples to better understand the harbor's biological environment.
Less glamorous but no less important, others went out to drain inlets and outlets on the shore, collecting mud samples for analysis. All the dirt, from land and sea, wound up with civil and environmental engineering graduate student Jesus Sanchez.
"This is pretty much just sandy mud and debris. This looks like beach sand," says Sanchez, picking up several of the 50 plastic sandwich bags filled with sediment that are sitting on his lab bench at Tufts.
"This is mostly just chips of eroded lime-stone with some mud and silts," he says, pointing to a bag that looks like instant oatmeal. "For the most part, what we're checking for are byproducts of car use, like combustible emissions, particles from brake pads and tires, petroleum byproducts, and various metals," says Sanchez, who will also send the samples to outside companies for chemical analysis.
These pollutants and others come from human, or "anthropogenic," activities. And, generally, the smaller the grain size, the higher the concentration of pollutants.
"Finer grain sediments are associated with higher concentrations of anthropogenic pollutants like toxic elements and persistent organic pollutants," says John Durant, a professor of civil and environmental engineering at Tufts who accompanied the graduate students to the islands. Some of these elements, such as nickel, lead, zinc, copper, chromium, and arsenic can be acutely toxic.
The team will estimate the amount of metals that storm water from Nassau's roadways and parking lots are contributing to the watershed over a year. Though dumping potentially hundreds of kilograms of zinc, phosphorus and other pollutants into the harbor might sound like a lot of contamination, the team can't get a good grip on just how bad it is or isn't until they determine the maximum amount of pollution that the harbor can handle and still meet water quality standards.
But from his experience researching contaminated waters in the U.S., Durant says that Nassau harbor isn't in bad shape. Yet.
"The harbor is actually a lot cleaner than I thought it would be," says Durant. "A lot of my work has been here in the Northeast, which is pretty contaminated, although it's better than it used to be. But compared to the Bahamas, it's awful."
However, Durant says the situation still needs to be monitored.
"I was pleasantly surprised by the clarity of the water and the relative cleanliness of the sediments, despite the amount of boat traffic that the harbor gets," he says. "Unlike a lot of the places around here in Boston, there's really good water flow out of the harbor."
In the Bahamas, funding for managing storm water is limited, staff support is in short supply and reallocation of funds from one environmental program to another is fraught with political pitfalls.
"We went to quite a few offices where we were basically thrown out—not literally—because they said they didn't have permission to share the data," says Akanda. "The storm sewers and the sanitary sewers are maintained by different parts of the government. They don't have any idea what the other department is doing."
"There are a lot of mismatched efforts and duplication of efforts. It was frustrating trying to navigate the different channels to try to get information and answers," says Berkowitz.
Kirshen says that "while access to data and officials at times was difficult and impeded the research, it does mirror what it is like to conduct research outside the U.S."
Adds Berkowitz, "It can be frustrating for Americans to come here and expect that things will work their way or on their time frame. In island communities, it's a lot slower."
The Bahamas also has a number of prominent nongovernmental organizations (NGOs) working on environmental water quality issues. UEP students met with Casuarina McKinney-Lambert, executive director of the Bahamas Reef Environment Educational Foundation (BREEF) of Nassau.
"BREEF thinks a non-regulatory, nongovernmental approach to environmental management works best in the Bahamas," says Resnick, who adds that public education is key.
The students conducted an informal survey of beachgoers at Arawak Cay and Fort Montague, which seemed to confirm that the general public was ill-informed.
"There's not much awareness about the issues," says Resnick.
The first step in raising awareness is having the research to support these efforts. And in that respect, the Tufts team has made significant strides.
"The number one priority for storm water management in the Bahamas is baseline data that's necessary to simultaneously educate and empower the public," says Kirshen.
Obtaining baseline measurements and making initial contact with major players in the environmental arena will be invaluable next year, when Tufts students return to continue the project. But perhaps most importantly, the students realize the value in an integrated approach to a problem like storm water management.
"To make an impact—to make it really work—you have to form a group that is multidisciplinary," says Akanda. "There are so many things to think about outside of an engineering point of view, that I realize I don't think of those angles."
Sanchez agrees: "I noticed that people were looking for factors that I wasn't looking for, such as how their communities were set up, why they were set up in certain ways. It really does impact where these sources of pollution are coming from and why."
"We used the engineering data to get at the policy issues, and the policy and planning aspects were used to try to solve some of the engineering issues that we were seeing," says Berkowitz. "It's really useful to understand each other's language and framework to analyze and solve these problems."
The Water: Systems, Science, and Society (WSSS) program is an interdisciplinary initiative involving Tufts arts, sciences, and engineering graduate students, faculty, and staff, as well as those from the university's Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy, The Fletcher School, The School of Medicine, and the Cummings School of Veterinary Medicine. The program aims to give its student participants the training and experience necessary to address water-related challenges around the world. To learn more
about WSSS, go to
http://www.tufts.edu/water/ or call 617-627-5589.
Article by Julia C. Keller, communications manager at Tufts School of Engineering.
Illustration by Betsy Hayes
Photo courtesy of the WSSS Program.
This article originally appeared in the fall 2008 edition of Alma Matters, the magazine for Tufts Arts, Sciences, and Engineering graduate alumni.