Environment: Case Studies

Nutrition

It won’t taste as bad as the boy thinks, and it could well save his life: It’s a 4-cent dose of vitamin A, given by a Nepalese volunteer. School researchers study the impact of nutrition on children from the day they are born. “Kids in these poor parts of the world have a one-in-five chance of not making it to their fifth birthday,” says the Bloomberg School’s James M. Tielsch, who is studying the effects of zinc and iron folate supplements. “We’re looking for interventions that are simple, cost-effective, and have a big impact.”

Air quality

What goes up may have to come down, but that doesn’t mean it should be a spectator sport. When multistory buildings are demolished, spectators by the hundreds often line up to watch. But Bloomberg School researchers have found such events create a severe but short-lived impact on downwind air quality that may place individuals at risk, especially the very young, the elderly, and those with weakened immune systems or heart or lung disease. Their recommendation for diehard demolition fans: Stand upwind, or better yet, stay home and watch it on TV.

Effective filter

In the impoverished nation of Bangladesh, the sari is a traditional garment for women. Researchers have found that it can also be a powerful public health tool: Cotton sari cloth, when folded at least eight times, is an effective filter for household water. By filtering out plankton, the cloth also removes bacteria that grow on the plankton—including the bacterium that causes cholera. Results from a study conducted in 65 villages in rural Bangladesh between 1999 and 2002 showed that cholera cases dropped 48 percent in communities where water was filtered in this way. 

“We were thrilled,” says Rita R. Colwell, an adjunct professor at the School and lead researcher on the project, which included the School’s R. Bradley Sack and David A. Sack. “I certainly expected a reduction, but to get almost a 50 percent reduction was wonderful.” 

Half a world away, scientists are working on a 21st-century version of the same technique: They are investigating the use of high-tech membranes, made of organic polymers and other newly developed materials, to filter and purify water. The filters strain out such potentially harmful organisms as Cryptosporidium and Giardia, both resistant to chlorine. 

“Just 10 to 12 years ago, we were talking about the dream of disinfecting water without using chemicals,” says Joseph G. Jacangelo, director of the School’s Center for Water and Health, which operates a membrane filtration lab in Baltimore. “In the last couple of years, the dream has started to be realized.”

Waterborne parasites

Parasitologist Thaddeus Graczyk is using FISH to test water—or more precisely, using a technique called fluorescent in situ hybridization to assess the infectious capacity of waterborne parasites. So far, the technique is limited to the lab; Graczyk is hoping to develop a practical field test kit. “Because of the very extensive population of people with impaired immune systems, who are at much greater risk for disease and death, it’s absolutely essential that drinking water be free of waterborne parasites,” Graczyk says.