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And here's a dilemma facing researchers working in the Amazon. They have documented that mercury used in illegal gold mining there ends up hundreds of miles downstream from the mines. But it's hard to measure what impact that mercury is having on people there because there's so little data on all the other things that might cause sickness. So researchers from Duke University have launched a health survey that is massive. NPR's Jason Beaubien traveled to the Peruvian Amazon and sent this report.
JASON BEAUBIEN, BYLINE: Life is so slow in the town of Salvacion that dogs sleep in the middle of the main streets. In the early morning, before the sun crests the lush hills that surround the town, the air is still cool and refreshing.
UNIDENTIFIED MAN: (Speaking Spanish).
UNIDENTIFIED WOMAN: (Speaking Spanish).
BEAUBIEN: Ernesto Ortiz and two of his colleagues have just arrived at the simple wood plank home of Valentino Escobar Gutierrez. They're about to start a health survey of Escobar's family that will take anywhere from two to four hours to complete. As the researchers layout their scales, test tubes and syringes, Escobar eyes their equipment with suspicion.
VALENTINO ESCOBAR GUTIERREZ: (Speaking Spanish).
ERNESTO ORTIZ: (Speaking Spanish).
GUTIERREZ: (Speaking Spanish).
BEAUBIEN: The 45-year-old Escobar wants to know why they need to take so much blood.
ORTIZ: (Speaking Spanish).
BEAUBIEN: Ortiz explains that each tube of blood will be used for a different condition, and he assures Escobar that they're taking only a tiny portion of all the blood that's in his body.
ORTIZ: (Speaking Spanish). (Laughter).
BEAUBIEN: Ortiz and his colleagues at Duke plan to enroll 5,000 people in this study. At each house, they'll take exhaustive medical histories. They'll ask about diet, income, education and past illnesses. They'll get blood, urine and hair samples for a battery of tests.
ORTIZ: We're going to do a sample for malaria, for dengue. We're also testing for TB - tuberculosis. We're also testing for chronic diseases - diabetes, hypertension, kidney function, nutritional status. So we're going to have a big picture of how things are going.
BEAUBIEN: They're also testing for mercury. This team from Duke, in earlier studies, has documented the environmental spread of mercury hundreds of miles downriver from the illegal gold mines. But it's been hard to assess the full effect of the mercury because there's little data on what other things might be affecting people's health here. The goal of this current study is to help change that. The census stretches from the foothills of the Andes, where there's little mining, all the way down into the plains of the Amazon basin, where there's a lot. Mercury used to extract gold ends up in local fish, where, Ortiz says, it can cause major developmental delays in children.
ORTIZ: If that happens during early childhood, there's no return. They won't be able to heal from that damage.
BEAUBIEN: You can't see or smell mercury in fish, so people have no idea whether they're consuming dangerous levels of the heavy metal. This study could flag that potential health threat.
FERNANDO MEDIETA: (Speaking Spanish).
BEAUBIEN: Fernando Medieta, who's in charge of the local health district, is excited about the Duke survey for other reasons. On this day, at his base at the small government hospital in Salvacion, Medieta is yelling into a CB radio. He's trying to connect with one of his employees at a health post several hours downriver. Medieta oversees 15 of these posts. They're small, bare-bones clinics scattered through the jungle. Ten of the posts are only accessible by river, and the most distant takes at least four days to reach by canoe.
MEDIETA: (Through interpreter) The principal problem that we're trying to combat in these areas is malnutrition among children under the age of five. It's extremely high. More than half the children are chronically malnourished.
BEAUBIEN: And there are numerous other health issues in the area. Water and mosquito-borne diseases are major problems. Chronic diseases such as diabetes and hypertension are on the rise. This study is funded by Texas-based Hunt Oil Company, which is exploring for natural gas in the region. The researchers stress that the health survey is an independent academic project controlled by Duke University. Medieta at the local health ministry says he'd never have the time or the resources to do such an exhaustive health survey like this on his own.
MEDIETA: (Through interpreter) This study is important because it's going to allow us to see the health of the whole population and allow us to come up with ways to make things better.
BEAUBIEN: Down the road, all the data that's collected might also help show how things like climate change, new roads or vaccination campaigns affect disease rates in this part of the Amazon basin. Jason Beaubien, NPR News, Salvacion, Peru.
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