Inside the simple wood-frame house, a 6-year-old boy plays with a piece of malleable metal, biting it as his younger sister watches. In the background, piled against the wall, are two long strips of the metal – lead sheathing from an electrical cable that the family sold for scrap.
Lead seems like an odd thing to find in an Achuar village deep in the Peruvian Amazon. But the metal is valuable here, since it is easily molded to make perfect weights for fishing lines and nets.
That convenience comes at a cost. Three out of every four children in communities in the Corrientes River basin have blood lead levels higher than those considered excessive under U.S. health guidelines.
The lead strips found inside the homes solved a mystery that had long puzzled researchers.
Scientists had expected to find that water polluted by oil drilling upriver was responsible for the villagers’ high lead levels. But to their shock, they discovered that children and teens were fashioning homemade fishing sinkers from scrap lead with their teeth.
"The results were really unexpected,” said Peruvian researcher Cynthia Anticona, who conducted the study as part of her doctoral research in public health at Umeå University in Sweden.
“When we did the fieldwork, I no longer had any doubt. I saw how 5- and 6-year-olds chewed pieces of lead,” she said. “We’d been looking everywhere, when the answer was right there.”
Children exposed to lead, which can damage developing brains, have lower IQs and behavioral problems, including aggressiveness. Many experts say there is no safe level of lead for children.
Older children and teens in the villages have the highest levels, especially boys, who fish more often than girls.
Such high lead levels in adolescents are surprising, according to Bruce Lanphear, a professor at Simon Fraser University in Vancouver, Canada, who is a leading expert on effects of lead exposure on children.
“This would be the equivalent of adolescents working in a lead-related hobby or workplace,” he said. “These are substantial exposures.”
Toddlers who crawl on the ground and put objects in their mouths are usually at the greatest risk of exposure, he said. Lead levels usually drop in adolescents, although by then the damage to their developing nervous systems has already been done. Little is known about the effects of exposure that occurs when a child is older, Lanphear said.
If the young fishermen replaced the lead with non-toxic sinkers, their blood lead levels should show a notable decline within a few months, he said.
But so far, nothing has changed in these Amazonian villages, which are so remote that it takes several days by boat to reach the nearest city. Up to 40 families, with an average of three or four children each, live in wooden houses with palm-thatch roofs. They have little access to health care.
When Anticona and her adviser, Miguel San Sebastián, who had studied the health impacts of oil pollution on indigenous communities in Ecuador in the 1990s, began their study in these villages, they were not thinking of fishing sinkers.
Several earlier studies had found lead and cadmium in water and in the blood of people along the Corrientes River, and a report published in 2006 by a Peruvian non-profit organization pointed to oil operations as the likely source of pollution in Achuar communities. In January, the Peruvian government fined Argentina-based Pluspetrol $11 million for pollution.
Anticona and San Sebastián had thought their investigation into sources of the lead would lead them to the oil fields.