State of the Planet

News from the Columbia Climate School

High School Students in Peru Discover Lead Contamination Hotspots

student sampling for lead in peru
A student samples dust from a sidewalk to test for lead contamination. Photo: Johny Ponce

As a new school year revs up in Peru this month, high school classes in four communities are testing for lead contamination in their hometowns. Equipped with a field testing kit developed at Columbia’s Earth Institute and adapted in Peru, the students are scooping up soil samples from streets, schoolyards, and homes with children under 6 years old. The classes have measured the lead content in about 400 soil samples since September of last year, digging up some startling results in the process.

map of lead samples in cerro de pasco peru
Map of the project’s findings in the city of Cerro de Pasco, Peru. All soil samples displayed here exceeded EPA recommended lead limits of 400 ppm. Orange markers indicate lead levels of 400-800 ppm; red indicates 800-5,000; and black indicates 5,000 or more. Image courtesy Johny Ponce and Franziska Landes

One area near a battery smelter in Ate, Lima, was surprisingly free of contamination. Meanwhile, the port of Callao, where Peru exports a lot of ore, contained some patches with concerning levels of the toxic metal. And the former mining town of Cerro de Pasco raised some major red flags.

“They found, around the school, incredible levels of contamination,” says Lex van Geen, research professor at Columbia’s Lamont-Doherty Earth Observatory. “The mining company says it’s doing things, it’s alright, but here you have soccer field that has Superfund-levels of lead contamination.”

Working with high school Science, Technology, and Environment (STE) classes, the project’s goal is to find lead contamination hotspots so that they can prevent exposure to the toxic metal. Funded by a USAID PEER grant, the “Lead-Free Kids Peru” project is led by Johny Ponce at the Center for Research in Environmental Health (CREEH) in Peru; van Geen and his PhD student Franziska Landes are collaborators on the project.

First Results

Lead is a neurotoxin. Exposure to high levels of it can cause anemia, weakness, and kidney and brain damage. Its effects are particularly dangerous for young children, whose brains are still developing. In addition to lower intelligence scores, lead exposure at an early age is linked to behavioral and emotional problems, and even higher rates of juvenile delinquency. The toxic metal is a problem in many areas of Peru due to mining, smelting, and other industrial activities.

results of lead testing in ate, peru
The district of Ate, Lima, is home to a battery smelter, yet the soil samples here exhibited mostly safe levels of lead. Green indicates less than 140 ppm; yellow indicates 140-400; orange indicates 400-800, and red indicates 800-5,000. Image courtesy Johny Ponce and Franziska Landes

Whereas the U.S. Environmental Protection Agency recommends limiting lead to 400 parts per million (ppm) in soil where children play, last fall the students in Cerro de Pasco collected a sample in their soccer field containing a disturbing 4,800 ppm of lead. And just up the road from the school, another sample registered at 15,000 ppm. Many other samples collected in the town surpassed safe levels as well.

Ponce says that one of the things that has surprised him most is that homes in Callao contain high levels of lead, on average. In one home, he says, a student collected dust containing lead levels of 1,300 ppm, indicating a high exposure for the family living there.

Scaling Up

Landes and van Geen have been tracking lead levels in Peru for several years. During their previous research, they found that parents collecting soil samples in the places where their children play were able to discover contaminated hotspots that scientists sampling blindly in a grid-like pattern had missed. The parents would gather samples using a simple kit that Landes put together, then bring the samples back for testing to learn where the dangerous areas of the neighborhood were.

callao lead findings
The port of Callao, where Peru exports a lot of ore, contained some patches with concerning levels of the toxic metal. Image courtesy Johny Ponce and Franziska Landes

The current project scales up from those findings, showing larger groups how to systematically collect and analyze the soil samples. The kids can test lead levels in the places that are most relevant for them, and in places where NGO workers might not have access — such as backyards and other private areas. The test kit gives results on the spot, and the results can later be verified using more advanced methods.

The project gives students hands-on experience of how science is done, and lets them help their communities at the same time, Landes points out. Eventually, the simple testing equipment may also empower communities monitor ongoing mining projects and make sure companies are cleaning up after themselves, van Geen suggests.

Prevention and Protection

Although the project doesn’t have funding to remediate areas contaminated by lead, the team says it’s still helpful for parents to know where the hotspots are.

“There are actions you can take on a personal level, in terms of knowing where to be careful,” says Landes. The main way lead enters the body is through the mouth, so she suggests keeping toddlers off the ground in contaminated areas, and washing their hands after they play in soil. She adds that “as a community, you can organize to put a fence up, cover the soil, and/or make sure it’s widely known that kids shouldn’t be playing there.”

soccer field in peru
In one school soccer field, the students collected a sample that contained “Superfund-levels of lead contamination,” says Lex van Geen from Columbia’s Lamont-Doherty Earth Observatory. Photo: Franziska Landes

For the most part, the students’ families and the communities have been interested in and grateful for the testing. “Some were surprised and others indicated that they already knew about the presence of lead,” says Ponce, “but they didn’t know what actions they should take.”

He says that the project is already helping to increase local awareness about lead exposure. Students whose parents work with lead said they would inform their families about practices that could protect them — such as changing out of dusty clothes before entering the home. And during meetings and home visits, Ponce says people mention that “they’re going to be more careful with their small children with respect to washing their hands and cleaning the home and toys.”

Ponce and his network of teachers started a new round of testing in March, and have expanded into a fourth location: the heavily polluted lead-smelting town of La Oroya. With two more years of funding remaining, the team hopes to work with a total of a dozen or so classes to collect and test 10,000 soil samples. They aim to publish the results in scientific journals.

Landes and van Geen also have ideas on how to refine their field testing kit and get it into more schools. “The longer-term goal is that this becomes more of a packageable unit that can be shared with instructors, and that doesn’t need a large team supporting it,” says Landes.

Ponce says the kit is very useful, and hopes that by the end of the project, it will be accepted by Peru’s Ministries of Education and Health, so that it can be officially included as part of the STE class and accessible across all of Peru.

van Geen hopes to see the test kit spread to other areas where lead contamination is a potential problem, such as parts of Bolivia, Eastern Europe, and Russia. “I would love to see every mining town’s school using the kit as part of the curriculum,” he says.

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