Invisible danger

Early monitoring

Yet there is an important qualification. "The survey does not tell us exactly where the lead is coming from," Wobil said. "The next step is to better identify the main sources and exposure pathways so that we can take targeted action to reduce and, where possible, eliminate children's exposure to lead."

Wobil believes the answer must therefore extend beyond treating individual cases. "The priority is to identify and remove the source of lead exposure and prevent further absorption," she said, adding that good nutrition and early monitoring of children's development can also help reduce risk and identify problems early.

Informal lead-acid battery recycling remains one of the major sources of exposure in the country.

The scale of the battery economy partly explains why electric three-wheelers account for roughly 60 to 65 percent of local lead-acid battery demand. Furthermore, the World Bank estimated that there were more than 1,100 informal used lead-acid battery recycling sites in Bangladesh as of 2022.

When used batteries are manually broken, washed, or smelted in informal facilities, lead dust can spread through the surrounding environment. In the Mirzapur research, researchers describe informal recycling as an important pathway for widespread soil contamination, particularly where recycling facilities operate close to homes and agricultural land.

But concentrating only on batteries risks making the story too simple. Wobil herself points out that everyday products can be difficult for families to identify as sources of contamination.

"Everyday products such as contaminated spices, cosmetics, or cookware can be particularly difficult to detect because they may look completely safe," she said.

Mahbubur Rahman, project coordinator and associate scientist at the International Centre for Diarrhoeal Disease Research, Bangladesh, has described a wider exposure landscape that includes lead-related industries, paint, contaminated food, cookware, toys, cosmetics, and traditional products.

He said exposure can spread through air, soil, food, agriculture, and livestock around polluted sites. In some industrial areas, elevated lead levels have been detected among people living even 1.5 to 2 kilometers from a source. In one investigation, 96 of 367 product samples screened positive for lead.