Locally manufactured aluminium cooking pots can release lead into food, exposing families to the toxic metal through everyday meals, according to a study by the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b) and Stanford University. Lead release was highest during the first uses of new pots.
The study, published in the Journal of Exposure Science & Environmental Epidemiology in October, found that rice cooked in new pots contained up to 305 micrograms of lead per kilogram, while khichuri contained up to 420 micrograms. Both levels were substantially higher than the US Food and Drug Administration's (FDA) limit of 10 micrograms per kilogram for food intended for babies and young children.
Researchers tested 7 used aluminium pots collected from households and 20 new pots purchased from a local supplier. Lead was detected in food cooked in every new pot and 6 of the 7 used pots.
The findings raise concerns about locally manufactured cookware, much of which is produced by melting scrap metal without adequate screening for contaminants.
Lead levels in food declined with repeated use of new pots but remained detectable during the third cooking. Researchers also found that scrubbing new pots with steel-wire sponges released about 5 times more lead than leaving them unscrubbed. Stirring food with metal spatulas also increased lead release.
Based on typical rice consumption among children in rural Bangladesh, researchers estimated that a child eating rice cooked in such a pot could ingest more than 5 times the FDA's reference level for daily lead intake from food. The estimate was based on a model rather than direct measurements of children's exposure.
“Lead can't be seen, smelled or tasted, so a pot that looks perfectly good can still be added to a family's food,” said Dr Jenna Forsyth, director of Project Unleaded at Stanford University's Human and Planetary Health program.
She said the study measured lead in both cookware and food to establish how everyday cooking pots could become a source of exposure.
Lead exposure can cause lasting damage to children's brain development, affecting learning and behavior. The World Health Organization (WHO) says there is no known safe level of lead in blood.
Dr Jesmin Sultana, assistant scientist at icddr,b's Environmental Health and Water, Sanitation and Hygiene (WASH) program, said families should choose cookware with credible evidence of food safety, particularly when preparing meals for young children.
She advised households using locally made pots to avoid steel-wire scrubbers and cooking acidic dishes in them. However, she cautioned that these measures could not reliably make contaminated cookware safe.
The researchers said responsibility for preventing exposure should not rest solely on consumers, as lead contamination can occur during manufacturing. They called on the Bangladesh Food Safety Authority (BFSA) and the Bangladesh Standards and Testing Institution (BSTI) to introduce and enforce clear safety requirements for cookware.
Proposed measures include screening scrap metal used in production, testing finished pots for lead release into food, and helping small-scale manufacturers access safer raw materials and testing facilities.
“Affordable cookware should also be safe cookware,” said Dr Md Mahbubur Rahman of icddr,b's Environmental Health and WASH program, urging authorities to establish and enforce standards for lead leaching from cookware.
The researchers acknowledged that the study was a small laboratory investigation and that further research is needed to assess other types of cookware and everyday cooking practices.
The study was supported by Stanford University's King Center on Global Development.