In a warning on Wednesday, the Bangladesh Food Safety Authority said harmful lead, or lead chromate, has been found in the turmeric used for cooking.

The authority issued the warning after the finding emerged from a joint study by icddr,b and Stanford University in the United States. It says it will run mobile courts next week to monitor everyone involved in the turmeric trade and take legal action against those responsible.

The icddr,b study says that around 2012-13, blood lead levels above the limit were found in pregnant mothers in nine districts of Bangladesh. The organisation then collected various kinds of samples to find the source of the lead, and later found lead mixed into turmeric.

Laboratory tests at Stanford University then showed the source was lead chromate, an illegally used colouring or brightening agent. Depending on the area, it is known locally as piuri, basanti rang, kanthali or sorshe phul rang.

Dr Mahabubur Rahman, a researcher at icddr,b, said lead chromate is used to make turmeric's colour brighter.

"To find its source we collected various kinds of samples of what the sources might be," Mr Rahman said. "Exploring this, we saw that when turmeric is processed, they use this lead chromate to make it shinier and brighter, to make it glossy."

In 2018 the same organisation published a research report saying it had found high levels of lead in pregnant mothers' bodies.

Source: BBC Bangla. First published in Bengali on The Agro News.