Authorities have arrested eight people after more than 200 children who consumed food at a preschool in China's north-west were found to have abnormally high levels of lead in their blood.
Health authorities identified 233 pupils at a preschool in the Gansu province city of Tianshui had abnormal levels of lead in their blood, out of a total of 251 children enrolled at the centre.
At least 201 of the children had been admitted to hospital.
The kindergarten's principal, surnamed Zhu, and an investor surnamed Li were detained along with six other people on suspicion of "producing poisonous or harmful food", state media reported.
Investigators found that they allowed kitchen staff to produce food using paint pigments purchased online that were later found to contain lead and were marked inedible.
Testing revealed that samples of three-colour steamed date cakes and corn rolls contained more than 2,000 times the national safety standard for food contaminants.
The cake, served at breakfast, returned a reading of 1,052 milligrams per kilogram and the roll, served at another meal, was found with 1,340 milligrams per kilogram.
The nationwide limit for lead in wheat and starch is 0.5 milligrams per kilogram, according to Chinese government records.
A parent told the state-run Jimu News tabloid that children were experiencing stomach pain and nausea and that some of their teeth turned black.
Food safety has improved in China following a series of scandals, including the 2008 discovery of toxic infant milk, which undermined public trust and consumer confidence.
Inspections by regulators in 2022 found safety issues were more common in the catering industry and agricultural products, according to state media reports.
ABC/wires
