While on the subject of lead poisoning, there's another source that few of us suspect - Ayurvedic herbal medicines. Researchers from Harvard Medical School tested a range of remedies, and discovered that 20 per cent of them, 14 of the 70 tested, had high levels of heavy metals, such as lead, mercury and arsenic. One in five were also freely available in corner shops in Boston, the researchers found.
Each of the 70 that were tested was manufactured in south-east Asia, and were intended for oral use.
Similar results have been obtained when Ayurvedic herbal treatments have been tested in other countries. In the UK 30 per cent of Ayurvedic remedies tested had high lead content, while another study found that of the 22 products purchased in India, 64 per cent contained lead and mercury, and 41 percent had arsenic.
Supporters of Ayurvedic medicine might point to the fact that the remedies have been used for several thousand years, and today they are still taken by 80 per cent of the 1 billion population in the Indian sub-continent, presumably without obvious side effects (although the previous story about cataracts might make us stop and pause).
Conspiracy theorists might also suggest that the study is remarkably helpful for the current lobby in the USA that is seeking to overthrow the DSHEA legislation, which safeguards the use of alternative remedies provided no health claims are made. Those who seek some controls might equally point to the cases of lead toxicity that have occurred among patients of Ayurvedic medicine.
But the statistics don't back up those who are seeking controls. Since 1978 just 55 cases of heavy metal intoxication from Ayurvedic and other herbal remedies have been reported from around the world. Prescription drugs are killing many more than that a day.
Of course two wrongs don't make a right, but it would be a wonderful day in heaven when researchers apply similar vigilance when they test drugs that are then deemed to be supposedly safe for us all to take.