Do ‘safe’ levels of lead harm children?

Picture of some lead balls

Picture of some lead balls

The BBC reports that ‘Safe’ levels of lead levels are harming children. The article reports a study by researchers at Bristol University, the gist of the article can be summarised in this quote

After taking account of factors likely to influence the results, they found that blood lead levels at 30 months showed significant associations with educational achievement, antisocial behaviour and hyperactivity scores five years later.

With lead levels up to five microgrammes per decilitre, there was no obvious effect.

But lead levels between five and 10 microgrammes per decilitre were associated with significantly poorer scores for reading ( 49% lower) and writing (51% lower).

A doubling in lead blood levels to 10 microgrammes per decilitre was associated with a drop of a third of a grade in their Scholastic Assessment Tests (SATs).

The italics and emboldening of the text are mine. I have highlighted this text because it is at the heart of the reason that I simply don’t believe this story. Before you make up your mind you may wish to see the extensive documentation on this issue of the US CDC. There you will find extensive survey data, and if you look for ‘tips’ you may find the following text:

How are children exposed to lead?

Lead-based paint and lead contaminated dust are the main sources of exposure for lead in U.S. children. Lead-based paints were banned for use in housing in 1978. All houses built before 1978 are likely to contain some lead-based paint. However, it is the deterioration of this paint that causes a problem. Approximately 24 million housing units have deteriorated leaded paint and elevated levels of lead-contaminated house dust. More than 4 million of these dwellings are homes to one or more young children.

Who is at risk?

All children under the age of 6 years old are at risk because they are growing so rapidly and because they tend to put their hands or other objects, which may be contaminated with lead dust, into their mouths. However, children living at or below the poverty line who live in older housing are at greatest risk. Additionally, children of some racial and ethnic groups and those living in older housing are disproportionately affected by lead.

Once again the highlighting is mine. The truth is that that there is an overwhelming correlation between poverty and poor educational and behavioural achievement. This is the case for all kinds of reasons. And despite the fact that people have tried to compensate for it in studies I simply don’t believe it can be compensated for. What this story is really about is this: poverty is bad for children’s development. Lead toxicity – at these ‘safe’ levels at least – is really the very least of these children’s problems.

P.S. If you do want to reduce your child’s exposure to lead then the CDC have the following advice for you:

  • avoid using traditional home remedies and cosmetics that may contain lead;
  • avoid eating candies imported from Mexico; (I read this as candles!)
  • shower and change clothes after finishing a task that involves working with lead-based products such as stain glass work, bullet making, or using a firing range.

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