Recently, we’ve seen huge product recalls due to lead content. Once the issue became public, more and more items were included. However, another source of lead may be much more significant. In the US alone, about 400,000 children (2% of the under-five population) have chronic lead poisoning due to contaminated soil. This high number compares to drastically fewer cases of acute lead poisoning from toys and jewellery containing lead.
A recent review article published in Applied Geochemistry examined soil studies and found that older cities have high lead levels. This is the result of lead accumulation from past use of leaded gasoline, lead paint, and industrial discharge. Older urban areas have higher lead levels than newer cities and rural areas, and the lead poisoning cases are also much higher. Levels over 10 micrograms of lead per decilitre of blood are considered medically significant. Compare this to the 1960s limit set by the Centers for Disease Control and Prevention (CDC): 60 micrograms per decilitre (seizures occur above this level). Some experts argue that the current level is still too lax, and that industrial lobbying has meant slower government responses.
Most attention has been given to lead in toys. Because parents and other relatives provide these items for children, it is particularly painful to realize that a gift has been toxic. Old house paint has also been blamed for many cases of acute lead poisoning – and there are many warnings for parents pointing out the problem.
Chronic lead poisoning results from children eating dirt either deliberately or accidentally. Bare soil can be found in gardens, playgrounds, building sites, and other locations. Babies and young children typically put things in their mouths, and may get dirt on their hands or rub it in their eyes. This allows lead to enter the body, where it quickly can have detrimental effects.
Chronic cases are characterized by lower lead levels in the blood, so they can be quite difficult to diagnose. But the effects are still very serious. Lead becomes incorporated into the nervous system, leading to permanent damage. Learning and behavioural problems, along with bone and organ effects, are the result. Unlike acute lead poisoning, which can be treated through chelation therapy, chronic lead poisoning is harder to treat.
Lead poisoning is characterized by various symptoms, including digestive problems (stomach ache, diarrhea, colic), low energy, headaches, and irritability. Over a longer time, children may show slowed growth, hearing loss, and learning disabilities.
So what can you do, if you are an urban family? Covering dirt yards with grass is one approach. Preventing dry soil from blowing around is also important – using pressurized clean water to soak soil can help. It’s also important that the whole area is considered, since soil blows around. Even better, but much more expensive, is to replace all the contaminated soil. An intermediate solution would be adding a new layer of soil and adding grass. Any remediation would be costly and potentially impractical for many older cities.
Certainly, keep an eye on children playing in dirt, to prevent dirt ingestion. Make hand-washing a frequent practice, especially before meals. Consider staying inside on windy (dusty) days. Knowing the risks makes it much easier to prevent problems. After all, playing outside is a childhood joy.