Lead is a naturally occurring element in our environment. Its past and current use in several products mean we can be exposed to it from several sources. Lead is particularly dangerous for children under 6 years old. The Enquirer/Mike Nyerges


Given that lead is a metal whose health effects have been known for centuries, why does it still pose a health problem? Short answer: Humans once used a lot of it and it's hard to get rid of. Here are answers to six questions about lead.

What exactly is lead?

It's a bluish-gray metal that's heavy in weight with a low melting temperature that occurs naturally in the Earth's crust. Lead is usually found combined with two or more other elements to form lead compounds.

Why is the metal used?

Metallic lead is resistant to corrosion, so it's not easily attacked by air or water, explains the national Centers for Disease Control and Prevention. Lead also is easily molded and shaped. Today, lead is used most often in storage batteries in cars and other vehicles. But lead and lead alloys also are commonly found in weights, shot and ammunition, cable covers and sheets used to shield patients from radiation when getting an X-ray. It was formerly used in paint.

What does lead do to humans?

Lead can disrupt numerous crucial bodily functions, so it can cause a variety of symptoms from vomiting to madness to death. 

Humans have used lead for centuries and sometimes suffered because of it. The ancient Romans used it for cooking pots, water pipes, plates and goblets. (While the Romans may have suffered diseases such as gout as a result, their lead levels weren't high enough to cause their empire to collapse.) 

Lead is a particular problem for children, especially their developing brains and nervous systems. It’s a potent blocker of receptors of glutamate, a neurotransmitter crucial for learning. One of every five cases of attention deficit hyperactivity disorder is attributed to lead exposure, according to the American Academy of Pediatrics.

Lead stops other metals such as calcium, iron and zinc from doing their normal jobs in the body. When lead displaces zinc, it results in cells "around the body being short of oxygen, causing a cascade of associated problems," the Royal Society of Chemistry's Chemistry World webpage says.

Finally, children's bodies are less able to get rid of lead, the CDC says. Roughly 99 percent of the lead taken into an adult will leave in their body wastes in a couple of weeks; but only about 32 percent of the lead taken into a child's body will follow that same path, leading it to accumulate in their bones and teeth.

Isn't lead banned in many products?

Yes, it was taken out of U.S. gasoline for motor vehicles decades ago, after having been used to stop "engine knock." (Tetraethyl lead may still be used in gasoline for off-road vehicles and airplanes.) It's also banned in paint and other coatings in products for children.

But lead paint remains in 37 million American housing units built before 1978, according to the pediatric academy. In most cases, the paint is "encapsulated" behind other non-lead layers of paint, so it can't be broken off as chips or end up as dust. It's another matter if the lead-based paint is disturbed in a renovation or a demolition.

Lead also can be found in fishing sinkers and bullets, as well as some specialty paint and hobby materials, the pediatrics academy says.

So why use lead in paint?

Lead compounds were used as a pigment in paints, dyes and ceramic glazes and in caulk. Besides giving a tint to whatever product it was used in, the lead pigments were highly opaque so small quantities could cover large areas. White lead is water resistant, making it durable and washable.

What are other sources of lead?

To start with, water. Even though a 1986 federal law and subsequent rules have reduced exposures to lead in tap water, the metal still can be found in some water taps, interior water pipes, pipes connecting the house to a water main or the soldering used on any of those pipes. (Many Flint, Michigan, residents still can't safely drink water at home because lead was released from pipes when a change in water sources caused the metal to corrode.)

The CDC says additional potential sources include toys made in foreign countries, spices (particularly from India), artificial turf (if it is made with nylon or nylon-blended fibers that are old and weathered), candy (either with lead-tinted ingredients or wrappers that leach the metal into the candy), toy jewelry (California officials posted online pictures of examples sold in that state in 2017) and folk medicines.

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