For those with the highest cadmium levels, the odds of having a learning disability were 3.21 times higher than for the children with the lowest exposures. For special education, the odds were 3 times higher. No association was found with attention deficit hyperactivity disorders.
“The three times higher risk is high for such low cadmium levels,” said Aimin Chen, an assistant professor of environmental health at University of Cincinnati’s College of Medicine. He was not associated with the study.
But Chen said the link at this point is preliminary because researchers have not yet looked for any specific, more definitive neurological effects, such as reduced IQs, memories or vocabularies -- outcomes already linked to two other toxic metals, lead and mercury.
The connection to both learning disabilities and special education could indicate cadmium has an array of effects on a child’s brain just like lead does. Those two outcomes “are actually a mixture of different brain function problems,” Chen said.
Lead has been studied and regulated for many decades, leading to a large amount of evidence that it reduces children's IQs at low concentrations and contributes to attention disorders and even violent behaviors. It interferes with the development of synopses, or connections between neurons, that allow a child to learn.
Since cadmium is also a heavy metal, it might have similar effects on the brain, Lanphear and Wright said. But unlike lead, cadmium “is relatively understudied as respect to brain toxicity,” Wright said.
One big difference turned up in the new study: No link was found between cadmium and attention deficit disorders. “It stands out because one thing we’ve found fairly consistently with lead, tobacco and others is that it seems that some of these contaminants might increase the risk for ADHD,” Lanphear said. That could be a sign that cadmium is working on a different part of the brain, not the prefrontal cortex.
Another big mystery is the source of the cadmium in the kids. Cadmium stays in the body for long periods, so the tests measured amounts the children were exposed to over years.
Cadmium is in tobacco smoke, but surprisingly, concentrations in the kids were similar whether they lived with smokers or not. That “might mean for most kids [secondhand] smoking was not a major source,” Wright said.
An abundant element in the Earth’s crust, cadmium is found naturally in soil in some parts of the country. But it also is released by battery manufacturers, smelters, electroplating plants and other industries. It is one of the top chemicals reported in Superfund sites, found in virtually all of them, according to a Centers for Disease Control and Prevention document.
Renee Gardner, a postdoctoral fellow at Sweden's Karolinska Institutet who studies heavy metals, said “the most important source of exposure is food. Green leafy vegetables and grains are the biggest sources, though most plant foods have some cadmium in them.”
Since these foods are important nutritionally, they shouldn’t be avoided. But Gardner said that iron helps prevent absorption of cadmium, so parents worried about exposure should ensure their kids have adequate iron in their foods.
Some children may have been exposed through inexpensive jewelry. In 2010, the Associated Press tested children’s jewelry manufactured in China and found cadmium, prompting recalls by stores. Cadmium was being used to replace lead.
Last fall, the Consumer Product Safety Commission considered standards, but backed off when the industry set its own voluntary testing procedures and limits for cadmium in children’s jewelry. California set its own standards.
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14 Comments
Add Comment--- They shouldn’t be used unless proven safe,” he said.
Reply | Report Abuse | Link to thisSounds like a near-impossible task. Do we truly know that anything is "safe". Anything and everything in the world around us might be responsible for one thing or another over long-term exposure.
We can only use intelligence and past studies to come up with a list of possible dangers. Cadmium being a heavy metal probably should have already had a warning flashing- but other things.
Do we really know our paper cups that we put our coffee in isn't giving us alzheimers- or the material in our air-filters acting as the trigger that allows prions to move up to our brains?
Prooving something is safe is about as hard as prooving or disprooving a supreme being. You can't possibly run a test on everything that could possibly go wrong.
But Candium just sound so delicious!
Reply | Report Abuse | Link to thisA long long time ago, one of my university assignments was heavy metal contamination is the soils of Western Sydney.
Reply | Report Abuse | Link to thisCadmium was one of the metals I was doing AA spectroscopic analysis for. It has been know for a long time that it was as bad as lead.
prions to move up to our brains?
Reply | Report Abuse | Link to thisBirds....What are you really saying?
Most toxins are well known, Cadmium is one of them.
We have a good idea about what's toxic and NOT.
And can easily limit the known ones!
But, some people resist change.
Why?
Dear Marla Cone, keeping young children from ingesting heavy metals, in the form of objects, is part of good parenting. Renee Gardner said, "Iron helps prevent absorption of cadmium, so parents worried about exposure should ensure their kids have adequate iron in their foods." Good information to be sure; however, where iron is concerned many food products marketed for kids have iron added!
Reply | Report Abuse | Link to thisMy larger concern regarding iron & kids is poisoning of children by self-ingestion of moms iron pills! That is a heavy metal problem that IS a leading killer (in the poisoning area) of small children, and, by the way, primarily a parenting problem!
Richard Carlson
Use my brain? Well, my brain remembers recent recalls of children's jewelry and toys due to lead content. Corporations certainly knew that was not a good thing! I see no reason to place faith in a "free market system" when it comes to our well-being vs. their profits.
Reply | Report Abuse | Link to this"It interferes with the development of synopses, or connections between neurons, that allow a child to learn"
Reply | Report Abuse | Link to thisYou mean SYNAPSES, synopsis is something completely different.
In Europe the RoHS directive banned cadmium since 2002
Reply | Report Abuse | Link to thiswhy does the EU banned Cadmium from Europe since 2002 with the RoHS directive? Maybe they demonstrated Cadmium is neurotoxic 10 years ago.
Reply | Report Abuse | Link to thisMy husband's body was full of Cadmium when he was diagnosed with Lou Gehrig's Disease (ALS), which is a neurological disease that kills you within 3 years + and there is NO cure. He was an aircraft mechanic for most of his working life. I met another woman whose husband who died of ALS body was very high in Cadmium and was an aircraft mechanic. Additionally, there is a much higher incidence of veteran's that were in the air force to have ALS. So much so, ALS has been categorized as a disease that is connected to armed services. So I think a litte due diligence on our part in exposing ourselves to chemicals, being aware is on step in the right direction.
Reply | Report Abuse | Link to thisYour readers should be aware of the greatest danger of contamination of Cd is from CdTe Photovoltaic power projects that are built around the world. Just one company, First Solar has delivered 5GW of CdTe PV modules around the world, covering about 100 million square meter of the earth's surface with these panels, containing over 200,000 kg of Cd.
Reply | Report Abuse | Link to thisIt now has been established that this CdTe is water soluble in any kind of rain water, anything that is not distilled water. How can the US EPA tolerate this?
The irony of the industry is that if one believes in the importance and benefits of solar energy, as I do, one can use several other, either thin film of crystalline Silicon materials, at no higher costs to install PV electricity.
To top this, our premier scientific corporation, GE, has also selected CdTe as their material of choice to enter the PV industry with a $1 billion investment.
At the same time our primary competitor country in PV, China, does not even allow the installation of Cd containing PV materials.
I hope after your article calling our attention to the dangers of Cd to our children and grandchildren, our government will review the issue of CdTe
containing PV, covering the water tables of millions of Americans.
Are you serious??? Do you even understand what a true free market system is? It's one in which there are no regulations to protect the consumers. Everything is geared towards making money anyway a businessman under such system can dream of. Quality control??? Forget it. Poison in your food and drinking water? You better believe it. Punishment for the crooks? Maybe...if the consumer of such inferior products has the personal means to go after the cheats. I hate to break it to you; there is no such thing as a true free market system...not even our own (U.S market).
Reply | Report Abuse | Link to thisSince it's a low incident problem. Why all the fuss? Iron added is not the same as Iron digestible. Added usually means it goes in and goes out. Misses the stations, so to speak.
Reply | Report Abuse | Link to thisIron is easy to get, use iron cookware. I don't know how much of an iron pan is bio soluble, but it tastes good. And if it keeps out the cadmium form my greens, cool.
We are omnivores, eating many things protects us from the many things we eat.
We'll let SA sort it all out, we will be too busy eating the many things.
In a solar panel, the CdTe is sandwiched between other layers (metal and glass among others), and would not be in contact with any rain (thankfully for both us and the solar panel). But with this information on cadmium, proper disposal, at the end life, of the solar panel most certainly needs to be done.
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