A new study shows kids with higher levels of the metal manganese in their bodies have lower IQ scores. The study, published in the journal NeuroToxicology, looked at about 100 children between the ages of 7 to 9 in East Liverpool, Ohio. The town is about 40 miles northwest of Pittsburgh and has multiple industrial sources for manganese in its air. The metal is used to make batteries and stainless steel. Erin Haynes, an environmental epidemiologist at the University of Cincinnati, authored the study. Kara Holsopple talked to her about her findings.
Kara Holsopple: The school district there in East Liverpool requested the study. Why?
Erin Haynes: In December 2010, the Ohio EPA Division of Air Pollution Control published their report called “All Ohio Air Toxics Report.” It was a statewide air toxics study in which they had placed air monitors across the state, and they were sharing the data publicly. This is where the manganese air data came to light, and that the levels of manganese in the air in East Liverpool were by far the highest of all the monitors that they placed in Ohio. So the school board asked if I would come to East Liverpool and ask the question, “Does the manganese in our air have any health effects on our kids?”
KH: And your study found that there is some correlation.
EH: Yes. We we did a pilot study first and then we launched the bigger project which we just published. And we did see an association between the level of manganese in the child’s body and then lower IQ scores. So the higher the concentration within the child, the lower the IQ.
KH: And are you going to be doing any further testing?
EH: Absolutely. We are funded by the National Institute for Environmental Health Sciences to come back to the community. We’ll be recruiting the same kids who participated in the first round, and we’re going to follow all of them. I should mention that our study included IQ, but we also have other measures including child behavior and motor function. And the follow up study, when the kids come back, they will be 12 to 15…the brain is undergoing yet another phase of rapid development. So we’re going to take that opportunity and look for subtle changes in the brain and its relationship to the concentration of manganese in the body. So we’ll again look at brain function, but we’ll also be asking the families to participate in a brain scan to see how well the brain is functioning.
KH: From what I’ve read about your study, there are other socioeconomic factors that can affect a child’s IQ. Can you talk a little bit about how you took that into account for the study?
EH: We know that parent IQ is strongly connected to child IQ. So we included that measure in our study kids. We also factored in other known chemicals that impact the brain like lead. We also measured other metals and second hand tobacco smoke, another neurotoxin that is known to impact the brain. So after including all of these measures – education status of the parents, income, socioeconomic well-being of the family, parent IQ, and then all these other neurotoxicants – manganese still surfaced to be the main driver of the impact on child IQ and the decrease that we saw.
KH: Your study doesn’t take into account the source of the manganese or the levels of manganese that might be in the air in East Liverpool. But it does beg the question, how does manganese get into kids bodies?
EH: That’s a great question. Primarily it’s inhalation, through the nose breathing. Manganese particles can travel directly through the olfactory nerve and enter directly into the brain. Or they can be breathed through the lungs and then transported out into the blood and then up into the brain. Manganese is a nutrient. So your body is used to manganese and wants it. There are numerous ways that we as humans have for maintaining normal levels if we ingest manganese. So it’s in our food and our normal diet. Our bodies are able to, when we eat it, excrete what it doesn’t need. But if we inhale it and breathe it, it travels in different circuits and then can become toxic.
KH: Is there a stigma for these kids and their families to be identified as having a lower IQ as a result of their exposure?
EH: It’s a touchy subject, but I think that parents can take this information and advocate for additional resources for their school system in order to provide the the needed assistance and educational support that these children need.
KH: I know you presented the results of your study to community members there in East Liverpool recently. What was the reaction like?
EH: I love being able, as a scientist, to take the research that we do and then bring it back to the community who are the people who are most impacted, and just to share with them. I find it very rewarding for me. The data was well received by the community. There were lots of great questions and some very interesting dialogue that came out of the meeting. And I also asked the community while I was there for new research ideas. I think they are the ones living there, they know what’s going on in their community. So even new research questions came out during the meeting.