- Children aged 7 and 9 years with higher levels of manganese are at a risk of lowered IQ scores
- Increased levels of manganese in the hair samples of the children affects the IQ score, processing speed and working memory in children
- Further research is required to investigate the link between manganese exposure and child cognition
Children residing in East Liverpool, Ohio were found to have higher levels of Manganese (Mn), which lowered their IQ scores, reveals a new study.
The study conducted was led by environmental health researchers at the University of Cincinnati (UC) College of Medicine and was published online in the journal NeuroToxicology.
The research team analyzed the blood and hair samples of about 106 children who were in the age group of seven and nine years and also from the surrounding communities, who have been part of the study from March 2013 to June 2014, and were from East Liverpool.
The research team worked along with a trained registered nurse from East Liverpool. The participants and their caregivers were assessed for their cognitive learning and were given questionnaires at the time of taking their blood and hair samples.
In this study, the research team that increased Mn in hair samples was found to be linked to declining in full-scale IQ, processing speed, and working memory.
Manganese, an element found in combination with iron and various other minerals plays a crucial role in growth and development of the brain. However, excessive exposure to manganese can lead to neurotoxicity.
Manganese is widely used in the production of steel, batteries, alloys, and fertilizers. It is also added to unleaded gasoline.
Manganese Concentrations Exceed Reference Levels
East Liverpool school district officials in 2013 approached Erin Haynes, DrPH, associate professor in the Department of Environmental Health, who is the lead author of the study.
The research team was prompted by concerns about students' academic performance and found that Mn concentrations have exceeded the reference levels given by U.S. Environmental Protection Agency (EPA) for more than a decade.
Haynes said that there are socioeconomic issues at play and are also compounded by significant environmental exposures.
Haynes has collaborated with the Kent State East Liverpool Campus, and the community group - Save our County Inc., which was formed in 1982 by East Liverpool residents in response to a hazardous waste incinerator, which was constructed in their community.
Haynes said, "Children may be especially sensitive to the neurotoxic effects of ambient Mn exposure, as their brains are undergoing a dynamic process of growth and development."
In East Liverpool, the school district superintendent requested to test students for manganese levels along with neuropsychological tests after being concerned about the elevated airborne levels of Mn.
A pilot study overseen by Haynes found that the levels of Mn were doubled in school children, reported the research team from other cohort CARES study.
Therefore, further research was pursued to investigate the link between Mn exposure and cognition of the child.
Children Sensitive to Manganese Exposure
East Liverpool is located in northeast Ohio along the Ohio River and has established a history of environmental exposures. The EPA records showed that the levels of manganese concentrations were elevated since 2000.
In 2005, EPA regarded East Liverpool to be a potential environmental justice area, afflicted with environmental exposures.
In 2010, EPA reported that detection by all monitors in East Liverpool showed that of manganese concentrations have "consistently exceeded" the health-based guidelines that were set by the agency.
About only 7.3 percent of the residents of East Liverpool have a college degree, and the declining population is now just 11,000.
The East Liverpool school district reports a higher than average percentage of students in special education (19%) compared with the Ohio state average of 13 percent. The school board heard Haynes' research study on manganese in Marietta, Ohio.
CARES Research Study Expanded
Communities Actively Researching Exposure Study's (CARES) original location was Marietta. The study was initiated in 2008, which was based on the concerns from the community about exposure to manganese that was from a nearby metallurgical manufacturing company.
Cambridge, Ohio serves as the comparison community, and ever since, the CARES research has expanded into East Liverpool.
In previous studies, the CARES research team found that whether too low or too high levels of manganese can lead to lower neurodevelopment.
Marietta and East Liverpool have the highest levels of manganese in the country, said Haynes, who continues to study these areas by further including neuroimaging.
Haynes said, "As we continue to advance our understanding of the impact of manganese on neurodevelopment, and help to define the lines between essential benefit and toxicological harm."
In this study, scientists from Cincinnati Children's Hospital Medical Center, Icahn School of Medicine at Mount Sinai, University of Albany, New York State Department of Health and the late Roxanne Burns, Ph.D., chair of the biology department at Kent State University East Liverpool Campus were also part of the study. Dr. Roxanne Burns had been a staunch supporter of this study and the community, and the research team is deeply indebted to her contributions, explained Haynes.
- Erin N.Haynes, HeidiSucharew, Timothy J.Hilbert, et al. Impact of air manganese on child neurodevelopment in East Liverpool, Ohio. NeuroToxicology (2017).