Air Manganese Study

In November 2011 US EPA researchers conducted a health study of airborne manganese exposure in East Liverpool, Ohio. This web page discusses results of the study, and provides background and other related information such as abstracts presented at meetings and published papers related to the study.

Workplace studies of occupations such as mining and welding have shown that inhaling high levels of manganese can lead to nervous system health effects. Few studies have been done on the health effects of airborne manganese exposure in community settings on adults. The main purpose of this study was to evaluate whether nervous system health effects (neurotoxicity) were detectable in community residents with long-term, airborne manganese exposure.

Background

In February 2008, the Ohio EPA completed an air quality study in East Liverpool that indicated residents were at risk from exposures to airborne manganese and chromium. Ohio EPA identified the S.H. Bell Company, a raw products storage and packaging facility, as the source of manganese and chromium sampled in community air monitors. The Director of the Ohio EPA requested that the Agency for Toxic Substances and Disease Registry (ATSDR) evaluate potential health impacts.

In November 2010, ATSDR completed a Health Consultation that concluded that the levels of airborne manganese in East Liverpool exceeded background levels and health-based guidelines. ATSDR stated that exposure to manganese concentrations in East Liverpool poses a public health hazard.

EPA's November 2011 study followed a protocol similar to previous manganese health studies conducted by San Francisco State University in Marietta, Ohio, and Mount Vernon, Ohio, so that data from all three communities could be compared.

Approach

In August 2009, a manganese health study was conducted by San Francisco State University in Marietta (a community near a smelter emitting manganese) and Mount Vernon (a community without a large airborne manganese source), Ohio. The East Liverpool study in November 2011 followed a similar protocol so that data from all three communities could be compared.

Researchers randomly selected (when possible) adults in each of the three communities between the ages of 30-75.They collected data from the study participants including a general health questionnaire, blood test, neurological and mood assessments, and neuropsychological tests.

Blood Tests

Researchers analyzed blood for heavy metals including levels of manganese, cadmium, lead and mercury, and of serum ferritin – an indicator of iron stored in the body.

Neurological Assessments, Neuropsychological Tests, and Mood

Researchers used a battery of assessment tools to measure cognitive flexibility (switching categories), information processing, working memory and attention, visual tracking speed, verbal skills, motor dexterity and strength, postural sway and tremors. Each of these test results yield important information about the brain function of study participants that can be used to evaluate the potential impact of manganese exposure.

Air Modeling

An EPA air dispersion model and measurements of manganese air concentrations at several fixed locations estimated the concentration of manganese in air outside the homes of study participants. These estimates, along with the distance from the source and the years of residency were used to calculate an "exposure index" for each resident. This exposure index helped estimate inhalation exposure to airborne manganese.

Results

No statistical differences were noted between residents of East Liverpool, Marietta and Mount Vernon communities for:

• General health categories (e.g., number of good, bad health days per month, smoking status, obesity, etc.)
• Amount of manganese consumed in diet (manganese is an essential nutrient and is found in many leafy green vegetables and beans)
• Blood manganese levels – the average blood manganese level in the general population ranges between 4-15 µg/L . The following levels were detected:
  • East Liverpool = 10.32 µg/L
  • Marietta = 9.65 µg/L
  • Mount Vernon = 9.48 µg/L
• Blood lead and serum ferritin levels
• Neurological assessment testing: Activities of Daily Living (the things we normally do to care for ourselves, such as eating, bathing, dressing, grooming, work, etc.) and motor (movement) scores
• Neuropsychological tests: tests of attention and memory tests
• Mood tests: mood disturbance (depression, bipolar disorder, etc.)

Statistical differences were noted between the three communities for:

• Blood: East Liverpool residents had higher average blood cadmium levels than Mount Vernon residents, but they were still within the normal range found in the general population. East Liverpool residents had lower blood mercury levels than Marietta residents.
• Neurological assessment:
  • East Liverpool residents showed slower movement initiation (results in delays in onset of movement) than Mount Vernon residents, but were slightly better than Marietta residents.
  • More hand tremors (involuntary shaking) were observed in East Liverpool residents than Marietta residents.
  • East Liverpool residents had more postural sway/instability (involuntary swaying or instability when standing on both feet) than Marietta and Mount Vernon
• Neuropsychological tests:
  • Scores in all three communities were within normal range, except for divided memory, visual memory, and motor speed.
  • East Liverpool residents had lower scores for immediate memory (daily living) than Marietta
  • East Liverpool residents had lower scores than Marietta and Mount Vernon for word reading, motor speed, motor strength and motor tactile.

The combined data from East Liverpool and Marietta showed that having a higher exposure index was related to lower neuropsychological and motor performance. Living a shorter distance from a manganese source was also associated with neuropsychological and motor performance. The strongest effects were seen for tremor, motor speed, and motor strength.

Study Information and Publications

• Study Fact Sheet
   
• Community Slide Presentation
   
• Publications: 
  • Anxiety affecting parkinsonian outcome and motor efficiency in adults of an Ohio community with environmental airborne manganese exposure
  • Blood Metal Concentrations of Manganese, Lead, and Cadmium in Relation to Serum Ferritin Levels in Ohio Residents
  • Characterization of air manganese exposure estimates for residents in two Ohio towns
  • Environmental Exposure to Manganese in Air: Associations with Cognitive Functions
  • Environmental Exposure to Manganese in Air: Associations with Tremor and Motor Function
  • Environmental exposure to manganese in air: Tremor, motor and cognitive symptom profiles
  • Manganese exposure and cognitive deficits: a growing concern for manganese neurotoxicity
  • Medication Use Associated with Exposure to Manganese in Two Ohio Towns 
  • Motor function in adults of an Ohio community with environmental manganese exposure 
  • Validity of Self-Reported Concentration and Memory Problems: Relationship with Neuropsychological Assessment and Depression 
     
• Abstracts presented at Scientific Meetings: 
  • Neuropsychological Motor Outcomes in Adults from Airborne Manganese Exposure
  • Exposure to Environmental Air Manganese and Medication Use
  • Generalized anxiety and major depressive syndrome measured by the SCL-90-R in two manganese (Mn) exposed Ohio towns
  • Motor and Executive Function Profiles in Adult Residents Environmentally Exposed to Manganese
  • Movement disorder symptoms associated with Unified Parkinson’s Disease Rating Scale (UPDRS) in two manganese (Mn)-exposed communities
  • Psychological symptoms and quality of life among residents exposed to long-term, low-dose environmental manganese (Mn)
  • Estimating Air-Manganese Exposures in Two Ohio Towns
  • Community Exposure to Air Manganese and Motor and Cognitive Outcomes
  • Cognitive Function Related to Environmental Exposure to Manganese

Technical Contacts

Danelle T. Lobdell, Ph.D., M.S.
U.S. EPA
Office of Research and Development

Dr. George Bollweg
U.S. EPA Region 5
Chicago, IL