1. Health Risk While Managing Mercury Contamination
Michael Austin
U of MN DEHS

2. Introduction AD for Industrial Hygiene and Safety
Support DEHS staff at UMC, UMM and UMD
Resource on art safety in UMTC – helped design the Regis Center for Art
Risk management – standard of safety relative to average home safety

3. How DEHS is involved Mercury Clean-Up Guidelines Work Team
Associated with implementing a an Environmental Procedures Plan
Included MDH and MPCA representatives
CPPM & DEHS Service Level Agreement Work Team
Roles and responsibilities
Meetings with MPCA to discuss enforcement interpretations

4. Shared Goals Minimize human exposure to mercury
Minimize release to the environment

5. Metrics Milligram (mg) 1/1,000 (thousands)
Microgram (ug) 1/1,000,000 (millions)
Nanogram (ng) 1/1,000,000,000 (billions)
To make comparisons easier we use nanograms / cubic meter as a reference for concentration in air

6. Why we care about mercury
Mercury and compounds are toxic
Damage to brain
Damage to kidneys
Neurological development of a fetus, infant or child can be impacted

7. Mercury containing devices are very common.
Devices include: fluorescent light bulbs, thermometers, light switches and pressure sensing devices.
These items have occasionally broken and caused low levels of contamination on floors and walls.
A high percentage of demolition debris from old buildings is contaminated with trace amounts of mercury.

8. How we are exposed Ingestion of mercury Inhalation of vapor
Mercury bioaccumulates in lakes and streams
Fish bioaccumulate methylmercury
Ocean shell fish have high organic mercury
Average intake is 500 ng/Kg/day (me 50,000 ng/day)
Inhalation of vapor
Natural degassing of mercury from the earth
Release of mercury by burning coal and wood
Dental amalgams
Spills

9. Simplified Inhalation Model (Borrowed from Rita Messing, MDH)

10. Elemental Mercury 70-80% of inhaled Hg is absorbed Poor absorption:
skin
GI tract (<1% absorbed)
Symptoms of high exposure and high, long term exposure:
Cough, metallic taste, inflammation of the mouth, chest tightness, chills, fever, weakness, GI upset, pneumonia, bronchitis
Mad Hatter- tremor, paresthesia, hyperexcitability, memory loss
Stomatitis – inflammation of the mouth
Erethism – excessive excitement

11. Typical Blood and Urine concentrations
95th percentile in U.S. population
Pb in blood
1-5 years 7000 ng/dL
6-11 years 4500 ng/dL
12-19 years 2800 ng/dL
Hg in blood
1-5 years 2300 ng/dL
16-49 years 7100 ng/dL
Hg in urine 5000 ng/L

12. Mercury health standards
200 ng/m3 chronic MRL – US Dept HHS ATSDR
300 ng/m3 RfC - EPA IRIS
300 ng/m3 - Minnesota Dept. of Health chronic exposure criterion for schools (breathing zone)
500 ng/m3 - Minnesota Dept. of Health residential standard
25,000 ng/m3 - American Conference of Government Industrial Hygienists (ACGIH TLV)
50,000 ng/m3 - MN OSHA PEL (a rule)
50,000 ng/m3 - NIOSH REL

13. U of MN health based spill cleanup goals
Based on task force discussions including MN Dept. of Health
Visible mercury always removed
500 ng/m3 in residential occupancies
850 ng/m3 in other public areas (residential exposure adjusted for time)
25,000 ng/m3 in work places with expectation of exposure

15. Questions and Comments