1. Human Impact of Methylmercury in the Water
Song-E Baek

2. CONTENTS What is Mercury?
The importance of Mercury in the Environments
Human Effects of Mercury
Studies of Mercury in the Environments
Conclusion

3. Mercury It exists in several forms: Elemental or Metallic Mercury
1. What is mercury?
Mercury
It exists in several forms:
Elemental or Metallic Mercury
Inorganic Mercury Compounds
Organic Mercury Compounds

4. Sources of Mercury Element in the earth's crust Mining
1. What is mercury?
Sources of Mercury
Element in the earth's crust
Mining
Fossil fuel combustion
Municipal solid waste

5. 1. What is mercury?
Methylmercury
Methylmercury is the most common organic mercury compound found in environment.
Microscopic organisms convert inorganic mercury into methylmercury.
Methylmercury accumulates up the food chain.

6. How Mercury Enters the Environment
2. The Importance of Mercury in the Environments
How Mercury Enters the Environment

7. 3. Human Effects of Mercury
Minamata Disease
First discovered in 1956 around Minamata Bay, Kumamoto Prefecture, Japan.
Occurred by Methylmercury.
In 1932, the Chisso Corporation began to manufacture acetaldehyde.

8. 3. Human Effects of Mercury
Minamata Disease

9. Children Effect of Methylmercury
3. Human Effects of Mercury
Children Effect of Methylmercury
Decreasing IQ
Brain damage
with mental retardation, incoordination
Eventual blindness
Seizures
Inability to speak
Muscle weakness

10. 4. Studies of Mercury in the Environments
Mercury in the Great Lakes
- Sediments act as a main, ultimate sink of contaminants.
- Polluted sediments can be stirred up and resuspended in water by dredging, by the passage of ships in navigation channels, and by wind and wave action, by fish and other organisms.
- Sediments can enter the benthic organisms during the feeding.

11. Mercury in the Great Lakes
4. Studies of Mercury in the Environments
Mercury in the Great Lakes
Environmental Pollution (2004) 129, 131–144
Concentrations of total mercury in the surface sediment (mg/g dry wt.)

12. 4. Studies of Mercury in the Environments
Mercury in the Great Lakes
Environmental Pollution (2004) 129, 131–144
Major urban industrial centers, such as Hamilton and Toronto, are located on Lake Ontario’s shore.
The Upper St. Lawrence River waters at Cornwall have the typical composition of the outflow of Lake Ontario for numerous chemical compounds.

13. 4. Studies of Mercury in the Environments
Mercury in Human Blood
Environmental Research (2004) 95,
Examine the followings in a sample of pregnant women
The temporal variation of Hg during pregnancy
Organic mercury level changes in fish consumption
The relation between different sources of fish (local and market fish) and maternal/cord blood

14. 4. Studies of Mercury in the Environments
Mercury in Human Blood
Environmental Research (2004) 95,
1. The temporal variation of Hg during pregnancy
- There was a decrease of all Hg in maternal blood concentrations over time.
- Cord blood levels were higher than maternal levels for organic Hg.

15. 4. Studies of Mercury in the Environments
Mercury in Human Blood
Environmental Research (2004) 95,
2. organic mercury level changes in fish consumption
- Cord blood Hg levels were significantly higher than maternal blood .
- The consumption of fish during pregnancy affects the levels of Hg in blood.

16. 4. Studies of Mercury in the Environments
Mercury in Human Blood
Environmental Research (2004) 95,
3. The relation between different sources of fish
and maternal/cord blood
- Canned tuna contributes the most organic Hg exposure among the consumed fish.

17. 4. Studies of Mercury in the Environments
Mercury Transport to the Infant
Archives of Toxicology (1996) 70,
Objective
: To determine the participation of the neutral amino acid carrier in MeHg transport through the placenta
Method
: Pregnant rats were intravenously administered MeHg on day 18 of gestation.
: The fetal blood was collected from the umbilical cord at 30min and 60min after administration.

18. 4. Studies of Mercury in the Environments
Mercury Transport to the Infant
Archives of Toxicology (1996) 70,
- Hg transfer into fetal blood cells following maternal administration of MeHg or HgCl2 at a dose of 1mg/kg by time.
- MeHg is transported to the infant through the placenta.
- Despite the easy penetration of MeHg, inorganic Hg was hardly transported through the placenta.

19. 4. Studies of Mercury in the Environments
Mercury Transport to the Infant
Archives of Toxicology (1996) 70,
MeHg metabolism in the placenta

20. Conclusions from the Studies
4. Studies of Mercury in the Environments
Conclusions from the Studies
Blood organic Hg concentration is related to fish consumption during pregnancy.
Organic Hg easily transport across the placenta.
Sources of Hg is not limited local fish but all fish we have.

21. Conclusion & Discussion
How can human reduce the risk of exposure to mercury?
FDA currently advises that pregnant women and women of childbearing age who may become pregnant limit their consumption of shark and swordfish to no more that one meal per month.
No consumption advice is necessary for the top ten seafood species that make up about 80% of the seafood sold in the United States: canned tuna, shrimp, pollock, salmon, cod, catfish, clams, flatfish, crabs, and scallops.

22. Conclusion & Discussion
It is applicable nationally and internationally for all circumstances in which environmental contamination of fish and wildlife exists just as those found in the Great Lakes basin.
To minimize maternal and fetal exposure to contaminants, we need to be aware of potential hazards of fish consumption.