1. Water Pollution
Mercury

2. D24
Explain how the accumulation of mercury, phosphates and nitrates affects the quality of water and the organisms that live in rivers, lakes and oceans.

3. Learning Targets I can explain why mercury pollution is a problem.
I can differentiate between bioaccumulation and biomagnification.

4. What is Mercury? An element on the periodic table
Metal in a liquid state
Has many uses
Has serious health effects when released into the environment
Reference:
Water Pollution
NIEHS (2012)

5. Sources of Mercury Natural Sources Human sources Volcanoes
Natural mercury deposits
Release from the oceans
Human sources
Coal combustion
Waste incineration
Metal processing

6. How does mercury enter the food chain?
Mercury from power plants, waste incinerators, smelting plants and natural sources is released into the air.
These particles are released as rain drops, and deposited in soil or water.
These airborne particles can travel thousands of miles.

7. Bacteria take in inorganic mercury and convert it to a different form called methyl- mercury
This form is more toxic and is harder for organisms to eliminate
The bacteria release the methyl-mercury, where it enters the food chain by being absorbed by phytoplankton

8. What organism is most likely to be contaminated with Hg?
Fish

9. How are these fish becoming so contaminated when the atmospheric levels of mercury are so low? Or How do fish in remote lakes become contaminated?

10. Mercury undergoes Bioaccumulation
What does this mean?
This is the process by which organisms build up mercury in their bodies. They take in mercury more quickly than they can get rid of it.
Over time, the organism will accumulate mercury, until it can even reach toxic levels.

11. It also undergoes Biomagnification
Mercury increases at each step in a food chain, because each organism takes the mercury from the organism that it eats which has taken in the mercury from the organisms that it ate … and so on … and so on

12. Biomagnification
The highest levels of mercury are found at the highest levels of the food chain.
Bigger fish, older fish, and carnivorous fish will have the highest levels of mercury.
And, the mercury concentrates in the muscles of the fish, which is the part that humans eat

13. Mercury Poisoning in Humans
Mild cases have the following symptoms:
Reduction in motor skills
Dulled sense of touch, taste and sight
Pregnant women should avoid ingesting mercury at all costs, as unborn babies are very sensitive to mercury poisoning.

14. Effects of more advanced mercury poisoning
Deterioration of the nervous system
Impaired hearing, speech, vision
Difficulty walking
Tremors, or involuntary muscle movements
Corrosion of skin and mucous membranes
Difficulty with chewing and swallowing

15. How Are Animals Affected?
Mercury can accumulate in fish and in the food chains that they are part of.
The effects that mercury has on animals are kidney damage, stomach disruption, damage to intestines, reproductive failure and DNA alteration.

16. Current levels of Mercury
Human activities have doubled or tripled mercury levels.
This also is increasing by about 1.5% per year

17. What can we do to help? Reduced the amount of coal use
Take part in Hazardous Household Waste Disposal days

18. Learning Target Checkpoint
Why is Hg pollution a problem?
What is the difference between bioaccumulation and biomagnification?

19. Reference
Krabbenhoft, D. P., & Rickert, D. A. (2008). Retrieved from U.S. Geological Survey website: