Earth ScienceMercury in the Environment

Santa Clara High SchoolTodd SpaceKenn Chase

Warm-up

Describe any health problems associated with eating canned tuna?

Article in USA TodayJune 19, 2003 warning

about high levels of mercury in canned tuna

Brown Lecture 2: Stanford EMSI High School Science Teachers Workshop, July 17, 2006

Discussion

1. Is this a tuna problem? Other fish, animals?

2. Where do tuna live?

3. Is this a local problem?

4. Where does the mercury come from?

Introduce Information about Local History on Hg

1. First mine in CA was a Hg mine (and it was in Santa Clara County).

2. Uses for Hg (including mining)

3. Sources of Hg in the Environment1. Biological conversions of Hg

2. Inorganic Influences

4. Where is it locally?

5. How did it get there?

The Problem

1. How did Hg get into the Biogeochemical cycle?

Class Hg Project

• The class will divide into 9 teams to research different aspects of the problem.

• Each group will report their findings to the class

• The class will then put together an “Environment Status Report” on Hg pollution to answer “The Problem”.

Research Teams

1. Hg Mining in California

2. Gold Mining in California

3. Bioaccumulation of Hg

4. History – Minamata Bay

5. Human sources of Hg

6. Chemistry of Hg

7. Human health risks of Hg

8. Environmental risks of Hg

9. Hg Fact Sheet

Activities (all teams)

Maps1. Mercury Mines

2. Gold Mines

3. Fault location, Ground movement data

4. Runoff and erosion patterns

5. Mercury levelsa) Water

b) Mud / sediments

c) Fish

All Groups

Requirements• PowerPoint

• Sources– Magazine (e-magazine OK)– Book– Internet (Provided Sources)– Ask an expert (USGS, Colleges, …)

• Set of Maps

1. Hg Mining

• History of Hg Mining (worldwide and local)

• Mining process (illustrate)

• Why is Hg mined?

• Hg mining Map(s).

• Presentation

2. Gold Mining

• History of gold mining (worldwide and local)

• Mining process (illustrate)

• How is Hg used in gold mining process?

• Gold mining Map(s).

• Presentation

3. Bioaccumulation

• Define bioaccumulation and contrast with biomagnification

• Where does Hg enter the food chain?

• Research concentration of Hg in plants and animals.

• Why does tuna have such high levels of Hg?

• Presentation

4. History – Minamata Bay

• Geography of Minamata Bay, Japan– Local economy and other interesting facts

• Chisso Manufacturing Company Information– Products, Process used

• Early signs and symptoms of Minamata Disease

• What was done and current status?

• Presentation

5. Human Sources of Hg

• Hg containing household items

• Industrial uses of Hg

• Sources of Hg pollution from human activities

• How can we safely dispose of Hg containing items?

• Presentation

6. Chemistry of Hg

• Symbol, Atomic Number, Atomic Mass• Physical properties

– Melting point, solubility, volatility

• Different forms of Hg– Compounds and Minerals– Methyl mercury and Dimethyl mercury

• Atomic and molecular models or illustrations

• Presentation

7. Human Health Risks of Hg

1. MCL (Maximum Contamination Level)

2. Symptoms of high and low level Hg poisoning

3. How do humans get Hg in their systems and how long does it last?

4. Toxicity of various forms of Hg

5. Presentation

8. Environmental risks of Hg

• How easily does Hg move in the environment?

• Where does Hg accumulate in the environment?

• Are there safe forms or places for Hg in the environment?

• What organisms are particularly sensitive to Hg?

• Presentation

9. Hg Fact Sheet

A 4 panel Brochure

• Basic facts about Hg.

• What can we do to keep Hg from polluting?

• Presentation

Conclusion

• With all you’ve learned from the groups, and what you know about Plate Tectonics:

• Where did the Hg come from?

Runoff and Erosion Patterns

Maps of;

1. Sierra Nevada Gold Country

2. San Joaquin / Sacramento River watershed

3. San Francisco Bay

4. Local Watershed (Santa Clara Valley / Peninsula)

Hg Distribution in Water and Soils

Measurements taken near historical mining areas and downstream into bay.

• Hg measurements in local waters

• Hg measurements in local soils and sediments

Hg Distribution in Local Plants, Fish and Animals

• Hg data for plants, fish and animals

• Look for patterns of concentration in organisms

• Look for geographic patterns.

Forms of Hg

• Different chemical species or form• Conditions or agents that change Hg into

other forms.• Characteristics of each form;

– solubility– toxicity– mobility– volatility– stability

Earth Science – Dynamic Earth Processes

3 b. Students know the principal structures that form at the three different kinds of plate boundaries.

3 c. Students know how to explain the properties of rocks based on the physical and chemical conditions in which they formed, including plate tectonic processes.

3 f. * Students know the explanation for the location and properties of volcanoes that are due to hot spots and the explanation for those that are due to subduction.

Earth Science – Biogeochemical Cycles

7. Each element on Earth moves among reservoirs, which exist in the solid earth, in oceans, in the atmosphere, and within and among organisms as part of biogeochemical cycles.

Earth Science – California Geology

9 a. Students know the resources of major economic importance in California and their relation to California's geology.

9 b. Students know the principal natural hazards in different California regions and the geologic basis of those hazards.

Investigation & Experimentation

h. Read and interpret topographic and geologic maps.

l. Analyze situations and solve problems that require combining and applying concepts from more than one area of science.

m. Investigate a science-based societal issue by researching the literature, analyzing data, and communicating the findings. Examples of issues include irradiation of food, cloning of animals by somatic cell nuclear transfer, choice of energy sources, and land and water use decisions in California.