1. Mercury Contamination in Brazil
Ozan Kurtulus
Louisa Meredith
Jeremy Trewin

2. Introduction
Hazardous environmental contaminant
In Japan, 2252 people have been affected and 1043 have died due to Minamata Disease caused by mercury pollution
Compound that can be found naturally in the environment
Mercury poisoning also occurs from exposure to a soluble forms of mercury known as methylmercury
Inorganic mercury is transformed into soluble methylmercury (MeHg+)
dangerous concentration of methylmercury can be ascribed to human activity.

3. Implications through bioaccumulation in the environment
Methylmercury works its way up the food chain
through bioaccumulation in the environment
Larger, predatory species of fish are a greater danger for consumption due to their high concentrations of methylmercury
Fish is the main diet in Amazonial communities
About 90% of the mercury in fish is methylated

4. Brazil – Artisanal Gold Mining
The modern gold rush in Latin America started in the 1980’s
400 ton of gold produced per year
30 to 50 ton per year from Brazil – 80% from Amazon region
An estimated 200,000 to 400,000 miners in the Amazon region
Mercury contaminants often caused by artisanal miners using poor mining practices, usually due to a lack of economic alternatives
Mercury is used in order to separate gold from the extracted ores
Often illegally dumped into nearby water streams

5. 100 to 200 tonnes of mercury released per year
Brazil - Logging
Mercury is released from cutting and burning of trees along river banks
Relatively newly found contributor of mercury contamination
through an investigation carried by Brazilian and Canadian researchers
100 to 200 tonnes of mercury released per year

6. Mercury Decontamination Methods
Solidification
Physically binds or encloses contaminants within a stabilized mass
Chemically reduces the hazard potential of a waste
Amalgamation is typically used to immobilize elemental mercury
dissolving the mercury in another metal to form a semisolid alloy known as an amalgam
Does not reduce the total mercury content of the waste
it reduces the leachability of mercury
product that still may require disposal in a landfill.

7. Mercury Decontamination Methods
Soil Washing
Water-based process
Physical particle size separation
Aqueous-based chemical separation
contaminants tend to bind to the finer soil particles rather than the larger particles
Not cost-effective for small quantities
Performed at the site of the contamination
Thermal Treatment
Physical methods to remove mercury from the contaminated medium
Heat is supplied under reduced pressure to the contaminated soil or waste, volatilizing mercury
The off-gas is treated by condensation to generate liquid elemental mercury
The treated medium may be used as fill material or disposed
Physical and chemical to reduce contaminant concentrations in soil
gravel)
Finer soil particles eg, clay
Concept: Physical methods can be used to separate the relatively clean larger particles from the finer particles because the finer particles are attached to larger particles through physical processes (compaction and adhesion). This process thus concentrates the contamination bound to the finer particles for further treatment
Performed on-site therefore reduce risk of the transport of contaminated materials

8. Mercury Decontamination Methods
Precipitation
Uses chemicals to transform dissolved contaminants into an insoluble solid
Solid is then removed from the liquid phase by clarification or filtration
Used to treat mercury-contaminated groundwater and wastewater
Can reduce mercury concentrations to less than 2 μg/L
Adsorption
Contaminants concentrate at the surface of a sorbent reducing their concentration
Adsorbent packed into a column
Contaminants are adsorbed as contaminated water is passed through the column.

9. Mercury Decontamination Methods
Membrane Filtration
Separates contaminants from water by passing it through a semi-permeable barrier or membrane
Membrane allows some of the constituents to pass through while blocking others

10. Mercury Decontamination Methods
Capping
Widely used to isolate contaminated sediment
In Situ Capping (ISC) is placed on site
Ex Situ Capping (ESC), contaminated sediment is dredged and relocated to another site
One or more isolating layers are placed over the sediment
Composed of sand or finer materials
absorbs the mercury preventing it leaching into overlying water
Advantages: Low cost, low adverse environmental effects
Disadvantages: Not a treatable process, can be damaged
Physical and chemical to reduce contaminant concentrations in soil
gravel)
Concept: Physical methods can be used to separate the relatively clean larger particles from the finer particles because the finer particles are attached to larger particles through physical processes (compaction and adhesion). This process thus concentrates the contamination bound to the finer particles for further treatment
Performed on-site therefore reduce risk of the transport of contaminated materials

11. Mercury Decontamination Methods
Dredging
Useful for heavily polluted areas
Used in the process of gold mining
Can cause damage to the environment through sediment re-suspension
Tested to prove a significant reduction in mercury
Must be well planned and implemented to avoid damage
Only a temporary solution
usually very costly and has issues with method of disposal
Physical and chemical to reduce contaminant concentrations in soil
gravel)
Concept: Physical methods can be used to separate the relatively clean larger particles from the finer particles because the finer particles are attached to larger particles through physical processes (compaction and adhesion). This process thus concentrates the contamination bound to the finer particles for further treatment
Performed on-site therefore reduce risk of the transport of contaminated materials

12. Mercury Decontamination Methods
Bioremediation
Use of Mercury-resisting bacteria
Enhances natural biological-chemical transformations that render pollutants harmless
Reduces toxic mercury to volatile elemental mercury
Existing passive adsorption and immobilization treatments
produce a large volume of mercury-loaded biomass, disposal of which is problematic
Microorganisms such as mer operon does not produce such results.
Potentially low costs
Promising new technology
Reduces toxic mercury: inorganic and organic

13. Summary No major remediation project planned
Current on-going problem
No major remediation project planned
Caused by local, illegal industry
Large area therefore difficult to assess and control mercury pollution
Large funds required
Densely polluted areas : combination of dredging and capping
For permanent remediation, investment in bioremediation is required
Large therefore difficult to control mercury pollutions
Start with densely polluted areas for maximum impact
For permanent remediation, investment in bioremediation is required