Alexa LaPlante

 

 

I researched the natural and industrial sources of mercury.

Some of the websites I used were:

The Regional Monitoring Program (SF Estuary)
www.sfei.org/reports/mercury/mercury.html

Purdue University
pasture.ecn.purdue.edu/~epados/mercbuild/src/merform.htm

Env. Protection Agency
www.epa.gov

Dental recycling North America (DRNA)
www.drna.com/ProblemMercurySources.html

USGS
www.usgs.gov

The natural sources of Mercury:

Volcanic activity: releases mercury found naturally in the earth's crust

Forest fires: can heat fuels from biomass that harbors concentrations of mercury from the biosphere to temperatures well above the boiling point of mercury (357 degrees C). The mercury can then be released into the atmosphere or decomposed.

Oceanic releases: through the evaporation of elemental mercury from the ocean's surface.

The Anthropogenic Sources of Mercury are:

Industrial products: mercury is used in more than 2000 industries and products. These include: thermometers, fluorescent lamps, mirrors, gold/silver extraction, batteries, dental amalgams, lubricants, dyes,floor wax, fabric softeners, chlorine bleach, etc. that leach into the soil and ultimately reach groundwater aquifers.

Coal-fired Power plants: Mercury is oxidized (as the flue gas cools & exits the plant) to its water soluble ionic form.Incinerators and coal-fired plants emit more mercury than any other point source of unregulated mercury emissions in the U.S.

Gasoline and Oil combustion: Mercury is vaporized through the combustion of crude oil. Vehicles release the greatest amount of mercury this way.

Smelting: Mercury is released into the atmosphere in the smelting of ores to yield pure metals.

Chlor-Alkali Plants: Elemental mercury is used as the electrode in electrochemical production of chlorine gas and caustic soda.

Mildew Suppression, Laundry facilities: Mercury is used to suppress mildew by laundry facilities. However, this source should become less problematic due to the US EPA ban of mercury used as a fungicide in interior latex paints.

Sewage Treatment: Mercury is concentrated in sewage sludge. Secondary treatment of water does not fully treat/remove inorganic dissolved contaminants, thus it can be released into the soil and/or into the atmosphere if it is dried up.

Mercury dumping from naval vessels: Mercury is used as ballast in its subsurface vessel fleet, and during inter-ship ballast transfer operations, elemental mercury is occasionally spilled into marine waters. This can result in the contamination of both sediment and water.

Overall, the pH and the alkalinity of water can affect the concentrations of mercury in a water body. Methyl mercury is produced, transported and accumulated by aquatic organisms significantly more efficiently at low alkalinity and pH.

Salinity can also impact mercury concentrations. For example, as runoff into the SF bay increases and the salinity decreases, the concentration of dissolved mercury increases. In addition, sulfate concentrations in water can impact microbial methylation of mercury. There is a window of sulfate concentration that promotes the highest mercury methlation rate (opt. Hg by SRB in sediments is at 200-500 mM.).

In aquatic sediments, mercury and other metal contamination is most strongly correlated with the proportion of fine particles. Aerobic and Anaerobic micro environments can affect oxygen metabolism and sulfur metabolism. Oxygen rich env. (upper sed) can favor O2 metabolism and oxygen poor env. lower sed) can favor sulfur metabolism, producing Hgs and Ch3Hgs.

 

Back

alexa.html

Alexa LaPlante

 

 

I researched the natural and industrial sources of mercury.

Some of the websites I used were:

The Regional Monitoring Program (SF Estuary)
www.sfei.org/reports/mercury/mercury.html

Purdue University
pasture.ecn.purdue.edu/~epados/mercbuild/src/merform.htm

Env. Protection Agency
www.epa.gov

Dental recycling North America (DRNA)
www.drna.com/ProblemMercurySources.html

USGS
www.usgs.gov

The natural sources of Mercury:

Volcanic activity: releases mercury found naturally in the earth's crust

Forest fires: can heat fuels from biomass that harbors concentrations of mercury from the biosphere to temperatures well above the boiling point of mercury (357 degrees C). The mercury can then be released into the atmosphere or decomposed.

Oceanic releases: through the evaporation of elemental mercury from the ocean's surface.

The Anthropogenic Sources of Mercury are:

Industrial products: mercury is used in more than 2000 industries and products. These include: thermometers, fluorescent lamps, mirrors, gold/silver extraction, batteries, dental amalgams, lubricants, dyes,floor wax, fabric softeners, chlorine bleach, etc. that leach into the soil and ultimately reach groundwater aquifers.

Coal-fired Power plants: Mercury is oxidized (as the flue gas cools & exits the plant) to its water soluble ionic form.Incinerators and coal-fired plants emit more mercury than any other point source of unregulated mercury emissions in the U.S.

Gasoline and Oil combustion: Mercury is vaporized through the combustion of crude oil. Vehicles release the greatest amount of mercury this way.

Smelting: Mercury is released into the atmosphere in the smelting of ores to yield pure metals.

Chlor-Alkali Plants: Elemental mercury is used as the electrode in electrochemical production of chlorine gas and caustic soda.

Mildew Suppression, Laundry facilities: Mercury is used to suppress mildew by laundry facilities. However, this source should become less problematic due to the US EPA ban of mercury used as a fungicide in interior latex paints.

Sewage Treatment: Mercury is concentrated in sewage sludge. Secondary treatment of water does not fully treat/remove inorganic dissolved contaminants, thus it can be released into the soil and/or into the atmosphere if it is dried up.

Mercury dumping from naval vessels: Mercury is used as ballast in its subsurface vessel fleet, and during inter-ship ballast transfer operations, elemental mercury is occasionally spilled into marine waters. This can result in the contamination of both sediment and water.

Overall, the pH and the alkalinity of water can affect the concentrations of mercury in a water body. Methyl mercury is produced, transported and accumulated by aquatic organisms significantly more efficiently at low alkalinity and pH.

Salinity can also impact mercury concentrations. For example, as runoff into the SF bay increases and the salinity decreases, the concentration of dissolved mercury increases. In addition, sulfate concentrations in water can impact microbial methylation of mercury. There is a window of sulfate concentration that promotes the highest mercury methlation rate (opt. Hg by SRB in sediments is at 200-500 mM.).

In aquatic sediments, mercury and other metal contamination is most strongly correlated with the proportion of fine particles. Aerobic and Anaerobic micro environments can affect oxygen metabolism and sulfur metabolism. Oxygen rich env. (upper sed) can favor O2 metabolism and oxygen poor env. lower sed) can favor sulfur metabolism, producing Hgs and Ch3Hgs.

 

Back