Ana Gonzalez

 

Websites:  

http://www.atsdr.cdc.gov/cxcx3.html

http://siri.uvm.edu/msds/index/gw.cgiy=79-01-6&start=0

http://siri.uvm.edu/msds/index/gw.cgiy=79-01-6&start=0

Trichloroethylene (TCE): C2HCl3 is a nonflammable, colorless liquid with a somewhat sweet order and a sweet , burning taste. Used as a solvent to remove grease from metal parts, paint remover, spot remover, etc.

Natural Sources:  

Industrial Sources:

Lifespan (residence times were not given):

 

Trihalomethanes are a group of organic chemicals formed in waterÊwhen chlorineÊreacts with natural organic matter (such as humic acids from decaying vegetation). Humic acids are present in all natural water used as sources of drinking water.Ê They are also found in dry-cleaning solvents; both airborne and drinking water contaminant.Ê Total trihalomethanes (TTHM) are not a single chemical but a class of compounds that includes: Ê

NATURAL ORGANIC COMPOUNDS IN WATER ÊÊÊ

Chlorine reacts with the natural organic carbon compounds in the water to form trihalomethanes.Ê These organic compounds include:

Humic Substances ÊÊÊ

Humic substances are the organic portion of soil that remains after prolonged microbial decomposition, and that is formed by the decay of leaves, wood, and other vegetable matter.Ê They can impart a yellowish-brown to brownish-black color to water; detectable to 0.1 ppm in water.Ê Humic substances are commonly classified on the basis of solubility.Ê If a material containing humic substances or humus is extracted with a strong base and the resulting solution is then acidified, the products are a) a nonextractable plant residue called humin, b) a material called humic acid that precipitates from the acidified (pH < 2) solution, and c) an organic material called fulvic acid that remains dissolved in the acidified solution.Ê The high molecular weight and polyelectrolytic humic substance macromolecules range from a molecular weight of a few hundred for fulvic acid to tens of thousands for the humic acid and humin fractions.ÊÊ Humic substances are excellent chelating agents that bind with and hold metal ions in water, and they also effectively exchange cations with water.

Fulvic Acid ÊÊÊ

A water-soluble, natural organic substance of low molecular weight which is derived from humus, often found in surface water. Fulvic acid contributes to the formation of trihalomethanes in chlorinated water supplies, and can contribute to organic fouling of ion exchange resin beds.ÊÊÊÊÊÊÊÊÊÊÊ

Webpages

http://www.usgs.gov/

http://www.atsdr.cdc.gov/cxcx3.html Ê

 

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ana.html
Ana Gonzalez

 

Websites:  

http://www.atsdr.cdc.gov/cxcx3.html

http://siri.uvm.edu/msds/index/gw.cgiy=79-01-6&start=0

http://siri.uvm.edu/msds/index/gw.cgiy=79-01-6&amp;start=0

Trichloroethylene (TCE): C2HCl3 is a nonflammable, colorless liquid with a somewhat sweet order and a sweet , burning taste. Used as a solvent to remove grease from metal parts, paint remover, spot remover, etc.

Natural Sources:  

  • Not known to occur as a natural product in the environment.

Industrial Sources:

  • Primarily through evaporation, spills, and leaks in storage tanks.
  • Misused as an ingredient in some septic tank cleaners
  • Air emission from metal degreasing plants, and wastewater from metal finishing, paint and ink formulation, electronic component operations, and rubber processing industries.
  • May occur as a result of bacterial breakdown of tetrachloroethylene.
  • Burring of community and hazardous waste.

Lifespan (residence times were not given):

  • Easily dissolves in water, and it remains there for a long time
  • Quickly evaporates from surface water, so it is commonly found as a vapor in the air.
  • Evaporates less easily from the soil, where it may stick to particles and remain for a long time
  • Stick to particles in the water, which will cause it to eventually settle to the bottom sediments
  • Does not build up significantly in plants and animals

 

Trihalomethanes are a group of organic chemicals formed in waterÊwhen chlorineÊreacts with natural organic matter (such as humic acids from decaying vegetation). Humic acids are present in all natural water used as sources of drinking water.Ê They are also found in dry-cleaning solvents; both airborne and drinking water contaminant.Ê Total trihalomethanes (TTHM) are not a single chemical but a class of compounds that includes: Ê

  • chloroform (CHCl3)
  • (predominated THM species) Ê
  • bromoform (CHBr3)
  • dichlorobromomethane (CHCl2Br)
  • dibromochloromethane (CHClBr2) Ê

NATURAL ORGANIC COMPOUNDS IN WATER ÊÊÊ

Chlorine reacts with the natural organic carbon compounds in the water to form trihalomethanes.Ê These organic compounds include:

Humic Substances ÊÊÊ

Humic substances are the organic portion of soil that remains after prolonged microbial decomposition, and that is formed by the decay of leaves, wood, and other vegetable matter.Ê They can impart a yellowish-brown to brownish-black color to water; detectable to 0.1 ppm in water.Ê Humic substances are commonly classified on the basis of solubility.Ê If a material containing humic substances or humus is extracted with a strong base and the resulting solution is then acidified, the products are a) a nonextractable plant residue called humin, b) a material called humic acid that precipitates from the acidified (pH < 2) solution, and c) an organic material called fulvic acid that remains dissolved in the acidified solution.Ê The high molecular weight and polyelectrolytic humic substance macromolecules range from a molecular weight of a few hundred for fulvic acid to tens of thousands for the humic acid and humin fractions.ÊÊ Humic substances are excellent chelating agents that bind with and hold metal ions in water, and they also effectively exchange cations with water.

Fulvic Acid ÊÊÊ

A water-soluble, natural organic substance of low molecular weight which is derived from humus, often found in surface water. Fulvic acid contributes to the formation of trihalomethanes in chlorinated water supplies, and can contribute to organic fouling of ion exchange resin beds.ÊÊÊÊÊÊÊÊÊÊÊ

Webpages

http://www.usgs.gov/

http://www.atsdr.cdc.gov/cxcx3.html Ê

 

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