Methyl Bromide Power Point
Transcript of Methyl Bromide Power Point
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Methyl Bromide
Darren Ma
ENT 110
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Soil Fumigants
Chloropicrin synthesized by John Stenhouse in 1848 as a
poison gas.
Most Fumigants used originally for biological warfare
Chemicals such as chlorine, hydrogen sulfide, mustard
gas (Bis(2-chloroethyl) sulfide), and different bromides.
Also used for refrigerants, fire extinguishers, fumigation
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Methyl Bromide Use
Soil Fumigation-agricultural use as a fungicide, herbicide
Structural Fumigation-pesticide, rodenticide
Commodity Fumigation-pesticide, fungicide, rodenticide,
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Methyl Bromide
Methyl Bromide is an odorless, colorless gas,
undetectable by humans until hours after exposure.
Mixed with small concentrations of Chloropicrin, which
can be smelled at very low doses(.3ppm) within seconds. Gases that leak out of the plastic tarp may be blown
downwind.
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Effects of Methyl Bromide-
Humans Nerve Poison
Chronic and Acute exposure are both dangerous
Light Exposure can cause dizziness, nausea, headaches,
and skin blisters with light exposure.
Moderate exposure can lead to lung irritation and
damage to heart, kidneys, and nervous systems.
Exposure of >2000ppm in one hour can be fatal.
Threshold Limit Value (TLV): 5ppm in the air
Permissible exposure limit (PEL): 20ppm for a 8 hour a
day, 5 day work week.
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Effects of Methyl Bromide-
Environmental Methyl Bromide is 50 times more effective at destroying
stratospheric ozone than CFC¶s on a per molecule basis.
Though there there are natural sourcesand emissions of methyl bromide,
man-made methyl bromide and other
manufactured compounds have
significantly contributed to ozone
depletion.
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Legislation and Regulation
1984 Vienna Conference: The Vienna Convention for the
Protection of the Ozone Layer. No legal binding
regulations
1987 Montreal Protocol on Substances That Deplete theOzone Layer- so far has been ratified by 196 countries.
-Timetable for reduction and phase out of ozone
depleting substances, mainly CFC¶s and HCFC¶s.
In 1995 the Montreal Protocol set the deadline
for a worldwide 50% reduction in methylbromide use by 2005, and a complete phase
out by 2010.
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Legislation and Regulation
U.S. Clean Air Act of 1990, amended in 1998 to include
phase-out of methyl bromide in the United States.
By 1994, EPA worked to reduce domestic use to 30,000
tons. By 2005, amount is reduced to 10,000 tons.
Complete phase-out was supposed to be in 2005, but
use still continues under: Quarantine and Preshipment
exemption, Critical Use exemption for agriculture.
Current projections is a reduction to 4.63% of 1991 levelsby 2012. (mainly for use in California)
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Alternative Tactics
Use of alternative chemicals such as Chloropicrin,
Dichloropropene, Dazomet, and others are still allowed
for the United States.
Carbon Dioxide and Nitrogen fumigation, in controlledenvironments.
For Agriculture- specifically California strawberry
production, we can use hydroponics!
Most successful alternatives consist of combinations of
chemical and non-chemical materials.