methyl bromide power point

8/2/2019 Methyl Bromide Power Point

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Methyl Bromide

Darren Ma

ENT 110



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



Methyl Bromide Use

Soil Fumigation-agricultural use as a fungicide, herbicide

Structural Fumigation-pesticide, rodenticide

Commodity Fumigation-pesticide, fungicide, rodenticide,



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.



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.



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.



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.



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)



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.

methyl bromide power point

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