Methyl Bromide, Ozone Depletion and Alternatives how global warming is affected by the methyl bromide, ozone depletion and what are the consequences and alternatives for the usage of methyl bromide are explained clearly in the above given ppt

1. Methyl Bromide and Ozone
Depletion

2. What is Methyl Bromide
• Methyl bromide is an odorless, colorless gas at normal
temperature and pressure.
• Used to control a wide variety of pests in agriculture and
shipping, including fungi, weeds, insects, nematodes (or
roundworms), and rodents.
• Introduced as a pesticide in 1932, methyl bromide was first
registered in the United States in 1961
• Farmers use methyl bromide primarily to treat soil to kill
nematodes, fungi, and weeds
• Chemical Name- Bromomethane.
• One of the Ozone Depleting chemical.

3. Methyl bromide damages the ozone layer
• In the atmosphere, methyl bromide depletes the ozone layer and allows increased
ultraviolet radiation to reach the earth's surface. Methyl bromide is a Class I ozone-
depleting substance as defined by the Montreal Protocol on Substances that Deplete the
ozone layer.
How does methyl bromide work?
• Methyl bromide fills air spaces in enclosed areas and penetrates cracks, crevices, and
pores in soil, commodities, and structures.
• To be an effective treatment, an appropriate concentration of methyl bromide must be
contained at the application site for a given period of time.
• Pesticide applicators cover methyl bromide treatment sites with plastic tarps or tents to
confine the gas.
• Methyl bromide leaves the application site after the treatment is complete
• Scientists believe that methyl bromide is toxic because it damages several sites in
organism’s cells. Methyl bromide binds to DNA, fats, and proteins

4. Source of Methyl Bromide
• Produced naturally from oceans and plants in land.
• Major natural source- Salt Marshes.
• Salt marshes – 0.1 percent of the Planet ‘s Surface.
• About 23 percent of Methyl Bromide and Methyl chloride
contribute to Ozone destruction from Peat bogs and fertile
areas.
• Industrial use of Methyl Bromide and Methyl chloride

5. • Plants – important source- Brassica Species- It takes up
Bromide from soil, produce Methyl Bromide and release
into atmosphere.
• United States Environmental Protection Agency estimated
72000 tonnes of Methyl bromide used.
• 20 percent- Fumigation
• 10 percent- vegetation burning
• 30 percent- oceans
• 40 percent- Salt marshes.
• More damaging to Ozone than CFC.

6. Other Harmful Effects
• Methyl bromide is highly toxic. Studies in humans indicate that the lung may be severely
injured by the acute (short- term) inhalation of methyl bromide. Acute and chronic (long- term)
inhalation of methyl bromide can lead to neurological effects in humans.
• Symptoms of acute exposure in humans include headaches, dizziness, fainting, apathy, weakness,
confusion, speech impairment, visual effects, numbness, twitching, and tremors; in severe cases
paralysis are possible.
• Neurological effects have also been reported in animals.
• Dermal exposure to methyl bromide can cause itching, redness, and blisters in humans.
• Kidney damage has been observed in humans who have inhaled high levels of methyl bromide.
• Inhalation of methyl bromide may cause the liver to become swollen and tender.
• Injury to the heart has been observed in mice and rats exposed to high concentrations of methyl
bromide by inhalation.

7. • The “Montreal Protocol on Substances that Deplete the Ozone Layer” established in 1987, recognised
methyl bromide as an ozone depleting substance along with chlorofluorocarbons (CFCs) and halons.
• Each bromine atom from methyl bromide was found to destroy about 60 times more ozone molecules
than each chlorine atom from CFCs on an atom-per-atom basis.
• The Montreal Protocol proposed phase-out schedule of methyl bromide both for developed and
developing countries under Copenhagen Amendment, 1992.
• For Developed Countries
– 25 percent by 1991
– 50 percent by 2001
– 70 percent by 2003
– Phase out by 2005
• For Developing Countries
– Freeze by 2002 at average of 1995-98 level
– 20 percent by 2005
Phase Out of Methyl Bromide under Montreal Protocol

8. Fumigation
• Very high proportion of Methyl Bromide is used for
Fumigation – Man- made emission.
• In 1994, MBTOC estimated 64 percent worldwide emission.
• Emission occur in 3 stages.
1. During Treatment- Leaks
2.Immediately
vented.
3.Following
after treatment- fumigation spaces are
Treatment- absorbed by soil particles,
commodities and structures, then gradually released.

9. • Agricultural growers inject methyl bromide about two feet into the ground to sterilize the soil
before crops are planted. Although the soil is covered with plastic tarps immediately after a
treatment, 50 to 95 percent of the methyl bromide eventually enters the atmosphere.
• Surface Application
• Mechanized injection.(25 cm & 80cm)
• 50 to 95 percent released into the atmosphere.
• Methyl bromide is also used to treat commodities such as grapes, asparagus, logs, and other
imported goods to prevent introducing pests to the United States. Treatments often fulfill official
quarantine requirements for international shipments.
• Methyl bromide is a toxic substance. Because it dissipates rapidly into the atmosphere, it is most
dangerous at the fumigation site.

10. Tobacco, 5%
Peppers, 5%
Strawberries, 13%
Tomatoes, 23%
Flowers, 5%
Sweet Potatoes, 1%
Curcubits, 7%
Nursery crops, 6%
Other produce, 12%
Replant, 5%
Others, 18%
WORLD SOIL USE OF METHYL BROMIDE BY CROPS

11. Quarantine and Pre- shipment Uses
• 22 percent of Global Methyl bromide.
• Toavoid transporting pest – Import & Export
Fumigation of Commodities
• Commodities in storage and Transportation – to be protected.
• Durable Commodity- Cereals, dry fruits, nuts.
• Perishable commodity- cut flowers, vegetables, ornamental flowers.
• Durable Commodity- 50-90 percent
• Perishable commodity- more than 90 percent
Fumigation of Building and Vehicles

12. Usage of Methyl Bromide worldwide (Source: MBTOC 2006 Assessment Report)

13. Usage of Methyl Bromide worldwide (Source: MBTOC 2006 Assessment Report) (Contd.)

14. Key sectors using Methyl Bromide in 2002 and 2010 (Source: MBTOC 2002 amd 2010
Assessment Report)

15. Alternatives to Methyl Bromide
• No single substance can replace the application of Methyl Bromide.
• IPM- Integrated Pest Management- adopted.
• The term Integrated Pest Management was first used in agriculture beginning in the 1970's in response to
growing knowledge about the negative side-effects of pesticide overuse. The approach emphasized the
integration of pest biology and cultural practices in controlling insect pests in crops.
• Govt. of India has adopted Integrated Pest Management (IPM) as cardinal principle and main plank of plant
protection in the overall Crop Production Programme since 1985. IPM is an eco-friendly approach that
encompasses cultural, mechanical, biological and need based chemical control measures. The IPM approach is
being disseminated through various schemes/projects at national and state level.
• Both chemical and non-chemical alternatives to methyl bromide exist, and several pest control
tools can manage the pests currently controlled with methyl bromide. Research on alternatives
is ongoing and EPA continues to prioritize the registration of alternatives to methyl bromide.

16. • In India methyl bromide fumigation forms an essential component in quarantine processing of import/ export
consignments by disinfestation and salvaging.
• The Directorate of Plant Protection, Quarantine, and Storage, established under the Ministry of Agriculture is the
regulating authority for granting approval for restricted use of methyl bromide and accreditation of fumigation
agency.
• The directorate plays a major role in the guidance and control of fumigation activities in the country under its
“National Standards for Phytosanitary Measures (NSPM)” and the NSPM-11 deals about the “Quarantine
Treatments and Application Procedures.
• The phasing out of the fumigant necessitates the impetus for research in finding a suitable alternative for the
Indian quarantine system.
• Several chemicals such as phosphine, sulfuryl fluoride, carbonyl sulfide, carbon disulfide, ethyl formate, ethylene
oxide, hydrogen cyanide, methyl iodide, and methyl isothiocyanate are being considered as alternative fumigants
to methyl bromide.
• But among them very few match the rapid action and penetration capabilities of methyl bromide on target pests.
Some taint the fumigated product, few are phytotoxic, leave unacceptable residues, or may be unlikely to be
registered for health or economic reasons )

17. Alternative Treatment for Soil
• Soil fumigation is the largest single use of Methyl Bromide.
• IPM approach will be necessary when soil-borne pest control is to be effective, sustainable, and environmentally
benign.
• Individual techniques may have constraints, but a package of methods can be used to provide effective pest
management for specific sites and situations.
• Many non-chemical alternatives for soil treatment are in use.
Non- chemical alternative- Biofumigation is based on the incorporation of fresh plant mass into the soil, which will
release several substances able to suppress soil-borne pests.
• MITC (methyl isothiocyanate are highly toxic to pests and pathogens. Plants from the Cruciferae family release
a large amount of these toxic compounds in soil and are considered the best material for
biofumigation.
• Biofumigation reduces weed competition and soil-borne pathogens and is a suitable tool for soil disinfection. As
in the case of solarization, it also increases nutrient uptake by plants
• Chemical Alternatives- Metam sodium, MITC.

18. Non- chemical alternative- Natural or artificial Plant growth substrates
Many crops such as tomatoes, peppers, strawberries, cut flowers, melons, cucurbits, nursery-grown
vegetable transplants, strawberry plants and tobacco seedlings are grown in soilless substrates around
the world.
A wide variety of substrates is used including artificial and natural materials such as rock wool, tuff
(volcanic scoria), clay granules, solid foams (e.g. polyurethane), glass wool, peat, coconut husk
materials, volcanic gravel (lapilli), pine bark, grape industry waste, sugarcane bagasse and others

20. Some of the Alternative fumigants for methyl bromide
1. Phosphine:
• This is the most widely used fumigant for insect control in the durable commodities throughout the world.
• It is increasingly used as a treatment to replace methyl bromide especially because of its low cost, fast
dispersion in the air and low residues.
• The versatility of use is a major advantage for phosphine, as it can be used in a variety of storage buildings,
during transit (e.g. in ship holds) or in plastic sheet enclosures.
• It is close to an ideal fumigant except for few drawbacks: slow activity, the rapid increase in insect resistance,
flammability at higher concentrations (>900 ppm) and corrosion of copper, silver and gold.
• The understanding of phosphine resistance mechanism, improved monitoring tactics and management of
resistance.
• The other problems like corrosion and flammability were found to be limited by using the combination of
heat (30–36◦C), carbon dioxide (3–7%) and phosphine at 80–100 ppm, while achieving a complete insect
control

21. 2. Carbon di sulphide:
• This is one of the oldest fumigants in use, and its use in France during 1869, against the grape phylloxera, was a landmark
in the history of applied entomology.
• Carbon disulphide was widely used as a soil or space fumigant in many countries and owing to the properties of high
flammability, requirement of longer exposure period and toxic residues in treated commodity, its usage had been
discouraged.
3. Botanicals:
• Plant essential oils and their components, especially monoterpenes, have the potential for the development as
alternative fumigants and they possess several advantages over conventional fumigants in terms of low mammalian
toxicity, environmental friendly, rapid degradation and local availability.
• Essential oils derived from more than 75 plant species have been evaluated for fumigant toxicity against stored product
pests and had been found to possess ovicidal, larvicidal, and repellent properties against various insect species
4. Hydrogen cyanide:
• Hydrogen cyanide was a widely used insecticidal and rodenticidal fumigant against the stored product pests on durables
and perishables for many years. The high dermal toxicity of the gas makes it hazardous to applicators, and residues are
often a concern.
• However, recent restrictions on the use of methyl bromide are resulting in the phytosanitary uses of old fumigants being
considered again and some countries started using hydrogen cyanide to disinfest oranges of surface pests with
insignificant injury to the fruit

22. 5. Ozone:
• The powerful oxidizing property makes ozone, an attractive candidate as a fumigant for controlling insects and fungi in
stored products.
• It is currently used to disinfect fruits, vegetables, and other foodstuffs of microorganisms and viruses; as a means of
reducing odor; and for removing taste, color, and environmental pollutants in industrial applications.
• Ozone controlled the major stored-grain insects viz., S. oryzae, Oryzaephilus surinamensis, Tribolium spp.,
and E. elutella and various fruit flies.
• The advantages of ozone as a fumigant include lower hazards, practically no residues in treated commodities,
reduction in transportation costs as it can be generated on site and its efficacy against wide range of pests.
• The main disadvantages are its poor penetration capabilities, requirement of longer exposure time, corrosive
properties on metals and phytotoxicity to live plants.
• The efficacy of ozone fumigation was reported to be enhanced by higher temperatures, lower oxygen levels, and
longer treatment times and modifying the method of application like closed-loop recirculation

23. 6. Sulfuryl fluoride:
• Another promising chemical is sulfuryl fluoride, which is widely used for the control of termites, and stored-product
insects.
• This chemical shows considerable promise and is undergoing registration procedures as a replacement for methyl
bromide in several countries including the United States, Great Britain, Italy, and France.
• The fumigant has a vapor pressure of about ten times higher (13,442 mm of Hg at 25ºC) than that of methyl bromide
and hence it is more penetrative into treated commodities which is a significant benefit in situations where insect
infestations are located deep within cracks or machinery in premises such as flour mills.
• The fumigant has several other advantages as a replacement for methyl bromide; it is non-reactive with structural
materials and components of electronic equipment, is non flammable, and has not caused problems of taint
following treatment of a wide range of materials. However, the sulfuryl fluoride was found to be less effective in
controlling the insect eggs.

24. Table below identifies a selection of possible chemical alternatives based on the use category

25. Table below identifies a selection of possible chemical alternatives based on the use category (Contd.)