For about fifty years, methyl bromide (MB) has been one of the most widely used fumigants in the world because of its:
MB of anthropogenic origin is, however, estimated to cause between 5 and 10 % of total ozone depletion in the earth's stratosphere. Ozone depletion increases the level of UV-B radiation which has been linked to skin cancer, eye cataracts, and degradation of the immune system. Direct exposure to MB leads to acute and chronic health problems including respiratory difficulties, neurological disorders and even death. In developing countries particular health hazards during application persist in spite of considerable training activities. Possible implications of UV-B radiation on ecosystems include yield reduction in different crops, impacts on forest trees, freshwater, wetland and marine ecosystems.
Because of these effects, in the ninth meeting of the parties to the Montreal Protocol (MP) held in September 1997, the phase-out of this fumigant in industrialised countries by the year 2005 was decided. Some countries agreed voluntarily on earlier phase-outs (including Austria, Denmark, Finland, Indonesia, Norway, Sweden and the United States of America - USA). In a number of countries, such as Germany and the Netherlands, specific treatments have already been phased out, partly for toxicological reasons. Many industrialised countries have reduced MB use for commercial, safety or environmental reasons. The phase-out date for developing countries has been fixed for the year 2015. According to the UNEP, eliminating MB is the most significant step to reducing ozone depletion.
The use of MB in developing countries (Article 5 (A5) countries of the MP) includes:
A5 countries use about 18 % of the global production of MB for agricultural purposes (14 510 t in 1992). In Africa, about 22 % of this quantity is applied, in Asia about 45 % and in South and Central America including the Caribbean about 31 %. From 1990 to 1994, the use of MB almost doubled in developing countries partly due to aggressive marketing. The main use is soil fumigation, accounting for about 70 % of the total, and the fumigation of durables (about 20 %). Data on the MB consumption in A5 countries, however, are in many cases not very reliable.
In most North African countries, the consumption of MB is steadily increasing since the freeze on applying MB in South European countries. Comparative advantages like cheaper labour led to a shift in vegetable production for the European market to the southern shores of the Mediterranean and, in consequence, to increased demand for MB. A similar development cannot be excluded for other regions too.
Technically feasible alternatives to MB fumigation are either available or in advanced stages of development for more than 90 % of applications. Alternatives for the fumigation of certain buildings such as mills or for some quarantine treatments, however, are not yet readily available. Extension services will have to be very knowledgeable so that an economic balance can be maintained during the transition period.
(Including Nurseries, Seedbeds and Re-plant Uses)
For this major MB use in A5 countries, alternative chemical, non-chemical and crop production methods exist, which, in many situations, will substitute MB to a large degree. Solarisation combined with biological control methods is one possible substitute for MB in tropical countries. Cultural practices for the management of soil-borne pests include: crop rotation, planting time strategies, grafting, deep ploughing, flooding, fallow, cover crops, intercropping, green manure, fertilisation and plant growth substrates. The Integrated Pest Management (IPM) approach developed by GTZ is of vital importance. The GTZ concept of IPM is identical with the one described in Agenda 21.
The substitution of MB fumigation of perishable commodities requires a large series of well-tuned individual alternatives. Production in zones that are officially recognised to be free from quarantine pests is already practised in some regions. This is a promising preventive option for specific areas and crops. Systems approaches based on IPM in the field and on sorting procedures can reduce pest pressure considerably. Feasible post-harvest alternatives include heat and cold treatments, controlled and modified atmospheres, physical removal of pests, and some combined methods. Fumigation with alternative gases and treatment with chemical dips seem to have only a limited potential as alternatives to MB.
Phosphine is extensively used to fumigate durable commodities and has a considerable potential for replacing MB. Recently developed application techniques reduce the exposure period. Some promising alternative fumigants like carbonyl sulfide exist. In countries where legislation allows it contact insecticides can be applied as a preventive measure. Further possible alternatives include inert dusts, controlled and modified atmospheres, cold storage, heat treatment and irradiation.
As alternative gases such as phosphine corrode electric and electronic installations, for the time being MB is difficult to substitute in the fumigation of mills and food production plants. However, promising trials have been conducted in order to solve the corrosion problem. Combined treatments (heat + fumigant or another insecticide) are being developed. Sanitation and IPM approaches may solve insect problems to a large extent.
Alternatives are available and, in some cases, are well established. Phosphine treatment has already widely replaced MB (e.g. in-transit fumigation of ships). Hydrogen cyanide, carbon dioxide, nitrogen-based controlled atmospheres and artificial cooling will play a more important role in the future. These techniques, however, require high technical standards.
Quarantine and pre-shipment applications of MB are exempt of control by the MP. However, a considerable number of the treatments mentioned above is already used for quarantine purposes or has a high potential for replacing application of MB. Major progress can be expected from the implementation of quality assurance systems that are audited by the quarantine authorities of the countries of origin. Obligatory MB fumigation of certain vegetables prescribed by some importing countries should be replaced by inspection procedures. Overly severe safety standards for quarantine treatments should be reviewed. A systems approach to quarantine security is considered to be a practical alternative to MB fumigations. It can be integrated into existing commercial procedures and is economically advantageous.
There are MB alternatives that are cheaper, others that are more or less equal and still others that are more expensive than MB. Many factors influence local prices. The information given in chapter 3 allows, however, to identify alternatives that are economically viable under varying conditions.
Changes in yields have frequently been reported in connection with MB alternatives. In some cases decreases occur, but many alternatives do not affect yields or contribute to considerable increases that outweigh higher application cost in some cases.
There is strong evidence that some alternatives for soil treatment present considerable net benefits for many crops in warm climates. Many of these alternatives are more labour-intensive and thus have a positive impact on rural labour markets. Additionally, new service and job opportunities will arise. Switching from production systems dependent on imported MB to labour-intensive systems using local resources would stabilise the national economies of A5 countries.
The detrimental effects of MB described in chapter 1 cause high costs that must be carried by society. These costs are often neglected in economic considerations concerning MB alternatives. Reduction of hidden costs through the substitution of MB may make funds available for further support of research on and implementation of alternatives.
The results of a recent study commissioned by the Canadian Government indicate clearly the overall benefits of the MP that amount to 224 billion USD plus human health benefits for the period between 1987 and 2060. Taking into account the proportion of anthropogenic MB in ozone depletion it can be estimated that 5-10 % of the total benefit is related to the substitution of this gas. This corresponds to an amount of 11 to 22 billion USD plus human health benefits. Due to the short-term benefits of MB substitution mentioned in chapter 2, the economic benefits would ensue faster than with CFCs and some other ozone-depleting substances.
The objectives of German development cooperation (which also serve as GTZ guidelines) include:
GTZ takes a special interest in phasing out MB in A5 countries because of its high ozone-depleting potential, and also because of the acute and chronic health hazards involved in its application. It should be noted that most of the chemical alternatives for soil treatments listed in chapter 3 involve similar health hazards. This is the major reason why GTZ does not favour the use of these substances.
In some instances recommendations made by GTZ go beyond the decisions of the parties to the MP. This applies especially to the smart use of the grace period for A5 countries. This grace period has advantages as it provides additional time to implement sound alternatives but it may also lead to severe new problems:
GTZ's work focuses on raising awareness and transferring know-how concerning feasible alternatives to MB in developing countries. The activities are coordinated by the Environmental Protection and Conservation of Natural Resources Section (PROKLIMA project) and the Plant Protection and Post-harvest Section. Specific topics are dealt with in a series of bilateral agricultural and quarantine projects.
GTZ has commissioned the elaboration of a compendium of feasible or promising MB alternatives (cf. chapter 3). The compendium is intended to assist decision makers and practitioners to adopt alternative solutions and is the first step in a sensitisation and training programme on alternative treatments.
GTZ is also actively involved in developing and testing MB alternatives under field conditions in several bilateral and regional projects. Priority activity areas are soil disinfection, the treatment of durable commodities, the development of economic instruments and the disposal of obsolete stocks of MB.
GTZ is carrying out successful experimental and extension work in this field in projects in Egypt, Jordan and Morocco:
Integrated Pest Management, Egypt (PN 90.2195.7)
The project measures to combat soil nematodes include testing the planting of Tagetes in summer, the grafting of cucurbits on resistant stocks and testing an algae-based product. The project also recommends enriching the soil with organic material, crop rotation and solarising the soil.
Sustainable Pest Management Systems, Jordan (PN 94.2085.2)
The project recommends the following alternatives:
Phytosanitary Control, Morocco (PN 90.2195.7)
Trials started during 1996 use Tagetes which are planted after tomatoes and act as trap crops in controlling nematodes.
For several years GTZ has been recommending MB alternatives such as good post-harvest management and phosphine fumigation in the following projects:
Post-harvest Project (PN 94.2153.8)
This supra-regional project has focused its training and extension work on hygiene and other preventive measures and on proper phosphine application in large-scale storage. Magnesium phosphide is recommended for quarantine purposes.
GTZ-assisted Plant Quarantine Project, Syria (PN 90.2227.8)
This project recommends the use of phosphine for quarantine fumigation. Fumigation trials planned by the project include applying ozone in cereal bag stacks under gastight sheets and using controlled atmospheres with elevated carbon dioxide concentrations in fumigation chambers.
In some countries, old stocks of MB in rusty and/or leaking containers seriously endanger human beings and the environment. The supra-regional
Pesticide Service Project (PN 96.2079.0)
assists developing countries to dispose of MB according to international environmental and safety standards and is working out guidelines and procedures to avoid similar problems in the future. Additionally, it provides advice on pesticide use and quality control including the choice and application of alternative synthetic and natural products intended to substitute MB.
In many cases, pesticide use in general is favoured by direct and indirect subsidies as well as by institutional factors in the crop protection subsector. The use of pesticides consequently exceeds its economic optimum. The
Pesticide Policy Project (PN 93.2183.7),
a supra-regional project assisted by GTZ and the University of Hannover, aims at analysing economic and institutional factors in crop protection. Economic instruments are being developed to phase out specific active ingredients such as MB and to support integrated protection programmes.
Future GTZ programmes will cover all interested countries, but will focus initially on Southern and Eastern Africa, the Middle East and Central America. GTZ will assist its partner countries to develop and implement MB management plans (MMPs). These plans will include:
Training activities will be geared towards specific needs in substituting MB. Following the "focal point" approach, the main cooperation partners will be the Ozone Officers in the respective countries.
The training programme will include:
Practically oriented training manuals will be developed within this programme.
At the same time, applied research activities will be supported in close cooperation with implementing agencies such as UNDP, UNEP, UNIDO, the World Bank and with international and national research institutions. Within the framework of demonstration projects, promising techniques will be tested under the specific conditions of A5 countries. These activities will be strictly oriented towards the principle of ownership.
The integrated pest and post-harvest management strategy developed by GTZ aims at reducing the use of synthetic pesticides in favour of less toxic and environmentally friendly methods. Therefore, GTZ encourages the rapid substitution of MB in developing countries and recommends the following:
Economic considerations and fumigation requirements set by major importing countries seem to be the biggest obstacles for a rapid substitution of MB in developing countries in the near future. Changes in practice are needed with which all parties may not be in agreement. In order to facilitate the process of substitution, the following is recommended:
These aims can best be achieved through country-oriented workshops and training seminars as described in chapter 7.
