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Human health and environmental hazards arising from the use of chemicals in developing countries
the Science of the Total Environment An I ~ m m l l o m ~ J ~ r l ~ r ~ s d ~ l l f l ¢ n ~ b Ina* t h . ~ , l ~ t ~ lU l ~ . n t I.~alJp with S l J .
ELSEVIER
The Science of the Total Environment 188 Suppl. 1 (1996) S135-S140
Human health and environmental hazards arising from the use of chemicals in developing countries R. Plestina, M. M e r c i e r International Programme on Chemical Safety, 1211 Geneva 27, Switzerland
1. Introduction The recognized or suspected harmful effects of chemicals on human health and the environment are derived from their inherent properties which cannot be influenced. However, the potential harmful effects may be reduced or even eliminated by the proper handling and judicious use of chemicals. There should be no argument over whether chemicals are essential on every segment of human activity, but also, nobody can deny that certain uses (misuses) outweight the benefits that chemicals offer. This permanent conflict of benefit against risk needs to be fully understood through an unbiased scientifically based risk-benefit evaluation. The massive expansion in the availability and use of chemicals throughout the world during the last few decades has led to increasing awareness of the potential risks that exposure to chemicals pose, both to human health and the environment. The growing generation of hazardous wastes and intentions for their uncontrolled transboundary movement is dealt with by the widely accepted Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal, adopted in 1989 (UNEP, 1994). It became obvious that fast industrial development can introduce various health and environmental risks that the community is unable to cope with. Many catastrophes caused by chemicals have
occurred in recent years such as massive poisoning with methylmercury in Iraq (WHO, 1976) or with TOCP in Morocco (Smith and Spalding, 1959). It should be mentioned, however, that naturally occurring toxins are also known to be the cause of massive outbreaks of acute poisoning as well as causing irreversible effects, including cancer, in exposed populations (Keeler and Tu, 1983; Hall and Strichartz, 1990). Although cancer is only one of the many serious effects that can result from exposure to chemicals, both man-made and naturally occurring, it has become a matter of considerable concern to the general public and much effort has been made to identify and classify chemicals according to the carcinogenic hazard they pose to humans. Intense international concern about the dangers of chemicals for human health and the environment, expressed at the United Nations Conference on the Human Environment, held in Stockholm in 1972 led to the establishment in 1980 of the International Programme on Chemical Safety which is a joint venture of the World Health Organization (WHO), the United Nations Environment Programme (UNEP) and the International Labour Office (ILO). The programme was initially set up specifically to provide assessments of the risks to human health and the environment from exposure to chemicals whatever
0048-9697/96/$15.00 © 1996 Elsevier Science B.V. All rights reserved PII S0048-9697(96) 05285-0
S136
R. Plestina, M. Mercier/The Science of the Total Environment 188 Suppl. 1 (1996) $135-$140
their origin, man-made or natural, or wherever they are found, thus providing the internationally evaluated scientific basis on which countries may develop their own chemical safety measures. Twenty years after the Stockholm Conference, the UN Conference on Environment and Development (UNCED) held in Rio de Janeiro requested the creation of an international strategy for the environmentally sound management of toxic chemicals. The conference considered that IPCS should be the nucleus for this strategy, and that cooperation with other organizations having an involvement in chemical safety should be strengthened. In addition, UNCED stressed the need to extend partnership with governments, industries, trade unions, consumers and professional bodies. It has been proposed that the strengthening of IPCS should be accompanied by the setting up of an intergovernmental forum for chemical risk assessment and management which is now underway. UNCED identified six programme areas that would form the objectives of the new IPCS: •
•
•
•
•
•
The evaluation of the risks to human health and the environment from exposure to chemicals should be accelerated, and international agreement concerning methods of risk assessment needs to be expanded. Harmonization on a worldwide scale is also essential for the classification and labelling of chemicals. Mechanisms are required to make the exchange of information on chemicals and their risks easier, and to deal with major accidents and poisonings that involve them. Activities to reduce the risks of chemicals and to develop the use of safer alternatives need to be promoted. To provide assistance to countries, especially the developing ones, to evaluate health and environmental hazards, and to bring in and enforce legislation when necessary. More information and stronger measures are needed in the fight to halt illegal international traffic in dangerous chemicals. Today the programme provides guidance to
countries on how to use available risk assessments to achieve risk reduction, and also helps to strengthen national capabilities to prevent and treat harmful effects of chemicals and to manage emergencies involving chemicals. Two basic aspects in promoting chemical safety that will be briefly discussed are risk evaluation and risk management, the former being of global and the latter of more regional or national significance and applicability. 2. Risk evaluation
Most of the new chemicals, drugs and pesticides in particular, before being allowed on the market, are extensively and meticulously tested to ascertain their biological potential to produce adverse effects. These studies are normally performed by the manufacturers, using widely accepted procedures. The results together with those published in open literature are critically reviewed by national or international groups of experts with the aim to assess human health and environmental risks arising from the use of chemicals which are likely to be inadvertently absorbed by users or the general population, or spread in the environment. The risk evaluation is a complex scientific process requiring the meticulous work of a multidisciplinary team of experts. It is not therefore surprising that with the exception of a limited number of certain types of chemicals (pesticides, food additives, some of the major air and drinking-water contaminants, and some hazardous industrial chemicals), few products have been tested appropriately for potential risks. The information available is, in most cases, inadequate to estimate the levels that can be tolerated safely by humans. The process of risk evaluation is particularly difficult for developing countries lacking infrastructure and having limited expertise. These countries frequently rely upon the results of risk evaluations performed by international organizations, a n d / o r national evaluation bodies. It should be pointed out, however, that for most chemicals in the environment, epidemiological data essential for assessment of risk to human
R. Plestina, M. Mercier / The Science of the Total Environment 188 Suppl. 1 (1996) $135-$140
health confirm neither the absence nor ence of a specific risk to humans, such or impairment of reproduction, as the come is normally remote, contrary poisoning.
the presas cancer final outto acute
3. IPCS activities in risk assessment of chemicals
Since the inception of the WHO Programme for the Promotion of Environmental Health in 1948, WHO activities in the field of assessment of chemical safety have been evolving, and are constantly being promoted further following several important W H O Resolutions. At present, the only truly international evaluations of the risk of toxic chemicals to humans and the environment are made by the International Programme on Chemical Safety (IPCS). Within the framework of the chemical risk evaluation process there are several specific IPCS activities, which are briefly described below. The international Register for Potentially Toxic Chemicals (United Nations Environment Programme (IRPTC/UNEP) puts together information collected from various international and national scientific institutions and also from independent reputable scientists who publish data in the open literature. This information is made available to M e m b e r States on request (IRPTC/UNEP, 1993). The Joint Meeting on Pesticide Residues (JMPR), sponsored by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO), provides Member States with estimates of the levels at which various pesticides can be safely tolerated by the human body, called the Acceptable Daily Intake (ADI). The recommended ADIs are then used by national regulatory agencies and by the Codex Alimentarius Commission to propose safe levels of pesticides in foodstuffs. The meetings have been held annually since 1963 and the evaluations are published by FAO and WHO (FAO, 1994; WHO, 1994b). The W H O group of experts has described the procedures in the toxicological evaluation processes (WHO, 1990). The Environmental Health Criteria (EHC) documents are designed for scientific experts who
S137
are responsible for the evaluation of risk to human health and the environment incurred by chemicals. They enable relevant authorities to establish policies for the safe use of these chemicals. The information is detailed enough to allow the scientific reader to make his or her own validation. Over 150 documents dealing with various chemicals or methodologies have been published. The majority of these documents deal with individual chemicals and some of them are devoted to the methodological aspects (e.g. WHO, 1991, 1992, 1993). Health and Safety Guides are designed for a wide range of administrators, managers, and decision-makers in various ministries and governmental agencies, as well as in commerce, industry, and trade unions, who are involved in various aspects of safe use of chemicals. They summarize toxicity information in simple, non-technical language and provide practical advice on safe storage, handling and disposal of the chemical, accident prevention and health protection measures, first aid and medical treatment in cases of overexposure, and clean-up procedures. So far, over 85 guides have been published. The International Chemical Safety Cards summarize essential product-identity data and health and safety information on chemicals for use by workers and employers in factories, agriculture, and other workplaces. The cards are prepared using standard phrases, complemented, when appropriate, with information specific to the chemical being used. The W H O Recommended Classification of Pesticides by Hazard and Guidelines to Classification is a document which was approved by the Twenty-eighth World Health Assembly in 1975 and has since gained wide recognition in a number of Member States and by pesticide registration authorities. Although the Classification takes into account acute oral or dermal toxicity, whichever higher, it also considers any irreversible effect that might be recognized. For practical reasons, a number of pesticides classified as Class III (slightly hazardous) are listed in a separate table as 'unlikely to present acute hazard in normal use'. The guidelines to classification is prone to permanent revision, based on docu-
S138
tL Plestina, M. Mercier / The Science of the Total Environment 188 Suppl. 1 (1996) S135-$140
mented scientific evidence; the latest version was published in January 1994 (WHO, 1994a). 4. Risk management It is easy to demonstrate that a certain chemical is toxic and hazardous in specific circumstances, but is virtually impossible to prove that it is harmless and safe. Therefore it is impractical for scientists to be requested to prove the absolute safety for any given chemical, and they should rather be requested to provide sound judgement of the degree of hazard under given conditions. This definitely varies among communities because the hazard acceptable for one group may not be acceptable a n d / o r applicable for another. For this reason risk assessment is valid globally but risk management should be elaborated upon for any specific situation, country or even area. As the amount of information on risk assessment has grown, the level of concern has increased rather than decreased. This poses a particular burden to decision makers who are supposed to weigh risk evaluation data against cost, benefit and even political considerations, before endorsing the use of a particular chemical. To facilitate this process in developing countries, chemical control boards should be established with representation of all interested parties having authority to implement and supervise the policy and regulations established by national regulatory authorities. The latter should follow as closely as possible the rules and recommendations described in the London Guidelines for the Exchange of Information on Chemicals in International Trade (UNEP, 1989) and the International Code of Conduct on the Distribution and Use of Pesticides (FAP, 1990). To facilitate the information exchange among the countries over 120 UN Member States have designated a national authority for the implementation of the information exchange and Prior Informed Consent procedure of the London Guidelines and the International Code of Conduct. Following assessment and identification of the risk arising from toxic chemicals, considerable attention should be paid to activities leading to a reduction of known hazards to an acceptable level.
This is done through three different areas of activity: (i) prevention of human poisoning; (ii) promotion of the safe use of chemicals at all levels; and (iii) education and training. The above-mentioned activities are implemented through a variety of joint programmes of various international and national organizations. 5. Prevention of poisoning This is a specific WHO objective which is now a major activity within IPCS. It includes the production of guidelines for poison control, the validation and availability of antidotes used in the treatment of poisoning and, in particular, the evaluation of existing antidotes used in the treatment of poisonings. The key role in these activities is the development of information systems for poison control, including harmonization and exchange of data. Particular attention is given to medical response to chemical emergencies in cases of accident. It is not known how many people are poisoned each year or how many die as a result of being poisoned by chemicals. A number of estimates have been made, but these may be unreliable since they are usually extrapolations based on statistics for a few countries or a few chemical substances. Furthermore, there is no international agreement yet on severity grading for different types of poisoning, and these estimates cannot indicate whether cases are mild, moderate or severe. Even death certificates are often quite unreliable in many countries. The few statistics available appear to indicate that the number of poisoning cases in developed countries is stabilizing but those in developing countries may be rising, or at least for those countries where figures are available, there is an improved identification of cases. Poisoning may occur accidentally or deliberately. A vast range of chemical substances is involved in poisoning cases worldwide, including those used in agriculture, industry, commerce, and the home. In developed countries pharmaceuticals are one of the important use groups of substances giving rise to poisoning; in developing countries pesticides form an important group,
tL Plestina, M. Mercier / The Science of the Total Environment 188 Suppl. 1 (1996) S135-S140
as do common industrial chemicals. Carbon monoxide poisoning, from poor fuel combustion in enclosed areas, is still common in both developed and developing countries. Toxic substances of natural origin, e.g. poisonous plants and venomous animals, also give rise to significant numbers of poisoning cases. In view of this situation, urgent intervention is required in many countries to restrict the availability of highly hazardous chemicals. Although many developing countries have passed legislation to control chemicals, enforcement is often inadequate or non-existent. Experience in developed countries has shown that restricting the availability of highly hazardous chemicals, together with proper packaging and labelling, significantly reduces the incidence of poisoning. Many of the poisonings are preventable if appropriate measures are elaborated and implemented. This applies particularly to the educational and training programmes. Wider use of the WHO Recommended Classification of Pesticides by Hazard, within the framework of the FAO Code of Conduct on the Distribution and Use of Pesticides, should be helpful in this regard. 6. Promotion of the safe and judicious use of chemicals
S139
Proper timing and assessment of overexposure to hazardous chemicals contribute significantly to the safety of, for example, pesticides used in agriculture or in public health or industrial chemicals. IPCS is assisting developing countries in recognizing the extent of the problem of risk from chemicals to which workers are exposed. Thus, WHO has produced a standard protocol for the assessment of exposure to certain types of pesticides in which determination of erythrocyte cholinesterase activity is crucial and the most appropriate tool for field assessment of exposure to organophosphorns pesticides. When used as part of the surveillance of workers, an individual can be withdrawn from further exposure if his erythrocyte cholinesterase activity decreases significantly from a well-established pre-exposure value. In the past few years, WHO has developed a field method for measuring whole blood cholinesterase activity. The method has been in use in the field for several years, and, along with the progress in technology, the method is being improved and the field kit modernized and subsequently commercialized. The methodology and recommendations for biological monitoring of exposure to various hazardous chemicals is being produced by WHO. 7. Education and training
Among various activities of IPCS in the area of the safe use of chemicals, special attention is paid to identify sources related to increases in health hazards. Recommendation for the restriction in availability is one of the essential elements which if endorsed, may considerably increase safety for the user and the general population. A number of guidelines concerning safety aspects during formulation, transport, distribution, storage application and disposal of unwanted chemicals and containers, when respected, would also significantly reduce the hazard from chemicals. Appropriate labelling is a conditional requirement for safety but it is essential that the label is read before use and instruction followed. Appropriate protecting clothing needs to be used, but without other measures, such as good working practice, its effect will be greatly reduced.
In order to support efforts to promote education in the safe use of chemicals, a number of educational and training programmes have been developed within IPCS and by many other national or international organizations. One of the recent programmes has been developed by IPCS for training the trainers in the safe use of pesticides. It is designed to be used at several distinct educational levels, adaptable to local needs. It includes: (i) basic level courses; (ii) intermediate courses; and (iii) advanced level courses. The course is divided into sections, each preceded by specific educational objectives. Each section is divided into one or more subjects, and each subject into a number of modules. Each module is supported by a visual aid in the form of a slide with key words or a photograph. A selection of modules is made from each section appropriate to
$140
R. Plestina, M. Mercier / The Science o f the Total Environment 188 SuppL 1 (1996) S135-Sl40
the educational objectives and background of the participants. The course manual is accompanied by an instruction manual designed to enable national authorities to create multilevel courses on the safe use of pesticides in individual countries, in the local language, and with their own resources. The format of the course is such that it can easily be modified in order to be adapted to national needs and for different levels of audience. IPCS also provides training on basic chemical safety (toxicology, ecotoxicology, risk assessment) for government officials and public health advisers, primarily from developing countries. This training defines the principles of chemical safety and their application to pesticide safety use as well as to other groups of chemicals. A series of linked training modules at an advanced level is in preparation. These modules are directed to government officials with responsibility for pesticides but also other chemicals, including registration and licensing, inspection, safe use and disposal. Courses at this level have also been conducted using existing training materials. References FAO, 1990. International Code of Conduct on the Distribution and Use of Pesticides (Amended Version), Food and Agriculture Organization of the United Nations, Rome. FAO, 1994. Pesticide residues in food: 1993 Evaluations. Part I - - Residues. FAO Plant Production and Protection Paper, Rome (in press). Hall, S. and Strichartz, G., (Eds.), 1990. Marine Toxins - Origin, Structure and Molecular Pharmacology Symposium Series 418, American Chemical Society, Washington DC.
IRPTC/UNEP, 1993. IRPTC Legal File 1992-1993 Regulations and Guidelines on Chemicals. An Extract of the IRPTC Data Bank, Volumes 1-3, United Nations Environment Programme, International Register for Potentially Toxic Chemicals, Geneva. Keeler, R.F. and Tu, A.T. (Eds.), 1983. Handbook of Natural Toxins, Volume 1 - - Plant and Fungal Toxins, Marcel Dekker, Inc. New York and Basel. Smith, H.V. and Spalding, J.M.K. 1959. Outbreak of paralysis in Morocco due to orthocresyl phosphate poisoning, Lancet, 2: 1019-1021. UNEP, 1994. Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal, Basel Convention Series/SBC No. 94/001, U N E P / B C / 9 4 / 1 , Geneva. UNEP, 1989. London Guidelines for the Exchange of Information on Chemicals in International Trade (Amended 1989), United Nations Environment Programme, Geneva. W H O , 1976. C o n f e r e n c e on intoxication due to allkylmercury-treated seed. Baghdad, Iraq, 9-13 September 1974, Supplement to Vol. 53 of the Bulletin of the World Health Organization, Geneva. WHO, 1990. Environmental Health Criteria No. 104. Principles for the Toxicological Assessment of Pesticide Residues in Food, World Health Organization, Geneva. WHO, 1991. Environmental Health Criteria No. 119, Principles and Methods for the Assessment of Nephrotoxicity Associated with Exposure to Chemicals, World Health Organization, Geneva. Who, 1992. Environmental Health Criteria No. 141, Quality Management for Chemical Safety Testing, World Health Organization, Geneva. Who, 1993. Environmental Health Criteria No. 144, Principles for Evaluating Chemical Effects on the Aged Population, World Health Organization, Geneva. Who, 1994a. The WHO recommended Classification of Pesticides by Hazard and Guidelines to Classification 1994-1995. (WHO/PCS/94.2), World Health Organization, Geneva. WHO, 1994b. Pesticide residues in food: 1993 Evaluations. Part II - - Toxicology, WHO/PCS/94.4, World Health Organization, Geneva.
ELSEVIER
The Science of the Total Environment 188 Suppl. 1 (1996) S135-S140
Human health and environmental hazards arising from the use of chemicals in developing countries R. Plestina, M. M e r c i e r International Programme on Chemical Safety, 1211 Geneva 27, Switzerland
1. Introduction The recognized or suspected harmful effects of chemicals on human health and the environment are derived from their inherent properties which cannot be influenced. However, the potential harmful effects may be reduced or even eliminated by the proper handling and judicious use of chemicals. There should be no argument over whether chemicals are essential on every segment of human activity, but also, nobody can deny that certain uses (misuses) outweight the benefits that chemicals offer. This permanent conflict of benefit against risk needs to be fully understood through an unbiased scientifically based risk-benefit evaluation. The massive expansion in the availability and use of chemicals throughout the world during the last few decades has led to increasing awareness of the potential risks that exposure to chemicals pose, both to human health and the environment. The growing generation of hazardous wastes and intentions for their uncontrolled transboundary movement is dealt with by the widely accepted Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal, adopted in 1989 (UNEP, 1994). It became obvious that fast industrial development can introduce various health and environmental risks that the community is unable to cope with. Many catastrophes caused by chemicals have
occurred in recent years such as massive poisoning with methylmercury in Iraq (WHO, 1976) or with TOCP in Morocco (Smith and Spalding, 1959). It should be mentioned, however, that naturally occurring toxins are also known to be the cause of massive outbreaks of acute poisoning as well as causing irreversible effects, including cancer, in exposed populations (Keeler and Tu, 1983; Hall and Strichartz, 1990). Although cancer is only one of the many serious effects that can result from exposure to chemicals, both man-made and naturally occurring, it has become a matter of considerable concern to the general public and much effort has been made to identify and classify chemicals according to the carcinogenic hazard they pose to humans. Intense international concern about the dangers of chemicals for human health and the environment, expressed at the United Nations Conference on the Human Environment, held in Stockholm in 1972 led to the establishment in 1980 of the International Programme on Chemical Safety which is a joint venture of the World Health Organization (WHO), the United Nations Environment Programme (UNEP) and the International Labour Office (ILO). The programme was initially set up specifically to provide assessments of the risks to human health and the environment from exposure to chemicals whatever
0048-9697/96/$15.00 © 1996 Elsevier Science B.V. All rights reserved PII S0048-9697(96) 05285-0
S136
R. Plestina, M. Mercier/The Science of the Total Environment 188 Suppl. 1 (1996) $135-$140
their origin, man-made or natural, or wherever they are found, thus providing the internationally evaluated scientific basis on which countries may develop their own chemical safety measures. Twenty years after the Stockholm Conference, the UN Conference on Environment and Development (UNCED) held in Rio de Janeiro requested the creation of an international strategy for the environmentally sound management of toxic chemicals. The conference considered that IPCS should be the nucleus for this strategy, and that cooperation with other organizations having an involvement in chemical safety should be strengthened. In addition, UNCED stressed the need to extend partnership with governments, industries, trade unions, consumers and professional bodies. It has been proposed that the strengthening of IPCS should be accompanied by the setting up of an intergovernmental forum for chemical risk assessment and management which is now underway. UNCED identified six programme areas that would form the objectives of the new IPCS: •
•
•
•
•
•
The evaluation of the risks to human health and the environment from exposure to chemicals should be accelerated, and international agreement concerning methods of risk assessment needs to be expanded. Harmonization on a worldwide scale is also essential for the classification and labelling of chemicals. Mechanisms are required to make the exchange of information on chemicals and their risks easier, and to deal with major accidents and poisonings that involve them. Activities to reduce the risks of chemicals and to develop the use of safer alternatives need to be promoted. To provide assistance to countries, especially the developing ones, to evaluate health and environmental hazards, and to bring in and enforce legislation when necessary. More information and stronger measures are needed in the fight to halt illegal international traffic in dangerous chemicals. Today the programme provides guidance to
countries on how to use available risk assessments to achieve risk reduction, and also helps to strengthen national capabilities to prevent and treat harmful effects of chemicals and to manage emergencies involving chemicals. Two basic aspects in promoting chemical safety that will be briefly discussed are risk evaluation and risk management, the former being of global and the latter of more regional or national significance and applicability. 2. Risk evaluation
Most of the new chemicals, drugs and pesticides in particular, before being allowed on the market, are extensively and meticulously tested to ascertain their biological potential to produce adverse effects. These studies are normally performed by the manufacturers, using widely accepted procedures. The results together with those published in open literature are critically reviewed by national or international groups of experts with the aim to assess human health and environmental risks arising from the use of chemicals which are likely to be inadvertently absorbed by users or the general population, or spread in the environment. The risk evaluation is a complex scientific process requiring the meticulous work of a multidisciplinary team of experts. It is not therefore surprising that with the exception of a limited number of certain types of chemicals (pesticides, food additives, some of the major air and drinking-water contaminants, and some hazardous industrial chemicals), few products have been tested appropriately for potential risks. The information available is, in most cases, inadequate to estimate the levels that can be tolerated safely by humans. The process of risk evaluation is particularly difficult for developing countries lacking infrastructure and having limited expertise. These countries frequently rely upon the results of risk evaluations performed by international organizations, a n d / o r national evaluation bodies. It should be pointed out, however, that for most chemicals in the environment, epidemiological data essential for assessment of risk to human
R. Plestina, M. Mercier / The Science of the Total Environment 188 Suppl. 1 (1996) $135-$140
health confirm neither the absence nor ence of a specific risk to humans, such or impairment of reproduction, as the come is normally remote, contrary poisoning.
the presas cancer final outto acute
3. IPCS activities in risk assessment of chemicals
Since the inception of the WHO Programme for the Promotion of Environmental Health in 1948, WHO activities in the field of assessment of chemical safety have been evolving, and are constantly being promoted further following several important W H O Resolutions. At present, the only truly international evaluations of the risk of toxic chemicals to humans and the environment are made by the International Programme on Chemical Safety (IPCS). Within the framework of the chemical risk evaluation process there are several specific IPCS activities, which are briefly described below. The international Register for Potentially Toxic Chemicals (United Nations Environment Programme (IRPTC/UNEP) puts together information collected from various international and national scientific institutions and also from independent reputable scientists who publish data in the open literature. This information is made available to M e m b e r States on request (IRPTC/UNEP, 1993). The Joint Meeting on Pesticide Residues (JMPR), sponsored by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO), provides Member States with estimates of the levels at which various pesticides can be safely tolerated by the human body, called the Acceptable Daily Intake (ADI). The recommended ADIs are then used by national regulatory agencies and by the Codex Alimentarius Commission to propose safe levels of pesticides in foodstuffs. The meetings have been held annually since 1963 and the evaluations are published by FAO and WHO (FAO, 1994; WHO, 1994b). The W H O group of experts has described the procedures in the toxicological evaluation processes (WHO, 1990). The Environmental Health Criteria (EHC) documents are designed for scientific experts who
S137
are responsible for the evaluation of risk to human health and the environment incurred by chemicals. They enable relevant authorities to establish policies for the safe use of these chemicals. The information is detailed enough to allow the scientific reader to make his or her own validation. Over 150 documents dealing with various chemicals or methodologies have been published. The majority of these documents deal with individual chemicals and some of them are devoted to the methodological aspects (e.g. WHO, 1991, 1992, 1993). Health and Safety Guides are designed for a wide range of administrators, managers, and decision-makers in various ministries and governmental agencies, as well as in commerce, industry, and trade unions, who are involved in various aspects of safe use of chemicals. They summarize toxicity information in simple, non-technical language and provide practical advice on safe storage, handling and disposal of the chemical, accident prevention and health protection measures, first aid and medical treatment in cases of overexposure, and clean-up procedures. So far, over 85 guides have been published. The International Chemical Safety Cards summarize essential product-identity data and health and safety information on chemicals for use by workers and employers in factories, agriculture, and other workplaces. The cards are prepared using standard phrases, complemented, when appropriate, with information specific to the chemical being used. The W H O Recommended Classification of Pesticides by Hazard and Guidelines to Classification is a document which was approved by the Twenty-eighth World Health Assembly in 1975 and has since gained wide recognition in a number of Member States and by pesticide registration authorities. Although the Classification takes into account acute oral or dermal toxicity, whichever higher, it also considers any irreversible effect that might be recognized. For practical reasons, a number of pesticides classified as Class III (slightly hazardous) are listed in a separate table as 'unlikely to present acute hazard in normal use'. The guidelines to classification is prone to permanent revision, based on docu-
S138
tL Plestina, M. Mercier / The Science of the Total Environment 188 Suppl. 1 (1996) S135-$140
mented scientific evidence; the latest version was published in January 1994 (WHO, 1994a). 4. Risk management It is easy to demonstrate that a certain chemical is toxic and hazardous in specific circumstances, but is virtually impossible to prove that it is harmless and safe. Therefore it is impractical for scientists to be requested to prove the absolute safety for any given chemical, and they should rather be requested to provide sound judgement of the degree of hazard under given conditions. This definitely varies among communities because the hazard acceptable for one group may not be acceptable a n d / o r applicable for another. For this reason risk assessment is valid globally but risk management should be elaborated upon for any specific situation, country or even area. As the amount of information on risk assessment has grown, the level of concern has increased rather than decreased. This poses a particular burden to decision makers who are supposed to weigh risk evaluation data against cost, benefit and even political considerations, before endorsing the use of a particular chemical. To facilitate this process in developing countries, chemical control boards should be established with representation of all interested parties having authority to implement and supervise the policy and regulations established by national regulatory authorities. The latter should follow as closely as possible the rules and recommendations described in the London Guidelines for the Exchange of Information on Chemicals in International Trade (UNEP, 1989) and the International Code of Conduct on the Distribution and Use of Pesticides (FAP, 1990). To facilitate the information exchange among the countries over 120 UN Member States have designated a national authority for the implementation of the information exchange and Prior Informed Consent procedure of the London Guidelines and the International Code of Conduct. Following assessment and identification of the risk arising from toxic chemicals, considerable attention should be paid to activities leading to a reduction of known hazards to an acceptable level.
This is done through three different areas of activity: (i) prevention of human poisoning; (ii) promotion of the safe use of chemicals at all levels; and (iii) education and training. The above-mentioned activities are implemented through a variety of joint programmes of various international and national organizations. 5. Prevention of poisoning This is a specific WHO objective which is now a major activity within IPCS. It includes the production of guidelines for poison control, the validation and availability of antidotes used in the treatment of poisoning and, in particular, the evaluation of existing antidotes used in the treatment of poisonings. The key role in these activities is the development of information systems for poison control, including harmonization and exchange of data. Particular attention is given to medical response to chemical emergencies in cases of accident. It is not known how many people are poisoned each year or how many die as a result of being poisoned by chemicals. A number of estimates have been made, but these may be unreliable since they are usually extrapolations based on statistics for a few countries or a few chemical substances. Furthermore, there is no international agreement yet on severity grading for different types of poisoning, and these estimates cannot indicate whether cases are mild, moderate or severe. Even death certificates are often quite unreliable in many countries. The few statistics available appear to indicate that the number of poisoning cases in developed countries is stabilizing but those in developing countries may be rising, or at least for those countries where figures are available, there is an improved identification of cases. Poisoning may occur accidentally or deliberately. A vast range of chemical substances is involved in poisoning cases worldwide, including those used in agriculture, industry, commerce, and the home. In developed countries pharmaceuticals are one of the important use groups of substances giving rise to poisoning; in developing countries pesticides form an important group,
tL Plestina, M. Mercier / The Science of the Total Environment 188 Suppl. 1 (1996) S135-S140
as do common industrial chemicals. Carbon monoxide poisoning, from poor fuel combustion in enclosed areas, is still common in both developed and developing countries. Toxic substances of natural origin, e.g. poisonous plants and venomous animals, also give rise to significant numbers of poisoning cases. In view of this situation, urgent intervention is required in many countries to restrict the availability of highly hazardous chemicals. Although many developing countries have passed legislation to control chemicals, enforcement is often inadequate or non-existent. Experience in developed countries has shown that restricting the availability of highly hazardous chemicals, together with proper packaging and labelling, significantly reduces the incidence of poisoning. Many of the poisonings are preventable if appropriate measures are elaborated and implemented. This applies particularly to the educational and training programmes. Wider use of the WHO Recommended Classification of Pesticides by Hazard, within the framework of the FAO Code of Conduct on the Distribution and Use of Pesticides, should be helpful in this regard. 6. Promotion of the safe and judicious use of chemicals
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Proper timing and assessment of overexposure to hazardous chemicals contribute significantly to the safety of, for example, pesticides used in agriculture or in public health or industrial chemicals. IPCS is assisting developing countries in recognizing the extent of the problem of risk from chemicals to which workers are exposed. Thus, WHO has produced a standard protocol for the assessment of exposure to certain types of pesticides in which determination of erythrocyte cholinesterase activity is crucial and the most appropriate tool for field assessment of exposure to organophosphorns pesticides. When used as part of the surveillance of workers, an individual can be withdrawn from further exposure if his erythrocyte cholinesterase activity decreases significantly from a well-established pre-exposure value. In the past few years, WHO has developed a field method for measuring whole blood cholinesterase activity. The method has been in use in the field for several years, and, along with the progress in technology, the method is being improved and the field kit modernized and subsequently commercialized. The methodology and recommendations for biological monitoring of exposure to various hazardous chemicals is being produced by WHO. 7. Education and training
Among various activities of IPCS in the area of the safe use of chemicals, special attention is paid to identify sources related to increases in health hazards. Recommendation for the restriction in availability is one of the essential elements which if endorsed, may considerably increase safety for the user and the general population. A number of guidelines concerning safety aspects during formulation, transport, distribution, storage application and disposal of unwanted chemicals and containers, when respected, would also significantly reduce the hazard from chemicals. Appropriate labelling is a conditional requirement for safety but it is essential that the label is read before use and instruction followed. Appropriate protecting clothing needs to be used, but without other measures, such as good working practice, its effect will be greatly reduced.
In order to support efforts to promote education in the safe use of chemicals, a number of educational and training programmes have been developed within IPCS and by many other national or international organizations. One of the recent programmes has been developed by IPCS for training the trainers in the safe use of pesticides. It is designed to be used at several distinct educational levels, adaptable to local needs. It includes: (i) basic level courses; (ii) intermediate courses; and (iii) advanced level courses. The course is divided into sections, each preceded by specific educational objectives. Each section is divided into one or more subjects, and each subject into a number of modules. Each module is supported by a visual aid in the form of a slide with key words or a photograph. A selection of modules is made from each section appropriate to
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the educational objectives and background of the participants. The course manual is accompanied by an instruction manual designed to enable national authorities to create multilevel courses on the safe use of pesticides in individual countries, in the local language, and with their own resources. The format of the course is such that it can easily be modified in order to be adapted to national needs and for different levels of audience. IPCS also provides training on basic chemical safety (toxicology, ecotoxicology, risk assessment) for government officials and public health advisers, primarily from developing countries. This training defines the principles of chemical safety and their application to pesticide safety use as well as to other groups of chemicals. A series of linked training modules at an advanced level is in preparation. These modules are directed to government officials with responsibility for pesticides but also other chemicals, including registration and licensing, inspection, safe use and disposal. Courses at this level have also been conducted using existing training materials. References FAO, 1990. International Code of Conduct on the Distribution and Use of Pesticides (Amended Version), Food and Agriculture Organization of the United Nations, Rome. FAO, 1994. Pesticide residues in food: 1993 Evaluations. Part I - - Residues. FAO Plant Production and Protection Paper, Rome (in press). Hall, S. and Strichartz, G., (Eds.), 1990. Marine Toxins - Origin, Structure and Molecular Pharmacology Symposium Series 418, American Chemical Society, Washington DC.
IRPTC/UNEP, 1993. IRPTC Legal File 1992-1993 Regulations and Guidelines on Chemicals. An Extract of the IRPTC Data Bank, Volumes 1-3, United Nations Environment Programme, International Register for Potentially Toxic Chemicals, Geneva. Keeler, R.F. and Tu, A.T. (Eds.), 1983. Handbook of Natural Toxins, Volume 1 - - Plant and Fungal Toxins, Marcel Dekker, Inc. New York and Basel. Smith, H.V. and Spalding, J.M.K. 1959. Outbreak of paralysis in Morocco due to orthocresyl phosphate poisoning, Lancet, 2: 1019-1021. UNEP, 1994. Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal, Basel Convention Series/SBC No. 94/001, U N E P / B C / 9 4 / 1 , Geneva. UNEP, 1989. London Guidelines for the Exchange of Information on Chemicals in International Trade (Amended 1989), United Nations Environment Programme, Geneva. W H O , 1976. C o n f e r e n c e on intoxication due to allkylmercury-treated seed. Baghdad, Iraq, 9-13 September 1974, Supplement to Vol. 53 of the Bulletin of the World Health Organization, Geneva. WHO, 1990. Environmental Health Criteria No. 104. Principles for the Toxicological Assessment of Pesticide Residues in Food, World Health Organization, Geneva. WHO, 1991. Environmental Health Criteria No. 119, Principles and Methods for the Assessment of Nephrotoxicity Associated with Exposure to Chemicals, World Health Organization, Geneva. Who, 1992. Environmental Health Criteria No. 141, Quality Management for Chemical Safety Testing, World Health Organization, Geneva. Who, 1993. Environmental Health Criteria No. 144, Principles for Evaluating Chemical Effects on the Aged Population, World Health Organization, Geneva. Who, 1994a. The WHO recommended Classification of Pesticides by Hazard and Guidelines to Classification 1994-1995. (WHO/PCS/94.2), World Health Organization, Geneva. WHO, 1994b. Pesticide residues in food: 1993 Evaluations. Part II - - Toxicology, WHO/PCS/94.4, World Health Organization, Geneva.