SESSION A

Keynote Address



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LEAD IN THE AMERICAS: A call for action SESSION A Keynote Address

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LEAD IN THE AMERICAS: A call for action This page in the original is blank.

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LEAD IN THE AMERICAS: A call for action LEAD AT THE WORKPLACE AND IN THE ENVIRONMENT: IS IT PREVENTABLE? JORMA RANTANEN* Although International Labour Organization Convention No. 13 on White Lead prohibited the use of lead paint as early as 1921 (ILO, 1921), lead paints continue to contribute to thousands of acute lead poisonings annually and to chronic lead effects in individuals in both industrialized and developing countries. As shown in Table 3-1, emissions of lead into air, water, and soil are higher than those of any other toxic metal, and the mobilization of toxic metals into the environment exceeds the total toxic burden of all radioactive and organic waste (Nriagu and Pacyna, 1988). There is convincing evidence, however, that the total annual consumption of about 8.9 million tons of newly mined lead, as well as similar TABLE 3-1 World Metal Emissions into Water, Soil, and Air (in kilograms per year) Toxic metal Water 106 kg/yr−1 Soil 106 kg/yr−1 Air 106 kg/yr−1 As 12–70 64–132 12–25.6 Cd 2.1–17 9.9–45 3.1–12 Cr 45–239 — 7.3–53.6 Hg 0.3–8.8 2.2–18 0.9–6.2 Ni 33–194 160–673 24–87 Pb 97–180 808–1,893 289–376 V 2.1–21 48–242 30–142 Zn 77–375 1,193–3,294 70–194 Source: Adapted from Nriagu and Pacyna, 1988. * Finnish Institute of Occupational Health, Helsinki, Finland

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LEAD IN THE AMERICAS: A call for action amounts of recycled lead, could be substantially reduced at relatively little economic cost, and that present technologies and multisectoral preventive actions could, in a relatively short time and in an economically feasible manner, effect a remarkable reduction in both environmental and occupational exposures. There are several obstacles in the way of such preventive programs. These include a lack of awareness of the magnitude and severity of lead poisoning in most of the populations of the world, short-sighted economic objectives, and poor local availability of expertise and technologies in support of prevention and control activities. MANAGEMENT OF LEAD HAZARDS IN AN INDUSTRIALIZED COUNTRY-THE CASE OF FINLAND The Finnish Lead Program began in the 1960s with the implementation of systematic diagnosis and treatment of lead-poisoned workers from the battery industries, metal foundries, metal scrapping concerns, and dockyards. Intensive studies of lead poisoning in the Finnish population began with a focus on hematological effects, clinical symptoms, and blood lead concentrations in occupationally exposed workers. The value of δ-aminolevulinic acid dehydratase (ALA-D) as an indicator of lead exposure was quickly recognized. As a result, studies were expanded to detect early biologic effects of lead exposure, including neurologic, psychologic, cardiovascular, reproductive, and carcinogenic effects. The findings of these studies were considered in the World Health Organization's recommendations on health-based exposure limits (WHO, 1977) and helped in the development of a field-feasible test battery of psychometric effects of lead poisoning. As a result of the growing evidentiary base linking occupational lead exposures to adverse health outcomes, guidance values for biological monitoring and guidelines for health surveillance of workers potentially exposed were established in Finland (Hernberg, 1995). Further preventive actions included setting a lower exposure limit for workroom air (0.1 mg/m3), using non-lead technologies where possible, implementing local exhausts and dust control, introducing safer work practices, and promoting careful personal protection. The impact of these actions can be seen in the decline of the numbers of workers exposed to lead and the decreasing proportion of workers exceeding threshold blood lead levels of 2.4 µmol/L (see Figure 3-1). The environmental lead exposure plan developed in Finland originated, in part, with the industry sector, which substantially reduced their emissions

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LEAD IN THE AMERICAS: A call for action Figure 3-1. Blood lead level monitoring measurements, 1973-1994, Biomonitoring Laboratory, Finnish Institute of Occupational Health. Source: Valkonen, 1995. in water (60 percent decrease between 1980 and 1989) and in air (16percent decrease between 1987 and 1990) in Finland. Once industries began controlling their lead emissions, automotive traffic ended up contributing 75 percent of environmental lead emissions. Thanks to the introduction of unleaded gasoline in the mid-1980s, vehicular emissions to air have now fallen by 88 percent. As a result, lead emissions in urban air in Finland are virtually zero at present. Since only about five industries are now responsible for 99 percent of the industrial lead emissions, the possibility for further reduction in environmental lead burden is excellent. MANAGEMENT OF LEAD HAZARDS IN THE WORKPLACE OF DEVELOPING AND NEWLY INDUSTRIALIZED COUNTRIES Although systematic data, particularly on lead exposures in the developing world, are not widely available, there is sporadic evidence that suggests both a high prevalence and intensity of lead-related health problems in developing and newly industrialized countries. There is thus a need for systemic and

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LEAD IN THE AMERICAS: A call for action representative surveys of environmental lead exposures, as well as biological monitoring of individual lead exposures. Lead surveys were elements of Finnish development aid programs from the beginning. In the early 1980s, for example, a lead survey was carried out in Kenyan battery industries. Results indicated unexpectedly high blood lead levels among battery workers, but also among the canteen and office personnel, thus indicating a widespread, indirect contamination of the work environment (Kurppa et al., 1985). An interesting, but not well-established, observation was that lead-related clinical symptoms manifested at lower blood lead levels among malarious individuals than among people without malaria. Disappointingly, while general hygienic measures reduced the exposures of the office and canteen personnel, they had little effect on production line workers, who maintained high blood lead levels. The authors concluded that preventive measures appeared to have little effect because of the low level of awareness of the dangers of lead poisoning in these workers. The risk of lead exposure on the job is a worldwide problem. A systematic survey of workers in four Asian countries showed that approximately 30 percent of the workers surveyed had elevated blood lead levels (Chia and Koh, 1992; Phoon et al., 1985), and some Central and Eastern European countries report elevated levels in up to 100 percent of the workers tested (Cikrt, 1990; Kaloyanova, 1991). These examples demonstrate clearly that lead poisoning remains a major occupational health and environmental problem in many parts of the world, despite the availability of relatively simple preventive educational and control measures that could bring about a clear reduction in exposures and in adverse health effects in most of these populations in a relatively short time. WHAT IS THE ROLE OF RESEARCH IN THE MANAGEMENT OF LEAD HAZARDS? The Finnish Lead Program was instituted because of research findings indicating high blood lead levels in exposed workers; our preventive actions have been similarly supported by research data. Our activities in developing countries have been strongly oriented toward risk surveys to estimate population lead burden and sources of exposure. Our assessments of health risk and methods for exposure detection and measurements of early effects have been based on decades of research effort. On the basis of these experiences, the question—how much and what kind of research

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LEAD IN THE AMERICAS: A call for action (if any) is needed to identify, control, and prevent lead hazards in developing countries—can be posed. Our experience demonstrates that several kinds of research efforts are needed to identify and prevent lead poisoning. These include: surveys of environmental lead levels and sources of exposure; research on body lead screening methods to ensure accuracy and reliability; surveys of lead levels in selected representative samples of the general population, with particular focus on identification of high-risk groups; monitoring of health effects in lead-poisoned populations; evaluation of feasibility and effectiveness of proposed preventive and control activities; evaluation of the effectiveness of ongoing prevention and control activities; setting of appropriate standards to ensure occupational and environmental safety and health. Two points should be stressed in undertaking the above research activities. First, these activities should not displace current interventions to reduce lead exposures. Second, research activities must be developed and conducted at the local level by regional or local scientists and health providers representing a broad range of expertise and perspective. SUSTAINABLE PREVENTION OF LEAD POISONING Control of lead exposure requires preventive measures at the global, national, and local levels. In developing countries, identification of lead problems has, in most instances, brought effective preventive measures and regulatory actions (East African Regional Programme on Occupational Health and Safety, 1991). Often, simple precautions such as adding ventilation and local exhausts, or health education, have brought about dramatic reductions in blood lead levels. The Finnish Lead Program has developed a wealth of data and experience on the detection of occupational lead poisoning and effective strategies for prevention and control. Based on our experience, the list of preventive actions that we recommend to national, regional, and local decisionmakers and other involved parties are:

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LEAD IN THE AMERICAS: A call for action Survey the national, regional, and local situations and identify the activities and population groups at highest risk of lead exposure. Raise public awareness, motivation, and knowledge of the sources and dangers of lead poisoning through educational campaigns that are both broadly directed and targeted to high-risk groups. Encourage the adoption of lead-free technologies where possible. Set stringent standards—for example, 0.1 mg/m3 of respirable lead-containing dust for workers and a ceiling of 40 µg/dl for blood lead levels in occupationally exposed workers—and ensure their enforcement. Introduce hygienic work practices in high-risk work environments and make personal protectors available. Monitor work environments and workers to identify exposed individuals and assess the effect of preventive and control measures. Examine the health of lead-exposed workers periodically. Educate workers about hygienic habits and other behaviors in lead-contaminated environments—for example, cigarette smoking—that may increase risk of lead ingestion or inhalation and poisoning.