Source: RISK newsletter,
Second Quarter 1996, published by the Society for Risk Analysis
(Dr. Eiji Yokoyama, retired director general of Japan’s National Institute of Public Health, former president of the Japan Section of SRA, and current president of the Japan Society for Atmospheric Environment, addressed the December 1, 1995, plenary session of the joint annual meeting of the Society for Risk Analysis and the Japan Section of SRA held in Honolulu. His remarks are summarized in the following article.)
After launching his career as a respiratory clinician at the University of Tokyo School of Medicine in 1954, Dr. Eiyi Yokoyama was always concerned about the health effects of environmental pollutants, particularly air pollutants, and he and his colleagues began to push for pollution control in Japan. However, it was not until the early 1980s that they became aware of the potential for applying risk assessment and management techniques to their work.
Addressing the first plenary session of the joint annual meeting of SRA and its Japan Section, Dr. Yokoyama pointed out that Japan’s rapid industrialization from the mid-1950s to the mid-1960s was accompanied by intense environmental problems that resulted in serious health injuries to the populace. For example, asthma-like attacks were observed in elderly residents in areas severely polluted by smoke from the combustion of high-sulfur oil at petrochemical plants, and other diseases were caused by releases of mercury and cadmium. In 1967, the Basic Law for Environmental Pollution Control was passed to set an environmental quality standard, or goal, for pollutant reduction. The goal was defined as the level below which human health could be protected and living environments could be conserved. Subsequently, specific standards were set for ambient air, water, and soil pollution and for noise.
Setting Ambient Air Standards. With respect to ambient air, standards were set for five pollutants--SO2, CO, suspended particulate matter, NO2, and photochemical oxidants--and in 1968 an Air Pollution Control Law was enacted that provided the broad basis for controlling the emissions of pollutants, both from stationary sources and from automobiles.
Two systems of control have been applied to stationary sources. The first was determined on a facility-by-facility basis and focuses on SO2, NO2, soot and dust, and some toxic chemicals.
The second is a total emission control system used in areas where emission standards on a facility-by-facility basis are inadequate. It was introduced for SO2 in 1974 (now applying to 24 regions) and for NO2 in 1981 (now applying to four regions).
With regard to automobiles, each car is required to meet permissible limits of exhaust emission established for CO, hydrocarbons, NO2, and diesel particulates.
Ambient SO2 and NO2. Dr. Yokoyama said that the ambient concentrations of SO2 and NO2 are continuously monitored at stations located in residential areas and along roadsides with heavy traffic. The results show considerable success in the reduction of SO2 levels. NO2 levels, however, remain too high, even though the early 1970s emission standards for NO2 have been revised downward five times for stationary sources and eight times for gasoline- and diesel-powered vehicles.
Countermeasures have not been effective in reducing NO2 concentrations, he explained, because the use of automobiles in Japan has tripled during the last 20 years. In 1992, a new law, generally called the NOx Law, was enacted to restrict the use of vehicles that cannot meet the NO2 emission standards in certain specified areas.
Ambient Photochemical Oxidants. With respect to photochemical oxidants, Dr. Yokoyama said that efforts to reduce air pollution from photochemical oxidants began in 1970 with the first regulations on hydrocarbon emissions from automobiles. In 1976, guidelines were set for ambient concentrations of non-methane hydrocarbons, and in 1982 the government called for the reduction of hydrocarbon emissions from stationary sources. While the situation has been considerably improved, the threshold for issuing a warning (0.12 ppm as an hourly average) is still exceeded periodically.
Chemical Substance Pollution. Japan has also experienced environmental pollution from chemical substances resulting from the careless use of various products. Typical of these have been PCBs (polychlorinated biphenyls), which were found to be widely distributed throughout the environment and even in human tissues, including breast milk. To confront these problems, Japan enacted a Chemical Substances Control Law in 1974 which states that any chemical substance to be produced or imported in annual amounts exceeding 1 ton must first be examined for its biodegradation, bioaccumulation and chronic toxicity.
According to its test results, a chemical substance is categorized as a Class I Specified Substance, a Class II Specified Substance, or a Designated Substance, and it is subject to regulations specific for its particular category. For instance, a substance that is highly bioaccumulative, less biodegradable, and chronic-toxic will be registered as a Class I Specified Substance, and, in principle, its production, importation and use is prohibited. At present, nine substances are included in this category. Another 23 substances are in Class II, and 135 are Designated Substances. About 300 new substances are subjected to these tests annually.
The carcinogenicity of chemical substances is of particular concern. As in other industrialized nations, cancer mortality in Japan is steadily increasing--by about a factor of 2.5 for all cancers during the last 40 years. For lung cancer, the mortality is much higher. Adjusted for age, lung cancer mortality has increased a factor of 13 for males and a factor of 9 for females. The impact of smoking is clear, but it is also commonly suspected that various chemical carcinogens in all media, particularly in ambient air, are also responsible for the increase in lung cancer. Dr. Yokoyama feels that new ideas based on the practice of risk assessment and management are necessary to properly manage these carcinogenic chemicals.
The first official step in this direction occurred in 1992, he said, when the administration in Japan used the concept of risk assessment for amending the nation’s drinking water quality standards. Following, in principle, the World Health Organization’s guidelines, values of carcinogenic substances classified as Group I and 2A by the International Agency for Research on Cancer (IARC) were set for drinking water on the basis that a 10–5 increment of a lifetime cancer risk is a safe level. In the same year, the environmental quality standard for water pollution was similarly amended.
More recently, the Air Pollution Control Law has been amended to include more carcinogenic substances. Only a few chemicals-—cadmium, chlorine, fluorine, lead--and their compounds had previously been regulated, with asbestos added as a special particulate in 1989. Hazardous substances like benzene in automobile fuels have now been added.
In another recent development, Dr. Yokoyama chaired a special committee for reviewing countermeasures against hazardous air pollutants. The key recommendation in the committee’s 1995 report was that risk assessment be used in determining the regulation of hazardous air pollutants, particularly non-threshold chemicals.
Development of Risk Assessment in Japan. Dr. Yokoyama believes that the administrative acceptance of risk assessment and management practices in Japan is somewhat behind international trends, but that is changing.
Risk assessment was first used in Japan in the late 1970s by groups engaged in food safety and civil engineering research, but the real push for risk assessment and management came from two workshops on risk analysis and management, the first one held in Tsukuba in 1984 as a joint U.S.A.-Japan workshop organized by the University of Tsukuba and Vanderbilt University. The other was held in Osaka in 1987. Both workshops compared risk assessment processes between the United States and Japan. Similar workshops on the risk assessment and management of toxic chemicals were held three times from 1989 to 1993 by the National Institute for Environmental Research of Japan and U.S. Environmental Protection Agency.
At the 1987 Osaka workshop, the Japanese participants decided to establish the Japan Section of the Society for Risk Analysis. This occurred in 1988, and the section now has more than 300 members engaged in various disciplines. They are also active in environmental issues and in various social activities throughout Japan.
Dr. Yokoyama feels that there are fundamental differences in approaches to risk analysis and management between Japan and the United States. In Japan, negotiation and consensus building are very important to decision making on the regulations of environmental pollution, whereas in the United States more emphasis is placed on rigorous scientific analysis and open discussion. He attributes the differences to the different social and cultural backgrounds of the two nations.
Still, he says the two nations are moving toward the same goals. In 1993, Japan replaced the 1967 Basic Law for Environmental Pollution Control with the Basic Environment Law, which defines the basis of policies for environmental conservation consistent with sustainable development. The Basic Environmental Plan, which was established as a long-term comprehensive national plan for environmental conservation under the Basic Environment Law, requires the development of risk assessment and management practices as measures against hazardous chemical substances in the environment.
In conclusion, Dr. Yokoyama pledged that the Japan Section of
the Society for Risk Analysis would continue to promote research
in risk assessment and management in Japan, and stated that he
believed that the joint annual meeting of the section with SRA
was providing support to those efforts.