MEDICAL RADIOACTIVE WASTE MANAGEMENT IN SAUDI ARABIA

Transcription

1 MEDICAL RADIOACTIVE WASTE MANAGEMENT IN SAUDI ARABIA Rasheed Al-Owain, Yousef Aldorwish King Abdulaziz City for Science and Technology Institute of Atomic energy Research P.O.Box 6086 Riyadh Saudi Arabia ABSTRACT The application of radioactive materials in medical diagnosis and therapy is extremely important and continuously growing. By using radioactive tracer elements, physicians can learn of the presence of disease. Radiation therapy is useful in controlling the spread of many types of cancer. Both types of activities result in the production of low-level radioactive waste. A very wide spectrum of radionuclides is available for hospital usage such as Tritinm-3, Carbon-14, Cobalt-57, and other sources, which are generally classified as low level short lived radioactive waste. The experience of more than a decade of handling radioactive materials has established a solid ground for the future management of radioactive waste in general and medical radioactive waste in particular. The current status and future plan for the medical radioactive waste generated and their impact on the environment in Saudi Arabia is described, as well as the impact of medical radioactive waste on the broader aspects of radioactive waste management. INTORDUCTION Radioactive waste management in Saudi Arabia gains a lot of momentum during the last decay, due to the large usage of radioactive materials in different applications. Fortunately, Saudi Arabia has no high level waste application, so most of the radioactive wastes that are produced is in categories of low level wastes and small quantity considered as an intermediate level. All low-level radioactive waste, regardless of its source, must be carefully managed to minimize risk to people and the environment. The low level radioactive wastes are generated from mainly medical facilities, such a hospitals, which have grown to depend on the use of radioactive materials for diagnosing and treating patients. By using radioactive tracer elements, physicians can learn of the presence of disease. Radiation therapy is useful in controlling the spread of many types of cancer. Both types of activities result in the production of low -level radioactive waste. This can include contaminated syringes, linens, paper products, and waste liquids, as well as protective clothing worm by both hospital personnel and patients. The second source of low- level radioactive waste is Industrial process. Radioactive materials are used extensively to measure the thickness of materials. And the last source is the research institutions through experimental activities.

2 King Abdulaziz City for Science and Technology (KACST) is the regulatory authority on nuclear atomic affairs in the Kingdom of Saudi Arabia. The institute of Atomic Energy Research (IAER), part of KACST, is in charge of radioactive waste management in the country. IAER is responsible for nuclear research and development, nuclear regulations, and licensing and managing of the imported and exported radioactive materials. Department of Radiation Protection in IAER is in charge of the management of the radioactive wastes in Saudi Arabia. The scope of work on the radioactive waste management includes developing relevant laws and regulations to keep the radioactive waste under control and to minimize their impact on humans and their environment. With this knowledge and experience, we can effectively and safely manage Saudi s radioactive waste. By knowing the type of waste and the kind of radiation it emits, we can: Package the waste in materials that reduce the radiation, so that it is safe to handle and transport; Safely store it in facilities that use effective shielding; and Dispose of it in the ground using natural rock and soil, and install barriers like concrete to ensure the radioactivity does not enter the environment. This will prevent radiation from harming humans, animals or plants. RADIOACTIVE WASTE GENERATION IN THE KINGDOM OF SAUDI ARABIA Radioactive waste in Saudi Arabia is generated from various applications such as medical, industrial, and research intuitions. These wastes are classified as low-level radioactive and small quantity consider as an intermediate level. The radioactive wastes, generated by these activities are divided physically into two groups; liquid wastes and solid wastes. Solid wastes divided into two groups, compactable solid wastes and non-compactable solid wastes. The non-compactable solid wastes such as spent sealed sources, metals, etc. compactable waste such as, clothes, gloves, etc. The application of radioactive materials in medical diagnosis and therapy is very important and expanding rapidly. In many cases alternative methods are not available. The main areas of application are diagnostic techniques, radiotherapy and research. These represent the use of not only small quantities of unsealed sources, but also highly concentrated sealed sources housed in shielded assemblies. These medical radioactive waste generally classified as low level short lived sources. They represent more than 50% of radioisotope applications as shown in Figure 1. Most industrial uses use particular forms of radioactive material such as sealed sources, luminous displays, and specialized electronic devices for notdestructive testing, evaluation of plant performance and development of products. The quantities of radioactive materials used depend largely on the development and level of the national technology. As of now, one of the main source of radioactive waste in Saudi Arabia is the spent sealed radioactive sources which are imported to the country by different users under the supervision of Institute of Atomic Energy Research

3 (IAER). These sealed sources consists of different types such as Cs-137, Sr- 90, and C0-60. Users of radioactive material in research centers and universities are commonly involved in monitoring the environmental pathways associated with materials as diverse as fertilizers, drugs, minerals, and pesticides. Co-60 has proved to be very valuable gamma rays emitters source. A very wide spectrum of radionuclides is available for research and study centers, they represents only 11% of the total radioisotope applications. PRESENT STATUS OF MEDICAL RADIOACTIVE WASTE IN THE KINGDOM OF SAUDI ARABIA The increasing use of unsealed radionuclides in medical applications for diagnostics and for therapy as shown in figure 2, presents the need for safe management of radioactive wastes in order not to pollute the environment. A study showed that hospitals and possibly other institutions are disposing off a considerable amount of radioactive iodine in the domestic sewage system [3]. I-125 and I-131 were the most frequently detected medical radionuclides. The general approach to medical radioactive waste management in Saudi Arabia is that the licenses are responsible and must ensure compliance with the temporary regulations prepared by IAER. King Abudalaziz City for Science and Technology (KACST) has its mission to make sure that the use of radionuclide isotopes in the country does not pose undue risk to human and their environment and trying to delivers this objective. These regulations allow the disposal of radioactive wastes into the environment without particular authorization, if the amount of radioactivity is below fixed limits ( some of these are limits listed in table I ). Table I. Disposal limits for Radioactive Wastes According to IAER law. Nuclide Max. Concentration Liquid Wastes B q/l Max Concentration Gas wastes Bq/m^3 Sr I I Cs TI Ir Rh-103m Tc Nd Bi Ir Ra Am

4 FUTURE STATUS OF MEDICAL RADIOACTIVE WASTE IN THE SAUDI ARABIA In order to minimize the impact of radioactive wastes left after the various applications in these very expanding applications of radioisotopes in the modern life of the people of Saudi Arabia, there should be a plan to control this growing use of the radioactive materials to prevent the hazard waste from effecting human health and the environment. Since it is not very difficult to manage the radioactive wastes deriving from medical use of radioisotopes. A stiff law and regulations should be implemented on all kind of medical radioactive wastes. KACST should to adopt the following procedure to manage the radioactive wastes coming form all the medical facilities: 1. Collection of the wastes from all the country users. 2. Storage in three different places (West, Central, and East Sites) for deposing for an appropriate number of half lives 3. Disposal, by means of conventional system for waste treatment, when the amount of radioactivity is below the limits, which are defined by national laws. While a national repository plan has been considered by IAER (4), waste minimization may be applied at the source of waste generation (i.e. hospitals). The waste minimization idea can be initiated with the simple physical separation of noncompactable waste (i.e. glass, metals) for compactable wastes (plastics, paper goods). This initial process is a highly desirable goal in a country that has no national repository facility. Table II, showed types and quantities of different isotopes that are used in different medical applications. CONCLUSION An emerging situation in medical waste management is arising from radiation sources used in medicine and other fields. When these sources are no longer useable, they must be disposal of safely. How ever, many of the disused sources have not been or might not properly managed, sometimes remaining problems from competent authority and their control serious incidents have occurred in some other countries where mismanage d sources caused unwanted situations before being recovered or controlled. In response to this kind of cases, KACST should launch an action plan to assist hospitals and all users in improving their capabilities for ensuring the safe control and disposal of radioactive wastes. The safe management of radioactive waste should relies on an advance laws and regulations that can be dealt with all the times. The central authority (KACST) should have the responsibility to treat, condition, transport and to store all wastes been generated by the produces in the safest manner. Three different sites is an option to be looked at in the central, western and eastern provinces.

5 Table II. Usage of different Isotopes in different medical applications Usage of different Isotopes in different medical applications X-Ray Measurment Devices Therepy Nuclear Medicine Istopes Impor ted Exported Reminer Imported Exported Reminer Imported Exported Reminer Imported Exported Reminer Am Am-241/Be C Cd CO C Cs Fe I Ir Ra

6 REFERENCES 1- Kutbi,I et al, Radioactive Waste Management in Saudi Arabia, Final Report, AT-13-21, Nov Institute of Atomic Energy Research Data Base, Riyadh, Saudi Arabia, Al Marshad, A et al, Monitoring of Radioactive Chemical Waste in the Aquate Environment of WADI HANIFA, South of Riyadh City. The Arabian Journal for Science and Engineering, vol. 22, No. 1A, Al Owain, R. and Al Marshad, A., The Status of Radioactive Waste Management in Saudi Arabia, Proceedings of the Sixth International Conference on Radioactive Waste Management and Environmental Remediation, Singapore, October 12-16, 1997.

7 11% 36% 53% Industrial Medical Research Fig. 1: Percentage of Radioisotope Applications in Industrial, Medical, and Research in Saudi Arabia (1996) No. of Units Years Fig. 2: Total Number of Medical Units in Saudi Arabia ( ).

8 40 Number of Units Central West South East North Regions of Saudi Arabia (1418) Fig. 3: Geographical Distribution of Number of Medical Units in the different regions of Saudi Arabia (1418).