tailieunhanh - Radiation and Health - Chapter 13

Bức xạ, cả hai nền tự nhiên và nhân tạo, là một phần của môi trường của chúng tôi phải được xem xét như một lợi ích và nguy cơ. Để đánh giá bức xạ một số công việc phải được đưa vào tài khoản, chẳng hạn như: 1. Liều bức xạ Khi một tình huống xảy ra ô nhiễm phóng xạ, điều quan trọng là để có được thông tin chính xác về liều bức xạ có liên quan đến. Nó sẽ là một sự lãng phí nguồn lực thực hiện ngay các biện pháp đối phó nếu liều. | Chapter 13 Radiation and the Environment Radiation both natural background and man-made forms a part of our environment which must be considered as both a benefit and a risk. In order to judge radiation a number of things must be taken into account such as 1. The radiation dose When a situation occurs with radioactive pollution it is important to get accurate information about the radiation doses that are involved. It would be a waste of resources to immediately implement countermeasures if the doses involved are smaller than the variations in natural background radiation. To date no general agreements have been reached with regard to the dose levels where actions should be taken. For example in the case of radon the recommendations from WHO World Health Organization are that 800 Bq m3 should be considered as an action level. The equivalent dose involved would be approximately 20 mSv per year. 2. Type of radiation In order to perform dose calculations and estimate health risks it is important to have information on the radiation source . the isotopes involved . As pointed out in previous chapters there is a clear distinction between Y-emitting isotopes and those which emit a- and P-particles. 2003 Taylor Francis 182 Radiation and Health 3. The amount of pollution The amount of radioactive material released to the environment should be given in Bq or in Ci and not in volume or weight since a large release in weight may contain small amounts of radioactivity and vice versa. In the example of the Chernobyl accident a large fallout of Cs-137 resulted both to areas around the reactor as well as far away. In Scandinavia areas were found with fallout of 100 kBq m2. However the total release of Cs-137 was in fact only a few kilograms see exercises in Chapter 14 . Here a small amount of material produced an easily measurable amount of radioactivity at a great distance from the accident. 4. The form and dispersion of the release It is important to have information on the