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In an event of a nuclear or dirty bomb explosion and a radiological accident, there is a need for self-indicating instant radiation dosemeter for monitoring radiation exposure. The self-indicating instant radiation alert dosemeter (SIRAD) is a credit card size radiation dosemeter for monitoring ionising radiation from a few hundredths of a Gray to a few Gray. It is always active and is ready to use. It needs no battery. The dosemeter develops colour instantly upon exposure, and the colour intensifies with dose. It has a colour chart so that the dose on the active element may be read by matching its colour with the chart that is printed next to it on the card. However, in this work, the dose is measured by the optical density of the element. The dosemeter cannot be reset. The response changes by <1% per degrees C from -20 to +60 degrees C. The shelf-life is >3 y at room temperature. It contains no hazardous materials. The dosemeter would meet the requirements of instantly monitoring high dose in an event of a nuclear or dirty bomb explosion or a radiation accident.

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Chromium-51 and zinc-65 were detected as far as 115 and 15 kilometers, respectively, from the mouth of the Columbia River; zinc-65 also was found at a few isolated stations. Zirconium-95 and niobium-95 from atmospheric fallout occurred in the river effluent but they were most abundant in surface waters further offshore. Distribution of the radionuclides is controlled largely by surface currents and by upwelling of sea water near the coast.

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