Popis: |
Bacteriophage T7 as a biologic sensor was used for systematic underwater UV measurements at the freshwater lake Gyekenyes, Hungary. Time evolution of the biologically effective doses, cumulated daily doses and daily dose-profiles have been measured. Measurements were undertaken not only in different water depths but also just above the water surface (15 cm height) and also on the beach. The exponential attenuation of daily doses in water has been confirmed. Although the values of HT7 above the water's surface and on the beach were similar, the dose rates were very different between the two sides of the water surface, i.e. just under it (at 5 cm depth) and above it (at 15 cm height). Their ratio has been found to be dependent on the zenith angle with a maximum of not more than 0.5, and at higher zenith angles it is about 0.3. |