Measurement of UV radiation using suspensions of microorganisms

The measurement of solar UV radiation is usually performed using physical d evices Like photodiodes or photomultipliers or with chemical substances (ac tinometry). The application of biological material such as microorganisms f or this purpose has gained increasing importance in the last few years. The microorganisms may be dried and spread on a flat surface or they may be in aqueous suspensions contained in UV-transparent vessels. If the measuremen ts are done on flat surfaces, the irradiance weighted by the action spectru m of the dried microorganism used is the result of the measurement. If aque ous suspensions of microorganisms are used, contained for instance in spher ical vessels, the fluence weighted by the action spectrum of the microorgan isms in the aqueous suspension is the result. A problem of this method of m easurement can be that inside the vessel the distribution of UV radiation i s usually not homogeneous, causing distributions of fluences among the irra diated microorganisms, which may result in variation of the results dependi ng on the mixing characteristics of the suspension during irradiation. (C)1 999 Elsevier Science S.A. All rights reserved.