QUANTIFICATION OF BIOLOGICAL EFFECTIVENESS OF UV RADIATION - Environmental UV Radiation: Impact on Ecosystems and Human Health and Predictive Models - page 63

10 2

10 1

10 0

10 -1

10 -2

10 -3

0 100 200 300 400 500 GC

ozone, DU

Figure 8. Biologically effective irradiance E eff for different ozone column thicknesses (x) determined
by the biofilm technique in a space experiment and the E eff value measured in Köln on 6 August
1993 (). The dashed line shows the corresponding curve modeled for DNA damage. (modified from
ref. 63).

of sunlight. During austral spring 1990, when stratospheric ozone concentrations
fluctuated between 170 and 380 DU, the potential biological effect of in-water UV-B
reaching depths down to 29 m was closely correlated to stratospheric ozone levels 72 .
Personal UV dosimetry . To estimate the individual biologically effective UV
dose, personal carry-along dosimeters are required, because they measure the dose in
dependence of the individual behavior. Personal dosimeters, based on the uracil
dosimeter 36 , the spore dosimeter 73 , and the DLR-Biofilm 66 have been applied at various
instances, such as school children and different professional groups. Using the
DLR-biofilm for personal dosimetry of astronauts on board of the space station MIR, it
was concluded that long-term stay in space may lead to an underexposure and thereby to
a Vitamin D deficiency 74 . In contrast to the general living module in space, the area
behind a quartz window which was used by the astronauts for “sun-bathing” led to a
severe overexposure, as measured by the DLR-Biofilm.

4. Conclusions

To assess the risks to human health and ecosystems from an enhanced UV-B
radiation, accurate and reliable UV monitoring systems are required that weights the
spectral irradiance according to the biological responses under consideration. Biological
dosimetry meets these requirements by directly weighting the incident UV components
of sunlight in relation to the biological effectiveness of the different wavelengths and to
potential interactions between them. Bacteria, viruses and biomolecules have been
developed as biological dosimeters. Their responses to environmental UV radiation,