According to CEC (1993c), recent measurements in Antarctica by American scientists demonstrated that a 58 per cent decrease in stratospheric ozone resulted in ground-level increases of 300 per cent for UV-B, 31 per cent for UV-A, and 32 per cent for visible light. In order to determine how important such increases were in biological terms, the scientists referred to 'action spectra': the results of a complicated series of scientific experiments on a given type of organism which attempt to determine which wavelengths of light or radiation are most important to the organism, ie, which wavelengths elicit certain biological reactions. If the increases in radiation in Antarctica are assessed according to the action spectra of different biological targets, the calculated biologically effective radiation doses are those shown in Table 16.5.
Table 16.5 - Effective UV-B radiation doses Source: Reported by CEC 1993c Action spectrum for: | Method used | Increase in biologically effective dose (%) |
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DNA damage | Setlow | 638 | Erythema | Robertson-Berger | 415 | Generalised plant damage | Caldwell | 689 | Fish | Hunter | 267 |
Note: Figures represent percentage increases in the biologically effective radiation dose from UV-B in Antarctica assessed according to the action spectra of four biological targets. |