More than 3700 fertilized toad eggs were used in a series of
studies designed to determine the effects of UV-B radiation (290-
315 nm) on temporal developmental patterns, systematic development
and viability prior to metamorphic climax. The eggs were
exposed to radiation from either "white-light" fluorescent lamps
(Vita-Lite, Duro-Test Corporation, North Bergen, New Jersey) or
"white-light" fluorescent lamps plus fluorescent sunlamps (Westinghouse-
FS40). Several radiation exposure schedules were
utilized (chronic or varied, daily exposures) and, in all but one
study, filters were utilized - Kodacel cut-off filters to transmit
wavelengths longer than 290 nm and Mylar cut-off filters to
transmit wavelengths longer than 315 nm. These filters provided
a transmission "window" in the UV-B region.
Exposure of the developing tadpoles on a daily basis to
eleven or more Sunburn Units of UV-B radiation per day resulted
in the development of tadpole populations with lordotic posture,
hyperplasia in the presumptive cornea and other dorsal epithelial
tissue, increased pigmentation in the presumptive cornea,
desquamation of areas of the dorsal surface, and increased
mortality. Exposure of the tadpoles on a daily basis to 4.4
Sunburn Units of UV-B radiation per day resulted in a significant
lengthening of the time periods required to achieve
metamorphic climax.
Biological photoreactivation of ultraviolet damage was
demonstrable with three groups of tadpoles exposed to comparable
daily exposures of UV-B radiation (11.0 Sunburn Units
per day) at a comparable rate (1.1 Sunburn Units per hour)
from similar sources. The critical differences between the
groups was the duration of exposure to UV-A and visible
radiation (0, 2 and 4 hours) following the termination of the
UV-B exposure
