222
A. D. BONEY
Takeuchi (1960b) reported on the radioactivity of Porpkyra tenera from
Hiroshima Bay, and Tsuruga (1 962a,b) subsequently studied the
absorption of ruthenium- 106 by marine algae. Measurements of activity
due to this isotope were made on Porphyra tenera and a number of
other algae in 1958 and 1959. Contamination was considered to be due
to fallout from test explosions, since the influence of the 1945 A-bomb
on the city should by now have gone, and there was no discharge of
radioactive effluent from the neighbourhood. Other seaweeds with a
fairly high ruthenium-106 content were GbiopeZtis furcuta, Monostroma
nitidum and Polysiphonia fragilis. These are plants of the intertidd
belt, and it was suggested that the fallout contamination could be
present in rainwater. Under field conditions species of the lower-zoned
Sargmsum showed lower values for ruthenium-106, although when
measured in the laboratory it accumulated very high concentrations of
the nuclide. In general the seaweeds rapidly absorbed the nuclide. I n
a review of radioactive wastes and marine algae (planktonic and benthonic) Eppley (1962) showed that there was both active and passive
uptake of ionic and particulate forms of radionuclides.
Other relevant studies involving radionuclides and marine algae
include the pioneer experiments by Spooner (1949) using strontium-90
and yttrium-90 with brown, green and red algae. This work showed that
whilst Fucus serratus extracted strontium-90 from seawater by a
process of ion exchange, Ulva l a c t w and the red algae Gigartina
stellata and Rhodymenia palmuta extracted small and negligible amounts
of the element. By contrast, yttrium-90 was heavily taken up by the red
and green algae, but to a much lesser extent by Fucus serratus. The
uptake of cobalt-60 by Rhodymenia palmata was studied by Scott and
Ericson (1954). The element formed stable complexes within the cells
as either a direct or indirect result of photosynthetic activity, and these
compounds were in a state of continuous metabolic turnover. More
cobalt-60 was taken up than could be linked with vitamin B,, manufacture by the plant. Bowen (1966) studied the strontium-90 contents of
sea water and marine algae, and considered that even though the
algae were natural ion-exchange systems, the hazard from strontium-90
in sea water was (at that time) negligible when compared with the
amounts of naturally radioactive material present.
Other experimental eltudies on the uptake of radionuclides by
seaweeds include the work of Kelly and Baily (1951) on the uptake of
radioactive iodine by Ascophyllum nodosum and of Shaw (1959) on the
uptake of iodine-131 by Laminaria digitata; this latter paper also
summarizes earlier work on the uptake of radio-iodine by marine algae.
The potentialities of using the uptake of zinc-65 as a means of measuring
A. D. BONEY
Takeuchi (1960b) reported on the radioactivity of Porpkyra tenera from
Hiroshima Bay, and Tsuruga (1 962a,b) subsequently studied the
absorption of ruthenium- 106 by marine algae. Measurements of activity
due to this isotope were made on Porphyra tenera and a number of
other algae in 1958 and 1959. Contamination was considered to be due
to fallout from test explosions, since the influence of the 1945 A-bomb
on the city should by now have gone, and there was no discharge of
radioactive effluent from the neighbourhood. Other seaweeds with a
fairly high ruthenium-106 content were GbiopeZtis furcuta, Monostroma
nitidum and Polysiphonia fragilis. These are plants of the intertidd
belt, and it was suggested that the fallout contamination could be
present in rainwater. Under field conditions species of the lower-zoned
Sargmsum showed lower values for ruthenium-106, although when
measured in the laboratory it accumulated very high concentrations of
the nuclide. In general the seaweeds rapidly absorbed the nuclide. I n
a review of radioactive wastes and marine algae (planktonic and benthonic) Eppley (1962) showed that there was both active and passive
uptake of ionic and particulate forms of radionuclides.
Other relevant studies involving radionuclides and marine algae
include the pioneer experiments by Spooner (1949) using strontium-90
and yttrium-90 with brown, green and red algae. This work showed that
whilst Fucus serratus extracted strontium-90 from seawater by a
process of ion exchange, Ulva l a c t w and the red algae Gigartina
stellata and Rhodymenia palmuta extracted small and negligible amounts
of the element. By contrast, yttrium-90 was heavily taken up by the red
and green algae, but to a much lesser extent by Fucus serratus. The
uptake of cobalt-60 by Rhodymenia palmata was studied by Scott and
Ericson (1954). The element formed stable complexes within the cells
as either a direct or indirect result of photosynthetic activity, and these
compounds were in a state of continuous metabolic turnover. More
cobalt-60 was taken up than could be linked with vitamin B,, manufacture by the plant. Bowen (1966) studied the strontium-90 contents of
sea water and marine algae, and considered that even though the
algae were natural ion-exchange systems, the hazard from strontium-90
in sea water was (at that time) negligible when compared with the
amounts of naturally radioactive material present.
Other experimental eltudies on the uptake of radionuclides by
seaweeds include the work of Kelly and Baily (1951) on the uptake of
radioactive iodine by Ascophyllum nodosum and of Shaw (1959) on the
uptake of iodine-131 by Laminaria digitata; this latter paper also
summarizes earlier work on the uptake of radio-iodine by marine algae.
The potentialities of using the uptake of zinc-65 as a means of measuring