234
Sea and River Weeds
Szefer [673] determined uranium and thorium in samples of seaweeds and plants
collected from the Gdansk Bay coastal region of the open Baltic and from Zarnowieckie
Lake. Average concentrations of uranium and thorium, respectively, were 0.07-0.41 and
0.01-0.60 mg kg-I dry weight in seaweeds, and 0.09-0.22 mg kg-I dry weight in lake
plants. Calculated concentration factors for uranium and thorium in Baltic seaweeds
were 40-50 and 280-320 respectively. Discrimination factors with respect to calcium
were 2.2-4.7 for uranium and 16-28 for thorium, with affinity of the seaweeds for
uranium and thorium being inversely related to their degree of calcification. Calculated
enrichment factors for uranium, thorium, and calcium (sea salt corrected) with respect
to aluminium as a normalizer were 5.8, 1.4 and 24 respectively, indicating that the
biological affinity of thorium and, to a lesser extent, uranium was weaker than that of
calcium.
Ward [674] studied temporal variations of metals in the seagrass posidonia australis,
and its potential as a sentinel accumulator near a lead smelter. Posidonia australis from
three sites in the hypersaline Spencer Gulf were sampled in October 1980 and February,
May, and September 1981. Site A was closest to the Port Pirie lead smelter, with sites B
and C 8 and 16 km, respectively, from site A. Site A had the lowest density and smallest
standing crop of P. australis, and the highest leaf concentrations of cadmium (198541 mg kg-I dry weight), manganese (112-537 mg kg-I), lead (116-379 mg kg-I), and
zinc (728 -4241 mg kg-I), At all sites, concentrations of cadmium, copper, lead, and zinc
in plant leaves were generally lowest in summer and autumn, and highest at the end of
winter. The reverse was true for manganese. Compared with plants from sites B and C,
site A plants also had significantly higher concentrations of cadmium (5.63 mg kg-I),
lead (167 mg kg-I), and zinc (379 mg kg-I) in the epibiota. Nickel was highest
(3.65 mg kg-I) in the epibiota of site B plants but there were no site related differences in
epibiotic copper. Concentrations of cadmium, copper, and zinc in the epibiota were
generally higher than those in the leaves, whereas the reverse was true of manganese
and nickel. Epibiotic metal concentrations did not vary significantly with time.
10.2
Non-Metals
10.2.1
Iodine
Kulvere [675] used cold vapour atomic absorption spectrometry to determine iodine
in seaweed. The method is based on the interfering effect of iodine in the determination of mercury.
10.3
Organic Carbon Parameters
Weiss and Gnauck [676] developed a bio-assay method based on the production of
carbon dioxide, measured by infra-red gas analysis, by submerged macrophytes.
Results obtained with the water moss Fontinalis antipyretica show that the carbon
dioxide balance becomes unstable at the same concentration of copper that affects the
Sea and River Weeds
Szefer [673] determined uranium and thorium in samples of seaweeds and plants
collected from the Gdansk Bay coastal region of the open Baltic and from Zarnowieckie
Lake. Average concentrations of uranium and thorium, respectively, were 0.07-0.41 and
0.01-0.60 mg kg-I dry weight in seaweeds, and 0.09-0.22 mg kg-I dry weight in lake
plants. Calculated concentration factors for uranium and thorium in Baltic seaweeds
were 40-50 and 280-320 respectively. Discrimination factors with respect to calcium
were 2.2-4.7 for uranium and 16-28 for thorium, with affinity of the seaweeds for
uranium and thorium being inversely related to their degree of calcification. Calculated
enrichment factors for uranium, thorium, and calcium (sea salt corrected) with respect
to aluminium as a normalizer were 5.8, 1.4 and 24 respectively, indicating that the
biological affinity of thorium and, to a lesser extent, uranium was weaker than that of
calcium.
Ward [674] studied temporal variations of metals in the seagrass posidonia australis,
and its potential as a sentinel accumulator near a lead smelter. Posidonia australis from
three sites in the hypersaline Spencer Gulf were sampled in October 1980 and February,
May, and September 1981. Site A was closest to the Port Pirie lead smelter, with sites B
and C 8 and 16 km, respectively, from site A. Site A had the lowest density and smallest
standing crop of P. australis, and the highest leaf concentrations of cadmium (198541 mg kg-I dry weight), manganese (112-537 mg kg-I), lead (116-379 mg kg-I), and
zinc (728 -4241 mg kg-I), At all sites, concentrations of cadmium, copper, lead, and zinc
in plant leaves were generally lowest in summer and autumn, and highest at the end of
winter. The reverse was true for manganese. Compared with plants from sites B and C,
site A plants also had significantly higher concentrations of cadmium (5.63 mg kg-I),
lead (167 mg kg-I), and zinc (379 mg kg-I) in the epibiota. Nickel was highest
(3.65 mg kg-I) in the epibiota of site B plants but there were no site related differences in
epibiotic copper. Concentrations of cadmium, copper, and zinc in the epibiota were
generally higher than those in the leaves, whereas the reverse was true of manganese
and nickel. Epibiotic metal concentrations did not vary significantly with time.
10.2
Non-Metals
10.2.1
Iodine
Kulvere [675] used cold vapour atomic absorption spectrometry to determine iodine
in seaweed. The method is based on the interfering effect of iodine in the determination of mercury.
10.3
Organic Carbon Parameters
Weiss and Gnauck [676] developed a bio-assay method based on the production of
carbon dioxide, measured by infra-red gas analysis, by submerged macrophytes.
Results obtained with the water moss Fontinalis antipyretica show that the carbon
dioxide balance becomes unstable at the same concentration of copper that affects the