28
2. Interpreting Selenium Concentrations
els of about 5 to 8 Ilg Se/g in fish exposed to agricultural irrigation
drainwater (Greenberg and Kopec 1986; Saiki and Palawski 1990; Saiki
et al. 1992).
Several field and laboratory studies conducted in the United States
describe the effects of selenium on bluegill sunfish, Lepomis macrochirus,
and other centrarchids (Table 2.2). Cumbie and Van Horn (1978) and
Lemly (1985a, 1985b) found that selenium levels of 12 to 16 Ilg Se/g in
skeletal muscle and 40 to 60 Ilg Se/g in ovaries were associated with
reproductive failure and mortality of all 9 species of centrarchids present
in a power plant cooling reservoir in North Carolina. Similar effects
were reported for centrarchids in a selenium-contaminated reservoir
in Texas; the skeletal muscle residues for the centrarchids were in the
8 to 36 Ilg Se/g range (Garrett and Inman 1984). Several physiologically important changes in blood parameters, in tissue structure in
major organs (ovary, kidney, liver, heart, gills), and in organ weight/
body weight relationships have also been described for centrarchids in
these contaminated reservoirs (Sorensen et al. 1984; Sorensen 1986,
1988). Selenium residues of 20 to 80 Ilg Se/g were associated with the
various pathological conditions.
Finley (1985) fed selenium-laden invertebrates from a contaminated
reservoir to juvenile bluegill and found that mortality occurred when
skeletal muscle tissues contained 20 to 32 Ilg Se/g and liver tissue contained 32 to 86 Ilg Se/g. Whole-body concentrations of only 4 to 6 Ilg
Se/g were associated with mortality when juvenile bluegill were fed
selenomethionine-spiked commercial diets in the laboratory (USFWS
1990).
Gillespie and Baumann (1986) brought selenium-laden adult bluegill from a contaminated power plant reservoir into the laboratory and
spawned them artificially to produce crosses between clean and contaminated parents. The results showed that the contaminated females
(selenium levels of 8 to 36 Ilg Se/g in carcasses, 12 to 55 Ilg Se/g in
ovaries) did not produce viable offspring. Fertility and hatchability of
the eggs were not affected, but the high level of selenium (12 to 55 Ilg
Se/g) transferred from the eggs to the developing embryos during
yolk-sac absorption resulted in edema, morphological deformities, and
death prior to the swim-up stage. Similar findings were reported by
Waack et al. (1987).
In a laboratory study, Coyle et al. (1993) evaluated the effects of
waterborne and dietary selenium (6:1 ratio of waterborne sodium selenate and sodium selenite; seleno-L-methionine-spiked commercial
diet) on the reproductive success of bluegill. Offspring from females
that contained whole-body selenium residues of 16 to 18 Ilg Se/g (3038 Ilg Se/g in ovaries, 40-45 Ilg Se/g in eggs) failed to survive beyond
the swim-up stage (5-7 days posthatch). No effect was observed on
adult fish, spawning frequency, eggs per spawn, or hatchability of eggs.
2. Interpreting Selenium Concentrations
els of about 5 to 8 Ilg Se/g in fish exposed to agricultural irrigation
drainwater (Greenberg and Kopec 1986; Saiki and Palawski 1990; Saiki
et al. 1992).
Several field and laboratory studies conducted in the United States
describe the effects of selenium on bluegill sunfish, Lepomis macrochirus,
and other centrarchids (Table 2.2). Cumbie and Van Horn (1978) and
Lemly (1985a, 1985b) found that selenium levels of 12 to 16 Ilg Se/g in
skeletal muscle and 40 to 60 Ilg Se/g in ovaries were associated with
reproductive failure and mortality of all 9 species of centrarchids present
in a power plant cooling reservoir in North Carolina. Similar effects
were reported for centrarchids in a selenium-contaminated reservoir
in Texas; the skeletal muscle residues for the centrarchids were in the
8 to 36 Ilg Se/g range (Garrett and Inman 1984). Several physiologically important changes in blood parameters, in tissue structure in
major organs (ovary, kidney, liver, heart, gills), and in organ weight/
body weight relationships have also been described for centrarchids in
these contaminated reservoirs (Sorensen et al. 1984; Sorensen 1986,
1988). Selenium residues of 20 to 80 Ilg Se/g were associated with the
various pathological conditions.
Finley (1985) fed selenium-laden invertebrates from a contaminated
reservoir to juvenile bluegill and found that mortality occurred when
skeletal muscle tissues contained 20 to 32 Ilg Se/g and liver tissue contained 32 to 86 Ilg Se/g. Whole-body concentrations of only 4 to 6 Ilg
Se/g were associated with mortality when juvenile bluegill were fed
selenomethionine-spiked commercial diets in the laboratory (USFWS
1990).
Gillespie and Baumann (1986) brought selenium-laden adult bluegill from a contaminated power plant reservoir into the laboratory and
spawned them artificially to produce crosses between clean and contaminated parents. The results showed that the contaminated females
(selenium levels of 8 to 36 Ilg Se/g in carcasses, 12 to 55 Ilg Se/g in
ovaries) did not produce viable offspring. Fertility and hatchability of
the eggs were not affected, but the high level of selenium (12 to 55 Ilg
Se/g) transferred from the eggs to the developing embryos during
yolk-sac absorption resulted in edema, morphological deformities, and
death prior to the swim-up stage. Similar findings were reported by
Waack et al. (1987).
In a laboratory study, Coyle et al. (1993) evaluated the effects of
waterborne and dietary selenium (6:1 ratio of waterborne sodium selenate and sodium selenite; seleno-L-methionine-spiked commercial
diet) on the reproductive success of bluegill. Offspring from females
that contained whole-body selenium residues of 16 to 18 Ilg Se/g (3038 Ilg Se/g in ovaries, 40-45 Ilg Se/g in eggs) failed to survive beyond
the swim-up stage (5-7 days posthatch). No effect was observed on
adult fish, spawning frequency, eggs per spawn, or hatchability of eggs.