erythrophthalma, and microalgae, such as Chlorella sp., coexisted after Cyclidium
glaucoma disappeared from the system and maintained a constant population. As a
functional parameter, from the time series of the DO concentration in the microcosm,
a 0.1 mg/L addition of Cs increased the activity and coped with the Cs load, and the
1 mg/L addition system recovered its activity through microbial interactions, material circulation, and energy flow among the microorganisms in the microcosm after
the activity decreased due to the addition of Cs. Because the P/R ratio (functional
parameter) is ~1, and the system was estimated to be stable, all addition systems
were estimated as stable. From these results, with respect to the P/R ratio, the
ecosystem function in the microcosm was judged to be stable when Cs addition
concentrations were less than 1 mg/L. As a result of having analyzed the ecosystem
influence of the Cs from the P/R ratio and microbial abundance (structural parameter), and because Cyclidium glaucoma was not observed, though the activity of the
system was restored at a Cs concentration of 1 mg/L, it was thought that differential
structuring of the system occurred.
From these outcomes, the m-NOECs of both the structural parameter and functional parameter were estimated to be less than 1 mg/L of Cs. Additionally, when it
was assumed that a radiation of 3000 Bq was emitted from 1 mg of Cs based on the
137 Cs data from the Chernobyl nuclear power plant accident (Iimoto 2012; Minai
et al. 2011), 0.02 mg of Cs existed in a 200 ml volume of microcosm culture fluid by
the addition of 0.1 mg/L of Cs, and the half-life of
137 Cs was applied to calculate the
type of radiation exposure dose in the microcosm (Iimoto 2012) for 30 years; the
radiation exposure dose, D, was approximately 30 Sv. That is, in the microcosm,
approximately 30 Gy/day would be irradiated at a Cs concentration of 0.1 mg/L. It
was shown that there was a difference of ~10 times the radiation exposure (hot run)
and m-NOEC of the metal load (cold run) in the microcosm when following the
conversion mentioned above because there was some influence at the 23 Gy/day
dose rate and almost no influence at the 10 Gy/day dos rate observed from the
gamma beam irradiation experiment, and it was estimated that the radiation exposure
had an influence that was approximately ten times as strong as that of the metal load.
Here, the ecosystem influence of the addition of Cs was analyzed using a cold run,
using the cold Cs, but it is difficult to convert values from Bq to Gy and Sv because
they rely on different definitions for radioactive Cs, and further examination is
necessary to complete the ecosystem impact assessment of Cs pollution.
7.10.12 I 2
Iodine was supplied for assessment, and a no-addition system (control) and addition
systems (8 and 10 mg/L) were adjusted and added 16 days after the start of culturing.
The endpoints were abundance (structural parameter) and the concentration of DO
(functional parameter), and the population was measured using an optical microscope and counted from the start of culturing on days 0, 2, 4, 7, 14, 16, 18, 20,
23, and 30; it was evaluated from the results of B 16–30 (days 16–30), which was the
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K. Murakami et al.
glaucoma disappeared from the system and maintained a constant population. As a
functional parameter, from the time series of the DO concentration in the microcosm,
a 0.1 mg/L addition of Cs increased the activity and coped with the Cs load, and the
1 mg/L addition system recovered its activity through microbial interactions, material circulation, and energy flow among the microorganisms in the microcosm after
the activity decreased due to the addition of Cs. Because the P/R ratio (functional
parameter) is ~1, and the system was estimated to be stable, all addition systems
were estimated as stable. From these results, with respect to the P/R ratio, the
ecosystem function in the microcosm was judged to be stable when Cs addition
concentrations were less than 1 mg/L. As a result of having analyzed the ecosystem
influence of the Cs from the P/R ratio and microbial abundance (structural parameter), and because Cyclidium glaucoma was not observed, though the activity of the
system was restored at a Cs concentration of 1 mg/L, it was thought that differential
structuring of the system occurred.
From these outcomes, the m-NOECs of both the structural parameter and functional parameter were estimated to be less than 1 mg/L of Cs. Additionally, when it
was assumed that a radiation of 3000 Bq was emitted from 1 mg of Cs based on the
137 Cs data from the Chernobyl nuclear power plant accident (Iimoto 2012; Minai
et al. 2011), 0.02 mg of Cs existed in a 200 ml volume of microcosm culture fluid by
the addition of 0.1 mg/L of Cs, and the half-life of
137 Cs was applied to calculate the
type of radiation exposure dose in the microcosm (Iimoto 2012) for 30 years; the
radiation exposure dose, D, was approximately 30 Sv. That is, in the microcosm,
approximately 30 Gy/day would be irradiated at a Cs concentration of 0.1 mg/L. It
was shown that there was a difference of ~10 times the radiation exposure (hot run)
and m-NOEC of the metal load (cold run) in the microcosm when following the
conversion mentioned above because there was some influence at the 23 Gy/day
dose rate and almost no influence at the 10 Gy/day dos rate observed from the
gamma beam irradiation experiment, and it was estimated that the radiation exposure
had an influence that was approximately ten times as strong as that of the metal load.
Here, the ecosystem influence of the addition of Cs was analyzed using a cold run,
using the cold Cs, but it is difficult to convert values from Bq to Gy and Sv because
they rely on different definitions for radioactive Cs, and further examination is
necessary to complete the ecosystem impact assessment of Cs pollution.
7.10.12 I 2
Iodine was supplied for assessment, and a no-addition system (control) and addition
systems (8 and 10 mg/L) were adjusted and added 16 days after the start of culturing.
The endpoints were abundance (structural parameter) and the concentration of DO
(functional parameter), and the population was measured using an optical microscope and counted from the start of culturing on days 0, 2, 4, 7, 14, 16, 18, 20,
23, and 30; it was evaluated from the results of B 16–30 (days 16–30), which was the
124
K. Murakami et al.