was observed during the periods of subacute influence and chronic influence.
Additionally, it was revealed that many populations decreased in the highconcentration systems from B 16–30 . As a functional parameter, the amplitude of
the DO was damped by addition concentrations of more than 8 mg/L, and it is
thought that the system collapsed (Fig. 7.27). The P/R ratios in all systems were
stable at ~1. From these results, the m-NOEC of the structural parameter was
estimated to be 1.5 mg/L of Co because microorganisms in the microcosm perished
in more than 2 mg/L during the period of chronic influence. Meanwhile, the
m-NOEC of the functional parameter was estimated to be 6 mg/L because the
system collapsed with concentrations of more than 8 mg/L of Co from the viewpoint
of changes in the DO concentration over time.
7.10.10 Ni and Co
Cobalt and Ni were supplied for assessment, and a no-addition system (control) and
complexed addition systems (Co 0.2 mg/L + Ni 0.02 mg/L, Co 0.4 mg/L + Ni
0.04 mg/L, Co 0.6 mg/L + Ni 0.06 mg/L, Co 0.8 mg/L + Ni 0.08 mg/L, Co 1 mg/
L + Ni 0.1 mg/L, Co 3 mg/L + Ni 0.3 mg/L, Co 5 mg/L + Ni 0.5 mg/L, and Co
10 mg/L + Ni 1 mg/L) were adjusted and loaded 16 days after culturing began. The
addition concentration was set on the basis of the m-NOEC of Co and Ni. 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
ratio of the abundance and population density (N 30 ) on the 30th day. The DO
DO(mg/L)
Time(hour)
0
2 8 8
240
192
144
96
48
4
12
10
8
6
control
1.0mg/L
2.0mg/L
1.5mg/L
6.0mg/L
8.0mg/L
10mg/L
4.0mg/L
Fig. 7.27 Time course of DO in Co-added microcosm N-system
122
K. Murakami et al.
Additionally, it was revealed that many populations decreased in the highconcentration systems from B 16–30 . As a functional parameter, the amplitude of
the DO was damped by addition concentrations of more than 8 mg/L, and it is
thought that the system collapsed (Fig. 7.27). The P/R ratios in all systems were
stable at ~1. From these results, the m-NOEC of the structural parameter was
estimated to be 1.5 mg/L of Co because microorganisms in the microcosm perished
in more than 2 mg/L during the period of chronic influence. Meanwhile, the
m-NOEC of the functional parameter was estimated to be 6 mg/L because the
system collapsed with concentrations of more than 8 mg/L of Co from the viewpoint
of changes in the DO concentration over time.
7.10.10 Ni and Co
Cobalt and Ni were supplied for assessment, and a no-addition system (control) and
complexed addition systems (Co 0.2 mg/L + Ni 0.02 mg/L, Co 0.4 mg/L + Ni
0.04 mg/L, Co 0.6 mg/L + Ni 0.06 mg/L, Co 0.8 mg/L + Ni 0.08 mg/L, Co 1 mg/
L + Ni 0.1 mg/L, Co 3 mg/L + Ni 0.3 mg/L, Co 5 mg/L + Ni 0.5 mg/L, and Co
10 mg/L + Ni 1 mg/L) were adjusted and loaded 16 days after culturing began. The
addition concentration was set on the basis of the m-NOEC of Co and Ni. 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
ratio of the abundance and population density (N 30 ) on the 30th day. The DO
DO(mg/L)
Time(hour)
0
2 8 8
240
192
144
96
48
4
12
10
8
6
control
1.0mg/L
2.0mg/L
1.5mg/L
6.0mg/L
8.0mg/L
10mg/L
4.0mg/L
Fig. 7.27 Time course of DO in Co-added microcosm N-system
122
K. Murakami et al.