results that the populations of microorganisms in the system were not affected by
complexed soap concentrations below 30 mg/L. As a result, it can be estimated that
the m-NOEC of soap is less than 30 mg/L.
7.1.6 Complexed Soap
The addition concentration of complexed soap was adjusted to 10, 30, 50, 100,
150, and 200 mg/L, and it was added on the 16th day of the stable state into the
microcosm. Complexed soap used in this experiment was composed of 58% soap
and a lime soap-dispersing agent (LSDA). The endpoint was the population density
(structural parameter) 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, and it was evaluated
from the results of B 16–30 (days 16–30), which was the ratio of abundance and
population density (N 30 ) on the 30th day. Using the structural parameter, the
abundance of microorganisms maintained with the addition of 10 mg/L and
30 mg/L of complexed soap was the same as in the control system. Cyclidium
1
2 3
4
5
6
7 8
9
1 0
1 1
1 2
1 3
1 4
control
2 mg/L
1
2
3
4
5
6
7 8
9
1 0
1 1
1 2
1 3
1 4
4 mg/L
1 2
3
4 5 6 7
8
9
10 11 12
13
14
8 mg/L
Production(mg O
2 /L)
Respiration(mg O 2 /L)
9
6
3
0
9
6
3
0
9
6
3
0
9
6
3
0
9
6
3
0
1.5
1
0.5
0
2
1.5
1
0.5
0
2
9
6
3
0
Fig. 7.5 Time course of P/R ratio in TMAC-added microcosm N-system
78
K. Murakami et al.