common soil conditioner. The m-NOEC in the microcosm test was evaluated to be
0.05 mg/L using the structural parameter and to be 0.1 mg/L based on the functional
parameter.
7.3.9 Pentachlorophenol
The effect of pentachlorophenol (PCP) on microcosms was investigated by
Dr. Sugiura. PCP was added at the start of the microcosm culture (day 0), and the
abundance of organisms and amounts of respiration and production were tracked.
With the addition of PCP, both the respiration volume and production volume
became larger than in the control system. The m-NOEC of PCP was estimated to
be 0.07 mg/L (Sugiura 1992).
7.3.10 Atrazine
The effect of atrazine was investigated by Dr. Sugiura. Atrazine was added and
adjusted to concentrations of 0.07, 0.1, and 0.15 mg/L at the start of the microcosm
culture (day 0). The locus of DO differed depending upon the amount of atrazine
added. With the addition of atrazine, both the respiration volume and production
volume became larger than in the control system. The m-NOEC of atrazine was
estimated to be 0.03 mg/L (Sugiura 1992).
a) control
b) 0.1mg/L
c) 1mg/L
d) 4mg/L
Respiration(mg O 2 /L)
Production(mg O
2 /L)
9
6
3
0
9
6
3
0
9
6
3
0
9
6
3
0
9
6
3
0
9
6
3
0
9
6
3
0
9
6
3
0
Fig. 7.14 Time course of P/R ratio in Alachlor-added microcosm N-system. (a) Control. (b)
0.1 mg/L. (c) 1 mg/L. (d) 4 mg/L
92
K. Murakami et al.