decrease in and recovery of Tolypothrix sp. at the 8 mg/L SDS load, and a decrease in
the abundance of Tolypothrix sp., a decrease and recovery of Cyclidium glaucoma, and
an increase in the abundance of Lecane sp. at the 16 mg/L SDS load were observed.
The influence of SDS was evaluated using the functional parameter (i.e., the P/R
ratio) by statistically comparing the production and respiration volumes 14 days after
the addition of the SDS load. Of the system after SDS was understood for life in a
system as an example of a more complimentary analysis, and the toxicity became
extinct, there was no difference between the addition and control systems, and the
m-NOEC for SDS was estimated as 4 mg/L (Figs. 7.3 and 7.4). The respiration volume
in the microcosm deviated from that of the control system after the 3rd day of SDS
addition and was later restored in the 8 mg/L SDS load system. A change in the
respiration volume was recognized on the next day following the addition of SDS and
recovered afterward. However, a difference in the production volume between the
control system and the experimental microcosm was produced at the end for the
evaluation period, with the production volume being adversely affected in the
16 mg/L SDS load system.
A tendency toward an increase in the abundance of biota was observed, but it was
able to judge it from 4 mg/L of SDS addition system (the m-NOEC) because there
were no changes in the ecological balance of production and respiration. It was found
that there was a negative influence on the population at an SDS concentration of 8 mg/
L, but the density recovered to the control system level, whereas it could not recover in
the 16 mg/L SDS load system. These results were similar to the predicted values from
the mesocosm test of SDS according to the high correlation between the mean of the
natural ecosystem (mesocosm test) (mean NOEC) and the m-NOEC. From these
results, it can be estimated that the m-NOEC of SDS is 4 mg/L.
7.1.4 Trimethyldodecyl Ammonium Chloride (TMAC)
In the addition system with 10 mg/L of trimethyldodecyl ammonium chloride
(TMAC), an increase in the abundance of the cyanophycean, Tolypothrix sp., and
the ciliate, Cyclidium glaucoma, was observed, and the reverse was noted for the
populations of the rotifer, Philodina erythrophthalma, and the oligochaete,
Aeolosoma hemprichi. With the increase in the abundance of Tolypothrix sp. in
particular, the color of the microcosm changed from green to brown. This is the
reverse of the pattern reported for the decrease in the abundance of Tolypothrix
sp. observed in the 16 mg/L SDS addition system.
A statistically significant difference between the addition and control systems was
not recognized, and the m-NOEC was estimated as equal to 1 mg/L of TMAC
(Fig. 7.5). There was a significant difference at the TMAC concentration of 10 mg/L.
An impact assessment was performed by concentration setting of common ratio 2 in
TMAC to calculate the m-NOEC. As significant differences emerged at the 0.2 mg/L
TMAC load, the amount of production and respiration changed remarkably as the
7 Example Assessments of the Microcosm N-System
75
the abundance of Tolypothrix sp., a decrease and recovery of Cyclidium glaucoma, and
an increase in the abundance of Lecane sp. at the 16 mg/L SDS load were observed.
The influence of SDS was evaluated using the functional parameter (i.e., the P/R
ratio) by statistically comparing the production and respiration volumes 14 days after
the addition of the SDS load. Of the system after SDS was understood for life in a
system as an example of a more complimentary analysis, and the toxicity became
extinct, there was no difference between the addition and control systems, and the
m-NOEC for SDS was estimated as 4 mg/L (Figs. 7.3 and 7.4). The respiration volume
in the microcosm deviated from that of the control system after the 3rd day of SDS
addition and was later restored in the 8 mg/L SDS load system. A change in the
respiration volume was recognized on the next day following the addition of SDS and
recovered afterward. However, a difference in the production volume between the
control system and the experimental microcosm was produced at the end for the
evaluation period, with the production volume being adversely affected in the
16 mg/L SDS load system.
A tendency toward an increase in the abundance of biota was observed, but it was
able to judge it from 4 mg/L of SDS addition system (the m-NOEC) because there
were no changes in the ecological balance of production and respiration. It was found
that there was a negative influence on the population at an SDS concentration of 8 mg/
L, but the density recovered to the control system level, whereas it could not recover in
the 16 mg/L SDS load system. These results were similar to the predicted values from
the mesocosm test of SDS according to the high correlation between the mean of the
natural ecosystem (mesocosm test) (mean NOEC) and the m-NOEC. From these
results, it can be estimated that the m-NOEC of SDS is 4 mg/L.
7.1.4 Trimethyldodecyl Ammonium Chloride (TMAC)
In the addition system with 10 mg/L of trimethyldodecyl ammonium chloride
(TMAC), an increase in the abundance of the cyanophycean, Tolypothrix sp., and
the ciliate, Cyclidium glaucoma, was observed, and the reverse was noted for the
populations of the rotifer, Philodina erythrophthalma, and the oligochaete,
Aeolosoma hemprichi. With the increase in the abundance of Tolypothrix sp. in
particular, the color of the microcosm changed from green to brown. This is the
reverse of the pattern reported for the decrease in the abundance of Tolypothrix
sp. observed in the 16 mg/L SDS addition system.
A statistically significant difference between the addition and control systems was
not recognized, and the m-NOEC was estimated as equal to 1 mg/L of TMAC
(Fig. 7.5). There was a significant difference at the TMAC concentration of 10 mg/L.
An impact assessment was performed by concentration setting of common ratio 2 in
TMAC to calculate the m-NOEC. As significant differences emerged at the 0.2 mg/L
TMAC load, the amount of production and respiration changed remarkably as the
7 Example Assessments of the Microcosm N-System
75