glaucoma disappeared within 2 days of the addition of complexed soap concentrations of up to 50 mg/L, but slowly recovered in the 4 days after the addition of
complexed soap and maintained a density of 1.2 Â 10
2 N/mL. With the addition of
200 mg/L of complexed soap, Cyclidium glaucoma disappeared from the system. It
seems that the recovery of Cyclidium glaucoma was due to the degradation of
complexed soap by bacteria. The population density of Tolypothrix sp. slowly
decreased to approximately 3.0 Â 10
1 cm/mL with 15 days after the addition of
complexed soap concentrations of up to 50 mg/L. The reason for the slow decrease
in the population of Tolypothrix sp. was considered to be light inhibition by soap
scum. The populations of Lecane sp. and Philodina erythrophthalma also slowly
recovered at complexed soap concentrations of up to 50 mg/L, ranging from
3.0 Â 10
1 N/mL to 8.9 Â 10
1 N/mL. The reason for the slow recoveries of Lecane
sp. and Philodina erythrophthalma is considered to be their predation upon bacteria,
which increased in abundance due to the organic nature of complexed soap. With the
addition of 200 mg/L of complexed soap, the population of Aeolosoma hemprichi
slowly decreased and finally disappeared from the system. Only Chlorella sp. was
independent of complexed soap at all concentrations. It follows from these results
that the population of microorganisms in the system was not affected by complexed
soap concentrations below 30 mg/L. As a result, it can be estimated that the
m-NOEC of complexed soap is less than 30 mg/L.
7.2 Germicides
Germicides (antiseptics) are antimicrobial substances, and they are applied to living
tissues/skin to reduce the possibility of infection, sepsis, or putrefaction. Blast
disease has been known as one of the serious blights on rice in Japan, and a
preventative method of sterilizing seed rice with formalin was developed in the
1930s. Organomercuric agents were used widely after World War II, but due to
another type of organic mercury-causing Minamata disease, of which the risk was
noted in the 1960s, organomercuric agents were prohibited from use. For treating
rice blast disease, blasticidin and kasugamycin were discovered and developed for
agricultural use. Furthermore, some effective chemical agents for blast disease, such
as dithiocarbamate in the 1960s and azole and benzimidazole in the 1970s, were
developed. New chemical agents, including quinone outside inhibitors (QoI), have
even been developed recently.
7.2.1 2,3,4,6-Tetrachlorophenol
2,3,4,6-Tetrachlorophenol (TCP) is used as an insecticide, sterilizer, wood preserver,
and formicide (ant-specific insecticide). The organism that is the most susceptible to
its effects is the water flea, and its ECOSAR class is that of phenols. The amount of
7 Example Assessments of the Microcosm N-System
79
complexed soap and maintained a density of 1.2 Â 10
2 N/mL. With the addition of
200 mg/L of complexed soap, Cyclidium glaucoma disappeared from the system. It
seems that the recovery of Cyclidium glaucoma was due to the degradation of
complexed soap by bacteria. The population density of Tolypothrix sp. slowly
decreased to approximately 3.0 Â 10
1 cm/mL with 15 days after the addition of
complexed soap concentrations of up to 50 mg/L. The reason for the slow decrease
in the population of Tolypothrix sp. was considered to be light inhibition by soap
scum. The populations of Lecane sp. and Philodina erythrophthalma also slowly
recovered at complexed soap concentrations of up to 50 mg/L, ranging from
3.0 Â 10
1 N/mL to 8.9 Â 10
1 N/mL. The reason for the slow recoveries of Lecane
sp. and Philodina erythrophthalma is considered to be their predation upon bacteria,
which increased in abundance due to the organic nature of complexed soap. With the
addition of 200 mg/L of complexed soap, the population of Aeolosoma hemprichi
slowly decreased and finally disappeared from the system. Only Chlorella sp. was
independent of complexed soap at all concentrations. It follows from these results
that the population of microorganisms in the system was not affected by complexed
soap concentrations below 30 mg/L. As a result, it can be estimated that the
m-NOEC of complexed soap is less than 30 mg/L.
7.2 Germicides
Germicides (antiseptics) are antimicrobial substances, and they are applied to living
tissues/skin to reduce the possibility of infection, sepsis, or putrefaction. Blast
disease has been known as one of the serious blights on rice in Japan, and a
preventative method of sterilizing seed rice with formalin was developed in the
1930s. Organomercuric agents were used widely after World War II, but due to
another type of organic mercury-causing Minamata disease, of which the risk was
noted in the 1960s, organomercuric agents were prohibited from use. For treating
rice blast disease, blasticidin and kasugamycin were discovered and developed for
agricultural use. Furthermore, some effective chemical agents for blast disease, such
as dithiocarbamate in the 1960s and azole and benzimidazole in the 1970s, were
developed. New chemical agents, including quinone outside inhibitors (QoI), have
even been developed recently.
7.2.1 2,3,4,6-Tetrachlorophenol
2,3,4,6-Tetrachlorophenol (TCP) is used as an insecticide, sterilizer, wood preserver,
and formicide (ant-specific insecticide). The organism that is the most susceptible to
its effects is the water flea, and its ECOSAR class is that of phenols. The amount of
7 Example Assessments of the Microcosm N-System
79