2.5 mg/L of cafenstrole. With the addition of 5.0 mg/L of cafenstrole, Aeolosoma
hemprichi disappeared within 2 days after addition, and both Lecane sp. and
Cyclidium glaucoma disappeared from the system on the 7th day following chemical
addition. In this way, predatory microanimals that contribute to the material circulation and energy flow in the microcosm were deemed susceptible to cafenstrole.
7.4 Pesticides
Pesticide has been widely used and it improved crop yields dramatically, and our life
has become rich. On the other hand, pesticide is recognized that it influences lives
including humans very seriously such as defoliant which has been sprayed in the
Vietnam War. Biological toxicity of pesticide is regulated by various bioassay tests,
but its ecosystem toxicity is not enough cleared.
7.4.1 Chlorpyrifos
Dursban 4E, an emulsification pesticide, was prepared as Chlorpyrifos. This is
because Leeuwangh et al. (1994) and Daam and van den Brink (2007) used Dursban
4E, which is an emulsification pesticide product as Chlorpyrifos, Daam et al. (2008)
used Dursban 40EC, and López-Mancisidor et al. (2008a, b) used Chas 48EC, an
emulsification pesticide product, in their mesocosm experiments. Chlorpyrifos was
added at the start of microcosm cultivation, and the microcosm test was conducted
with concentrations of 125, 250, 500, and 1000 μg/L, with the common ratio set to 2.
At any concentration loaded, the P/R ratio was around 1, but the production and
respiration amounts were significantly lower at a Chlorpyrifos loading of 1000 μg/L
(Fig. 7.15). The NOEC of Chlorpyrifos was estimated to be 500 μg/L. Even if an
organism perished with the addition of 10,000 μg/L of Chlorpyrifos, there was no
observed impact on the production or respiration at all. Chlorpyrifos is a neurotoxin
and reduces the activity of animals and causes a drop in the respiration amount per
individual. It was thought that the amount of respiration in the entire microanimal
population in the microcosm decreased because the population decreased with a rise
in death rates. However, it was thought that no influence appeared in the amounts of
production and respiration when chlorpyrifos was added during the stationary period
because the respiration amount had been supplemented by decomposition of the
microanimals and the increase in the abundance of many organisms with the
decrease in predation. On the other hand, the community structure of the system
changed when chlorpyrifos was added when the culture began because Chlorpyrifos
drove the succession of microanimals in the microcosm, and it is thought that, as a
result, an influence on production and respiration appeared.
The NOEC of Chlorpyrifos in the mesocosm test was reported as 0.06 μg/L.
However, NOEC of the microcosm test was 500 μg/L, which is much higher.
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K. Murakami et al.
hemprichi disappeared within 2 days after addition, and both Lecane sp. and
Cyclidium glaucoma disappeared from the system on the 7th day following chemical
addition. In this way, predatory microanimals that contribute to the material circulation and energy flow in the microcosm were deemed susceptible to cafenstrole.
7.4 Pesticides
Pesticide has been widely used and it improved crop yields dramatically, and our life
has become rich. On the other hand, pesticide is recognized that it influences lives
including humans very seriously such as defoliant which has been sprayed in the
Vietnam War. Biological toxicity of pesticide is regulated by various bioassay tests,
but its ecosystem toxicity is not enough cleared.
7.4.1 Chlorpyrifos
Dursban 4E, an emulsification pesticide, was prepared as Chlorpyrifos. This is
because Leeuwangh et al. (1994) and Daam and van den Brink (2007) used Dursban
4E, which is an emulsification pesticide product as Chlorpyrifos, Daam et al. (2008)
used Dursban 40EC, and López-Mancisidor et al. (2008a, b) used Chas 48EC, an
emulsification pesticide product, in their mesocosm experiments. Chlorpyrifos was
added at the start of microcosm cultivation, and the microcosm test was conducted
with concentrations of 125, 250, 500, and 1000 μg/L, with the common ratio set to 2.
At any concentration loaded, the P/R ratio was around 1, but the production and
respiration amounts were significantly lower at a Chlorpyrifos loading of 1000 μg/L
(Fig. 7.15). The NOEC of Chlorpyrifos was estimated to be 500 μg/L. Even if an
organism perished with the addition of 10,000 μg/L of Chlorpyrifos, there was no
observed impact on the production or respiration at all. Chlorpyrifos is a neurotoxin
and reduces the activity of animals and causes a drop in the respiration amount per
individual. It was thought that the amount of respiration in the entire microanimal
population in the microcosm decreased because the population decreased with a rise
in death rates. However, it was thought that no influence appeared in the amounts of
production and respiration when chlorpyrifos was added during the stationary period
because the respiration amount had been supplemented by decomposition of the
microanimals and the increase in the abundance of many organisms with the
decrease in predation. On the other hand, the community structure of the system
changed when chlorpyrifos was added when the culture began because Chlorpyrifos
drove the succession of microanimals in the microcosm, and it is thought that, as a
result, an influence on production and respiration appeared.
The NOEC of Chlorpyrifos in the mesocosm test was reported as 0.06 μg/L.
However, NOEC of the microcosm test was 500 μg/L, which is much higher.
94
K. Murakami et al.