Recommendation
A book recommended for all environmental researchers
It is well known that more than 100,000 types of chemical substances are used by
humans, but only a small number of them are regulated, and such regulations vary
from country to country. Approximately 50 of them are being used and regulated in
Japan. There are physicochemical methods and biological methods for assessing the
environmental impacts of chemical substances, but most evaluations are performed
using physicochemical methods. Furthermore, physicochemical techniques are not
useful for unknown substances and cannot evaluate compounded effects or past
effects. On the other hand, biological methods, called biological response tests (i.e.,
bioassays), present a way to evaluate such impacts by relying on real organisms.
Biological response tests on wastewater are often referred to as Whole Effluent
Toxicity (WET) tests, and standard test methods have been established in Europe,
the United States (US), and Japan, and they may be used in some areas for regulating
wastewater.
Because death is the strongest response that organisms may have to chemical
substances, chemical concentrations are often shown as half-lethal concentrations
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