This is because effects depend on internal concentrations, and that it takes time for the compound to penetrate the body of test organisms.

It is preferable to obtain test organisms from in-house culture units.

The test organisms are exposed for 48 hours under static conditions with five concentrations of the effluent.

Growth is defined as the dry weight per original number of test organisms when group weights are obtained.

Acclimation of test organisms (temperature mean and range) 11.

Many vitamins and minerals are vital for the correct function of cells in the test organism.

The health and sensitivity of test organisms is also assessed by reference toxicant testing.

Some species of test organisms can be obtained from commercial stock certified as "disease-free".

For this reason, it is recommended that only approximately 10% of the test organisms be exposed initially to the dilution water.

Many of these methods use the same test organism or are designed for the same exposure time.