ISO 14593:1999

This International Standard specifies a method, by analysis of inorganic carbon, for the evaluation in an aqueous medium of the ultimate aerobic biodegradability of organic substances at a given concentration of microorganisms.

This International Standard is applicable to organic compounds which are:

a) water-soluble under the test conditions;

b) poorly water-soluble under the test conditions, in which case special measures may be necessary to achieve a good dispersion of the compound (see ISO 10634);

c) volatile; d) not inhibitory to the test microorganisms at the concentration chosen for the test.

In this test, biogenically produced inorganic carbon is measured in situ in the test vessels in such a manner that the rate measured nearly equals the rate of microbial production.

NOTE 1 The conditions described in this International Standard do not always correspond to the optimal conditions for allowing the maximum degree of biodegradation to occur. For alternative biodegradation methods see ISO 15462.

NOTE 2 With highly volatile substances, losses to the gaseous phase can be minimized by reducing the volume of the headspace. However, there should be sufficient oxygen in the test system to prevent biodegradation being oxygen-limited.

NOTE 3 The presence of an inhibitory effect can be determined as specified in 8.3, or by using any other method for determining the inhibitory effect of a substance on bacteria (see, for example, ISO 8192).