MITI degradation test

OECD 30IC (Modified MITI test - Ready degradability test)... 

Training (acyclic) n = 47 Overall 85% correct (92% for easily degrad.) (79% for non-easily degrad.) Validation (acylic) n = 240 (MITI test) Overall 89% correct (97% for easily degrad.) (61% for non-easily... 

Training (monocyclic arom.) n = 60 Overall 85% correct Validation (monocyclic arom.) n = 57 (MITI test) Overall 84% correct (87% for easily degrad.) (83% for non-easily degrad.)... 

Degner et al. (1993) used the model with a dataset of 774 chemicals with MITI test data and found 80.7% correct estimates for easily degradable/non-degradable classifications. They were unable to classify 18 chemicals due to a lack of indicator variables. 

A9.4.3.3.1 Sometimes degradation is reported for tests terminated before the 28 day period specified in the standards (e.g, the MITI, 1992). These data are of eourse directly applicable when a degradation greater than or equal to the pass level is obtained. When a lower degradation level is reached, the results need to be interpreted with caution. One possibility is that the duration of the test was too short and that the chemical... 

Solubility In natural systems, microbes produce emulsifiers that render insoluble matter accessible for degradation. All of the systems currently available were developed for water-soluble materials and, although the use of artificial solvents or emulsifiers is permitted in the test guidelines, their use is restricted to 100 ppm in tests related to ecotoxicology and product classification, and neither is permitted in the MITI test. This approach is, in most cases, ineffective with oils since much higher concentrations are needed to achieve solubility, which renders the conditions of the test doubtful. 

OECD Guidelines for the Testing of Chemicals, Method 301C Degradation and Accumulation Modified MITI Test (I), Organisation for Economic Co-operation and Development Paris, France, 2003. 

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