Comparison of biodegradation performance of OECD test guideline 301C with that of other ready biodegradability tests

Abstract

The Organisation for Economic Co-operatoin and development (OECD) Guidelines for the Testing of Chemicals list 7 types of tests for determining the ready biodegradability of chemical compounds (301A-F and 310). The present study compares the biodegradation performance of test guideline 301C, which is applied in Japan's Chemical Substances Control Law, with the performance of the other 6 ready biodegradability tests (RBTs) listed in the guidelines. Test guideline 301C specifies use of activated sludge precultured with synthetic sewage containing glucose and peptone (301C sludge) as a test inoculum; in the other RBTs, however, activated sludge from wastewater treatment plants (WWTP sludge) is frequently employed. Analysis based on percentage of biodegradation and pass levels revealed that the biodegradation intensity of test guideline 301C is relatively weak compared with the intensities of RBTs using WWTP sludge, and the following chemical compounds are probably not biodegraded under test guideline 301C conditions: phosphorus compounds; secondary, tertiary, and quaternary amines; and branched quaternary carbon compounds. The relatively weak biodegradation intensity of test guideline 301C may be related to the markedly different activities of the 301C and WWTP sludges. These findings will be valuable for evaluating RBT data in relation to Japan's Chemical Substances Control Law.

Biodegradation tests of mercaptocarboxylic acids, their esters, related divalent sulfur compounds and mercaptans

“…Though CBT is meant to be the most stringent test, in some instances, degradation in CBT was higher than in MRT. Such a phenomenon has been known for many years, and recent comparisons between 301C and 301X test results based on a large experimental basis revealed that for some compounds, 301C was more efficient, for others, 301X for each X from {A, B, D, E, F} (Kayashima et al 2014 ).…”

Investigation of OECD 301F ready biodegradability test to evaluate chemical fate in a realistic environment

“…The OECD 301C tests produce very conservative results that are not comparable to those in real environmental conditions 39) from the viewpoints of (1) the biodegradation activity of microorganisms, (2) the concentration or dispersibility of test chemicals, and (3) the kinds and numbers of microorganisms. In order to develop suitable test methods for properly evaluating the biodegradability of chemicals in a realistic environment, we first compared the biodegradability of the standard activated sludge used in the 301C tests with that of the activated sludge without any cultivation.…”

Effect of test concentration in the ready biodegradability test for chemical substances: Improvement of OECD test guideline 301C

“…Kayashima et al have suggested 32 chemical substances that are unlikely to be readily biodegradable in test guideline 301C but are readily biodegradable in other ready biodegradability tests. In the present study, we retrieved the microbial toxicity test data for these substances from the European Chemicals Agency database and IUCLID CD‐ROM .…”

“…Recent studies have reported that the diversity of bacteria is reduced by pretreatment of activated sludge in ready biodegradability tests (not limited to test guideline 301C) . Furthermore, Kayashima et al compared biodegradability results between test guideline 301C and other ready biodegradability tests and found that the test results were variable and depended on the type of activated sludge used (test guideline 301C sludge and sewage treatment plant sludge). Another problem is related to test concentration.…”