2,5-di-tert-butyl-p-benzoquinone

Endpoint summary

Description of key information

The ready biodegradability of 2,5 -di tertiary butyl 1,4 -benzoquinone (Yapox 2255) was tested using the CO2 Evolution Test. The test item was added to two vessels at the concentration of 60 mg/L of mineral medium (equivalent to 15.3 mg of Total Organic Carbon/L). Two control treatments containing only the medium only the inoculum, one reference item treatment and one toxicity control treatment containing the test item and the reference item were also tested. All the treatments were added with equal volume of inoculum which was collected from the secondary effluent treatment plant receiving predominantly domestic sewage.

Treatment mixtures were aerated for 29 days with carbon dioxide (CO2) free air. The CO2 released was trapped in a series of bottles containing barium hydroxide, which were connected to the outlet of each vessel. The residual barium hydroxide was measured on Days 2, 4, 7, 9, 12, 15, 17, 21, 25 and 29 after the initiation of the test.

The mean per cent degradation of test item was 104.44% at the end of the test while, the percent degradation of reference item was 123.02% and the toxicity control was 123.46% at the end of the test. It was observed that the mean degradation of test item reached 18.35% on Day 7 and further reached 55.76% on Day 17; and 66.18% on Day 21. Therefore, the degradation of test itme, 2,5 -di tertiary butyl 1,4 -benzoquinone (YAPOX 2255) reached less than 60% pass level in 10 day window period after reaching 10% of ThCO2 production and within the 28 -d period of the test.

The test fulfilled the validity criteria.

Based on the results, it was concluded that the test item is biodegradable as 104.44% mean degradation was achieved at the end of test. Since, the test item degradation reached less than 60% pass level in 10 day window period after reaching 10% of ThCO2 production, the test item is not considered to be readily biodegradable.