Reaction products of cyclohexanone with buta-1,3-diene and hydrogen peroxide and iron sulphate and methanol, hydrolysed, ammonium salts

Endpoint summary

Description of key information

Ready biodegradation

The ready biodegradability of UB20-LDB (50%) was assessed according to OECD Guideline 301B (Ready Biodegradability: CO2 Evolution Test), EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test) and EPA OPPTS 835.3110 (Ready Biodegradability).

 

The test item, at a concentration of 9.4 mg carbon/L, was exposed to activated sewage sludge micro-organisms with mineral medium in sealed culture vessels in the dark at temperatures between 21 to 24°C for 35 days. The study was extended from 28 days to 35 days to determine if greater than 60% biodegradation could occur. Due to technical necessity, ammonium salts of UB‑20 was supplied and presented to the test system as the test item UB20-LDB (50%) - a 50:50 solution of ammonium salts of UB-20 in ethylene glycol. For this reason, the test design included an additional solvent control containing ethylene glycol alone. The performance of the ammonium salts of UB‑20 was determined by correcting the CO₂ recovery from UB20-LDB (50%) by subtraction of the contemporary CO₂ yield in the solvent control. Biodegradation was assessed by the determination of CO2 produced. Control solutions with inoculum and the reference item, sodium benzoate, together with a toxicity control were used for validation purposes.

 

All validity criteria given in the OECD Test Guidelines were met and the study is considered reliable. The toxicity control attained 65% biodegradation after 14 days, 61% biodegradation after 28 days and 73% biodegradation after 35 days thereby confirming that the test item did not exhibit an inhibitory effect on the sewage treatment micro-organisms used in the test. The reference item (sodium benzoate) attained 89% biodegradation after 14 days with greater than 60% degradation being attained in a 10-day window, thus confirming the suitability of the inoculum and test conditions.

 

The biodegradation of the ammonium salts of UB‑20 determined by difference (as outlined above) attained 50% after 28 days and 66% biodegradation after 35 days. Since degradation did not reach the 60% threshold within 28 days, the ammonium salts of UB‑20 do not qualify for classification as readily biodegradable. However, exceedance of 60% biodegradation under the conditions of a ready biodegradability test following extension of the incubation to 35 days signifies that the ammonium salts of UB‑20 are not persistent (P) or very persistent (vP) according to EU definitions. The ammonium salts of UB-20 are considered to be inherently biodegradable according to the revised introduction to the OECD guidelines for the testing of Chemicals, Section 3.