2,2,4,4-tetramethylcyclobutane-1,3-diol, mixed isomers

Endpoint summary

Additional information

A ready biodegradation study conducted according to OECD 301B (CO2 Evolution Test) was conducted on 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD). Under the conditions of the study the substance can not be considered as readily biodegradable. Degradation of the test substance was not observed until approximately day 22 of the study (lag phase). Approximately 22 days later (day 44) greater than 60% degradation had occurred. At test termination on day 49 the cumulative degradation reached 72.6%. Based upon the slope of cumulative degradation, degradation had not plateaued at test termination. A separate activated sludge respiration inhibition study indicated that the substance does not inhibit wastewater treatment microorganisms at concentrations up to 1000 mg/L, therefore it appears that bacterial inhibition was not a factor in the results of the biodegradation study. The observed lag phase and subsequent degradation suggests that microorganisms capable of metabolizing TMCD were present in a low numbers in the inoculum used in the study and required a period of time (lag phase) to increase their population to allow biodegradation to occur. Based upon the amount of CO2 evolved and the degree of degradation observed, it is clear that the substance will undergo ultimate degradation and would not be expected to be persistent in the environment. As the substance clearly demonstrates ultimate biodegradation in a screening test and has a low tendency to sorb to soils or sediments (log Koc < 1.25), testing is not proposed to investigate further the degradation of the substance and its degradation products in water, sediments or soils.