A mixture of: 4-(2,2,3-trimethylcyclopent-3-en-1-yl)-1-methyl-2-oxabicyclo[2.2.2]octane; 1-(2,2,3-trimethylcyclopent-3-en-1-yl)-5-methyl-6-oxabicyclo[3.2.1]octane; spiro[cyclohex-3-en-1-yl-[(4,5,6,6a-tetrahydro-3,6',6',6'a-tetramethyl)-1,3'(3'aH)-[2H]cyclopenta[b]furan]; spiro[cyclohex-3-en-1-yl-[4,5,6,6a-tetrahydro-4,6',6',6'a-tetramethyl)-1,3'(3'aH)-[2H]cyclopenta[b]]furan]

Biodegradation in water and sediment: simulation tests

Description of key information

The PBT working group considered the substance potentially persistent (P) based on the study presented below (OECD TG 309)

The summary of the LR: In the water simulation test according to OECD TG 309 ca 40% of Cassiffix volatilised. In the surface water Cassiffix dissipated/degraded and showed T1/2 ranging from 2.9 - 13 days and 10 - 18 days for 20 µg/L and 100 µg/L, respectively. There was one key metabolite, called Cassiffix-Lactone and exceeding the 10% level (present at ca. 14%), which had a log Kow between 2.5 and 3. Based on these results Cassiffix is not persistent.

Key value for chemical safety assessment

Half-life in freshwater:

18 d

at the temperature of:

12 °C

Additional information

Cassiffix degradation in the OECD TG 309

Introduction: The biodegradation in surface water was measured in a water simulation test.

Method: An Aerobic Mineralisation in Surface water – Simulation Biodegradation Test performed according to OECD TG 309 and following GLP, the mineralisation, rate of degradation and dissipation of Cassiffix in surface water under aerobic conditions at 12°C was determined. 14C-labeled Cassiffix, consisting of four main constituents, was incubated under aerobic conditions in the laboratory in surface water (“pelagic test”) at 12 ± 2 °C in the dark for 59 days. The initial Cassiffix concentrations in the test system were 20 µg/L and 100 µg/L. Per test concentration ten flasks were prepared (including a sterile control). Additionally, two flasks were treated with benzoic acid as reference control. One untreated flask was used for monitoring pH and oxygen concentration. Oxygen concentration measurements indicated aerobic conditions in the water throughout the test. The results of the reference control (benzoic acid) showed that the test system was sufficiently viable but one replicate produces slightly lower CO2 values as captured in the NaOH traps. Sacrificial samples were taken on Day 1, 3, 7, 14, 28, 42, and 59. Volatiles were trapped by polyurethane foam (PUF), ethylene glycol monoethyl ether (EGME) and NaOH traps. The surface water was analysed by LSC directly. Concentrated extracts of surface water and PUF traps were analysed by LSC and LC. The metabolites formed were detected using liquid-chromatography-radio detection-mass spectrometry(LC-RAD-MS) and using a protonated ether bond. In addition, the log Kow of the test item constituents and its main metabolite were measured using HPLC. Several time zeros (dead times) were tested to find a realistic value.

Results: Under biotic conditions, Cassiffix dissipated and degraded into transformation products (of which one exceeded the 10% level), but not into significant amounts of CO2. Significant amounts of organic volatiles were detected in all test vessels with Cassiffix: 37.5 and 42% in the low and high concentration, respectively. Based on these results, it can be concluded that volatilization is the main route of dissipation. The captured radioactivity measurements in PUF extracts were not taken into account to determine kinetic parameters in surface water, as this amounts in the PUF traps is considered to have permanently dissipated from the relevant environmental compartment i.e. surface water. For the degradation of the remaining substance in surface water kinetic half-lives were modelled for each of the four constituents of Cassiffix. T1/2 ranged from 2.9 - 13 days and 10 - 18 days for 20 µg/L and 100 µg/L, respectively.

One metabolite was identified which exceeded the 10% level and was found at 14.9 and 13.4%, in the low and high concentration, respectively: it was the formation of a ketone next the ether bond resulting in a lactone and a reduction in the same ring resulting in a double bond.

The log Kow of the four constituents ranged in the order of 5.1 to 5.5 the log Kow of the Cassiffix-Lactone was estimated to be between 2.5 and 3 and are further presented in the section Physico-chemical properties, partition coefficient: IUCLID section 4.7. The log Kow of Cassiffix-Lactone is set to 3.

Conclusion: In the water simulation test according to OECD TG 309 ca 40% of Cassiffix volatilised. In the surface water Cassiffix dissipated/degraded and showed T1/2 ranged from 2.9 - 13 days and 10 - 18 days for 20 µg/L and 100 µg/L, respectively. There was one key metabolite, called Cassiffix-Lactone and exceeding the 10% level (present at ca. 14%), which had a log Kow between 2.5 and 3. Based on these results Cassiffix is not persistent.