Oxacycloheptadec-10-en-2-one

Endpoint summary

Description of key information

Biodegradation in water

Biodegradation study of the test chemical was carried out with a total duration period of 28 days (Experimental study report, 2011).The test chemical was considered to be 100% pure.Specific density of the test substance is 0.9520 (20/4ᵒC). Identity of test substance was confirmed by comparing the infrared absorption spectrum of the sample provided by the sponsor with that of the sample tested in the test facility. Activated sludge was used as a test inoculum obtained fromsludge (surface water containing surface soils from rivers, lakes and marshes and inland seas and returned sludge from sewage treatment plants) was collected at 10 sites in Japan. The activated sludge was incubated insynthetic sewage (purified water containing glucose, peptone and potassium dihydrogen phosphate at a pH adjusted to7.0±1.0) for 19 hrs. Conc. of inoculum used for the study is 30 mg/l and initial test substance conc. used for the study was 100 mg/l. The test substance wasstored at room temperature in dark place.Aniline was used as a reference substance for the study.The suspended solid conc. was measured for determination of the activated sludge added. Measurement method used was according to JIS K0102-2010 14. After measurement, the suspended solid concentration of the activated sludge was determined to be 2660 mg/L.Sufficiently high activity of the activated sludge was confirmed by using aniline.Change in the BOD of the test solution was monitored continuously with a closed-system oxygen consumption measuring apparatus during the culture period. The temperature of the closed-system oxygen consumption measuring apparatus in the constant temperature bath was recorded every day.After the culture period, the test substance in the test solution was analyzed. From the preliminary test, it was found that the test substance is not soluble in the test solution. The dissolved organic carbon (DOC) in the test solutions of the (sludge + test substance) systems and the sludge blank system was analyzed for confirmation of whether there are water-soluble products generated. Analytical methods involve thepretreatment of the test solution of the (water + test substance) system was done to prepare a gas chromatography sample (GC) sample for analysis of the test substance. Pretreatment was also done of test solution of the (sludge + test substance) system and a sludge blank system to prepare total organic carbon analysis (TOC) samples for analysis of DOC (Dissolved Organic Carbon) and gas chromatography (GC) samples for analysis of the test substance. Quantification of the test substance was done by gas chromatography (GC).The average recovery rate of each test solution was 90% or more and the variability was within 5%.The test is carried at a temperature of25±1°C with a duration period of 28 days.Reference substance aniline undergoes 77% degradation after 28 days. The average percentage degradation of test chemical was determined to be 94 and 100% by oxygen consumption and GC parameter in 28 days. The amount of DOC detected was less than 1 mgC, indicating that no water-soluble products were formed. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

Biodegradation in water and sediment

Primary biodegradation in surface water from a Danish stream was determined by compound specified analysis. The study was performed following the modified OECD Guideline 309 (Aerobic Mineralisation in Surface Water - Simulation Biodegradation Test) under aerobic conditions. Natural water (stream of good ecological quality and without known point sources close to sampling point) sampled from Gudenåen (DK) 16th of June 2020. WGS84: 56°6'23.2"N 9°43'17.4"E at a dept of 5 -20 cm below surface was used as a surface water. The water was quite clear with a slight light brown hint. Total suspended solids was 2.0 mg/L, total dissolved solids was 210 mg/L. No pre-treatment was done of the natural water. Water kept at 20 ± 1.5°C during transport to lab (4 hours), then stored at 12°C until test setup within 30 hours of sampling. The temperature and pH at the time of collection of the sample was 20.0°C and 6.5 pH. Biomass i.e., plate count at 24 and 72 hr was 36 CFU/ml and 1281 CFU/ml, respectively. Water was not filtered. Dissolved non-volatile organic carbon (NVOC) was measured instead of DOC/TOC and was 4.4 mg/L. Study was performed using 20 mL amber headspace closed vials. A large no. of biotic test systems (15 -18 replicates) consisting of 14.5 ml surface water and 0.5 ml stock solution was prepared test vials. Stock solution was prepared in water by equilibrium partioning from a pre-loaded silicone rod (passive dosing). This method for preparing stock solutions avoids the need for solvents for spiking. A similar number of abiotic control test systems were prepared using 14.5 ml MilliQ water and 0.5 ml stock solution. Blanks were prepared with 15 ml MilliQ water. Aerobic conditions created by using aerobic natural water (initial oxygen content 9.0 mg/L at 20 °C)  and incubating using a headspace of 5 mL with a low test substance concentration of 0.002 mg/l. Test was conducted at a temperature of 12°C and pH of 6.5 under continuous darkness with conductivity of 334 µS/cm while rolling. pH of the test medium (natural water) was not adjusted. No aeration was provided during the study. Suspended solid concentrations uded in the study was 2.0 mg/l. At 5 -6 time-points, 3 biotic and 3 abiotic test systems were sacrificed for analysis (day 2, 6, 9, 14 and 21). Tests systems were put directly on the autosampler of the GCMS without storage. Blank test systems were prepared and incubated with biotic and abiotic test systems and analyzed at each time-point (signal well below the 3% dilution of initial test concentration). Analysis was carried out using direct immersion solid phase microextraction coupled to GC-MS. Carryover was < 1.0% and since test systems were analyzed alternating biotic and abiotic test systems this constitutes the detection limit in this test. Biodegradation was then evaluated by the ratio between peak areas in the biotic and abiotic test systems. Triplicate ratios of biotic/abiotic test system peak areas were calculated for each time point and used in Graph-pad Prism 8.4.3 to fit the first order degradation model with lag phase. The (pseudo-)first order (= half-life) (DT50) of the test chemical was evaluated to be 0.6 days at 12°C. Primary percentage degradation of the test chemical was determined to be >99% at 7 days. Thus, on the basis of results, test chemical was considered to be not persistent in surface water.

In accordance with column 2 of Annex IX of the REACH regulation, testing for this end point is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable in water.

 

Biodegradation in soil

In accordance with column 2 of Annex IX of the REACH regulation, testing for this end point is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable in water.

Additional information

Biodegradation in water

Various experimental key and supporting studies of the test chemical were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from study report (2011),biodegradation study of the test chemical was carried out with a total duration period of 28 days. The test chemical was considered to be 100% pure. Specific density of the test substance is 0.9520 (20/4ᵒC). Identity of test substance was confirmed by comparing the infrared absorption spectrum of the sample provided by the sponsor with that of the sample tested in the test facility. Activated sludge was used as a test inoculum obtained from sludge (surface water containing surface soils from rivers, lakes and marshes and inland seas and returned sludge from sewage treatment plants) was collected at 10 sites in Japan. The activated sludge was incubated in synthetic sewage (purified water containing glucose, peptone and potassium dihydrogen phosphate at a pH adjusted to7.0±1.0) for 19 hrs. Conc. of inoculum used for the study is 30 mg/l and initial test substance conc. used for the study was 100 mg/l. The test substance was stored at room temperature in dark place. Aniline was used as a reference substance for the study. The suspended solid conc. was measured for determination of the activated sludge added. Measurement method used was according to JIS K0102-2010 14. After measurement, the suspended solid concentration of the activated sludge was determined to be 2660 mg/L. Sufficiently high activity of the activated sludge was confirmed by using aniline. Change in the BOD of the test solution was monitored continuously with a closed-system oxygen consumption measuring apparatus during the culture period. The temperature of the closed-system oxygen consumption measuring apparatus in the constant temperature bath was recorded every day. After the culture period, the test substance in the test solution was analyzed. From the preliminary test, it was found that the test substance is not soluble in the test solution. The dissolved organic carbon (DOC) in the test solutions of the (sludge + test substance) systems and the sludge blank system was analyzed for confirmation of whether there are water-soluble products generated. Analytical methods involve the pretreatment of the test solution of the (water + test substance) system was done to prepare a gas chromatography sample (GC) sample for analysis of the test substance. Pretreatment was also done of test solution of the (sludge + test substance) system and a sludge blank system to prepare total organic carbon analysis (TOC) samples for analysis of DOC (Dissolved Organic Carbon) and gas chromatography (GC) samples for analysis of the test substance. Quantification of the test substance was done by gas chromatography (GC).The average recovery rate of each test solution was 90% or more and the variability was within 5%.The test is carried at a temperature of 25±1°C with a duration period of 28 days. Reference substance aniline undergoes 77% degradation after 28 days. The average percentage degradation of test chemical was determined to be 94 and 100% by oxygen consumption and GC parameter in 28 days. The amount of DOC detected was less than 1 mgC, indicating that no water-soluble products were formed. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

 

For the test chemical, 28-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical (Experimental study report, 2017). The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used for this study. 1 polyseed capsule were added in 500 ml D.I water and then stirred for 1 hour for proper mixing and functioning of inoculum. This gave the bacterial count as 10E7 to 10E8 CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism. The concentration of test and reference chemical (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test chemical and reference chemical. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 73.49% at 20 ± 1°C. Degradation of Sodium Benzoate exceeds 43.37% on 7th days & 58.43% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid.The BOD28 value of test chemical was observed to be 1.17 mgO2/mg. ThOD was calculated as 2.78 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 42.08%. Based on the results, the test item, under the test conditions, was considered to be ultimate inherently biodegradable in nature.

 

In a supporting study from peer reviewed journal (Daniel Salvito et. al., 2011),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of test chemical. The study was performed according to OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test).The percentage degradation of test chemical was determined to be 84% by O2 consumption parameter in 28 days. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

 

On the basis of above overall results for test chemical, it can be concluded that the test chemical is considered to be readily biodegradable in water.

Biodegradation in water and sediment

Primary biodegradation in surface water from a Danish stream was determined by compound specified analysis. The study was performed following the modified OECD Guideline 309 (Aerobic Mineralisation in Surface Water - Simulation Biodegradation Test) under aerobic conditions. Natural water (stream of good ecological quality and without known point sources close to sampling point) sampled from Gudenåen (DK) 16th of June 2020. WGS84: 56°6'23.2"N 9°43'17.4"E at a dept of 5 -20 cm below surface was used as a surface water. The water was quite clear with a slight light brown hint. Total suspended solids was 2.0 mg/L, total dissolved solids was 210 mg/L. No pre-treatment was done of the natural water. Water kept at 20 ± 1.5°C during transport to lab (4 hours), then stored at 12°C until test setup within 30 hours of sampling. The temperature and pH at the time of collection of the sample was 20.0°C and 6.5 pH. Biomass i.e., plate count at 24 and 72 hr was 36 CFU/ml and 1281 CFU/ml, respectively. Water was not filtered. Dissolved non-volatile organic carbon (NVOC) was measured instead of DOC/TOC and was 4.4 mg/L. Study was performed using 20 mL amber headspace closed vials. A large no. of biotic test systems (15 -18 replicates) consisting of 14.5 ml surface water and 0.5 ml stock solution was prepared test vials. Stock solution was prepared in water by equilibrium partioning from a pre-loaded silicone rod (passive dosing). This method for preparing stock solutions avoids the need for solvents for spiking. A similar number of abiotic control test systems were prepared using 14.5 ml MilliQ water and 0.5 ml stock solution. Blanks were prepared with 15 ml MilliQ water. Aerobic conditions created by using aerobic natural water (initial oxygen content 9.0 mg/L at 20 °C)  and incubating using a headspace of 5 mL with a low test substance concentration of 0.002 mg/l. Test was conducted at a temperature of 12°C and pH of 6.5 under continuous darkness with conductivity of 334 µS/cm while rolling. pH of the test medium (natural water) was not adjusted. No aeration was provided during the study. Suspended solid concentrations uded in the study was 2.0 mg/l. At 5 -6 time-points, 3 biotic and 3 abiotic test systems were sacrificed for analysis (day 2, 6, 9, 14 and 21). Tests systems were put directly on the autosampler of the GCMS without storage. Blank test systems were prepared and incubated with biotic and abiotic test systems and analyzed at each time-point (signal well below the 3% dilution of initial test concentration). Analysis was carried out using direct immersion solid phase microextraction coupled to GC-MS. Carryover was < 1.0% and since test systems were analyzed alternating biotic and abiotic test systems this constitutes the detection limit in this test. Biodegradation was then evaluated by the ratio between peak areas in the biotic and abiotic test systems. Triplicate ratios of biotic/abiotic test system peak areas were calculated for each time point and used in Graph-pad Prism 8.4.3 to fit the first order degradation model with lag phase. The (pseudo-)first order (= half-life) (DT50) of the test chemical was evaluated to be 0.6 days at 12°C. Primary percentage degradation of the test chemical was determined to be >99% at 7 days. Thus, on the basis of results, test chemical was considered to be not persistent in surface water.

In accordance with column 2 of Annex IX of the REACH regulation, testing for this end point is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable in water.

 

Biodegradation in soil

In accordance with column 2 of Annex IX of the REACH regulation, testing for this end point is scientifically not necessary and does not need to be conducted since the test chemical is readily biodegradable in water.