Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Biodegradation in water

Biodegradation study was conducted for 38 days for evaluating the percentage biodegradability of test chemical (T. Wind, et. al; 2006). The study was performed according to ISO 11734 Water quality - Evaluation of the "ultimate" anaerobic biodegradability of organic compounds in digested sludge - Method by measurement of the biogas production guideline under aerobic conditions.Laboratory scale continuously fed activated sludge units according to the OECD Draft Test Guideline 303 A: Simulation Test—Aerobic Sewage Treatment: Activated Sludge Units was used as a test inoculum for the study.Test inoculum activated sludge was also isolated from a sewage treatment work that received predominantly (approx. 90%) domestic sewage.The activated sludge was aerated for 24 h, without feed, before use and had a total suspended-solids (TSS) content of 3.4 g/L.The sludge recycle pumps were adjusted to give a recycle ratio ofapprox.1.0, and this resulted in an initial mixed-liquor suspended-solids (MLSS) concentration ofapprox.5.5 g/L in the aeration vessels. The contents of the aeration vessels were vigorously aerated (1.2 L/min) to keep the sludge in suspension and maintain dissolved O2 levels >1 mg/L. Each of the Husmann test unit consisted of a 3.5-L cylindrical aeration vessel and a 2.5-L cylindrical clarifier/settler. The aeration vessels were fitted with 0.4-L precontactor zones in order to reduce the possibility of sludge ‘‘bulking’’ (poor settling), a factor present when using the OECD synthetic sewage feed. The precontactor consisted of a 48- mm-diameter vertical tube positioned centrally in the aeration vessel and fitted with its own central sintered-glass sparger; the feed and recycled-sludge input streams were supplied to its top and passed into the main aeration vessel via holes at its bottom. The annulus of the aeration vessel was fitted with two further spargers positioned opposite each other to provide efficient aeration and mixing of the activated sludge. Each clarifier/settler was provided with a perforated horizontal disk that was normally positioned about 50mm below the clarified effluent outflow to act as a flocculation filter and retain any floating sludge. Sludge from the settler section was returned to the aeration vessel precontact zone using a peristaltic pump. The test run consisted of a 19-day sludge acclimation or ‘‘run-in’’ phase, followed by a further 19-day ‘‘evaluation’’ phase. At the start of the test (day 0), both test units were filled with 6L of activated sludge taken from a sewage treatment works that received predominantly (approx. 90%) domestic sewage. After day 7, a SRT of approx. 10 days was maintained in the units by the daily removal of 350mL activated sludge from the aeration vessel.The ‘‘control’’ unit did not receive test chemical.The test units were operated at 20°C with a hydraulic residence time (HRT) of 6 h and a sludge retention time (SRT) of about 10 days, which results in a loading rate that is typical of full-scale activated-sludge sewage treatment plants (STPs).During the run-in period of 19 days, the removal of total test chemical in the test units was monitored using a relatively fast, but less specific, high-performance liquid chromatography (HPLC-FI) method with fluorescence detection. It has a limit of quantitation (LOQ; defined as the sample analyte concentration producing a 10:1 signal-to-noise ratio on the analytical instrument) for total chemical of 5–10mg/L. In the evaluation phase the pyr+ LC/MS method was used for the determination of chemical fingerprints for influents and effluents based on the range of C12-18 chain lengths and EO 0-18 oligomers. This method was also used to confirm the chemical level in one of the samples during the run-in phase.The pyr+ LC/MS method has a LOQ for individual AEs in the range of 0.2–7.1 ng/L and for total alcohol ethoxylates (AEs) (all 114 ethoxymers) of 250 ng/L.The percentage removals of AEs by the test unit were calculated using test effluent analyses relative to the mean test influent analyses averaged over days 20, 23, and 27 (no influent analysis was performed on day 30).The percentage degradation of test chemical was determined to be 99.5% in 30 days. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (2018) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 20.9% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of test chemical in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.583%), indicates that test chemical is not persistent in sediment.

 

 

Biodegradation in soil

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (2018). If released into the environment, 77% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

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 peer reviewed journal (T. Wind, et. al; 2006), biodegradation experiment was conducted for 38 days for evaluating the percentage biodegradability of test chemical. The study was performed according to ISO 11734 Water quality - Evaluation of the "ultimate" anaerobic biodegradability of organic compounds in digested sludge - Method by measurement of the biogas production guideline under aerobic conditions. Laboratory scale continuously fed activated sludge units according to the OECD Draft Test Guideline 303 A: Simulation Test—Aerobic Sewage Treatment: Activated Sludge Units was used as a test inoculum for the study. Test inoculum activated sludge was also isolated from a sewage treatment work that received predominantly (approx. 90%) domestic sewage. The activated sludge was aerated for 24 h, without feed, before use and had a total suspended-solids (TSS) content of 3.4 g/L. The sludge recycle pumps were adjusted to give a recycle ratio ofapprox.1.0, and this resulted in an initial mixed-liquor suspended-solids (MLSS) concentration ofapprox.5.5 g/L in the aeration vessels. The contents of the aeration vessels were vigorously aerated (1.2 L/min) to keep the sludge in suspension and maintain dissolved O2 levels >1 mg/L. Each of the Husmann test unit consisted of a 3.5-L cylindrical aeration vessel and a 2.5-L cylindrical clarifier/settler. The aeration vessels were fitted with 0.4-L precontactor zones in order to reduce the possibility of sludge ‘‘bulking’’ (poor settling), a factor present when using the OECD synthetic sewage feed. The precontactor consisted of a 48- mm-diameter vertical tube positioned centrally in the aeration vessel and fitted with its own central sintered-glass sparger; the feed and recycled-sludge input streams were supplied to its top and passed into the main aeration vessel via holes at its bottom. The annulus of the aeration vessel was fitted with two further spargers positioned opposite each other to provide efficient aeration and mixing of the activated sludge. Each clarifier/settler was provided with a perforated horizontal disk that was normally positioned about 50mm below the clarified effluent outflow to act as a flocculation filter and retain any floating sludge. Sludge from the settler section was returned to the aeration vessel pre-contact zone using a peristaltic pump. The test run consisted of a 19-day sludge acclimation or ‘‘run-in’’ phase, followed by a further 19-day ‘‘evaluation’’ phase. At the start of the test (day 0), both test units were filled with 6L of activated sludge taken from a sewage treatment works that received predominantly (approx. 90%) domestic sewage. After day 7, a SRT of approx. 10 days was maintained in the units by the daily removal of 350mL activated sludge from the aeration vessel. The ‘‘control’’ unit did not receive test chemical. The test units were operated at 20°C with a hydraulic residence time (HRT) of 6 h and a sludge retention time (SRT) of about 10 days, which results in a loading rate that is typical of full-scale activated-sludge sewage treatment plants (STPs).During the run-in period of 19 days, the removal of total test chemical in the test units was monitored using a relatively fast, but less specific, high-performance liquid chromatography (HPLC-FI) method with fluorescence detection. It has a limit of quantitation (LOQ; defined as the sample analyte concentration producing a 10:1 signal-to-noise ratio on the analytical instrument) for total chemical of 5–10mg/L. In the evaluation phase the pyr+ LC/MS method was used for the determination of chemical fingerprints for influents and effluents based on the range of C12-18 chain lengths and EO 0-18 oligomers. This method was also used to confirm the chemical level in one of the samples during the run-in phase. The pyr+ LC/MS method has a LOQ for individual AEs in the range of 0.2–7.1 ng/L and for total alcohol ethoxylates (AEs) (all 114 ethoxymers) of 250 ng/L.The percentage removals of AEs by the test unit were calculated using test effluent analyses relative to the mean test influent analyses averaged over days 20, 23, and 27 (no influent analysis was performed on day 30).The percentage degradation of test chemical was determined to be 99.5% in 30 days. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

 

Another biodegradation study from authoritative database (J-CHECK, HSDB, PubChem, 2017 and EnviChem, 2014) was conducted for 14 days for evaluating the percentage biodegradability of test chemical. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I) under aerobic conditions. Activated sludge was used as a test inoculums for the study. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of test chemical was determined to be 88.4% and 100% by BOD and GC parameter in 14 days. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in water.

 

In a supporting study, biodegradation experiment was conducted according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)) for evaluating the percentage biodegradability of test chemical (Kondo, M, et. al; 1988). Initial test substance conc. used in the study was 2 mg/l. Namely, a water, acetone or DMSO solution (0.1 ml) of the test chemicals was added to a mixture of river/sea water (4.9 ml) from an unpolluted area and an autoclaved solution (5.0ml) of 0.2% peptone in a sterile test tube with a tight plug. After sealed with film and fixed at an angle of 30°in a dark box,the test tubes were incubated at 30°C and shaked at 120rpm. Inoculum used for the study was mixed culture obtained from different sources (Sea water from Enoshima Beach and River water from Tama River).The percentage degradation of test chemical in river and sea water was determined to be 100 and 97% by BOD parameter in 3 days. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

 

Additional biodegradation studyfrom peer reviewed journal (William H. Stahl et. al.; 1953)was conducted for 7 days for evaluating the percentage biodegradability of test chemical by using Pseudomonas aeruginosa QMB 1468 as the test inoculum. Bacteria have been repeatedly isolated from degraded plastic films andwas cultivated on Bacto nutrient agar. The ease of utilization of a particular substrate was evaluated by a quantitative measure of the growth of bacteria on it.Substrate (2 per cent for alcohol) was weighed or pipetted into 250 ml Erlenmeyer flasks to which was added 70 ml of a mineral salts solution (100 ml stock A1 + 100 ml stock B2 made up to 1 liter; pH 6.6). Bacto yeast extract was also added to a final concentration of 1 -10,000. The flasks were plugged with cotton and sterilized. Those substrates having boiling points below 180⁰C were filtered through Seitz bacterial filters and added to the previously sterilized mineral salts solution and yeast extract just before inoculation. After inoculation, the flasks were fastened to a horizontal shaker reciprocating about 90 times per minute, with a stroke of 3 in; incubator temperature was 30⁰C. The incubation time was 7 days, except where indicated otherwise. To obtain the weight of bacteria, a turbidimetric procedure was established. The contents of a flask were exhaustively extracted with ethyl ether in a separatory funnel, the bacteria remaining entirely in the aqueous phase. The total volume of this phase was measured and its turbidity determined in a Klett-Summerson photoelectric colorimeter. The value thus obtained was converted into dry cell weight by means of a standard curve prepared for this purpose. The growth of the test bacterium Pseudomonas aeruginosa QMB 1468 was observed with a dry cell weight of about 67 mgs thus utilizing test chemical as a substrate. Thus, based on this, test chemical is considered to be biodegradable in nature.

 

In an another supporting study from authoritative database (HSDB, 2017), biodegradationexperimentwas conducted for evaluating the percentage biodegradability of test chemical under aerobic conditions. Activated sludge was used as a test inoculums for the study. The zero order and first order biodegradation rates of test chemical in activated sludge were 0.0104 ppm/hr and 0.00523 1/hr, respectively. Using this first order degradation rate, the percentage degradation of test chemical was determined to be 50% in 5.6 days. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in water.

 

For the test chemicalfrom modelling database (EPI suite, 2018) and secondary source (OECD SIDS, 2006), Estimation Programs Interface Suite was run to predict the biodegradation potential of the test chemical in the presence of mixed populations of environmental microorganisms. The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that test chemical is expected to be readily biodegradable.

 

On the basis of above results for target chemical1-Tridecanol(from peer reviewed journals, authoritative databaseJ-CHECK, HSDB, PubChem & EnviChem andsecondary source OECDSIDS), it can be concluded that the test substance1-Tridecanolcan be expected to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (2018) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 20.9% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low whereas the half-life period of test chemical in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.583%), indicates that test chemical is not persistent in sediment.

 

Biodegradation in soil

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (2018). If released into the environment, 77% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

On the basis of available information, test chemical can be considered to be readily biodegradable in nature.