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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Phototransformation

The phototransformation of AAPB consisting of C8-, C10-, C12- , C14- , C16-, and C18-fatty acids was calculated using EPIWIN v3.11, AOPWIN v1.91. Based on a OH radical concentration of 500000 molecules/cm³ (24 h-day, average hydroxyl concentration) and the estimated atmospheric reaction rate constants (C8: 42.769 x 10E-12 cm³/molecule x s; C10: 45.595 x 10E-12 cm³/molecule x s; C12: 48.420 x 10E-12 cm³/molecule x s; C14: 51.247 x 10E-12 cm³/molecule x s; C16: 54.073 x 10E-12 cm³/molecule x s, and C18: 56.899 x 10E-12 cm³/molecule x s) half-lives ranging from 6.8 h (C18 derivate) to 9 h (C8 derivate) were calculated. The results indicate theoretically a rapid photodegradation (t1/2<10 h) of the components (C8 -C18 derivates) of AAPB. Due to the ionic character of the compound and the low vapor pressure, however, the occurrence of gaseous AAPB in air is expected to be negligible and therefore this degradation pathway is only of minor importance.

 

Hydrolysis

In accordance with column 2 of REACH Annex VIII, the hydrolysis test does not have to be conducted because AAPB is readily biodegradable. It is shown that biodegradation is the primary route of degradation in the environment.

In addition limited information is available from an EPIWIN calculation. However, there are no details whether the calculation model is validated for the substance under investigation, therefore reliability is not assignable. The stability (hydrolysis) of Coco AAPB was calculated using EPIWIN, HYDROWIN v1.67. Hydrolysis is not to be expected under environmental conditions: the calculated hydrolysis half-life time (t1/2) for Coco AAPB consisting of C8 -C18 fatty acids was found to be > 1 year.

 

 

Biodegradation in water

 

Screening tests

Coco AAPB

A variety of different screening studies for Coco AAPB are available, confirming the readily biodegradability. One reliable study (Klimisch 1) was selected as key study and described in more detail.

 

The ready biodegradability of Coco AAPB was investigated in a study conducted according to EPA OPPTS 835.3120 (Sealed Vessel Carbon Dioxide Production Test) and ISO/DIS 14593 over a period of 28 days and using activated sludge as inoculum. The biodegradation rate was determined by measurement of CO2 evolution. Inoculum blank and procedural/functional control with the reference substance sodium benzoate performed.

Coco AAPB proved to be readily biodegradable and fulfilling the 10 -d window criterion (87.2% biodegradation after 28 d). The functional control reached the pass level >60% after 14 d.

 

 

Experimental results from several guideline studies (e. g. OECD 301 A, 301 B, 301 D, 301 E) on the aerobic biodegradation of Coco AAPB are available. The following results were obtained from studies fulfilling the validity criteria: (ISO/DIS 14593: 87.2 - 93 % biodegradation after 28 d; DOC Die-Away Test: 92 % degradation after 28 d; ; Closed-Bottle-Test: 86 % degradation after 28 d; Modified OECD Screening Test: 100 % biodegradation after 28 d). (Data are summariesed in an overview table in Annex I).

 

C12 AAPB

The ready biodegradability of C12 AAPB was investigated in a study conducted according to EU Method C.4-F (Determination of the "Ready" Biodegradability - MITI Test) over a period of 28 days and using an inoculum taken from a purifying plant for municipal and industrial effluents, from an industrial effluent purifying plant and surface water and surface soil from a river bank. The biodegradation rate was determined by measurement of oxygen consumption. Inoculum blank and procedural/functional controls with the reference substance sodium benzoate were performed. In deviation from guideline 2 instead of 3 bottles containing test material and inoculum were used. Furthermore, a bottle containing test substance in water only was not included in the tests. The test item proved to be readily biodegradable. After 28 days the percentage of biodegradability was 82 % based on ThOD (ThOD=0.7 mg O2/mg; ThOD not further specified: ThODNH4 or ThODNO3) and 95 % based on COD (COD=0.60 mg O2/mg). The functional control reached the pass level > 60 % after 14 d.

 

C12 -18 AAPB

The inherent biodegradation of C12 -18 AAPB was investigated in a study conducted according to DIN 38 412, Part 25 (1984) and which is equivalent or similar to OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test) over a period of 15 days and using non-adapted industrial activated sludge as inoculum. The substance proved to be inherently biodegradable (elimination: 90.8 % after 15 d; biodegradation: 89.4 % after 15 d). The adsorption to sludge was determined to 13 % after 3 h. The reference substance diethylene glycol was biodegraded by 96.6 % after 8 d. Based on these results it can be assumed that C12 -18 AAPB will be readily biodegradable in OECD Guideline tests on ready biodegradation. This assumption is supported by Zahn-Wellens tests with Coco AAPB where similar results were obtained and the ready biodegradability could be shown.

 

C8 -18 AAPB

C8 -18 AAPB proved to be readily biodegradable. In a study conducted according to OECD Guideline 301 B (Ready Biodegradability: CO2Evolution Test) over a period of 28 days and using activated sludge obtained from a municipal wastewater treatment plant as inoculum, the test substance was biodegraded by 91.6 % after 28 d (10 d window criterion fulfilled). These results were supported by a further guideline study. In a supporting study conducted according to EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test), the test substance was biodegraded by 76.3 % after 28 d).

 

Anaerobic biodegradation

The anaerobic biodegradability of Coco AAPB was investigated in a study conducted according to ISO11734 (Water quality - Evaluation of the ultimate anaerobic biodegradability of organic compounds in digested sludge - Method by measurement of the biogas production) and equivalent or similar to OECD Guideline 311 (Anaerobic Biodegradability of Organic Compounds in Digested Sludge: Measurement of Gas Production) over a period of 60 days and using non-adapted digester sludge as inoculum. The biodegradation rate was determined by measurement of total biogas production. Inoculum blank and procedural/functional controls with the reference substance polyethylene glycol 400 were performed. The test item proved to be biodegradable under anaerobic conditions (total biodegradation: 80-90 % after 60 d). The functional control reached the pass level > 60 % after 60 d.

 

In a second study the anaerobic biodegradability of C8 -18 AAPB was investigated in a study conducted according to ECETOC Anaerobic Biodegradation (Technical Report No. 28, similar to OECD guideline 311) over a period of 62 days and digested sludge as inoculum.The biodegradation rate was determined by measurement of gas production and TIC. Inoculum blank, procedural/functional control with the reference substance sodium benzoate and toxicity control were performed. Deviations from guideline were not reported.

The test item proved to be well biodegradable under anaerobic conditions (ca. 80% after 62 d).The functional control reached the pass level >70% (80% after 62 d). In the toxicity control containing both test and reference item an inhibitory effect of the test item on the anaerobic biodegradation was not observed.

 

Conclusion

Experimental results from several guideline studies (e. g. OECD 301 A, 301 B, 301 D, 301 E) on the aerobic biodegradation of Coco AAPB, C12 AAPB and C8 -18 AAPB are available. Based on the results, Coco AAPB, C12 AAPB, and C8 -18 AAPB can be regarded as readily biodegradable. The inherent biodegradability of C12-18 AAPB was proven in a Zahn-Wellens Test. Based on these results, the AAPBs can be regarded as readily biodegradable.

The anaerobic biodegradability of Coco AAPB and C8-18 AAPB was investigated in studies conducted similar to OECD guideline 311. Based on the results of these studies, the AAPBs are considered to be biodegradable under anaerobic condition.

Simulation tests

Reliable data on the ultimate biodegradation of Coco AAPB were obtained from two guideline studies (OECD 303 A and EU Method C.10). The results were within the normal scientific variation of different tests. Therefore, based on the reliable results a mean elimination of 99 % was calculated for the AAPBs using a weight of evidence approach.

The ultimate biodegradation of Coco AAPB was investigated in a study conducted according to a modification of OECD Guideline 303 A (Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units). The test material was treated in a Porous Pot Activated Sludge Plant treating predominantly domestic sewage operating at a SRT of 6 d and a HRT of 6 h. The test and control plants were acclimatised at 20°C to the operating conditions and to sodium acetate for a period of 27 weeks. In the course of the definitive test, the 2 plants were coupled once a week after day 78 by interchanging half of the mixed liquor in each plant. The ultimate biodegradation (ratio DOC removal of control/DOC removal of test item) was determined to be 96.8-105.2 % (95 % confidence limit) during the test duration of 161 d. On the basis of the results, there was no evidence for the formation of water soluble residues from the principal component, Coco AAPB or of the minor present ingredients present in the sample. A significant difference in the amount of biomass produced by the two plants was determined. In the test plant receiving the test material, more biomass was produced in comparison with the control plant which received sodium acetate. The test item can therefore be considered as having no adverse effect on growth of sewage organisms. The student's t-value indicated no significant difference in the amount of nitrification attained by the two plants.

In a further study, the ultimate biodegradability of Coco AAPB was investigated according to OECD Guideline 303 A (Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units) and EU Method C.10 (Biodegradation: Activated Sludge Simulation Test). The test item proved to be easily biodegradable and/or accessible to elimination (97 +/- 4 % DOC removal over a period of 35 d).

 

Biodegradation in seawater

The biodegradability of Coco AAPB in seawater was investigated in a study conducted equivalent or similar to OECD 306 (Biodegradability in seawater - Closed Bottle Test) over a 28 d period and using aged seawater as inoculum. Biodegradation was determined based on oxygen consumption. Oxygen consumption due to nitrification was determined to be 0 mg O2/L. Inoculum blank, procedural/functional control and toxicity control were performed. The substance was biodegraded by 76 % after 28 d; thus the test substance can be classified as readily biodegradable in the marine environment. The reference substance sodium benzoate was biodegraded by 72 % within 7 d. In the toxicity control no inhibitory effects were observed (94 % biodegradation after 14 d). The other validity criteria were fulfilled (blank respiration < 30 % of the oxygen in the test bottle; temperature in the range: 20.0 +/- 1.4°C; BOD of the mixture of test and reference substance was equal to the sum of the BOD of the separate solutions of the two substances; microbial colony count: 4 x 10E3 cfu/mL).

In conclusion the ultimate biodegradation of the AAPBs was proven; a mean elimination of 99 % was calculated for the AAPBs. Based on the results of the biodegradation study in seawater, the AAPBs are considered as readily biodegradable in the marine environment.

Biodegradation in soil

In accordance with column 2 of REACH Regulation Annex IX, a study to simulate the ultimate degradation in soil (required in section 9.2.1.3) does not need to be conducted as the substance is readily biodegradable.

Bioaccumulation

Meylan et al. (1999) collected measured BCF (sources: AQUIRE, CITI, HSDB and EFDB), log Kow (sources: MEDCHEM 'star list', Sangster's LOGKOW DATABANK or sources referenced in the EFDB or KOWWIN estimates), and pKa values for ionizing substances (sources: SRC's PHYSPROP database, compilation of Perrin and Serjeant and Dempsey and reference handbooks such as Handbook of Organic Chemistry, the Handbook of Chemistry and Physics and other sources cited in the EFDB or calculated using pKalc 3.1 software or SPARC. The database of 694 compounds with recommended BCF values contained 84 compounds defined as ionic, including carboxylic acids, sulfonic acids, and quaternary ammonium compounds. Based on the correlation of measured log BCF values and log Kow, log BCF values were deduced. The results were used to develop the computer program BCFWIN. Therefore, BCFWIN v2.15 was used to calculate the BCF values for the C8-C18 derivates of AAPB. The calculation yielded values in the range between 3 (C8 fatty acid derivate) and 71 (C10 – C18 and C18 unsaturated fatty acid derivates). Based on the calculated BCFs a low potential for bioaccumulation is to be expected for AAPBs. Measured BCFs are not available.

Transport and distribution

Adsorption/desorption

A weight of evidence approach was used for evaluation, as the experimental determined values are used as training structure for the ACD calculated values.

In a screening study conducted according to OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)) the log Koc values of C12 and C14 AAPB were determined. Based on a corrected dead time value, the log Koc of C12 and C14 AAPB were determined to be 2.5 (Koc: ca. 320; C12 derivate) and 3.5 (Koc: ca. 3200; C14 derivate), respectively. Based on these results and taking into account the classification scheme of Blume and Ahlsdorf (1993) a medium (C12 derivate) and high sorption (C14 derivate) onto soil organic matter is to be expected.

Based on the Koc value determined by measurement, C12 AAPB was used as training structure for the ACD software and Kow values were calculated for C8, C10, C14, C16 and C18 AAPB (for this calculation to the IUCLID the following justification documents are attached: QSAR prediction report format (QPRF) and QSAR model reporting format (QMRF)). The soil sorption coefficient of AAPB containing C8-, C10-, C12-, C14-, C16-, and C18 fatty acids was calculated using the guideline conform EUSES algorithm for non hydrophobics. The calculation yielded Koc values of 89.3 (C8 derivate), 303 (C10 derivate), 726 (C12 derivate), 4870 (C14 derivate), 16500 (C16 derivate), and 56000 (C18 derivate). According to the classification scheme of Blume & Ahlsdorf (1993), a low (C8 derivate), medium (C10 derivate), high (C12 and C14 derivates), and very high (C16 and C18 derivates) sorption onto soil organic matter is to be expected.

As reported in HERA (2007), the Koc values for AAPB containing C8-, C10-, C12-, C14-, C16-, and C18 fatty acids were calculated using EPIWIN v3.11, PCKOCWIN v1.67. The calculation yielded Koc values of 264.7 (C8 derivate), 900.5 (C10 derivate), 3063 (C12 derivate), 10420 (C14 derivate), 35450 (C16 derivate), and 120600 (C18 derivate). According to the classification scheme of Litz (1990) these values indicate a low to very high sorption potential to the organic matter of soils and sediments depending on the chain length.

Based on the experimental determined Koc values of C12 and C14 AAPB, the Koc values calculated with EPIWIN seem to overestimate soil sorption. The values calculated with ACD/EUSES (reasoned in separate documents (QPRF, QMRF attached to IUCLID)) Koc and Kow values were used for further calculations (environmental exposure and risk assessment).