Rape oil, reaction products with diethanolamine

Biodegradation in water: screening tests

Description of key information

Based on the overall weight of evidence from reliable OECD guideline compliant biodegradation studies, the structural analogue of the test material, amides, C18(unsatd.), N,N-bis(hydroxyethyl is considered to be readily biodegradable. As such, it is considered that HE Rape Oil, reaction product with diethanolamine will also be readily biodegradable. 

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

A study was conducted to determine the ready biodegradability of the read across test substance, amides, C18(unsatd.), N,N-bis(hydroxyethyl), in the CO2-evolution test according to OECD guideline 301 B (modified Sturm test) in compliance with GLP. A solution of the test substance (15 mg/L) in the nutrient solution, corresponding to 10.2 mg TOC/L, was inoculated with activated sludge. The test vessels were aerated by the passage of carbon dioxide-free air and were incubated under aerobic conditions for 28 d. The biodegradation of the test substance was followed by titrimetric analyses of the quantity of the carbon dioxide produced on Day 1, 3, 6, 7, 9, 14, 17, 21, 24, 28 and 29 of the study. The reference substance used was sodium acetate at a concentration of 35 mg/L. The reference substance reached the pass levels for ready biodegradability after 7 d. For the test substance, the 10% biodegradation level was reached after 5 d. In the 10-d-window the pass level of a biodegradation of more than 60% was reached. The mean biodegradation came to 79% after 14 d and to a maximum of 86% after 28 d (after acidification).Therefore the test substance reached the pass level for ready biodegradability (60% ThCO2 and 10 d-window). Therefore, under the conditions of the study, the test substance can be considered to be readily biodegradable (Noack, 2003)

 

A study was performed to assess the ready biodegradability of the read across test substance, amides, C18(unsatd.), N,N-bis(hydroxyethyl), according to the OECD guideline 301D in compliance with GLP. The test substance was exposed to activated sewage sludge micro-organisms at a concentration of 3.0 mg/L with culture medium in BOD bottles in the dark at 20–24 ± 1⁰C for 28 days. The degradation of the test substance was assessed by the determination of oxygen consumption. The biodegradation was expressed as percentage BOD. The test substance attained the pass level of a biodegradation of >60% after 26 days and 70% degradation after 28 days. However, it did not meet the 10-day window validation criterion. The residual concentration of oxygen in the test substance did not fall below 0.5 mg/L at any time. All the other validity criteria were fulfilled (Noack, 2005).

 

A study was conducted to evaluate the ready biodegradability of the read across test substance, amides, C18(unsatd.), N,N-bis(hydroxyethyl), according to the OECD guideline 301F EU Method C.4-D in compliance with GLP. The test substance (100 mg/L) and reference substance (benzoic acid, sodium salt; 100 mg/L) was inoculated with activated sludge and kept in darkened, enclosed respirometer flask (22 ± 1degC)and observed for degradation by measurement of the dissolved oxygen concentration over 28 days period. Biodegradation is expressed as percentage oxygen uptake (corrected for blank uptake) of the theoretical uptake (ThOD).The pass level for ready biodegradability was 60% removal of ThOD (Theoretical Oxygen Demand) for respirometric methods. The % degradation of the test substance and reference substance was determined to be 58 and 83%, respectively after 28 days. The test substance was biodegraded to an average of 34% in a 10-d window within the 28-d period. There was no relevant adaptation time for the polyvalent microorganisms necessary to start the biodegradation process. Therefore, the test substance cannot be regarded as readily biodegradable. Nevertheless, the test substance can be regarded as 'moderately biodegradable' (Wehrhahn D, 2006).

 

A study was conducted to determine the inherent biodegradability of the read across test substance, amides, C18(unsatd.), N,N-bis(hydroxyethyl), in Zahn-Wellens/EMPA test according to OECD guideline 302 B (not in compliance with GLP). The reference substance reached the pass levels for ready biodegradability after 14 days. The test substance reached a degree of degradation of 96%after 28 d. The level of 10% degradation (begin of degradation) was reached after 0.5 days, the maximum level of degradation (97%) was reached after 14 d. The validity criteria according to the guideline were not completely fulfilled in the test as the elimination of the test substance after 3 h was relatively high (25%). The initial DOC content was significantly lower than expected. Therefore it can be concluded that the elimination of the test substance was additionally due to physicochemical adsorption effects. Under the conditions of the study, the degradation of the test substance was 96% after 28 days and therefore can be considered to be inherently biodegradable (Hirschen and Grohmann, 2002).

 

A study was conducted to determine the biodegradability of the read across test substance, amides, C18(unsatd.), N,N-bis(hydroxyethyl), according to the DIN Guideline 38 412, Part 25. A solution of the test substance was inoculated with activated sludge and Chemical Oxygen Demand was followed for 28 days. The reference substance used was sodium benzoate. The test substance degraded by 90.6% within 15 days. The reference substance degraded to > 95%. Under the test conditions, the test substance was considered to be readily biodegradable (Klein, 1987).

 

Overall, based on the above information, the read across test substance amides, C18(unsatd.), N,N-bis(hydroxyethyl) is considered to be readily biodegradable.

As such it is considered that HE Rape Oil, reaction product with diethanolamine will be readily biodegradable also.