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Environmental fate & pathways

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Abiotic degradation

The environmental stability of Butyldiethanolamine (BDEA) is not assessed experimentally. Concerning phototransformation in different compartments (i.e. air, soil and water) as well as hydrolysis, no information is available. Conclusively, exact predictions of abiotic degradation pathways cannot be made.

Biotic degradation

Biotic degradation of the substance BDEA was investigated in a ready and in an inherent biodegradation test. In an OECD Guideline 301 B study (CO2 -Evolution Test; BASF SE, 2014), the degree of observed biodegradation was 50 -60% CO2/ThCO2 after an exposure period of 60 days.

Based on the degree of biodegradation at the end of exposure, Butyldiethanolamine was assessed as partly or moderately biodegradable under the conditions of this test.

The biodegradation behaviour of the substance was further investigated in a study similar to OECD Guideline 302 B (BASF AG, 1987). A total exposure duration of 22 days and an initial concentration of 400 mg DOC/L (corresponds to 713 mg/L of test substance) was selected for the study design. For the test substance, 98 % (based on DOC removal) of biodegradation was observed after 22 d. A reference substance did not serve as positive control.

The biodegradability of the substance has been also tested according to OECD 301D (closed bottle test) in compliance with GLP (Taminco NV, 2011). The study duration was prolonged from 28 days to 42 days. A test concentration of 2.89 mg/L has been used. Sodium acetate served as reference substance (75% degradation after 28 days). After 28 days, 0 % of the test substance were biodegraded. After 42 days, biodegradation was not observed either. Both results are based on oxygen comsumption and refer to a Theoretical Oxygen Demand (ThOD) of 2186mg O2/g.

Based on these experimental results, the substance is considered as potentially biodegradable.With regard to the results of the OECD 302 B study (BASF AG, 1987), inherent biodegradation could be assumed for the substance. Since specific criteria for this study, however, were not fulfilled (no reference substance, inoculum from industrial STP), the substance is considered as inherently biodegradable, not fulfilling specific criteria.

Bioaccumulation

Bioaccumulation in aquatic organisms is not expected for Butyldiethanolamine. The first indication for that conclusion is given by the substance's specific log Pow of 0.58 at 25 °C and pH of 10 (equals Pow of ca. 3.8; experimentally determined; BASF AG, 1993). Such a low value indicates a lack of bioaccumulation potential. Bioaccumulation is expected for substances possessing a partition coefficient in the range of log Pow 4.5 to 6 according to ECHA REACH Guidance R.11 (PBT Assessment, November 2014).

The experimentally determined BCF value of < 39 for the read-across substance Dibutylethanolamine (CAS 102 -81 -8) according to OECD 305 C (NITE, 2011) confirms this conclusion. QSAR modelling using EPIWIN (BCFBAF v3.01) performed for Butyldiethanolamine (Chemservice S.A., 2015) also indicates a negligible bioaccumulation potential with an estimated BCF of 3.16 L/kg wet-wt.

Transport and distribution

No experimental results are available concerning the transport and distribution of Butyldiethanolamine in different environmental compartments.

The soil adsorption for BDEA has been calculated by KOCWIN v2.0 (Chemservice S.A., 2015). The traditional method gave a Koc of 2.279 L/kg, whereby the MCI method reveals a value of 10 L/kg as result. Both values lead to the conclusion, that the substance possesses a low to medium affinity to soil.

The distribution of BDEA between aqueous solutions and air was determined by calculation using the software tool HENRYWIN v3.20 (Chemservice S.A., 2016). Using the Bond Method, a Henry´s Law Constant of 2.04E-5 Pa*m3/mol at 25 °C was calculated. The Group Method estimated a HLC of 5.95E-9 Pa*m3/mol. These values indicate that the substance has only a low affinity to the air compartment.

Based on these overall conclusions as well as the high water solubility of the substance (WS = 10 g/L; Taminco BVBA, 2010) , the substance will mainly be present in the water compartment.