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Environmental fate & pathways

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Hydrolysis


A hydrolysis study was performed according to OECD Guideline 111. The major constituents of test item (2,2'-[[(5-methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol and 2,2'-[[(4-methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol hydrolyse directly and quantitatively when it is solved in the buffer solutions. Thus the test item is not considered to be hydrolytically stable at pH 4, 7 and 9. The determination of the hydrolysis rate is not possible because of the very fast hydrolysis. Methyl-1H-benzotriazole (tolyltriazole) was detected as hydrolysis product. Additionally the following transformation products were proposed: Formaldehyde (CAS No. 50-00-0), Diethanolamine (CAS No. 111-42-2).


 


Biodegradation


Two studies on biodegradability of the test substance are available.


The ready biodegradability of the test item was assessed over a 28 day period by the OECD Screening Test (OECD 301E). The test material attained up to 44 % biodegradation after 28 days whereas the positive control substance (Aniline) was 88 % degraded after 7 days. These results indicate that the test item cannot be classified as readily biodegradable under conditions of the test.


In the modified Zahn-Wellens test according to OECD 302 B the test substance was tested for inherent biodegradation. After 28 days the test substance was degraded to 61 % after 28 days, the reference was degraded to 100 % in 27 hours. It was concluded that the test substance is inherently biodegradable.


The constituents and proposed hydrolysis products are partially readily biodegradable (formaldehyde and diethanolamine) or of unknown biodegradability (tolyltriazole).


 


Bioaccumulation


The uvcb substance is not readily biodegradable but the main constituents hydrolyse fast. The log Pow of the remaining major constituents and proposed degradation products formaldehyde (CAS 50-00-0, logPow 0.35), diethanolamine (CAS 111-42-2, logPow -2.46 at 25°C, pH 6.8-7.3) and tolyltriazole (CAS 29385-43-1, logPow 1.08 at 25°C, pH 7-8) is below 3.


However, the BCF for the main component of the uvcb substance was calculated to be approx. 0.897- 3.16 L/kg ww (BCF) using EPI Win (BASF SE, 2013). Secondary poisoning is therefore, highly unlikely to occur in any extent for the test item.


 


Adsorption / Desorption


The main constituents of the substance hydrolyse fast. The remaining major constituents and proposed degradation products are


formaldehyde (CAS 50-00-0, logPow 0.35, diethanolamine (CAS 111-42-2, logPow -2.46 at 25°C, pH 6.8-7.3) and tolyltriazole (CAS 29385-43-1, logPow 1.08 at 25°C, pH 7-8). These substances are not expected to be very adsorptive.


However, the KOC for the main component of the uvcb substance was calculated to be approx. 0.56- 10 L/kg using EPI Win (BASF SE, 2013). Based upon these data, adsorption to soil is not expected (KOCWIN v2.00).


 


Assessment of the degradation products and constituents:


The following transformation products were proposed: Formaldehyde (CAS No. 50-00-0), Diethanolamine (CAS No. 111-42-2). Tolyltriazole (CAS 29385 -43 -1) is detected as degradation product and additionally a major constituent of the uvcb substance.


 


Formaldehyde is registered under REACH Regulation (EC) No 1907/2006. According to the disseminated registration data the substance is well water soluble, readily biodegradable, volatile and mobile in soil. The BCF was determined to be 0.396 (logPow = 0.35), thus it was not classified as PBT and vPvB. In addition, Formaldehyde has not be classified as environmental toxic according to Regulation (EC) No 1272/2008 (CLP/GHS) and according to Directive 67/548/EEC (DSD), repectively.


 


Diethanolamine is registered under REACH Regulation (EC) No 1907/2006. According to the disseminated registration data the substance is well water soluble, readily biodegradable and cationic under environmental conditions. Binding of the test substance to the matrix of soils (and sediments) with high capacities of cation exchange can not be excluded for the charged molecule if no biodegradation takes place. The logPow was determined to be -2.46 at 25°C, pH 6.8-7.3. As the logPow was lower than 3, thus in accordance with column 2 of REACH Annex IX no bioaccumulation study was performed. Therefore, the substance is not classified as PBT or vPvB. The substance is classified as as chronic aquatic cat. 3 (H412: Harmful to aquatic life with long lasting effects) according to Regulation (EC) No 1272/2008 (CLP/GHS). The substance is not classified according to Directive 67/548/EEC (DSD).


Relevant data from ECHA dissemination view: Molecular weight 105.136 g/mol, Vapour pressure 0.028 hPa, Water solubility 1,000 mg/L, logKow -2.46, pka 8.99, Henry's law constant 3.97E-6 Pa3m3/mol, logKOC 0.99 pH7 (estimate according to Franco & Trapp (2008) using a logKow of -2,46 and a pka of 8.99 as input parameter), Biodegradability: readily biodegradable


 


Tolyltriazole is subject to REACH registration (CAS 29385 -43 -1) according to Regulation (EC) No 1907/2006. However, data are not yet available. Also, no data on biodegradability are available so far and the estimated BCF-factor using EPIWIN was calculated to be 3.8 to 6.4 (logPow = 1.08 at 25°C, pH 7-8). Thus, the compound is not classified as PBT and vPvB. No data on tolyltriazole are available but QSAR estimations indicate that this substance is well water soluble, is probably not readily biodegradable, not bioaccumulating and mobile in soil.


Relevant data estimated using Epiwin 4.1 for CAS 29385 -43 -1:


Molecular weight 133.15 g/mol,Vapour pressure 100 Pa, Water solubility 1,925 mg/L, logKow1.08 , Henry's law constant 0.02 Pa3m3/mol, KOC 110 , Biodegradability: not readily biodegradable