(1-methyl-1,2-ethanediyl)bis[oxy(methyl-2,1-ethanediyl)] diacrylate

Bioaccumulation: aquatic / sediment

Description of key information

Accumulation of TPGDA in organisms is not to be expected.

Additional information

QSAR-disclaimer:

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore, according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

 According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

Assessment:

 The substance is an UVCB substance. The following four main constituents which concentrations at or above 0.1 % (w/w) were analytically determined:

1.    Constituent 1 (2-{2-[2-(acryloyloxy)-1-methylethoxy]-1-methylethoxy}-1-methylethyl acrylate), ca. 85% (w/w)

2.    Constituent 2 (2-Propenoic acid, 2-[2-(2-hydroxymethylethoxy)methylethoxy]methylethyl ester), ca. 4% (w/w)

3.    Constituent 3 (2-Propenoic acid (1 or 2), (4 or 5), (7 or 8)-trimethyl-10,14-dioxo-3,6,9,13-tetraoxahexadec-15-en-1-yl ester), ca. 3% (w/)

4.    Constituent 4 ((1 or 2)-methyl-2-{(1 or 2)-methyl-2-[(1 or 2)-methyl-2-(2-propenoyloxy)ethoxy]ethoxy}ethyl (5 or 6), (8 or 9), (11 or 12)-trimethyl-14-oxo-4,7,10,13-tetraoxahexadec-15-en-1-oate), ca. 2% (w/w)

 In accordance with Annex IX, Section 9.3.2 and Section 9.2.1.2 the assessment of bioaccumulation or bioconcentration and biodegradation of each constituent and impurity present in concentrations at or above 0.1% (w/w) must be performed. Therefore, in order to assess the bioaccumulation potential of TPGDA (CAS 42978-66-5) a weight-of-evidence approach with four main constituents was used. For the assessment of bioaccumulation(Q)SAR results were used.The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

Therefore, and for reasons of animal welfare, further experimental studies on aquatic bioaccumulation are not provided

According to Regulation (EC) 1907 (2006) Annex IX, section 9.3.2, column 2, a study on bioaccumulation does not need to be conducted as the substance has a low potential for bioaccumulation. The substance has a measured log Kow of 2.7 (BASF SE, 19L00100, 2019). 

In addition, in order to assess the bioaccumulation potential of the test substance, the BCF was calculated with several estimation models. The table below lists the applied (Q)SAR models, the estimated BCF values and basic information on the applicability domain (AD) for the compound. Detailed information on the model’s results and the AD are given in the endpoint study records of IUCLID Chapter 5.3.1. The selected models comply with the OECD principles for (Q)SAR models.

The following table provides results for the constituents of the substance (impurities or additives are not present in concentrations at or above 0.1 % (w/w)): (AD = Applicability Domain)

Model	Constituent 1	Constituent 2	Constituent 3	Constituent 4	AD
	BCF [L/kg]	BCF [L/kg]	BCF [L/kg]	BCF [L/kg]
BCF KNN/Read-Across v1.1.0 (VEGA v1.1.3)	19.05	17.8	16.2	3.31	No
BCFBAF v3.01 (EPI Suite v4.11): Arnot-Gobas BCF, upper trophic, incl. biotransformation	1.902	0.947	1.951	3.193	Yes
BCFBAF v3.01 (EPI Suite v4.11): Arnot-Gobas BCF, upper trophic, incl. biotransformation of zero	7.929	1.2	8.462	21.24	Yes
CAESAR v2.1.14 (VEGA v1.1.3)	2	2	1	0.17	No
Meylan v1.0.3 (VEGA v1.1.3)	7	3	8	15	No
BCFBAF v3.01 (EPI Suite v4.11): Meylan et al. (1997/1999)	7.36	3.16	7.72	14.8	Yes
BCF baseline model v.02.09 (OASIS Catalogic v5.11.19): incl. mitigating factors	3.715	2.754	3.981	1.959	No
BCF baseline model v.02.09 (OASIS Catalogic v5.11.19): not considering mitigating factors	31.84	11.35	33.11	59.29	No

 

Considering all models applied constituents of the registration item are estimated to have BCF values range between 0.947 and 59.29 L/kg. Based on the available information on the log Kow (log Kow = 0.41; calculated with KOWWIN v1.76; EPI Suite) can be concluded that accumulation of the compounds in organisms is not to be expected. The substances are within the applicability domain of the Meylan v1.0.3 and Arno t& Gobas models.

The remaining “non-specified constituents” sum up to a typical concentration of approximately 6.0 % (w/w). According to GC analytics, more than 45 peaks contribute to this part of the composition of the registration item. Though it is virtually not possible to identify each single peak and assess the respective substance(s) individually, a generic assessment of the environmentally relevant properties of these ingredients may be applied. Multifunctional acrylates are synthesized from alcohols and acrylic acid. As a consequence, the resulting products – including the “non-specified constituents” – are made of the same, similar chemistry. As shown by the evidence provided above, this chemistry basically is subject to ultimate biotic degradation: in none of the four main constituents, a potential metabolite that may be generated from the degradation of these compounds was identified. Therefore, from a scientific perspective, it is extremely likely that also the degradation of the chemically similar “non-specified constituents” of the registration item will not lead to the formation of a persistent metabolite. The raw materials used as well as the conditions of the reaction chosen during manufacture are targeted to produce 2-{2-[2-(acryloyloxy)-1-methylethoxy]-1-methylethoxy}-1-methylethyl acrylate. Side-products beyond the main constituents discussed above are expected to slightly vary in chain lengths and/or branching, but are not anticipated to significantly differ in terms of structural elements – if at all. Therefore, also these structures are deemed degradable by the same metabolic pathways. Consequently, there is no concern that (part of) the UVCB may persist in the environment.

 Hence, based on the available calculated data from the weight-of-evidence approach with main constituents, it is considered that TPGDA (CAS 42978-66-5) is not expected to accumulate within aquatic organisms.