2,2-dimethyl-1,3-propanediyl dioctanoate

Endpoint summary

Additional information

A detailed justification for grouping of substances is provided in section 5 of IUCLID.

The following table illustrates the read across approach taken within the NPG ester group of the polyol esters category. For practicality reasons, only the environmental fate parameters of the relevant substances used as part of a read across approach for the NPG esters of the category have been listed in the table below. The complete data matrix of all polyol esters for aquatic toxicity is however detailed within the category justification attached in IUCLID section 13 of this dossier.

Table: Ecotoxicological parameters for the aquatic toxicity of the NPG esters

ID	CAS	Short term toxicity to fish	Long term toxicity to fish	Short term toxicity to aquatic invertebrates	Long term toxicity to aquatic invertebrates	Toxicity to aquatic algae	Toxicity to microorganisms
1	68855-18-5 (a)	Experimetal result: LC50 (96h) >0.086 mg/L	Waiving	Waiving	-	Experimental result: ErC50 >0.0065 mg/L NOErC 0.0065 mg/L (solubility limit)	Experimental result: EC50 (3h) >1000 mg/L
2	31335-74-7	Experimental result: LC50 (96h) >180 mg/L RA: CAS 68855-18-5	Waiving	Waiving	RA: CAS 68855-18-5	RA: CAS 68855-18-5	Experimental result: EC10 (3h)>100 mg/L (RL4) RA: CAS 68855-18-5
3	85711-80-4 (b)	--	--	--	--	--	--
4	70693-32-2	RA: CAS 85186-86-3 RA: CAS 68855-18-5 RA: CAS11138-60-6	Waiving	RA: CAS 85186-86-3 RA: CAS 11138-60-6	RA: CAS 68855-18-5 RA: CAS 11138-60-6	RA: CAS 68855-18-5 RA: CAS 11138-60-6	RA: CAS 68855-18-5
5	Former 85186-86-3	RA: CAS 68855 -18 -5 RA : CAS 85186 -86 -3	Waiving	RA: CAS 85186 -86 -3	RA: CAS 68855 -18 -5 RA: CAS 42222 -50 -4	RA: CAS 68855 -18 -5 RA: CAS 85186 -86 -3	RA: CAS 68855 -18 -5
6	85186-86-3	Experimental result: LC50 (96h) >100 mg/L	Waiving	Experimental result: EL50 (48h) >100 mg/L	RA: CAS 68855-18-5	Experimental result: EL50 (72h) >100 mg/L	RA: CAS 68855-18-5
7	85186-95-4	RA: CAS 42222-50-4 RA: CAS 85186-86-3	Waiving	RA: CAS 85186-86-3 RA: CAS 42222-50-4	RA: CAS 68855-18-5	RA: CAS 85186-86-3 RA: CAS 42222-50-4	RA: CAS 68855-18-5
8	91031-85-5	--	--	--	--	--	--
9	91031-27-5	RA: CAS 68855-18-5 RA: CAS 85186-86-3	Waiving	RA: CAS 85186-86-3	RA: CAS 68855-18-5 RA: CAS 42222-50-4	RA: CAS 68855-18-5 RA: CAS 85186-86-3	RA: CAS 68855-18-5
10	85116-81-0	RA: CAS 42222-50-4 RA: CAS 85186-86-3	Waiving	RA: CAS 42222-50-4 RA: CAS 85186-86-3	RA: CAS 68855-18-5 RA: CAS 42222-50-4	RA: CAS 42222-50-4 RA: CAS 85186-86-3 RA: CAS 68855-18-5	RA: CAS 68855-18-5
11	42222-50-4	Experimental result: LC50 (96h) >10000 mg/L	Waiving	Experimental result: EL50 (48h) >100 mg/L		Experimental result: EL50 (72h) >100 mg/L	RA: CAS 68855-18-5
12	67989-24-6	--	--	--	--	--	--
13	85005-25-0	RA: CAS 42222-50-4	Waiving	Experimental result: EL50 (48h) >2000 mg/L	RA: CAS 68855-18-5	Experimental result: EL50 (72h) >2000 mg/L	RA: CAS 68855-18-5

(a) Category members subjected to the REACh Phase-in registration deadline of 31 May 2013 are indicated in bold font

(b) Substances that are either already registered under REACh, or not subject to the REACh Phase-in registration deadline of 31 May 2013, are indicated in normal font

In accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5, grouping and read-across, the polyol esters, which of course includes the polyol NPG group are not considered to be harmful to aquatic organisms based on the results from short-term studies with fish, aquatic invertebrates and algae and long-term results on toxicity to aquatic invertebrates. All polyol NPG esters are structurally similar and read-across was performed to the structurally most similar category member(s). The alcohol moiety neopentyl glycol is common to all NPG esters. The available studies cover the variability of the NPG esters, with different fatty acid chain lengths and degrees of saturation. Since the NPG esters also share a similar pattern in the ecotoxicological toxicity profile, all data gaps within the group were filled by interpolation. No trend in toxicity was observed since no effects were recorded up to the limit of water solubility. There is no convincing evidence that any one of the category members might lie out of the overall profile of this category.

In particular, short-term studies with freshwater species from all three trophic levels (algae, aquatic invertebrates and fish) are available. Three acute toxicity studies to fish according to internationally accepted guidelines are available for the NPG esters Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol (CAS No. 68855-18-5), Fatty acids, C8-18 and C18-unsatd., esters with neopentylglycol (CAS No. 85186-86-3) and 2,2-dimethyl-1,3-propanediyl dioleate (CAS No. 42222-50-4). No effects were observed up to the limit of water solubility. The available studies cover the variability of the category with representative fatty acid chain lengths. Thus, the data gaps can be covered by interpolation. In conclusion the NPG esters are of low toxicity to fish.

The same result was found in short-term toxicity studies with aquatic invertebrates for the NPG esters Fatty acids, C8-18 and C18-unsatd., esters with neopentylglycol (CAS No. 85186-86-3), Fatty acids, C14-18 and C18-unsatd., branched and linear, esters with neopentyl glycol (CAS No. 85005-25-0) and 2,2-dimethyl-1,3-propanediyl dioleate (CAS No. 42222-50-4). No toxicity was observed up to the limit of water solubility in the available studies. Based on the results from these studies, there is no convincing evidence that the other category members lie out of the overall toxicity profile.  In conclusion the NPG esters are of low toxicity to aquatic invertebrates.

Four standard guideline studies investigating the toxicity to aquatic algae are available for the following substances Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol (CAS No. 68855-18-5), Fatty acids, C8-18 and C18-unsatd., esters with neopentylglycol (CAS No. 85186-86-3), Fatty acids, C14-18 and C18-unsatd., branched and linear, esters with neopentyl glycol (CAS No. 85005-25-0) and 2,2-dimethyl-1,3-propanediyl dioleate (CAS No. 42222-50-4). No toxicity was observed up to the limit of water solubility. The available studies are covering the variability of the category with fatty acid chain lengths at the lower and upper end of the category. Thus, the data gaps can be covered by interpolation. In conclusion the NPG esters are of low toxicity to aquatic algae.

A long-term study with Daphnia magna is available for the NPG ester Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol (CAS No. 68855-18-5). Since this substance is the smallest among the NPG esters it is expected to be the most bioavailable and is thereby considered to represent the worst case for NPG esters. As no effects on reproduction occurred in this study, other NPG esters are not expected to have long-term effects on aquatic invertebrates either.

Toxicity to microorganisms was investigated in two studies within the polyol NPG group for the NPG esters Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol (CAS No. 68855-18-5) and 2,2-dimethyl-1,3-propanediyl dioctanoate (CAS No. 31335-74-7), respectively. No effects on respiration of activated sludge microorganisms were observed in any of the studies, which were both conducted according to an accepted guideline. A full report is only available for the first study with Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol. Based on structural similarities this study was used for read-across throughout the category. Although the reliability of the second study with 2,2-dimethyl-1,3-propanediyl dioctanoate cannot be properly evaluated due to insufficient documentation, the result supports the findings of the first study. In combination with results from the available biodegradation studies it can be concluded that no effects on the STP microorganism community and the subsequent degradation process in sewage treatment plants are anticipated. 

In conclusion, no effects on aquatic organisms were observed in the available studies for the NPG esters on any of the three trophic levels (fish, daphnia, algae) up to the limit of water solubility. The polyol esters category is a robust category with a large amount of reliable data which allows a conclusive overview about the overall ecotoxicity profile of all category members. In each case of read-across, the best suited read-across was chosen. Nevertheless, as it can be seen in the data matrix of the category justification in IUCLID Section 13, all reliable data in the category support the hazard assessment of each category member by showing a consistent pattern of results.

A detailed reference list is provided in the technical dossier (see IUCLID, section 13) and within CSR.