Fatty acids, C16-18, isotridecyl esters

Endpoint summary

Additional information

The long-chain aliphatic ester (LCAE) category covers mono-esters of a fatty acid and a fatty alcohol. The category contains both mono-constituent and UVCB substances. The fatty acid carbon chain lengths range is C8 - C22 (even- and un-even numbered, including saturated, unsaturated, branched and linear chains) esterified with fatty alcohols with chain lengths from C8 - C22 (even-numbered, including saturated, unsaturated, branched and linear) in varying proportions to mono-esters.

Fatty acid esters are generally produced by chemical reaction of an alcohol (e.g. myristyl alcohol, stearyl alcohol) with an organic acid (e.g. myristic acid, stearic acid) in the presence of an acid catalyst (Radzi et al., 2005). The esterification reaction is started by the transfer of a proton from the acid catalyst to the alcohol to form an alkyloxonium ion. The carboxylic acid is protonated on its carbonyl oxygen followed by a nucleophilic addition of a molecule of the alcohol to the carbonyl carbon of the acid. An intermediate product is formed. This intermediate product loses a water molecule and proton to give an ester (Liu et al., 2006; Lilja et al., 2005; Gubicza et al., 2000; Zhao, 2000). Mono-esters are the final products of the esterification.

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” In particular, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across).

Having regard to the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006, whereby substances may be considered as a category provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity, the substances listed below are allocated to the category of LCAE.

 

CAS	EC Name	Molecular weight	Fatty alcohol chain length	Fatty acid chain length	Molecular formula
CAS 20292-08-4 (b)	2-ethylhexyl laurate	312.53	C8	C12	C20H40O2
CAS 91031-48-0	Fatty acids, C16 - 18, 2-ethylhexyl esters	368.65; 396.7	C8	C16 - 18	C24H48O2; C26H52O2
CAS 26399-02-0	2-ethylhexyl oleate	394.67	C8	C18	C26H50O2
CAS 868839-23-0	propylheptyl octanoate	284.48	C10	C8	C18H36O2
CAS 3687-46-5	decyl oleate	422.73	C10	C18	C28H54O2
CAS 59231-34-4 (a)	isodecyl oleate	422.73	C10	C18	C28H54O2
CAS 36078-10-1	dodecyl oleate	450.78	C12	C18	C30H58O2
CAS 95912-86-0	Fatty acids, C8 - 10, C12 - 18-alkyl esters	312.53 – 424.74	C12 - 18	C8 - 10	C20H40O2; C22H44O2; C26H52O2; C28H56O2
CAS 95912-87-1	Fatty acids, C16 - 18, C12 - 18-alkyl esters	424.74 - 536.96	C12 - 18	C16 - 18	C28H56O2; C30H60O2; C34H68O2; C36H72O2
CAS 91031-91-3	Fatty acids, coco, isotridecyl esters	382.66 - 410.72	C13	C12 – 18	C25H50O2; C27H54O2
CAS 85116-88-7	Fatty acids, C14 - 18 and C16 - 18 unsaturated, isotridecyl esters	410.72 - 466.82	C13	C14 – 18	C27H54O2; C29H56O2; C31H60O2; C31H62O2
CAS 95912-88-2	Fatty acids, C16 - 18, isotridecyl esters	438.78 - 466.83	C13	C16 – 18	C29H58O2; C31H62O2
CAS 3234-85-3	tetradecyl myristate	424.74	C14	C14	C28H56O2
CAS 22393-85-7	tetradecyl oleate	478.84	C14	C18	C32H62O2
CAS 101227-09-2	Fatty acids, C16 - 18, 2-hexyldecyl esters	480.85; 508.90	C16	C16 – 18	C32H64O2; C34H68O2
CAS 94278-07-6	2-hexyldecyl oleate	506.89	C16	C18	C34
CAS 97404-33-6	Fatty acids, C16 - 18, C16 - 18-alkyl esters	480.85 - 536.97	C16 – 18	C16 – 18	C32H64O2; C34H68O2; C36H72O2
CAS 72576-80-8	isooctadecyl palmitate	508.90	C18	C16	C34H68O2
CAS 3687-45-4	(Z)-octadec-9-enyl oleate	532.92	C18	C18	C36H68O2
CAS 17673-56-2	(Z)-octadec-9-enyl (Z)-docos-13-enoate	589.03	C18	C22	C40H76O2
CAS 96690-38-9	Fatty acids, C16 - 18, 2-octyldodecyl esters	536.96; 565.01	C20	C16 – 18	C36H72O2; C38H76O2
CAS 93803-87-3	2-octyldodecyl isooctadecanoate	565.01	C20	C18	C38H70O2
CAS 17671-27-1	docosyl docosanoate	649.17	C22	C22	C44H88O2
CAS 111937-03-2 (c)	isononanoic acid, C16 - 18 alkyl esters	382.66; 410.72	C16 - 18	C9	C25H50O2; C27H54O2

(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.

(c) Surrogate substances are chemicals of structurally similar fatty acid esters. Available data on these substances are used for assessment of (eco-)toxicological properties by read-across on the same basis of structural similarity and/or mechanistic reasoning as described below for the present category.

Grouping of substances into this category is based on:

(1) common functional groups: all the members of the category are esters of a mono-functional alcohol with one carboxylic (fatty) acid chain. The fatty alcohol moiety has chain lengths from C8 - C22 (uneven/even-numbered, including saturated and unsaturated, and branched and linear chains) in varying proportions. The fatty acid moiety consists of carbon chain lengths from C8 - C22 (uneven/even-numbered) and includes saturated and unsaturated, and branched and linear chains bonded to the alcohol, resulting in mono-esters; and

(2) common precursors and the likelihood of common breakdown products via biological processes, which result in structurally similar chemicals: the members of the category result from esterification of the alcohol with the respective fatty acid(s). Esterification is, in principle, a reversible reaction (hydrolysis). Thus, the alcohol and fatty acid moieties are simultaneously precursors and breakdown products of the category members. Monoesters are hydrolysed by enzymes in the gastrointestinal tract. The rate varies depending on the acid and alcohol chain length, but is relatively slow compared with the ester bonds of triglycerides (Mattson and Volpenhein, 1969; Savary and Constantin, 1970). The hydrolysis products are absorbed via the lymphatic system and subsequently enter the bloodstream. Fatty acids can be oxidised or re-esterified and stored, depending on the need for metabolic energy. The oxidation occurs primarily via beta-oxidation, which involves the sequential cleavage of two-carbon units, released as acetyl-CoA through a cyclic series of reactions catalysed by several specific enzymes. This happens in the mitochondria and, to a lesser degree, the peroxisomes (Lehninger et al., 1993). Alternative oxidation pathways (alpha- and omega-oxidation) are available and are relevant for degradation of branched fatty acids. Unsaturated fatty acids require additional isomerization prior to entering the β-oxidation cycle. The alcohol is, in general, enzymatically oxidized to the corresponding carboxylic acid, which can then be degraded via β-oxidation (Lehninger et al., 1993). (Refer to IUCLID Section 5.3 “Bioaccumulation” and 7.3 “Toxicokinetics, metabolism and distribution” for details); and

(3) constant pattern in the changing of the potency of the properties across the category: the available data show similarities within the category in regard to physicochemical, environmental fate, ecotoxicological and toxicological properties.

a) Physicochemical properties:

The molecular weight of the category members ranges from 284.48 to 649.17 g/mol. The physical appearance is related to the chain length of the fatty acid moiety, the degree of saturation and the branching. Monoesters of short-chain and/or unsaturated and/or branched fatty acids are mainly liquid, while the long-chain fatty acids are generally solids. All the category members are non-volatile (vapour pressure:<0.0001 Pa (minimum) - 0.11 Pa (maximum)). The octanol/water partition coefficient increases with increasing fatty acid chain length, ranging from 7.67 (C8 (FA)/C12iso (FAlc.) ester)) to 20.51 (C22-monoester). The water solubility is low for all category members (< 1 mg/L or even < 0.05 mg/L).

b) Environmental fate and ecotoxicological properties:

Considering the low water solubility (< 1 mg/L or even < 0.05 mg/L) and the potential for adsorption to organic soil and sediment particles (log Koc > 5), the main compartments for environmental distribution are expected to be the soil and sediment. Nevertheless, persistency in these compartments is not expected since all members of the LCAE Category are readily biodegradable and are thus expected to be eliminated in sewage treatment plants to a high extent. Release to surface waters, and thereby exposure of sediment, is very unlikely. Thus, the soil is expected to be the major compartment of concern. Nevertheless, the category members are expected to be metabolised by soil microorganisms. Evaporation into air and the transport through the atmosphere to other environmental compartments is not expected since the category members are not volatile based on the low vapour pressure (vapour pressure: <0.0001 Pa (minimum) - 0.11 Pa (maximum)). All members of the category did not show any effects on aquatic organisms in the available acute and chronic tests representing the category members up to the limit of water solubility. Moreover, bioaccumulation is assumed to be low since the category members undergo common metabolic pathways and will be excreted or used as energy source for catabolism.

c) Toxicological properties:

The available data indicate that all the category members show similar toxicological properties. Thus, none of the category members caused acute oral, dermal or inhalation toxicity, or skin or eye irritation, or skin sensitisation. No treatment-related effects were noted up to and including the limit dose of 1000 mg/kg bw/day after repeated oral exposure in a total of 6 studies. In one study the NOAEL was set at 300 mg/kg bw/day, due to reduced food intake and weight loss observed in dams at the highest dose level. These adverse systemic effects subsequently caused impaired fertility in the dams, and reduced pup viability and body weight. However, considering all the available data the category members have a very limited potential for toxicity. The substances did not show a potential for toxicity to reproduction, fertility and development unless systemic toxicity was also evident at the same dose level. No mutagenic or clastogenic potential was observed.

The available data allows for an accurate hazard and risk assessment of the category and the category concept is applied for the assessment of environmental fate and environmental and human health hazards. Thus, where applicable, environmental and human health effects are predicted from adequate and reliable data for source substance(s) within the group, by interpolation to the target substances in the group (read-across approach), applying the group concept in accordance with Annex XI, Item 1.5, of Regulation (EC) No 1907/2006. In particular, for each specific endpoint the source substance(s) structurally closest to the target substance is/are chosen for read-across, with due regard to the requirements for adequacy and reliability of the available data. Structural similarities and similarities in properties and/or activities of the source and target substance are the basis of read-across.

A detailed justification for the grouping of chemicals and read-across is provided in the technical dossier (see IUCLID Section 13).

 

The aquatic toxicity data of the LCAE category members are presented in the following table.

Aquatic toxicity data of the LCAE category members

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
26399-02-0 (b)	--	--	EC50 (48 h) > 100 mg/L	NOEC (21 d) > 1 mg/L	EC50 (72 h) > 100 mg/L	--
3687-46-5	LC50 (96 h) > 3000 mg/L	Waiving based on CSA	RA: CAS 26399-02-0	RA: CAS 26399-02-0 RA: CAS 36078-10-1	RA: CAS 26399-02-0 RA: CAS 36078-10-1	RA: CAS 36078-10-1
59231-34-4 (a)	RA: CAS 3687-46-5 RA: CAS 36078-10-1	Waiving based on CSA	RA: CAS 26399-02-0	RA: CAS 26399-02-0 RA: CAS 36078-10-1	RA: CAS 26399-02-0 RA: CAS 36078-10-1	RA: CAS 36078-10-1
36078-10-1	LL50 (96 h) > 100 mg/L	Waiving based on CSA	Data waiving	NOEC (21 d)≥ 100 mg/L	NOELR (72 h) ≥ 100 mg/L	NOEC (3 h) ≥ 1000 mg/L
95912-86-0	LL50 (96 h) > 100 mg/L	Waiving based on CSA	Data waiving	NOELR (21 d) ≥ 10 mg/L	EC50 (72 h) > 1000 mg/L   NOELR (72 h) ≥ 1000 mg/L	EC10 (3 h) > 1000 mg/L
95912-87-1	LC50 (96 h) > 10000 mg/L	Waiving based on CSA	EL50 (48 h) > 100 mg/L	RA: CAS 36078-10-1 RA: CAS 26399-02-0 RA: CAS 3687-45-4	RA: CAS 36078-10-1 RA: CAS 26399-02-0	RA: CAS 36078-10-1 EC10 (30 min) > 10000 mg/L (RL3 study)
91031-91-3	RA: CAS 3234-85-3 RA: CAS 95912-86-0	Waiving based on CSA	RA: CAS 3234-85-3	RA: CAS 95912-86-0	RA: CAS 3234-85-3 RA: CAS 95912-86-0	RA: CAS 95912-86-0 RA: CAS 3234-85-3
85116-88-7	RA: CAS 36078-10-1 RA: CAS 3687-46-5	Waiving based on CSA	RA: CAS 26399-02-0	RA: CAS 26399-02-0 RA: CAS 36078-10-1	RA: CAS 26399-02-0 RA: CAS 36078-10-1	RA: CAS 36078-10-1
95912-88-2	RA: CAS 36078-10-1 RA: CAS 95912-87-1 RA: CAS 3687-46-5	Waiving based on CSA	RA: CAS 26399-02-0 RA: CAS 95912-87-1	RA: CAS 26399-02-0 RA: CAS 36078-10-1 RA: CAS 3687-46-5	RA: CAS 26399-02-0 RA: CAS 36078-10-1	RA: CAS 36078-10-1
3234-85-3	LC50 (96 h) > 100 mg/L (> 0.189 µg/L (measured))	Waiving based on CSA	EC50 (48 h) > 100 mg/L (> 0.128 µg/L (measured))	RA: CAS 95912-86-0	NOELR (72 h) ≥ 100 mg/L	NOEC (28 d): ≥ 100 mg/L RA: CAS 95912-86-0
22393-85-7	RA: CAS 36078-10-1 RA: CAS 3687-46-5	Waiving based on CSA	RA: CAS 26399-02-0	RA: CAS 36078-10-1 RA: CAS 26399-02-0	RA: CAS 36078-10-1 RA: CAS 26399-02-0	RA: CAS 36078-10-1
101227-09-2	LC50 (96 h) > 10000 mg/L	Waiving based on CSA	EL50 (48 h) > 1000 mg/L	RA: CAS 93803-87-3	RA: CAS 94278-07-6 RA: CAS 93803-87-3	RA: CAS 93803-87-3
94278-07-6	--	--	EL50 (48 h) > 0.104 g/L	--	EL50 (72 h) > 0.104 g/L	--
97404-33-6	RA: CAS 36078-10-1 RA: CAS 95912-87-1 RA: 3687-46-5	Waiving based on CSA	RA: CAS 26399-02-0 RA: CAS 95912-87-1	RA: CAS 26399-02-0 RA: CAS 36078-10-1 RA: 3687-46-5	RA: CAS 26399-02-0 RA: CAS 36078-10-1	RA: CAS 36078-10-1
72576-80-8	RA: CAS 36078-10-1 RA: CAS 95912-87-1	Waiving based on CSA	RA: CAS 95912-87-1	RA: CAS 3687-45-4 RA: CAS 36078-10-1	RA: CAS 36078-10-1	RA: CAS 36078-10-1
3687-45-4	RA: CAS 36078-10-1 RA: CAS 95912-87-1	Waiving based on CSA	RA: CAS 95912-87-1	NOELR (21 d) ≥ 100 mg/L	RA: CAS 36078-10-1	RA: CAS 36078-10-1
17673-56-2	RA: CAS 36078-10-1 RA: CAS 95912-87-1	Waiving based on CSA	RA: CAS 95912-87-1	RA: CAS 3687-45-4	RA: CAS 36078-10-1	RA: CAS 36078-10-1
96690-38-9	RA: CAS 93803-87-3	Waiving based on CSA	RA: CAS 93803-87-3	RA: CAS 93803-87-3	RA: CAS 93803-87-3	RA: CAS 93803-87-3
93803-87-3	LL50 (96 h) > 100 mg/L	Waiving based on CSA	EL50 (48 h) > 86 mg/L	Expert statement: Study technically not feasible	EL50 (72 h) > 100 mg/L NOELR (72 h) ≥ 100 mg/L	NOEC (14 d) ≥ 14.2 mg/L
17671-27-1	RA: CAS 36078-10-1 RA: CAS 95912-87-1	Waiving based on CSA	RA: CAS 95912-87-1	RA: CAS 3687-45-4	RA: CAS 36078-10-1	RA: CAS 36078-10-1

(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. Lack of data for a given endpoint is indicated by “--“.

 

CSA: Chemical Safety Assessment

In accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5, grouping and read-across, the LCAE Category members are not considered to be harmful to aquatic organisms based on the results from available short-term studies with fish, aquatic invertebrates and algae and available long-term results on toxicity to aquatic invertebrates.

All category members are structurally similar and read-across was performed to the structurally most similar category member(s). The available studies cover the variability of the category with different alcohol and fatty acid chain lengths. The data gaps within the category were filled by interpolation and if necessary by extrapolation since the category members are characterized by a similar pattern in the ecotoxicological toxicity profile. No trend in toxicity was observed since no effects were recorded up to the limit of water solubility, hence the use of extrapolation does not decrease the confidence in the read across approach in this case. There is no convincing evidence that any one of the category members might lie out of the overall profile of this category.

The LCAE Category members are expected to be metabolized in aquatic organisms to a high extent (see IUCLID Section 5). Moreover, the enzymatic hydrolysis products (fatty acid and fatty alcohol) can be used as energy source and are major constituents of living organisms (e.g. part of the phospholipid bilayer, muscle tissue and liver). Considering this it is assumed that aquatic toxicity is unlikely to occur.

Short-term toxicity to fish

Short-term toxicity studies to fish conducted according to internationally accepted guidelines are available for the LCAE category members 9-Octadecenoic acid (9Z)-, decyl ester (CAS 3687-46-5), fatty acids, C16 - 18, C12 - 18-alkyl esters (CAS 95912-87-1), tetradecyl myristate (CAS 3234-85-3), fatty acids, C16 - 18, 2-hexyldecyl esters (CAS 101227-09-2), 2-octyldodecyl isooctadecanoate (CAS 93803-87-3), dodecyl oleate (CAS 36078-10-1) and fatty acids, C8 - 10, C12 - 18-alkyl esters (CAS 95912-86-0). No effects were observed up to the limit of water solubility. The available studies cover the variability of the category with different fatty alcohol, and representative fatty acid chain, lengths.

Thus, most of the data gaps can be covered by interpolation. For the category members containing fatty acids and fatty alcohols > C18 the data gaps were filled by extrapolation. This approach is justified since it is very unlikely that toxicity occurs based on the nature of the substances, i.e. the LCAE category members are characterized by very low water solubility limiting the dissolved (bioavailable) concentration in the water phase to an extent that aquatic toxicity is unlikely to occur. Moreover, it is known from literature that very long chain alcohols (> C16) and long chain fatty acids (> C14) are not harmful to aquatic organisms. The toxicity of long chain fatty acids correlates with the hydrophobicity (log Kow) of the substance (Onitsuka et al., 1989). A “cut-off” point of log Kow 4.2 was established where aquatic toxicity is of negligible concern. No toxicity of fatty acids was observed for substances with log Kow > 4.2. The same was shown for long-chain alcohols (> C16). Due to the limited water solubility and low environmental concentration acute effects to fish are very unlikely (OECD, 2006).

Long-term toxicity to fish

There are no long-term fish studies available for the LCAE category members. The chemical safety assessment according to Annex I of Regulation (EC) No 1907/2006 does not indicate the need to investigate further the long-term toxicity to fish. Thus, in accordance to Annex IX, column 2 no further long-term toxicity test to fish is proposed. Available short-term studies for fish, aquatic invertebrates and algae, all indicate no potential for aquatic toxicity. Moreover NOEC values obtained from algal growth studies and daphnia reproduction studies are clearly above the limit of water solubility. As there was no sign that invertebrates are less sensitive than fish in the short-term tests, it cannot be expected that a long-term test with fish will generate different results than the existing long-term tests with aquatic invertebrates. Due to their ready biodegradability it is not likely that aquatic organisms will be exposed to the LCAE category members since they will be ultimately degraded in sewage treatment plants. Thus, based on the above mentioned results, it can be excluded that any substance within the category will exhibit chronic toxicity to fish up to the limit of water solubility. Hence due to animal welfare reasons and to avoid unnecessary vertebrate tests, no further long-term test with fish was proposed.

Short-term toxicity to aquatic invertebrates

Short-term toxicity studies with aquatic invertebrates are available for the category members2-ethylhexyl laurate (CAS 26399-02-0), fatty acids, C16 - 18, C12 - 18-alkyl esters (CAS 95912-87-1), tetradecyl myristate (CAS 3234-85-3), fatty acids, C16 - 18, 2-hexyldecyl esters (CAS 101227-09-2), 2-hexyldecyl oleate (CAS 94278-07-6) and 2-octyldodecyl isooctadecanoate (CAS 93803-7-3).No toxicity was observed up to the limit of water solubility in the available studies. The available studies cover the variability of the category with different fatty alcohol and representative fatty acid chain lengths. Most of the data gaps were covered by interpolation. Extrapolation was only conducted for the substances with longer chain fatty acids (≥ C16) and alcohols (≥ C18) which can be adequately justified for the short-term toxicity to fish endpoint due to the lack of toxicity and similar profile. In conclusion the LCAE category members are of low acute toxicity to aquatic invertebrates.

Long-term toxicity to aquatic invertebrates

Four long-term toxicity studies with aquatic invertebrates are available for the LCAE category members 2-ethylhexyl laurate (CAS 26399-02-0), dodecyl oleate (CAS 36078-10-1), fatty acids, C8 - 10, C12 - 18-alkyl esters (CAS 95912-86-0) and (Z)-octadec-9-enyl oleate (CAS 3687-45-4). No effects were observed up to the limit of water solubility. Moreover, one expert statement is available for 2-octyldodecyl isooctadecanoate (CAS 93803-87-3) showing that the study is technically not feasible (Bogers, 1998). It was not possible to determine the concentrations of the test substance analytically. It was further stated that it would be unlikely that bioavailable concentrations will ever occur in the water phase due to the characteristics of the substance (log Kow > 7). The high hydrophobicity (log Kow > 7) is characteristic for all category members. Thus, it can be expected that the bioavailability in the water phase is negligible.

The available study with the category member 2-ethylhexyl oleate is characterized as an ester of a C8 (branched) alcohol and C18:1 fatty acid thus covering the LCAE category members containing a small chain alcohol component (C8-C14) and category members containing fatty acids with a chain lengths of C18 (unsaturated and saturated). The second study with the category member dodecyl oleate (CAS 36078-10-1) is covering the LCAE category members with a fatty acid chain length of C16-C18 and fatty alcohol chain lengths C10iso-C14. The third study with the category member fatty acids, C8 - 10, C12 - 18-alkyl esters (CAS 95912-86-0) is essential for the assessment of the long-term toxicity to aquatic invertebrates for the category members characterized by fatty acid chain length of C8-C14 and fatty alcohol chain lengths of C12-C14. Additionally, the fourth study with (Z)-octadec-9-enyl oleate was performed to cover the upper end of the LCAE category members characterized by fatty acid chain lengths of C16-C22 and fatty alcohol chain lengths of C18-C22. The structural variety of the LCAE category members is sufficiently covered by the available studies. All results do not lie out of the overall ecotoxicological profile of the category. Since the available chronic studies did not show chronic toxicity to aquatic invertebrates and it is known from literature (Onitsuka et al., 1989; OECD, 2006) that fatty acids and fatty alcohols are not harmful to aquatic organisms as justified in the endpoint summary for the acute fish endpoint, the LCAE category members are not harmful to aquatic invertebrates.

Toxicity to aquatic algae

Studies with aquatic algae are available for the LCAE category members 2-ethylhexyl laurate (CAS 26399-02-0), dodecyl oleate (CAS 36078-10-1), tetradecyl myristate (CAS 3234-85-3), 2-hexyldecyl oleate (CAS 94278-07-6), 2-octyldodecyl isooctadecanoate (CAS 93803-7-3) and fatty acids, C8 - 10, C12 - 18-alkyl esters (CAS 95912-86-0). No toxicity was observed up to the limit of water solubility in the available studies. The available studies cover the variability of the category with different alcohol components and representative fatty acid chain lengths. The assessment of the lower end of the category is supported by the study with fatty acids, C8 - 10, C12 - 18-alkyl esters. Most of the data gaps were estimated by interpolation. Extrapolation was conducted for the substances with longer chain fatty acids (≥ C16) and alcohols (≥ C18) like adequately justified for the short-term toxicity to fish endpoint mentioned above. In conclusion the category members are of low toxicity to aquatic algae.

Toxicity to microorganisms

Toxicity to microorganisms was investigated for the category members dodecyl oleate (CAS 36078-10-1), fatty acids, C8 - 10, C12 - 18-alkyl esters (CAS 95912-86-0), fatty acids, C16 - 18, C12 - 18-alkyl esters (CAS 95912-87-1) and 2-octyldodecyl isooctadecanoate (CAS 93803-7-3).

The study with fatty acids, C16 - 18, C12 - 18-alkyl esters (CAS 95912-87-1) was not considered to be reliable since only one single species (Pseudomonas putida) was tested and the test method did not meet today’s standard. Nevertheless, no effects on O2-consumption were observed. This result is in line with the results obtained from the other available studies. They were performed according to OECD 209. In some cases a toxicity control from the biodegradation study was used to derive a NOEC. No effects on respiration of activated sludge microorganisms were observed in all available studies and no inhibition of the biodegradation was recorded in the biodegradation studies. The studies cover the variability of the category members regarding the fatty acid and fatty alcohol chain length. 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 is anticipated for the LCAE category members.

Conclusion

No effects on aquatic organisms were observed in the available studies for the LCAE category members in any of the three trophic levels (fish, daphnia, algae) for substances within the category up to the limit of water solubility, neither in the short-term toxicity tests nor in long-term tests with aquatic invertebrates. The LCAE 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.