Oxoaluminium, C16-C18-alkyl esters

Endpoint summary

Description of key information

Based on read across, the substanceis not considered to be acutely toxic to fish, invertebrates or inhibitory to algal growth as the substance is expected to have acute LL or EL50s of >100 mg/L (WAF).

Additional information

Based on read across to aluminium, benzoate C16-18 fatty acids complexes, the substance is not considered to be acutely or chronically toxic to fish, invertebrates or inhibitory to algal growth as the substance is expected to have acute LL or EL50s of >100 mg/L (WAF). No data are available for the toxicity to sediment organisms but sediment toxicity data are not a data requirement at the registered tonnage band.

Short-term toxicity

The literature search identified no ecotoxicological data for the substance and no experimental ecotoxicity data are available for the substance. The hazard testing was conducted on the substance prepared as a 50% w.w. concentration in pharmaceutical white oil. The presence of the oil restricts the solubility of the substance and reduces its bioaccessibility to the aquatic environment therefore, no testing was carried out on the substance as no meaningful results would be achieved. Instead, in order to provide a worst-case scenario for the aquatic ecotoxicity potential for the substance, data have been read across from a structural analogue which was tested in in isolated form (i.e. extracted from base oil).

No novel aquatic ecotoxicity testing on the substance was carried out but novel proprietary data were read across from aluminum, benzoate C16-18-fatty acids complexes. This substance is considered suitable for read-across as it contains a fatty acid moiety coordinated to an aluminium atom. Although it also contains a coordinated benzoate ion, under environmental relevant conditions the benzoate ion has a LC or EC50s of > 100 mg/L for fish (OECD SIDS 2001) and therefore does not contribute any additional toxicity to the substance.

Because of the low aqueous solubility of aluminum, benzoate C16-18-fatty acids complexes, the substance was tested as a Water Accommodated Fraction (WAF). Amounts of test item were added to the surface of the dilutent at the appropriate loading rate. After the addition of the test item, the media was stirred by a magnetic stirrer using a stirring rate such that a vortex was formed to give a dimple at the water surface. The stirring was stopped after 23 hours and the mixture allowed to stand for 1 hour. A wide bore glass tube, covered at one end with Nescofilm was submerged into the vessel, sealed end down, to a depth of approximately 5 cm from the bottom of the vessel. A length of Tygon tubing was inserted into the glass tube and pushed through the Nescofilm seal and the WAFs removed by mid-depth siphoning (the first approximate 75-100 mL discarded), using a glass wool plug if dispersed test item was seen in the aqueous phase, to give the WAF.

While ensuring that media were compatible with the water chemistry requirements of the test species, the tests on the three taxa were conducted using water from the same source with similar characteristics. As the water solubility of the substance is likely to be influenced by the hardness of the water, the ecotoxicity tests were all conducted in media with the same hardness, approximately 150 mg/L CaCO3. As the substance could not be analysed directly, both the aluminium and the total organic carbon were measured in the exposure media.

The acute toxicity of aluminum, benzoate C16-18-fatty acids complexes to rainbow trout (Oncorhynchus mykiss) and Daphnia magna and toxicity to algal growth showed no effects at a water accommodated fraction nominal loading rate of 100 mg/L. Therefore, for fish the 96 hour LL50 is > 100 mg/L (WAF), for Daphnia the 48 hour EL50 is >100 mg/L (WAF) and for algal growth inhibition the 72 hour EL50 is >100 mg/L (WAF). The toxicity to fish, Daphnia and toxicity to algal growth were determined in GLP-compliant, limit tests following OECD guidelines 203, 202 and 201 respectively (Harlan 2013).

Long-term ecotoxicity

No data are available for the long-term ecotoxicity of the substance.

REACH Chapter R5 (ECHA 2011) states that chronic aquatic ecotoxicity testing may be triggered if the CSA indicates that there is a need to investigate further the effects on the environment. Testing may be triggered if additional testing could alter the conclusions on classification, PBT assessment or the level of concern. The substance in isolated form (i.e. extracted from base oil) is considered readily biodegradable but the substance at 50% w.w. concentration in pharmaceutical white oil (i.e. as representative of the form in which it is marketed and used) is considered not readily biodegradable and this conclusion has been used in the hazard assessment. The substance has a low potential for bioaccumulation and is expected to show no acute toxicity at up to 100 mg/L (WAF) based on read across to aluminium, benzoate C16-18 fatty acids complexes. Additional chronic toxicity tests would therefore not lead to changes in the classification or the conclusion that this substance is neither PBT nor vPvB. As the substance is not classified or considered to be PBT/vPvB, an exposure assessment is not required and so additional chronic testing is not required to refine this assessment (ECHA R7b 2012).

However, some read across data are available to provide information on the potential for long-term ecotoxicity of the substance. Algal studies report both acute and chronic endpoints and therefore the data collected from the algal growth inhibition study for aluminum, benzoate C16-18-fatty acids complexes will be read across and used to provide chronic data for this trophic level. The toxicity of aluminum, benzoate C16-18-fatty acids complexes to algal growth showed no effects at a water accommodated fraction loading rate of 100 mg/L. Therefore, the 72 hour NOErLR is 100 mg/L (WAF) (Harlan 2013).

Data read across from Al are also used provide data on the potential for long-term ecotoxicity of the substance. The organic moieties of the substance, and the structural analogue Aluminum, benzoate C16-18-fatty acids complexes, are namely stearic acid, palmitic acid, benzoic acid and isopropyl alcohol (2-propanol). The organic moieties are known to have low toxicity to aquatic organisms and are not classified for hazardous effects on the environment. Therefore, it is assumed that any potential for long-term ecotoxicity would be due to the Aluminium (Al) component of the substances.

The long term ecotoxicity data for Al, as detailed in IUCLID, for algae (Raphidocelis subcapitata, formally Pseudokirchneriella subcapitata), invertebrates (Ceriodaphnia dubia and Daphnia magna) and fish (Pimephales promelas) are summarised in Table 30.

 

Table30. Toxicity of Al to standard freshwater organisms under a range of environmental conditions (taken from Gensemer et al. 2017) 

	Method	Parameter	Endpoint	pH	Hardness	DOC	Concentration.	C.L.
					mgCaCO3/L	mg/L	Total Al µg/L
R. subcapitata	OECD 201	72 h EC10	Growth	6.2	24	0.3	146	92-231
R. subcapitata	OECD 201	72 h EC10	Growth	7.0	24.3	0.3	1263	857-1862
R.subcapitata	OECD 201	72 h EC10	Growth	8.1	24.3	0.3	1083	631-1860
C. dubia	US EPA 2002	7 d EC10	Reproduction	6.3	25	0	20.1	11-37
C. dubia	US EPA 2002	7 d EC10	Reproduction	6.4	60	0	104.1	74-146
C. dubia	US EPA 2002	7 d EC10	Reproduction	6.4	25	2	143	52-393
C. dubia	US EPA 2002	7 d EC10	Reproduction	7.0	25	0.5	190	90-320
C. dubia	US EPA 2002	7 d EC10	Reproduction	8.0	25	0.5	770	450-1030
D. magna	OECD 211	21 d EC10	Reproduction	6.3	140	2	709.4	655-769
P. promelas	Norberg et al. 1985	7 d EC10	Dry weight	6.0	12	0.08	116.9	n.d.
P. promelas	Norberg et al. 1985	7 d EC10	Dry weight	7.1	24	0.81	985.3	516-1882
P. promelas	Norberg et al. 1985	7 d EC10	Dry weight	8.0	24	0.72	4662	2400-9057

n.d. = not determinable

C.L. = Confidence Limits

The toxicity of Al varies due to changes in environmental parameters such as pH, hardness and dissolved organic carbon (DOC), with low pH increasing Al toxicity due to changes in the speciation of Al. There are two main mechanisms of action for Al toxicity;

1. Effects on ion regulation due to exposure to dissolved monomeric species of Al (e.g. Al³⁺ or amorphous Al(OH)₃), at low pH, or

2. Effects of respiration due to the accumulation of precipitated forms of Al at circumneutral pH.

The effects of Al toxicity to aquatic organisms at low pH can be mitigated by increased water hardness and DOC which reduce its bioavailability. The data reported in IUCLID covers effects on standard test organisms taking into consideration changes in the relevant environmental parameters. The data covers a circumneutral pH range of 6-8 which would cover most natural surface waters in Europe. The data have been reported based on total Al concentration because the aquatic toxicity results should cover both the dissolved phase and also the presence of Al solids which can cause adverse physical effects (Gensemer et al. 2017).

The most sensitive toxicity value was for the invertebrate C. dubia with a reported EC10 of 20.1 (11-37) µg/L total Al at pH 6.3, with low water hardness (25 mg/L as CaCO3) and no added DOC. This is a highly conservative toxicity estimate because C. dubia are not tolerant of low pH even in the absence of stressors (i.e. the validity criteria for the test in control animals could not be met at pH 6 and the test was therefore conducted at pH 6.3) (Gensemer et al. 2017). The data provided in Table 31 (Table S1 in the supplemental data from Gensemer et al. 2017) shows that a moderate increase in DOC or water hardness reduces the toxicity of Al to C. dubia to a concentration that is more consistent with other organisms i.e. > 100 µg/L based on total Al. The ecotoxicity data in Table 31 (Table S1 in the supplemental data from Gensemer et al. 2017) has been used in the development of a biotic ligand model (BLM) for Al which can be used to predict chronic Al toxicity under different environmental conditions (Santore et al. 2017) and has been to derive a Predicted No Effect Concentration (PNEC) for total Al of 74.4 μg/L (Cardwell et al. 2017). This PNEC is consistent with other quality standards for Al, as detailed in Table 31, except for standards for waters expected to have a pH < 6.5.

Table 31. Water quality standards for Aluminium across multiple jurisdictions taken from Cardwell et al. 2017)

 

Jurisdiction	Standard type	Water quality conditions^1	Standard value	Unit	Reference
USA	CMC	pH 6.5 - 9	750	μg/L acid-soluble Al	US Environmental Protection Agency (EPA). 1988.
	CCC	pH 6.5 - 9	87
New Mexico	CMC	e^(1.3695[ln(hardness)]+1.8308)	1167	μg/L total recoverable Al	NMED (New Mexico Environment Department). 2013.
	CCC	e^(1.3695[ln(hardness)]+0.9161)	467
Colorado	CMC	e^(1.3695[ln(hardness)]+1.8308)	1167^2	μg/L total recoverable Al	CWQCC (Colorado Water Quality Control Commission). 2013
	CCC	e^(1.3695[ln(hardness)]+0.1158)	238^2
Canada	WQG	pH < 6.5	5^1	μg/L dissolved Al (0.45 μm)	CCREM (Canadian Council of Resource and Environment Ministers). 1987.
	WQG	pH > 6.5	100^1
Australia/ New Zealand	Trigger value	pH < 6.5	0.8	μg/L acid-soluble Al	ANZECC (Australian and New Zealand Environment and Conservation Council). 2000.
	Trigger value	pH > 6.5
European-style calculation	PNEC	ETX	74.4	μg/L total Al (unfiltered)	Cardwell et al. 2017
US EPA-style calculation	CCC	Al BLM	125^3	μg/L total Al (unfiltered)	Cardwell et al. 2017

 

¹ Some standards apply to the water quality conditions detailed while others can be modified for different conditions based on the specified modelling approach.

² Normalized for bioavailability: Hardness 46 mg/L as CaCO3 (Lake Superior Water)

³ Normalized for bioavailability (water quality characteristics for Lake Superior water with BLM Parameters): Ca: 13.62 mg/L, Mg: 2.83 mg/L, Na: 1.44 mg/L, K: 0.5 mg/L, SO₄: 1.42 mg/L, Cl: 3.85 mg/L, Alkalinity: 41.9 mg/L as CaCO₃, DOC: 1.5 mg/L, Temp: 10°C, pH: 7.5.

 

CMC: Criteria Maximum Concentration

CCC: Continuous Criterion Concentration

WQG: Water Quality Guideline

PNEC: Predicted No Effect Concentration

BLM: Biotic Ligand Model

The above data suggests that, under reasonable, normal environmental conditions, Al will not cause a concern for chronic toxicity at concentrations below 74.4 μg/L. The ERGTC have generated data to show that the substance has a low water solubility of ≤ 12.5 µg/L at 20°C based on total Al concentration and, therefore, is unlikely to occur in water at concentrations high enough to cause a toxicity concern. Additionally, the ERGTC have generated data to show that the structural analogue, Aluminium, benzoate C16-18-fatty acids complexes has a low water solubility, ≤ 16 µg/L at 20°C, based on total Al concentration, and, therefore, is also unlikely to occur in water at concentrations high enough to cause a toxicity concern.

Furthermore, the substance and the structural analogue are not used in isolated form but as grease thickeners within base oil. The ERGTC have conducted leaching studies on the aluminium salts in deionised water which show that, when present within a grease base, the grease thickeners are not bioaccessible. The leaching studies were conducted using Water Accommodated Fractions (WAF) at a loading rate of base grease (thickener in a base oil to form a grease matrix) of 1000 mg/L. The base grease samples for the separate leaching studies contained the substance at 50% in medicinal white oil or the structural analogue at 3.5 or 25%. In these leaching studies, no Al was detected in water at the analytical method (ICP-MS) limit of detection (LOD) of 5 µg/L. On the basis of the information presented, neither of the Al thickeners are expected to cause a concern for chronic toxicity to aquatic organisms. Therefore, experimental testing to satisfy REACH data requirements for these endpoints are waived.

This substance has been registered by a Member of the European REACH Grease Thickeners Consortium (ERGTC). A number of decisions have been made in the dossier with regard to the approach taken for registering the substance including the testing strategy and the justification for waiving certain endpoints. Several of the decisions reflect the technical difficulties of testing the substance and the relevance of data with regard to the potential for exposure, given that the substance typically occurs in situ in base oil. A face to face meeting between the ERGTC and ECHA was held in Helsinki on 8th September 2016 which discussed many of these topics and a copy of the minutes from the meeting are attached to the dossier (See section 13 of IUCLID). Therefore, if there are any queries or concerns which arise when the dossier is reviewed, it is requested that the reviewer discuss these with the ERGTC ([e-mail]) as there may be background information and previous discussions between the ERGTC and ECHA which are relevant.