Zinc bis[12-hydroxyoctadecanoate]

Short-term toxicity to fish

Description of key information

Zinc bis[12-hydroxyoctadecanoate]:
Based on similar structural analogy, water solubility and zinc content of zinc bis[12-hydroxyoctadecanoate] (CAS 35674-68-1) and Fatty acids, C16-18, zinc salts (CAS 91051-01-3), a 1:1 read-across of ecotoxicological data of Fatty acids, C16-18, zinc salts is applied to zinc bis[12-hydroxyoctadecanoate].
The acute toxicity of the structural analogue (i. e. a similar fatty acid zinc salt: substance fatty acids, C16-18, zinc salts) to fish is above the water solubility limit of around 1 mg/L. Therefore, the acute toxicity of zinc bis[12-hydroxyoctadecanoate] to fish is also expected to be above the water solubility (ranging from < 0.01 - 1.69 mg/L). For a comprehensive overview of the ecotoxicity of zinc, see the hazard assessment of "Zinc" within the framework of Regulation (EC) No 1907/2006 (see Appendix 1 of the CSR).
ZINC:
Key data (lowest LC50 values) are: 
-for Oncorrhynchus Mykiss: 0.169 mg Zn/l (single value) at neutral/high pH and low hardness
-for Pimephales promelas (single values) : 0.780 mg Zn/l  at low pH (high hardness) and 0.330 mg Zn/l at neutral/high pH, high hardness
-for Pimephales promelas: LC50 0.780 mg Zn/l (at low pH); 0.33mg Zn/l at neutral/high pH

Additional information

Zinc bis[12-hydroxyoctadecanoate]

Based on similar structural analogy, water solubility and zinc content of zinc bis[12-hydroxyoctadecanoate] (CAS 35674-68-1) and Fatty acids, C16-18, zinc salts (CAS 91051-01-3), a 1:1 read-across of ecotoxicological data of Fatty acids, C16-18, zinc salts is applied to zinc bis[12-hydroxyoctadecanoate].

 

Aquatic fish toxicity data on fatty acids, C16 -18, zinc salts are available from a study performed according to EU Method C.1 (Acute Toxicity for Fish) in the former version of 1992 (Henkel KGaA, 1995), from a study performed according to OECD Guideline 203 (Fish, Acute Toxicity Test) but reported only in a short study report (TÜV Bayern Sachsen E.V., 1992) and from an old publication (Dowden and Bennett, 1965). None of the studies do fully comply with the requirements of the recent guidelines regarding performance and/or documentation. However, in accordance to the judgement given on the same set of data in the EU risk assessment zinc distearate carried out within the framework of EU Existing Chemicals Regulation (EEC) No 793/93 (Final report R074_0805_env, May 2008), the total set of data is regarded as sufficient to come to a conclusion on the intrinsic aquatic fish toxicity of the substance. In accordance to Annex XI of Regulation (EC) No 1907/2006, the total set of data is used in a weight of evidence approach to fulfil REACH data requirements on aquatic fish toxicity. In the most reliable study (Henkel KGaA, 1995), the acute toxicity of fatty acids, C16 -18, zinc salts to fish was investigated according to EU Method C.1 (Acute Toxicity for Fish) in the former version of 1992. Fish (Danio rerio) were exposed for 96 hours to nominal concentrations of 0 (control), 1000, 3000 and 10000 mg/L under semi-static conditions. Up to and including the highest nominal test concentration neither behavioural abnormalities nor mortality occurred. Test was conducted at nominal concentrations far exceeding the water solubility by 3 to 4 orders of magnitude. Measures to disperse the test substance in the test water were used. The actual test concentrations were below the detection limit (1 mg/L) of the analytical method used. Therefore, a numeric value for the actually test concentrations can not be given. However, due to the very high level of nominal test concentrations and the measures used to disperse the test substance in the test medium, it is very likely that the actual test concentrations included the water solubility limit which is in the range of 1 mg/l (c.f. EU risk assessment zinc distearate carried out within the framework of EU Existing Chemicals Regulation (EEC) No 793/93 (Final report R074_0805_env, May 2008). Effects were also not observed at nominal fatty acids, C16 -18, zinc salts concentrations up to the water solubility limit in two further studies. In accordance with the evaluation of the EU Risk assessment, from the results of these tests it is concluded, that the toxicity of the substance fatty acids, C16 -18, zinc salts to fish is (far) above the water solubility limit of around 1 mg/L.

In addition, information on acute fish toxicity of zinc dilaurate is available from a study performed according to OECD Guideline 203. Fish (Danio rerio) were exposed for 96 hours to nominal concentrations of 0 (control), 0.1, 1, 10 mg/L under static conditions. At all tested concentrations, including the highest nominal test concentration, neither behavioural abnormalities nor mortality occurred.The acute toxicity of zinc dilaurate to fish is above the water solubility limit ranging from 5.2 to 6.4 mg/L (Muckle, 2009). Thus, acute toxicity data from another structural analogue, i.e. zinc dilaurate - a zinc salt of a shorter-chained fatty acid (C12) and thus relatively higher zinc content, support the conclusion that zinc salts of fatty acids are not toxic to fish.

The test results are not suitable to derive a PNEC, since a measured value on actually tested concentrations was not provided. However, a PNEC for aquatic fish toxicity is not necessary either as up to and including the water solubility limit, the test substance has proved to be non-toxic to fish. Therefore, the information available, is reliable, adequate, relevant and sufficient to come to a final conclusion on the intrinsic aquatic fish toxicity of the test substance and thus meet the criteria for a weight of evidence approach under REACH.

Conclusions from EU RAR Zinc distearate (CAS-No.: 557-05-1 & 91051-01-3 EINECS-No.: 209-151-9 & 293-049-4) Part 1 - Environment (Final report R074_0805_env, May 2008:"In the three available acute toxicity tests with fish (TÜV, 1992: fish species not reported; Berger, 1995a,b: zebrafish Brachydanio rerio; Dowden & Bennett, 1965: bluegill Lepomis macrochirus), no effects were observed at nominal zinc distearate concentrations up to the water solubility limit or at nominal concentrations that were 3 to 4 orders of magnitude higher than the water solubility limit. From these data, although very limited, it is concluded that the toxicity of zinc distearate to bacteria and the acute toxicity of zinc distearate to Daphnia magna and fish is (far) above the water solubility limit of around 1 mg/L)".

A similar lack of aquatic toxicity to fish is considered for zinc bis[12-hydroxyoctadecanoate] (CAS 35674-68-1). For a comprehensive overview of the acute aquatic toxicity of (soluble) zinc to fish, see the hazard assessment of soluble zinc within the framework of Regulation (EC) No 1907/2006 below.

Zinc:

Good quality and relevant data for 5 species. Tests were done according to standard protocol or equivalent.

Data are grouped per species according to

-pH: low (6 -<7) - neutral/high (7 -8.5)

-and hardness: low/medium (<100mg CaCO3/l) and medium/high (>100 mg CaCO3/l).

Fish are generally less sensitive than invertebrates and algae.

Key data (lowest LC50 values) are:

-for Oncorrhynchus Mykiss: 0.169 mg Zn/l (single value) at neutral/high pH and low hardness

-for Pimephales promelas (single values) : 0.780 mg Zn/l at low pH (high hardness) and 0.330 mg Zn/l at neutral/high pH, high hardness

-for Pimephales promelas: LC50 0.780 mg Zn/l (at low pH); 0.33mg Zn/l at neutral/high pH