Fatty acids, C16-18, zinc salts

Endpoint summary

Description of key information

Fatty acids, C16-18, zinc salts:

Aquatic toxicity: freshwater, short-term toxicity

Invertebrates:The acute toxicity of Fatty acids, C16-18 zinc salts toDaphnia magnawas determined according to OECD 202 in M7 medium at pH 6 and 8 (Bouwman et al., 2003). The EC₅₀was not reached up to a loading rate of 100 mg Fatty acids, C16-18 zinc salts/L. At this loading, the zinc concentration at the beginning of the test was 1170 μg Zn/L at pH 8 and 800 μg Zn/L at pH 6. The test report concludes: “No daphnids became immobilised during the test period... Although all daphnids exposed to the undiluted water fraction had test substance on their bodies at the end of the test, this did not hinder them”. It is concluded, that the toxicity of the substance fatty acids, C16-18, zinc salts to daphnia is (far) above the water solubility.

Fish: Information on fish toxicity is 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 older publication (Dowden & Bennett, 1965). In the most reliable study (Henkel KGaA, 1995), fish (Danio rerio) were exposed for 96 hours to nominal concentrations of 0 (control), 1000, 3000 and 10000 mg/L under semi-static conditions. The nominal concentrations far exceed the water solubility of Fatty acids, C16-18, zinc salts by 3 to 4 orders of magnitude. Measures to disperse the test substance in the test water were used. At all tested concentrations, including the highest nominal test concentration, neither behavioural abnormalities nor mortality occurred. In addition, no effects were 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 on zinc distearate (Final report R074_0805_env, May 2008), it is concluded, that the acute toxicity of fatty acids, C16-18, zinc salts to fish is above the water solubility limit of around 1 mg/L.

Algae: The toxic effects of the dissolved fractions of Fatty acids, C16-18, zinc salts on the growth rate of algae (Pseudokirchneriella subcapitata) were studied in three tests according to OECD Guideline 201 (Wenzel, 2010a,b and 2013). Whereas in the first test, the dissolved fraction of a loading of 100 mg/L in a non-standard test medium was diluted in series to allow the calculation of toxicity parameters (EL10, EL50) (Wenzel, 2010a), the dissolved fractions of several loadings (1, 10, and 100 mg/L) in non-standard test medium were tested in the second test according to OECD Series No. 23 (Wenzel, 2010b). In the third test by Wenzel (2013a), lower concentrations were applied (i.e. 0.01, 0.1, 1.0, 10 and 100 mg/L) in the standard test medium to enable the classification for a potential aquatic hazard based on respective loading of the applied dissolved fractions. The EL50 value for the 72-h inhibition of growth rate of Pseudokirchneriella subcapitata in the standard test medium is estimated with > 100 mg/L.

 

Aquatic toxicity: freshwater, long-term toxicity:

Based on the comprehensive data set on aquatic long-term toxicity of zinc and mean values for standard species (i.e.Pseudokircherniella subcapitata, Daphnia magna, Oncorhynchus mykiss), algae appear to be the most sensitive taxa; respective NOEL/EL10 estimates for the long-term toxicity of zinc to invertebrates and fish are substantially higher (more than factor of 4) than the NOEL/EL10 value for algae. Thus, chronic toxicity data for algae determine the worst-case hazard and testing of further species is scientifically not justified. Chronic toxicity data of fatty acids, C16-18, zinc salts are available for algae. The long-term toxic effects of dissolved fractions of fatty acids, C16-18, zinc salts on the growth rate of algae (Pseudokirchnerella subcapitata) were studied in a state-of-the-art test according to OECD Guideline 201 (Wenzel, 2013a). Thedissolved fractions were prepared according to OECD Series No. 23 in the standard test medium to enable the classification for a potential chronic aquatic hazard based ondissolved fractions. Thus,dissolved fractions of the loadings 0.01, 0.1, 1.0, 10 and 100 mg/L were tested; the EL10 value for the 72-h inhibition of growth rate of P. subcapitata in standard test medium amounts to 3.31 mg/L.

Only limited long-term data are available for the aquatic toxicity of fatty acids, C16-18, zinc salts. Thus, read-across to the assessment entities soluble zinc substances and C16-18 fatty acids is applied since zinc cations and fatty acid anions (C16-18) determine fate and toxicity in the environment.Since C16 -18 fatty acids have a low potential for ecotoxicity, the freshwater hazard assemment of fatty acids, C16-18, zinc salt is based on zinc ions.Please refer to the endpoint summary of the respective assessment entityfor further details.

Marine toxicity:

Marine toxicity data are not available for Fatty acids, C16-18, zinc salts. Thus, read-across to the assessment entities soluble zinc substances and C16-18 fatty acids is applied since zinc cations and fatty acid anions (C16-18) determine fate and toxicity in the environment. Since C16 -18 fatty acids have a low potential for ecotoxicity, the marine hazard assessment of fatty acids, C16-18, zinc salt is based on zinc ions.Please refer to the endpoint summary of the respective assessment entityfor further details.

Conclusions:

The toxicity of Fatty acids, C16-18, zinc salts to bacteria and the acute toxicity of Fatty acids, C16-18, zinc salts to algae, Daphnia and fish is above the water solubility limit of around 1 mg/L.The chronic endpoint of the most sensitive trophic level, i.e. the estimated EL10 value for the 72-h inhibition of algal growth rate by Fatty acids, C16-18, zinc salts in a standard test amounts to 3.31 mg/L(based on testing the dissolved fractions of individual loadings). These conclusions are consistent with conclusions from the EU RAR for the structural analogue 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: "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)."