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Short-term toxicity to aquatic invertebrates

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FATTY ACIDS, C14-18 AND C16-18-UNSATD., ZINC SALTS:
Based on similar structural analogy, water solubility and zinc content of Fatty acids, C14-18 and C16-18-unsatd., zinc salts (CAS 67701-12-6) 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 Fatty acids, C14-18 and C16-18-unsatd., zinc salts.
The acute toxicity of the structural analogue (i. e. a similar fatty acid zinc salt: fatty acids, C16-18, zinc salts) to invertebrates is above the water solubility limit of around 1 mg/L. Therefore, the acute toxicity of Fatty acids, C14-18 and C16-18-unsatd., zinc salts to invertebrates is also expected to be above the water solubility. 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 EC50 values) are:
-for Ceriodapnia dubia: 0.413 mg Zn/l (single value) at low pH and low hardness
-for Ceriodapnia dubia: >0.53 mg Zn/l (single value) at low pH and high hardness
-for Ceriodapnia dubia: 0.147 mg Zn/l (geomean value) at neutral/high pH and low hardness
-for Ceriodapnia dubia: 0.228 mg Zn/l (geomean value) at neutral/high pH and high hardness

Key value for chemical safety assessment

Additional information

FATTY ACIDS, C14 -18 AND C16 -18 -UNSATD., ZINC SALTS:

Based on similar structural analogy, water solubility and zinc content of Fatty acids, C14-18 and C16-18 -unsatd., zinc salts (CAS 67701-12-6) 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 Fatty acids, C14-18 and C16-18-unsatd., zinc salts.

Acute toxicity of the structural analogue fatty acids, C16-18, zinc salts to the water flea Daphnia magna at pH 6 and 8: the EC50 was not reached up to a loading rate of 100 mg fatty acids, C16-18, zinc salts/L; the EC50 is > 100 mg/L. The toxicity of the substance fatty acids, C16-18, zinc salts to Daphnia magna is (far) above the water solubility limit of around 1 mg/l. 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): "The acute toxicity of zinc distearate to the water flea Daphnia magna was determined according to OECD 202 in M7 medium at pH 6 and 8 (see also Chapter 1). Up to a loading rate of 100 mg zinc distearate/L the EC50was not reached. The zinc concentration (detected using ICP-MS) at the beginning of the test was 1.2 mg Zn/L at pH 8 and 0.8 mg Zn/L at pH 6, at a loading rate of 100 mg zinc distearate/L."

Since the structural analogue is not toxic to aquatic invertebrates up to and including its water solubility limit of around 1mg/L, Fatty acids, C14-18 and C16-18-unsatd., zinc salts is also not expected to be an acute hazard to aquatic invertebrates. This is supported by the results of a screening study on another structural analogue zinc bis[12-hydroxystearate] (Rudolf 2002) in which an EC50 was not reached at a nominal loading of 1000 mg/L (Rudolf 2002).

Furthermore, the toxicity of zinc dilaurate to Daphnia magna is above the water solubility limit ranging from 5.2 to 6.4 mg/L; an EC50 was also not reached up to 10 mg zinc dilaurate/L at pH 7.8. 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 acutely toxic to invertebrates. In sum, a derivation of a respective PNEC does not appear to be necessary. However, the PNEC water does not cover only short-term toxicity but also long-term toxicity. As aquatic long-term toxicity data are not available, a read-across to insoluble/slightly soluble zinc substances is made, and the PNEC water as derived in the Chemical Safety Assessment of "Zinc" within the framework of Regulation (EC) No 1907/2006 is read-across to Fatty acids, C14-18 and C16-18-unsatd., zinc salts. For a comprehensive overview of the ecotoxicity of zinc, see the hazard assessment of "Zinc" within the framework of Regulation (EC) No 1907/2006 as follows:

ZINC:

Many good quality and relevant data for 5 standard 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).

Ceriodaphnia dubia is for all test conditions the most sensitive species.

Key data (lowest EC50 values) are:

-for Ceriodapnia dubia: 0.413 mg Zn/l (single value) at low pH and low hardness

-for Ceriodapnia dubia: >0.53 mg Zn/l (single value) at low pH and high hardness

-for Ceriodapnia dubia: 0.147 mg Zn/l (geomean value) at neutral/high pH and low hardness

-for Ceriodapnia dubia: 0.228 mg Zn/l (geomean value) at neutral/high pH and high hardness