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Short-term toxicity to fish

No data on the toxicity of stearoyl chloride is available. There is a fish study available for palmitoyl chloride (BASF AG, 1998).

 

Palmitoyl chloride hydrolyses rapidly in water therefore fish are mainly exposed to its hydrolysis product, palmitic acid. Test concentrations were clearly above the solubility limit of palmitoyl chloride and palmitic acid as unsoluble test material was visible and the test solutions were cloudy. Test concentrations were analytically verified. No toxic effects within the range of water solubility were observed. The LC50 was determined to be ca. 115 mg/L (BASF, 1998).

With high probability, palmitoyl choride is acutely not harmful to fish.

A semi-static test was performed with sodium stearate (CAS 822 -16 -2; Onitsuka et al., 1989). The LC50 was determined to be 125 mg/L.

A limit test was performed with the hydrolysis product stearic acid (Leach, 1977). After 96-h no toxic effect was observed at the tested concentration of 12 mg/L, which is clearly above the limit of water solubility.

 

The hydrolysis product hydrochloric acid (HCl) was tested in a semi-static acute toxicity test according to OECD 203 withCyprinus carpio. The 96 -h LC50 was 4.92 mg/L (acid equivalent to pH 4.3; OECD 2002). The hydrolysis product HCl is acutely toxic for fish (pH-dependent).

 

Short-term toxicity to aquatic invertebrates

No data on the toxicity of stearoyl chloride and its hydrolysis product stearic acid are available.There is one study with sodium oleate (CAS 143 -19 -1) available, which can be used for a read-across approach. The 24 -h EC50 was determined to be 4.2 mg/L (Huber, 1991, in HERA, 2003).

The hydrolysis product hydrochloric acid (HCl) was tested in a semi-static acute toxicity test according to OECD 202 with Daphnia magna. The 48-h EC50 was 0.492 mg/L (acid equivalent to pH 5.3; OECD 2002). Hydrochloric acid is acutely very toxic to aquatic invertebrates.

 

Toxicity to aquatic algae and cyanobacteria

No data on the toxicity of stearoyl chloride are available. However, since the test substance rapidly hydrolyses in water, algae are mainly exposed to the hydrolysis product stearic acid.

 

The toxicity of stearic acid to algae was assessed via a study with the green alga Pseudokirchneriella subcapitata (Kamaya et al., 2003). Solvent (DMSO) was used to achieve the desired test concentrations. The 72 -h EC50 (cell number) of 11.72 mg/L indicates that stearic acid is acutely harmful to aquatic algae. The determined EC50 lies clearly above the water solubility limit (0.6 mg/L). Therefore it can be assumed that stearic acid is acutely harmful to aquatic algae, but no toxic effects will occur within the range of water solubility. Hydrochloric acid is acutely very toxic to aquatic algae.

 

The hydrolysis product hydrochloric acid (HCl) was tested in an algae growth inhibition test according to OECD 201 with Pseudokirchneriella subcapitata. The 72-h ErC50 was 0.492 mg/L (acid equivalent to pH 5.3), the 72 -h NOEC was 0.097 (acid equivalent to pH 6; OECD 2002).

 

Toxicity to microorganisms

The inhibition of the degradation activity of activated sludge is not anticipated when introduced in appropriately low amounts.