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Description of key information

Short-Term Toxicity to Aquatic Invertebrates

The purpose of this study was to evaluate the acute toxicity of hexyl salicylate to Daphnia magna in a 48 hour, semi-static study with renewal of the test media after 24 hours. This study was carried out to OECD Guideline 202. Nominal exposure concentrations were 0 (control), 0 (solvent control), 0.05, 0.1, 0.23, 0.5 and 1.0 mg/L, the corresponding mean measured concentrations were 0.03, 0.072, 0.140, 0.310 and 0.726 mg/L. The results of the study are based on the mean measured exposure concentrations. The 48 hour EC50 was calculated to be 0.357 mg/L (with 95% confidence limits of 0.228 to 0.871 mg/L), the corresponding no-observed effect concentration was 0.140 mg/L (Pavic and Wydra 2008).

Short-Term Toxicity to Fish

Data from two fish acute toxicity studies are presented: Danio rerio were exposed to the hexyl salicylate at nominal test concentrations of: 0, 1, 10 and 100 mg/L. This study was carried out to OECD Guideline 203, the study appears to have been conducted as a range-finding test with a concentration spacing factor or 10 and only three concentrations tested. Hexyl salicylate was tested over the limit of solubility, without specific preparation and with no analytical verification. At the end of the 96 hour exposure period there was 20% mortality in the nominal 100 mg/L test treatment, therefore the 96 hour LC50 was observed to >100 mg/L (Licata-Messana, 2000).

A read-across report was also provided as support for this data point. The acute toxicity of amyl salicylate toDanio reriowas determined. Based on mean measured concentrations the 96 hour LC0 was determined to be 0.95 mg/L, the corresponding 96 hour LC100 was determined to be 1.90 mg/L. The 96 hour LC50 of 1.34 mg/L was determined by dividing the 96 hour LC0 and LC100 values (Bruns et al, 1992). Due to the similar structural, physical and chemical properties of amyl salicylate, it was considered appropriate for the purposes of read-across to hexyl salicylate.

Toxicity to Aquatic Algae

Two algal studies were performed, one with hexyl salicylate and the other with Cis-3 -Hexenyl Salicylate as a read-across study. The hexyl salicylate study was conducted with a wide spread of concentrations, the highest two of which were above the expected water solubility value, additionally no analytical verification was performed. The Cis-3-Hexenyl Salicylate study was conducted with a range of concentrations that were less than the limit of water solubility and with analytical verification. Therefore the results of the Cis-3-Hexenyl Salicylate study will be used to provide the appropriate endpoint for algae. Due to the similar structural and chemical properties of Cis-3-Hexenyl Salicylate, it was considered appropriate for the purposes of read-across to Hexyl Salicylate.Based on the Cis-3-Hexenyl Salicylate the 72 ErC50 of 0.61 mg/L is the appropriate endpoint. 

Toxicity to microorganisms

No data has been generated to fulfil this data requirement. However, a biodegradation study with hexyl salicylate was conducted according to OECD guideline 301F with a nominal concentration of 100 mg/L.  Under the conditions of the test, hexyl salicylate underwent 91 % biodegradation after 28 days. Biodegradation reached 82 % at the end of the 10-day window (days 2 to 12).

Thus, hexyl salicylate should be regarded as readily biodegradable according to this test.

 

At the concentration used in the test (100 mg/L), hexyl salicylate is not inhibitory to the micro-organisms.

 

In the absence of toxicity study conducted according to OECD guideline 209 the ECHA guidance document, Chapter R7.8.16.1 states the following: “The assumption that the substance under investigation is not inhibitory to the micro-organisms when dosed in the test system is implicit in ready biodegradability testing (i.e. ... OECD 301F). If a compound degrades well in a ready biodegradability test, or does not inhibit the degradation of a positive control at a certain concentration, this concentration can be used as a NOEC value”.

 

Therefore it is considered appropriate to set the NOEC for this endpoint as 100 mg/L.

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