Sodium long chain alkyl salicylate

Short-term toxicity to aquatic invertebrates

Description of key information

48 h EC50 0.15 mg/L (Daphnia magna); OECD 202, EU Method C.2 and OECD 23

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.15 mg/L

Additional information

In the key study, the toxicity potential of the test material to the water flea Daphnia magna was investigated in accordance with the standardised guidelines OECD 202, EU Method C.2 and OECD 23 under GLP conditions. The study was awarded a reliability score of 1 in accordance with the principles for assessing data quality set forth by Klimisch et al. (1997).

The batch of test material tested was not completely soluble in test medium at the initial loading rate prepared. Preparation of test solutions started with a loading rate of 100 mg/L, applying two days of magnetic stirring to ensure maximum dissolution of the test material in the test medium was reached. The resulting dispersion was filtered through a 0.20 µm membrane filter. The resulting Water Soluble Fraction (WSF) was used as highest test concentration and used to prepare the lower test concentrations by subsequent dilution in test medium.

A final EC50 test was performed based on the results obtained in a preliminary test and an initial full test. Twenty Daphnia magna per test group (4 replicates, 5 per replicate) were exposed to an untreated control and to test groups representing 0.10, 0.22, 0.46, 1.0, 2.2 and 4.6 % of a WSF prepared at a loading rate of 100 mg/L. The total exposure period was 48 hours and samples for analytical confirmation of actual exposure concentrations were taken at the start and at the end of the exposure period.

Analysis of the samples taken at the start of the final test showed measured concentrations of 0.016, 0.029, 0.070, 0.14, 0.29 and 0.67 mg/L for the test groups containing 0.10, 0.22, 0.46, 1.0, 2.2 and 4.6 % WSF, respectively. The measured concentrations decreased by 6 % (2.2 % WSF) and 47 % (0.1 % WSF) during the 48-hour exposure period. Based on these results, the average exposure concentrations were calculated to correspond with 0.011, 0.023, 0.056, 0.11, 0.28 and 0.63 mg/L.

The study met the acceptability criteria and was considered valid.

Under the conditions of this study the 48 h EC50 was 0.15 mg/L based on average exposure concentrations (95 % confidence interval between 0.12 and 0.19 mg/L).

Further information is available in the form of two disregarded studies.

In the first, the test was carried out using methodology similar to that outlined in the standardised guideline OECD 202 under GLP conditions, however there were shortcomings. The test material was not wholly soluble in water and was used as an homogeneous emulsion. There was no attempt to remove impurities such as xylene and no analysis of test material levels took place during the study. Effects are considered likely to be the result of physical contact with oil droplets combined with toxicity of impurities. The study was awarded a reliability score of 3 in accordance with the principles for assessing data quality set forth by Klimisch et al. (1997).

Daphnia magna were exposed to the test material for 48 hours. The 24 and 48 hour EC50 values were estimated to be 1.1 and 0.24 mg/L, respectively.

 

In the second disregarded study, no guideline was followed although the study did take place under GLP conditions. The test material was administered as an aqueous extract of mineral oil added to artificial seawater. However, toxic impurities are likely to have been present and there was no analytical monitoring of substance levels during the study. No attempt was made to remove the potential for microemulsion by filtration or centrifugation. Effects are, again, considered likely to be the result of physical contact with oil droplets combined with toxicity of impurities. The study was awarded a reliability score of 3 in accordance with the principles for assessing data quality set forth by Klimisch et al. (1997).

Acartia tonsa were exposed for 48 hours under semi-static conditions. Immobilisation was > 80 % in all three test material solutions.