Ammonium (di C8-C10, branched, C9 rich, alkylnaphthalene sulphonate)

Endpoint summary

Description of key information

Short-term toxicity tests for the aquatic organisms are available for structural analogues on three trophic levels.

The short-term toxicity test result in fish, the 98h-LC50 was beyond the range tested, i.e. exceeded the highest average exposure concentration of 0.28 mg/l. This was considered to correspond to the maximum soluble concentration in test medium. Therefore, under the test conditions, and given the solubility characteristics of the test material, neither the 98h-LC50 or a level causing any observable effect can be attained.

An Acute Toxicity Study in Daphnia magna was conducted with test substance based on OECD TG 202. Twenty daphnids per group (5 per vessel, 4 vessels) were exposed to a control and WAFs prepared at loading rates of 4.6, 10, 22, 46 and 100 mg/l in the final test. Total exposure time was 48 hours and samples for analytical confirmation of the exposure concentrations were taken at the start and at the end of the test. Analysis of the samples taken at the start of the final test showed measured concentrations being highly variable and not directly related to the applied loading rates. Therefore, the effect parameters were expressed in terms of average exposure concentration. The highest average exposure concentration was measured in the WAF prepared at 10 mg/l and corresponded to 0.27 mg/l. The study met the acceptability criteria prescribed by the protocol and was considered valid. For Daphnia magna exposed to the test substance the 48h-EC50 was beyond the range tested, i.e. exceeded the average exposure concentration of 0.27 mg/l. Due to the very low solubility of di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA) in test medium, concentrations that might be toxic to Daphnia magna could not be reached. The effects observed at the higher measured concentrations of the test substance were mechanical rather than toxic.

A Fresh Water Algal Growth Inhibition Test was conducted for the test substance with Pseudokirchneriella subcapitata. The study procedures were based on the OECD guideline No. 201, 2006; Annex 5 corrected 28 July 2011. Under the conditions of the DNNSA study with Pseudokirchneriella subcapitata, reduced growth rate of this fresh water algae species significantly at a TWA concentration of 1.2 mg/l. The EC50 for growth rate reduction (ERC50: 0-72h) was beyond the range tested, i.e. exceeded a TWA concentration of 1.2 mg/l. The lowest EC10 in this study is for cell number (yield) which is 0.20 mg/L and the EC10 for growth rate is 0.80 mg/L.

In a semi-static daphnia reproduction study (OECD 211) daphnids were exposed during 21 days at loading rates of 0, 0.46, 1.0, 2.2, 4.6 and 10 mg/L (WAF) to close analogue of the substance (its calcium salt). Mean measured concentrations were NA, 0.0052, 0.17, 0.14, 0.20 and 0.28 mg/L. Effects on growth were reported at a loading rate of 2.2 mg/L. The NOEL for reproduction and mortality were 4.6 and 10 mg/L(expressed as loading rate).