Alkenes, C11-14, hydroformylation products, distn. residues, reaction products with maleic anhydride and sodium bisulfite, sodium salts

Endpoint summary

Additional information

The acute toxicity of the test item Alkenes, C11-C14, hydroformylation products, distn. residues, reaction products with maleic anhydride and sodium bisulfite, sodium salts has been investigated with fish (zebrafish), invertebrates (daphnia magna), algae (desmodesmus subspicatus) and microorganisms. In addition a reproductive toxicity study according to OECD 211 with daphnia magna was performed. In view of the difficulties associated with the evaluation of aquatic toxicity of poorly water soluble test items, a modification of the standard method for the preparation of aqueous media was performed in all studies. An approach endorsed by several important regulatory authorities in the EU and elsewhere (ECETOC 1996 and OECD 2000), is to expose the organisms to a Water Accommodated Fraction (WAF) of the test item in cases where the test item is a complex mixture and is poorly soluble in water and in the permitted solvents. All tests were performed under GLP.

The results can be summarized as follows:

Toxicity toward fish

A semi-static test with daily renewal of the test media was performed with the water accommodated fractions* (WAF) of nominal 6.25 - 12.5 - 25.0 - 50.0 - 100 mg/L. Per definition of the WAF, all terms related to concentration levels will be given as loading levels. Duration of the test was 96 hours.

All effect levels are given based on the nominal loading levels of the test item Alkenes, C11-C14, hydroformylation products, distn. residues, reaction products with maleic anhydride and sodium bisulfite, sodium salts. The LC₅₀after 96 h was determined to be 97.5 (50.0 – 100) mg/L.

A long-term toxicity study with fish is not available and not required, as fish apparently seem to be less sensitive to the test substance compared to invertebrates and algae.

Toxicity towards invertebrates

In the acute immobilisation test with Daphnia magna (STRAUS), the effects of the test item Alkenes, C11-C14, hydroformylation products, distn. residues, reaction products with maleic anhydride and sodium bisulfite, sodium salts were determined according to OECD 202 (2004).

The study was conducted with 5 water accommodated fractions (WAF) of the test item Alkenes, C11-C14, hydroformylation products, distn. residues, reaction products with maleic anhydride and sodium bisulfite, sodium salts with loading rates in the range of 6.25 to 100 mg/L under semi-static conditions over a period of 48 h. In this study the EC₅₀ was determined being 21.5 mg/L and the NOEL was found being 12.5 mg/L.

In addition the reference substance was investigated in an OECD 211 daphnia reproduction test under semi-static conditions with 21 days of exposure, applying a water accommodated fraction method as endorsed by the OECD for poorly soluble UVCB substances.

Whereas at a loading rate of 2.5 mg/L no mortality and effects on reproductive performance have been observed (NOEL), at 5.0 and 10.0 mg/L the reproductive performance was significantly reduced. At 20 mg/L (highest dose tested) no reproductive output was recorded due to 100% mortality of daphnids. At 1.25 mg/L no mortality was observed whereas the mortality at 2.5 mg/L loading rate was 10% (one daphnid out of 10 found dead after 21 days), at 5 mg/L 30 % and at 10 mg/L 80%.

Thus, the NOEL found in this study was 2.5 mg/L loading rate whereas the EC₅₀ determined was 6.17 mg/L for reproduction and 6.54 mg/L for mortality.

Toxicity towards algae

The toxicity of Alkenes, C11-C14, hydroformylation products, distn. residues, reaction products with maleic anhydride and sodium bisulfite, sodium salts (batch number: Rif. 7018) to the unicellular freshwater green alga desmodesmus subspicatus was determined according to the principles of OECD 201 to assess the effects on growth rate and yield over a period of 72 hours.

The study was conducted under static conditions with an initial cell density of 4332 cells/mL. Three replicates were tested for each loading level and six replicates for the control. Environmental conditions were determined to be within the acceptable limits.

All test item loadings and the control were analytically verified via analysis of organic carbon (TOC, according to DIN EN 1484) at the start and at the end of the test.

As outcome a NOEL of 2.0 mg/L for growth rate inhibition and yield inhibition was found and the ErC50 was determined being 5.23 mg/L.

Toxicity towards microorgansims

A Respiration Inhibition Test with activated sludge according to OECD Guideline No. 209 was carried out with the test item Alkenes, C11-C14, hydroformylation products, distn. residues, reaction products with maleic anhydride and sodium bisulfite, sodium salts. Test system was activated sludge of a municipal treatment plant. The test was carried out under static conditions with the test item concentrations 100 - 180 - 320 - 580 - 1000 mg/L. The respiration rates of the control, reference and test item replicates were measured after a contact time of three hours, and the inhibitory effects of the test and reference item were determined in comparison to the control respiration rates. The mean inhibition of respiration for the test item replicates ranged from 1% to 30 %. The NOEC was determined being 320 mg/L in this study whereas the EC₅₀ was found being above 1000 mg/L. Thus, the test item is not toxic to activated sludge.