Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Short-term toxicity to fish: Based on measured concentrations, the 96-hour LC50 was > 0.74 mg/L for Brachydanio rerio.

Short-term toxicity to aquatic invertebrates: Based on nominal concentrations, the 48h EC50 for Daphnia magna was 0.56 mg/L.

Long-term toxicity to aquatic invertebrates: No adverse effects on either the number or sex of offspring or body size of Daphnia magna were observed up to 20 μg/L test item (NOEC = 20 µg/L).

Toxicity to aquatic algae and cyanobacteria: Based on the nominal concentrations of the test item, the 72h IC50 for Desmodesmus subspicatus was 7.66 mg/L (95% confidence limits 3.51 - 16.7 mg/L). The 72h IC10 was 0.81 mg/L (95% confidence limits 0.09 - 7.49 mg/L).

Toxicity to microorganisms: The test substance is not toxic to microorganisms at a concentration of 100 mg/L.

Additional information

Short-term toxicity to fish: The acute toxicity of the test item to zebrafish (Brachydanio rerio) was determined in a 96 -hour static limit test conducted according to OECD Guideline 203 and EU Method C.2 (1998). Fish were exposed to a nominal concentration of 100 mg/L of the test item (measured concentration 0.74 mg/L) in reconstituted water, alongside a control group. The test solution was prepared by ultrasonication of the test item in the test media for 1 hour, followed by aeration and stirring for 23 hours. The solution was filtered before use. Each treatment contained one replicate with 10 fish. The 96 -h LC50 was determined to be > 0.74 mg/L. This test is reliable with restriction (Klimisch 2) as test concentrations were only measured at t = 0h.

Short-term toxicity to aquatic invertebrates: The effects of 4 -methylbenzylidene camphor were determined in an acute immobilisation test with Daphnia magna, according to OECD 202 guideline (2011). The study was conducted under static conditions over a period of 48 hours with five nominal concentrations of the test item (0.4, 0.8, 1.6, 3.2, 6.4 mg/L). Twenty daphnids were exposed per treatment group (four replicates, each containing five daphnids). There was no analytical verification of the test item concentration (although chemical analysis was undertaken for a chronic daphnid study conducted and reported in the same publication). Based on nominal concentrations, the 48h EC50 for Daphnia magna was 0.8 mg/L (95% confidence intervals: 0.72 - 0.88 mg/L). The 48h EC10 was 0.46 mg/L (95% confidence intervals: 0.33 - 0.63 mg/L).

In a second study (key study), the test item was assessed in a 48-hour acute study with Daphnia magna. The study reports that OECD guideline 202 was followed, however limited methodological details are reported. Five test concentrations were used, between 0.1 and 1000 μg/L. The 48-hour EC50 for Daphnia magna was 0.56 mg/L. The study is assigned a Klimisch score of 2 (reliable with restrictions) as although it followed a standard test guideline the paper reports limited details.

As the results from both studies are similar, the study with the more sensitive result (EC50 = 0.56 mg/L) is taken as the key value for this endpoint.

Long-term toxicity to aquatic invertebrates: The chronic toxicity of 4-methylbenzylidene-camphor to Daphnia magna was determined in two 21 -day studies conducted according to OECD Guideline 211. In the first study, test organisms were exposed to five nominal concentrations of 1.28, 3.2, 8, 20 and 50 μg/L 3-(4-methylbenzylidene-camphor) under semi-static conditions with media renewal every 48 hours. The offspring produced by each parent animal were counted daily. Reproduction and body length were reduced at 50 μg/L test item. No adverse effects on either the number or sex of offspring or body size were observed up to 20 μg/L test item. This study is considered to be reliable with restrictions (Klimisch 2) as limited method details are provided and no details are reported of whether analysis of test concentrations was conducted (2010).

In the second study, test organisms were exposed to five nominal concentrations of 0.013, 0.025, 0.05, 0.1, 0.2 mg/L test item under semi-static conditions with media renewal twice a week. The reproductive output was analysed daily by counting the number of living offspring per parent animal. The time of first release of neonates was also recorded and the body length of parent daphnids were measured at the end of the test. The test item did not affect the number of released neonates significantly at nominal concentrations up to 0.2 mg/L. However, the length of the parental animals was significantly decreased (p < 0.01) after 21 d at the highest nominal test concentration (0.2 mg/L). The time-weighted mean concentrations of 0.13 and 0.2 mg/L nominal concentrations were determined to be 0.058 and 0.07 mg/L, respectively. This study is considered to be reliable without restrictions (Klimisch 1) (2011).

Both studies show adverse effects on body length in the range 0.050 (nominal) to 0.070 (TWA) mg/L test item. Adverse effects on reproductive success were also observed in one study at 0.050 mg/L test item (nominal), however no effects on reproduction were observed in the second study up to 0.070 mg/L test item (TWA), the highest concentration tested. The NOEC is therefore considered to be 0.020 mg/L test item (nominal), based on adverse effects on body length. Although the effects on reproduction were not confirmed in the second study, the NOEC is also relevant to Daphnia reproduction as the worst-case scenario.

Toxicity to aquatic algae and cyanobacteria: In the algal growth inhibition test with Desmodesmus subspicatus, the effects of the test item were determined according to OECD 201 guideline (2011). The study was conducted under static conditions over a period of 72 hours with 5 concentrations of the test item (0.5, 1.0, 2.0, 4.0, 8.0 mg/L). The test included 5 replicates in the controls and 3 replicates for the solvent control (ethanol) and each test concentration. The concentrations of the test item were not analytically verified and partly above the water solubility of 1.08 mg/L. Based on the nominal concentrations of the test item, the 72 hour IC50 for Desmodesmus subspicatus was 7.66 mg/L (95 % confidence limits: 3.51 - 16.7mg/L). The 72 hour IC10 was 0.81 mg/L (95% confidence limits 0.09 - 7.49 mg/L). The study is considered to be reliable with restriction (Klimisch 2) as it was conducted according to guideline, however no analytical verification of test concentrations was performed and some test concentrations were above the water solubility of the test item of 1.08 mg/L.

Toxicity to microorganisms: The toxicity of the test substance to microorganisms was determined in a ready biodegradability study conducted according to OECD Guideline 301F (1994). A nominal concentration of 100 mg/L test substance plus 100 mg/L aniline (positive control) was incubated with activated sludge for 28 days under aerobic conditions, alongside an inoculum blank and a positive control. Oxygen consumption was measured electrolytically daily. The test substance is not toxic to microorganisms. This study is considered to be reliable without restriction (Klimisch 1).