Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Sediment toxicity

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

In a study according to OECD TG 218 with spiked sediment the lowest available endpoints, based on emergence rate of Chironomus riparius, were (endpoints based on nominal concentrations) an EC50 (28d) of 0.078 mg teflubenzuron/kg dry sediment and a NOEC (28d) of 0.05 mg teflubenzuron/kg dry sediment.

Key value for chemical safety assessment

EC50 or LC50 for freshwater sediment:
0.078 mg/kg sediment dw
EC10, LC10 or NOEC for freshwater sediment:
0.05 mg/kg sediment dw

Additional information

No screening information on the toxicity of the test item to sediment dwelling organisms is available, but data of a valid and GLP-compliant water-sediment study: A long-term Sediment-Water Chironomid Toxicity Test using spiked sediment according to OECD TG 218 (ECT, 2003).


The presented key study was peer-reviewed during the assessment of teflubenzuron according to Council Directive 91/414/EEC.


 


Key information


ECT (2003): A study on the toxicity of BAS 309 I (teflubenzuron) to the sediment dweller Chironomus riparius according to the OECD draft new guideline 218 for the testing of chemicals: "Sediment-water chi­ronomid toxicity test using spiked sediment", February 2001. Unpublished report, report No. G3ME, according to Draft Assessment Report (2007) according to Council Directive 91/414/EEC, crossreference: MCA 8.2.7/01


The toxicity of the test item to sediment organisms was evaluated in a 28 days Sediment-Water Chironomid Toxicity Test using spiked sediment according to OECD TG 218. For the application, the test substance was dissolved in acetone, and mixed homogeneously with quartz sand. After evaporation of the solvent, the treated quartz sand was added to the sediment. After preparation of the test vessels with spiked sediment, the test system was allowed to stabilise for 7 days before addition of the larvae of Chironomus riparius. The larvae were exposed for 28 days with following concentrations: 0.2, 0.1, 0.05, 0.025, 0.0125 and 0.00625 mg a.s./kg sediment (dry weight), in addition to one control and one solvent control (4 replicates per treatment level; 6 per con­trol).


 The Analytical verification of test item in the sediment, overlaying water and pore water was performed on DAY 0 (test start without midges) and Day 28 (test termination) for the controls and 0.0125, 0.05 and 0.2 mg/kg sediment (dw).


Recoveries in the sediment were in a range between 82.93 and 90.33% on day 0. For the total test system 78.31 and 84.25% were recovered at the end of the test (day 28). The mean overall recovery (days 0 and 28) was 84.02%. Until the end of the test the main fraction of the test item applied to the system were associated to the sedi­ment. Only negligible amounts could be measured in pore water and overlying water. Therefore the effect concentrations (NOEC, LOEC and ECx) are based on nominal (i.e. applied) sediment concentrations.   


During the 28 days exposure period the measured oxygen concentrations aver­aged 91% and were always higher than 60% (recommendation in the guideline) except on one occasion (treatment 0.05 mg/kg, day 20, replicate 1) where oxygen concentration was 58%. The pH of the overlying water ranged between 7.34 and 8.10. The requirements of the guideline concerning test performance (pH 6 - 9) were fulfilled. The temperature of the overlying water varied between 20.7 and 22.1 °C during the exposure period. This had no influence on the test results, because the difference of 1.4 was in the range of ± 1.0 °C required by the guideline proposal. The maximum difference for one day in all replicates was 0.8 °C.


Statistical analysis showed no effect on the emergence ratio at doses ≤ 0.05 mg/kg sediment (dry weight). At doses ≤ 0.1 mg/kg sediment (dry weight), statistical analysis showed no effect on the development rate. The recorded observations showed that, at 0.1 mg/kg (dry weight) a great part of the emerged midges lay on the water surface (25 of 37). These midges were complete developed but ratite. The NOEC based on observations concerning the test animals is 0.05 mg/kg (dry weight), the corresponding LOEC is 0.1 mg/kg (dry weight).


The test item showed a dose-dependent effect on the development and the emergence of the test system Chironomus riparius. The most sensitive parameter was the emergence ratio (ER). In comparison to the control the emergence ratio of male and female midges pooled was statisti­cally significantly inhibited at a nominal concentration level of 0.1 mg/kg sedi­ment (dw). Therefore, the NOEC(ER) has to be regarded as 0.05 mg/kg sediment (dw). The results indicated a different sensitivity of sexes. The emergence ratio of female midges was slightly more affected by the test item (NOEC(ER, female): 0.05 mg/kg sediment (dw)) than emergence ratio of male midges (NOEC(ER, male): 0.1 mg/kg sediment (dw)). For the parameter development rate (DR) there were no indications on different sensitivities of sexes. In comparison to the control the development rate of male and female midges pooled was statistically significantly inhibited at a nominal concentration level of 0.2 mg/kg sediment (dw). Therefore, the NOEC(DR) has to be regarded as 0.1 mg/kg sediment (dw).


During the evaluation of teflubenzuron according to Council Directive 91/414/EEC, the 28-d NOEC based on emergence was determined as key value for the risk assessment (please refer to the Draft Assessment Report for teflubenzuron prepared according to the Council Directive 91/414/EEC, Volume 3 – B.9 (AS), 2007). 


 


Conclusion


In a study according to OECD TG 218 with spiked sediment (ECT, 2003; crossreference: CA8.2.7/01) the lowest available endpoints, based on emergence rate of Chironomus riparius, were (endpoints based on nominal concentrations) a EC50 (28d) of 0.078 mg a.s./kg dry sediment and a NOEC (28d) of 0.05 mg a.s./kg dry sediment.