Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

The acute effects of dibenzoyl peroxide on earthworms (Eisenia foetida foetida) were determined according to the OECD Guideline 207 (1984) and GLP requirements (Chastenet, 2015). The valid experiment concluded that 14d-LC50 was higher than 1000 mg a.i./kg dw.

A valid experiment has also been performed in order to determine the effects of dibenzoyl peroxide on nitrogen transformation according to OECD guideline 216 and GLP requirements (Bangert, 2015). The objective was to determine the effects of the substance on soil microbial activity. The results were 28d-EC10 = 1000 mg a.i./kg dw and 28d-EC50 = 2300 mg a.i./kg dw.

Dibenzoyl peroxide is considered as a soil hazard category 2 substance (Table R.7.11 -2 of Chaper R.7c, Version 2.0 November 2014). Indeed, the substance has a Log Kow < 5 and is readily biodegradable, confirming that there is no indication for high adsorption or high persistence in soil. Nevertheless, EC/LC50 below 1 mg/L were determined in acute toxicity tests, leading to the conclusion that the substance is very toxic to aquatic organisms.

For a soil hazard category 2 substance, a risk characterisation ratio (RCR) based on Equilibrium Partitioning Method (EPM) should be calculated, together with a confirmatory short-term soil toxicity testing.

PNEC soil calculated from EPM = 0.0025 mg/kg soil dw. The following formula has been applied : PNEC soil = (Ksoil water / RHOsoil) x PNECaqua x 1000 With: RHOsoil = bulk density of wet soil = 1700 kg/m3, using a Koc value of 6310, a vapour pressure of 0.009 Pa and a PNEC freshwater of 0.02 µg/L. Finally, a conversion factor of 1.13 is used for converting wet to dry weight.

From the result obtained on acute toxicity to earthworms, an assessment factor of 1000 is applied on 14d-LC50. Therefore, PNEC soil calculated from the OECD 207 test = 1 mg/kg soil dw.

In addition, a long-term toxicity test on microorganisms is available and an assessment factor of 100 can be applied on the 28d-EC10 value. PNEC soil calculated from OECD 216 test = 10 mg/kg soil dw.

The lowest PNEC soil is derived from EPM and thus it was used to calculate the RCR for the soil compartment. No risks (PEC/PNEC < 1) has been identified. In accordance with the Integrated testing strategy for terrestrial toxicity testing (Figure R.7.11 -3 of Chapter R.7c, Version 2.0 November 2014), there is no need to perform additional short-term or long-term studies on soil organisms.