2-ethylhexyl benzoate

Endpoint summary

Description of key information

In a test according to OECD 222 (Envigo 2018) 8 groups of 4 replicates (each 10 worms) were treated with the test item at test rates of 16.3, 29.4, 52.9, 95.3, 171.5, 308.6, 555.6 and 1000 mg a.i./kg dry soil, mixed into the soil during 4 weeks. Mortality of 32.5% was recorded at 1000 mg a.i./kg dry soil treatment rate. There was no statistically significant adverse effect on biomass as a function of adult bodyweight at any test item treatment rate. A non statistically significant reduction in the number of juveniles produced at any test item treatment rate up to and including 1000 mg a.i./kg dry soil. A NOEC(mortality) of 555.6 mg a.i./kg dry soil and a NOEC(reproduction) of 1000 mg a.i./kg dry soil were achieved.

A study according to OECD 208 (Envigo 2018) was performed with four dicotyledons, (cabbage, carrot, lettuce and tomato) and two monocotyledons, (oat and onion), to determine the toxicity of the substance to seedling emergence and seedling growth during 15 - 18 days following a minimum of 50% germination in the controls. There were no statistically significant effects on germination or survival in any plant species at any treatment rate except for onion at 1000 mg a.i./kg dry soil where a 53% reduction in germination was recorded. The NOEC values for effects on height were 1000 mg a.i./kg dry soil for carrot and lettuce, and 500 mg a.i./kg dry soil for cabbage, tomato, oat and onion. The NOEC values for effects on wet weight were 500 mg a.i./kg dry soil for cabbage, carrot, lettuce, tomato and onion and 125 mg a.i./kg dry soil for oat.

Soil microorganisms were exposed to the test item at concentrations of 10, 32, 100, 320 and 1000 mg/kg soil dry weight for 28 days at temperatures of between 19 to 22 °C in the dark with the addition of powdered Lucerne-green-grass meal to act as a respiratory substrate. The inhibitory effect of the test item on nitrogen transformation was assessed by the determination of nitrate concentration in the soil samples on Days 0 and 28 and compared to data obtained from the control soil samples. The effect of the test item on the nitrogen transformation activity of the soil microorganisms gave an EC50 of 41 mg/kg soil dry weight, 95% confidence limits of 34 - 50 mg/kg soil dry weight.  The No Observed Effect Concentration (NOEC) was 10 mg/kg soil dry weight.

Additional information

2-ethylhexyl benzoate is readily biodegradable (77% CO2 evolution in 28 days; Dickinson, 2008), has a log Koc value of 4.07 and is poorly water soluble (water solubility 0.4 mg/L in A. bidest). If direct/indirect application of the substance on soil occurs (indirect via sludge application), the substance will again be rapidly degraded until ultimate biodegradation.

The NOEC of 10 mg/kg soil dry weight is the starting point for the derivation of the PNEC. In the risk assessment (CSR 2018) all environmental concentrations were far below the PNEC value and the RCR values are < 0.01.