Aniline

Toxicity to terrestrial plants

Description of key information

NOEC(14d): 0.3 mg/m3 Brassica pekinensis 
EC50(14d): 33 mg/kg soil d.w. Lactuva sativa

Additional information

Aniline reaches soils via deposition from the atmosphere or by degradation of plant protection agents. As already stated in section 5.2.3 aniline can be biodegraded or be bound onto the soil organics, where the reaction product accumulates. Therefore, for the assessment of plant toxicity of Aniline, one has to consider both, the soil and the atmospheric compartment. Reliable short term toxicity tests are available for both compartments.

Atmospheric compartment:

To allow the derivation of a PNECpIant for a risk assessment of the atmosphere, a plant fumigation test was performed with aniline (BASF, 2002). Three species of higher plants (Avena sativa, Brassica pekinensis and Abies grandis) were exposed in laboratory exposure chambers for 14 days to 3 aniline concentrations (0.1 mg/m3, 0.3 mg/m3 and 1 mg/m) and a control. Aniline concentrations were measured by HPLC. Daily means were calculated based on two measured samples per concentration and exposure. Mean measured concentrations were 0.158 mg/m3, 0.334 mg/m3 and 1.22 mg/m3. Seeds (Avena and Brassica) and germinated plants (Abies, 1 year old plants) were acclimatised in the exposure chambers for 8 days before exposure to aniline. Endpoints were plant length, wet and dry weight as well as macroscopic changes for Avena sativa and Brassica pekinensis. For Abies grandis only macroscopic and microscopic changes were recorded. The EC50 for all tested parameters for Avena sativa and Brassica rapa was > 1 mg/m3. The NOEC values for all tested endpoints were 1 mg/m3 for Avena sativa and 0.3 mg/m3 for Brassica pekinensis. Macroscopic and stereo microscopic observations in Abies grandis showed no changes in the habit of the plants. For the derivation of the PNECplant the lowest NOEC of 0.3 mg/m3 found for Brassica pekinensis is used as basic value. An assessment factor of 50 is proposed as the exposure period for the three tested plant species was only 14 days. There are indications from a study of Cheeseman et al. (1980) that certain tree species may react sensitive to aniline. As it is not appropriate to examine adequately the effect of aniline on trees in a 14-day laboratory test this is considered by the height of the assessment factor.

Therefore PNECplants = 0.3 mg/m3 / 50 = 6 μg/m3

Soil compartment:

Hulzebos et al. (1993) determined the toxicity of aniline to Lactuca sativa in natural soil and in nutrient solution. Both tests were conducted by two institutes (TNO and RIVM). A 14-day EC50 for growth inhibition of 33 mg/kg soil (dw) was found by RIVM and of 56 mg/kg soil (dw) by TNO. The content of organic matter was 1.4% for the soil used by TNO and 1.8% for the soil used by RIVM. For the test with nutrient solution different exposure times were used by the two laboratories. TNO derived a 14-day EC50 of 7.9 mg/l and RIVM found for 21-day exposure an ECSO of 17 mg/l. All effect values are related to nominal concentrations. The authors showed that the concentration of aniline had dropped to < 30% after 14 days.

 

The lowest EC50 value found for soil exposure is used for the determination of the PNEC50. An assessment factor of 1,000 has to be applied. This leads to a PNEC of 33 μg/kg (dry weight).