4,4'-benzylidenedianiline

Endpoint summary

Description of key information

The median effective concentration (EC₅₀) of DATIPH (4,4'-Benzylidenedianiline) to Daphnia magna was investigated under static exposure conditions over a period of 48 h.

40 individual Daphnia divided in 2 test vessels were exposed to each concentration of the test substance.

The nominal concentrations of DATIPH, as selected by a preceding non-GLP range finding test, were 6.4, 16, 40, 100 and 250 mg/l, respectively.

Due to the limited water solubility of the test material, only the water accommodated fractions of DATIPH were tested.

After 24 h of incubation the following percentage of immobilization of the total of 40 individuals was observed at the respective nominal concentrations:

250 mg/l (45%). No significant effects (≤10% of a total of 40 individuals) were observed at 100, 16 and 6.4 mg/l and in the blank control. The 15% immobilization observed at 40 mg/l were considered to be an outlier.

After 48 h of incubation the following percentage of immobilization of the total of 40 individuals was observed at the respective nominal concentrations:

250 mg/l (82.5%), 100 mg/l (45%), 40 mg/l (25%), 16 mg/l (15%). No significant effects (<10% of a total of 40 individuals) were observed at 6.4 mg/l and in the blank control. Immobilization at 48 h was increased as compared to the effects after 24 h.

Based on the immobilization data the median effect concentration (EC₅₀) of DATIPH to Daphnia magna for 24 h was estimated to be >11.7 mg/l with respect to the time-weighted average of the measured concentrations. The 48 h EC₅₀ was calculated to be 6.76 mg/l (95% confidence limits: 5.75 - 8.32 mg/l).

The experimentally determined no-effect concentration (NOEC, EC₀) was 5.50 and 2.27 mg/l with respect to the time-weighted average of the measured concentrations after an exposure of 24 and 48 h.

Based on these results, it is concluded that 4,4'-Benzylidenedianiline should not be classified as hazardous to the aquatic environment Category Acute 1 according to CLP ( Regulation (EC) No 1272/2008 on classification, labelling and packaging (CLP) of substances and mixtures), since the calculated EC50 value for crustacea after a 48-hour exposure period is above the trigger value of 1 mg/L.

It should, however, be classified as Aquatic Chronic 2 as no result is available for chronic toxicity effects and the result for acute toxicity on crustacea indicates an EC50 between 1 and 10 mg/L.

Additional information

The inhibitory effect of DATIPH (4,4'-Benzylidenedianiline) on the oxygen consumption of activated sludge microorganisms of a municipal sewage treatment plant was investigated under aerobic static conditions. The inhibitory effect may include the effect on respiration and nitrification. The exposure time of the test substance on the activated sludge was 3 hours.

The nominal concentrations of DATIPH were 10, 100 and 1000 mg/l, respectively.

No chemical analysis of test concentrations was conducted. For the estimation of the effective concentration leading to 20, 50, and 80% respiration inhibition (EC₂₀, EC₅₀andEC₈₀) the nominal content of the test substance was used, assuming the test compound to be stable in water over 3 h.

At all applied test concentrations, the test substance showed no significant toxic effects to the activated sludge. The respiration rates were in the same range as determined for the two blank controls.

The EC₂₀, EC₅₀and EC₈₀values of DATIPH were estimated to be >1000 mg/l.

These results should however be considered carefully as the validation criteria have not been entirely fulfilled. Given the small variation between the two blank measurements, the test is however deemed reliable.

All concentrations of test substance are given in total nominal content (dissolved and undissolved).