1,2-dichloro-4-(trichloromethyl)benzene

Short-term toxicity to aquatic invertebrates

Description of key information

IC50 (48h) =  48.7 mg/l

Additional information

The acute toxicity of the test item 3,4-dichlorobenzotrichloride to Daphnia magna was determined in a 48‑hour static test according to the OECD Guideline for Testing of Chemicals, No. 202 (2004) and to Council Regulation EC 440/2008 (C.2).

For this purpose, juvenile daphnids (> 24 hours old at test initiation) were exposed to an aqueous test medium containing the test item at five different concentrations in a geometric series, namely 10.0, 17.8, 31.6, 56.2 and 100.0 mg/L.The exposed organisms were checked for immobilization 24 and 48 hours after test initiation.

The pH of the control (test medium without test item) after preparation was 6.88 while the pH of stock test solution (100 mg/L) was 3.06, therefore it was corrected before the beginning of the test by adding 9 drops of a NaOH solution (1N) obtaining a pH value of 6.83 (within the provided range 6-9). 

The room temperature was in the range 21.3 –during the test period, according to the OECD’s recommended range (20 ± 2 °C).

Light intensity during the 48 hours of test period was in the range 382-394 Lux, within the range 200-1500 Lux.

At the end of test period, in the negative control, no immobilization was observed and no daphnids were found trapped on the test water surface. These values comply with the specified validity criterion that immobilization in the negative control group should not exceed 10% at the end of the test. 

The obtained experimental results allowed to calculate the NOEC, the LOEC and the IC₅₀values at 24 and 48 hours. The results are as reported below:

Time	NOEC (mg/L)	LOEC (mg/L)
24 h	56.2	100.0
48 h	31.6	56.2

 

Time	IC50(mg/L)	95% Confidence range (mg/L)
24 h	87.5	75.7 – 101.3
48 h	48.7	41.4 – 57.3