α,α,α-trichlorotoluene

Short-term toxicity to aquatic invertebrates

Description of key information

The methodology used in these studies is similar to OECD Guideline 202. The test species was Daphnia magna which was exposed to benzotrichloride under static conditions for 24 hours.
Range finding study: EC0(24h) = 42 mg/L and EC100(24h) = 56 mg/L [Bringmann and Kühn (1982)]
EC50(24h) >100 mg/L [Bringmann and Kühn (1977)]
EC50(24h) = 50 mg/L [Bringmann and Kühn (1982)] for this study a valid result was obtained for the reference substance potassium dichromate

Additional information

Several aquatic toxicity tests have been undertaken with benzotrichloride. However as discussed in the OECS SIDS (2004), benzotrichloride reacts with water rapidly, forming benzoic acid and hydrochloric acid. As a consequence the effects observed in these studies can be attributed to the degradation products benzoic acid and hydrochloric acid. Thus, benzotrichloride itself does not appear to be hazardous to the aquatic environment.

Since the OECD SIDS (2004), no new studies were available.

 

Bringmann and Kühn (1977, 1982) used an acute immobilization test similar to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) to exposeDaphnia magna (strain IRCHA in the study of 1982) to benzotrichloride under static conditions for 24 hours. Both studies first performed a range finding study assessing the EC0(24h) and EC100(24h). The results hereof are not reported in Bringmann and Kühn (1977), however in 1982 these authors assessed the EC0(24h) and EC100(24h) at 42 and 56 mg/L respectively.

In both studies, series of 10 dapnids of max. 24h old (3 replicas in 1977 and 2 in 1982) were exposed to a dilution series of the test substance. The test medium used was dechlorinated, oxygen saturated tap water with hardness of 285.6 mg/L CaCO₃ in the study of 1977 and standardized synthetic medium made according to DIN 38412 part 11 in the study of 1982. In both studies the pH of the test medium was approximately 7.6 to 8.0 and the temperature 20-22°C. In the test of Bringmann and Kühn (1977) the estimated EC50(24h) was >100 mg/L. On the other hand, according to the study of these authors in 1982 the estimated EC50(24h) of benzotrichloride was 50 mg/L. The latter test used a reference substance (potassium dichromate) for which a valid result was obtained (average EC50: 1.3 mg/L; required range: 0.9 - 1.9 mg/L).

The validity criteria of the OECD Guideline 202 could not be checked for these studies as no data was available. Furthermore benzotrichloride cannot be classified based on the CLP regulation (EC) N° 1272/2008 since the test duration was 24h instead of the required 48h.