Disodium [3-[4,5-dihydro-4-[(2-hydroxy-5-nitrophenyl)azo]-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonato(3-)][1-[[2-hydroxy-5-(phenylazo)phenyl]azo]-2-naphtholato(2-)]chromate(2-)

Endpoint summary

Description of key information

Short-term toxicity to aquatic invertebrates: EC50 (48 h) = 18 mg/l (nominal)

Short-term toxicity to Aquatic plants (Lemna): ErC50 (7d): 22.7 mg/l EyC50 (7d): 227 mg/l

Additional information

Adequate chronic toxicity data are not available for the substance, therefore the aquatic toxicity assessment and classification are based mainly on the short-term toxicity data available on the substance under registration and on Similar substance 1.

Despite the substance has a log Kow lower than 4 (indicating a low potential for bioaccumulation), it is not rapidly (bio)degradable.

According to the CLP Regulation (EC n. 1272/2008), acute aquatic toxicity is normally determined using a fish 96-hour LC50 , a crustacean species 48-hour EC50 and/or an algal species 72- or 96-hour EC50; nevertheless it is also specified in the Regulation that data on other species (e.g. Lemna) shall also be considered if the test methodology is suitable.

Data are available for Daphnia magna and the toxicity to aquatic plants (Lemna minor) is evaluated though read-across approach, based on the structural similarity of the two main components of target and source substances.

According to the CLP Regulation (EC n. 12720/2008) criteria for the identification of the classification categories for hazardous to the aquatic environment, the acute toxicity test on Daphnia fixed the effect level between 10 and 100 mg/l; this classification category is confirmed by the Lemna study, in which the EC50 related to the effects on the growth rate is recorded in the same range of values.

In conclusion, the substance is classified as Aquatic Chronic 3 (H412) according to the CLP Regulation (EC 1272/2008).