Reaction mass of 2,4-bis(xylylazo)resorcinol and 2,4-bis[(4-dodecylphenyl)azo]resorcinol and 2-[(4-dodecylphenyl)azo]-4-(2,4-xylylazo)resorcinol

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is highly insoluble in water, hence indicating that aquatic toxicity is unlikely to occur

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
The water solubility of the UVCB substance was determined to be < 1.0 x 10-5 g/L, partition coefficient (n-Octanol/water) Pow 3.16 x 106, log10Pow> 6.5 and estimated absorption coefficient was estimated to range be between Koc range: 1.172e+006 - 5.518e+008  L/kg log Koc range: 6.0689 - 11.154 [EPISUITE (KOCWIN v2.0)], respectively.

Using the ECOSAR program (developed by the US Environmental Protection Agency’s Office of Chemical Safety and Pollution Prevention, v 1.11), the predicted effect levels for both acute and chronic endpoints with daphnids exceeded the estimated water solubility by more than 10X for a majority of the individual components of the test material mixture. Thus, no acute or chronic toxicity effects at water saturation were predicted for the test material, and the study was deemed scientifically not necessary.

Description of key information

No acute or chronic toxicity effects at water saturation were predicted for the test material, therefore acute testing with aquatic algae is waived since the study is scientifically not necessary.