Sodium bis[2-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]benzoato(2-)]chromate(1-)

Endpoint summary

Description of key information

• There is a high probability that the product is not acutely harmful to fish.
• Acutely toxic to aquatic invertebrates.
• There is a high probability that the product is not acutely harmful to aquatic plants.
• The inhibition of the degradation activity of activated sludge is not anticipated when introduced to biological treatment plants in appropriate low concentrations.

Additional information

Short-term toxicity to fish

In a 96-hour acute toxicity study, zebrafish (Danio rerio) were exposed to the test item at a loading rate of 0 (control) and 100 mg/L under static conditions in accordance with the OECD 203 test guideline. The water pH, temperature and dissolved oxygen were within acceptable guideline specifications. The 96 hour LC₅₀/ LL₅₀was > 100 mg/L based on the loading rate of the test substance. The test substance had no observable acute effect onfishup to its saturation limit in test media and under test conditions.The results in this study are consistent with all validity criteria and the test is valid according to the guidelines of this study. No deviations from test guidelines or other incidents occurred during the course of the reported test which may have influenced the results.   

Short-term toxicity to daphnia
A Klimisch 1 GLP study (BASF, 2000) was performed according to OECD guideline 202, EU method C.2, EPA OPPTS 850.1010 and other guidelines to determine the mobilization of Daphnia magna in an aqueous extract (eluate) of the test substance after 48 hours (observation times: at start of test, 24 and 48 hours after start of the test). The following concentrations of the test substance were used: 100, 50, 25, 12.5, 6.25, 3.13, 1.56, 0.78 and 0.39 mg/L (dilution factor: 2). The effect concentrations at which 0%, 50% and 100% of the animals are immobile, were determined: EC0 (48 h) = 0.688 mg/L (nominal 6.25 mg/L); EC50 (48 h) = 2.56 mg/L (nominal 23.3 mg/L); EC100 (48 h) = 11 mg/L (nominal >100 mg/L).

Toxicity to aquatic plants

In a 7 day growth inhibition study study,Lemna gibbawere exposed to the test item at loading rates of 0 (control), 0.032, 0.1, 0.32, 1.0 and 3.2 mg/L under static conditions in accordance with the OECD 221 guideline. The water pH and temperature were within acceptable guideline specifications. Plant growth (as frond number) and phytotoxic effects were observed on day 2, 5 and test termination.The ErL 10 based on growth rate and frond number was determined at 1.11 mg/L and 0.43 mg/L based on dry weight. The ErL50 values were > 3.2 mg/L loading rate.The results in this study are consistent with all validity criteria and the test is valid according to the guidelines of this study. No deviations from test guidelines or other incidents occurred during the course of the reported test which may have influenced the results.

Toxicity to microorganisms 
A Klimisch 1 GLP (study (BASF,1999) was performed according to OECD guideline 209 and ISO guideline 8192 to determine the inhibitory effect of the test substance on the oxygen consumption of activated sludge after 180 minutes of incubation time. The used concentrations were 98, 499 and 1000 mg/L of the test substance and 1, 10 and 100 mg/L of the used reference product 3,5-dichlorophenol. The effect concentration values for the test substance and the reference product were based on added nominal concentrations and not on analytically determined values. The following nominal concentrations at 20%, 50% and 80% respiration inhibition of activated sludge were determined for the test substance: EC20 (3 h) ca. 280 mg/L (reference product: ca. 2.1 mg/L), EC50 (3 h) >500 mg/L (reference product: ca. 13 mg/L); EC80 (3 h) >500 mg/L (reference product: ca. 67 mg/L).