Disodium 2-(11-oxido-3-oxo-3H-dibenzo[c,h]xanthen-7-yl)benzoate

Endpoint summary

Description of key information

Short-term toxicity to fish:

In an 96 h acute toxicity test according to OECD Guideline 203 in Poecilia reticulata (Guppy), using an aqueuos formulation containing 6.3 % of the test item, an LC50 of > 100 mg/L was determined.

Short-term toxicity to aquatic invertebrates:

In a short-term toxicity study in Daphnia magma according to OECD guideline 202, an EC50 of 6.6 mg/L (95 % CI: 4.778 to 9.116 mg/L) was determined.

Toxicity to aquatic plants other than algae:

In a growth inhibition test with Lemna minor exposed to Mordant Red 27 over 7 days exposure, the ErC50 and EyC50 values for growth rate and yield for frond number was found to be 30.982 (95% CL: 22.942 and 44.366 mg/L) and 9.411 mg/L (95% CL: 7.311 and 12.437 mg/L), respectively. The ErC50 and EyC50 values for growth rate and yield for biomass (dry weight) was found to be 108.866 (80.554 and 153.387 mg/L) and 47.687 mg/L (33.920 and 71.828 mg/L), respectively. The ErC10 and Ey10 values for growth rate and yield for frond number was found to be 1.232 (95% CL: 0.652 – 1.957) and 0.446 mg/L (95% CL: 0.233 - 0.712), respectively. The ErC10 and EyC10 values for growth rate and yield for biomass (dry weight) was found to be 5.182 (95% CL: 3.120 – 7.731) and 1.690 mg/L (95% CL: 0.866 – 2.753), respectively. The NOEC (No observed effect concentration) and LOEC (Lowest observed effect concentration) for frond number was found to be 1.230 and 0.410 mg/L. The NOEC (No observed effect concentration) and LOEC (Lowest observed effect concentration) for dry weight (Biomass) was found to be 1.230 and 0.410 mg/L.

Additional information

Short-term toxicity to fish:

In an acute toxicity test according to OECD Guideline 203, the acute lethal toxicity of an aqueous formulation containing 6.3 % test item to Poecilia reticulata (Guppy) was investigated under static exposure conditions over a period of 96 h. The nominal concentrations of the formulation were 1, 10 and 100 mg/L, respectively. Therefore, this study represents a screening test. The individual test concentrations were prepared by dilution of a stock solution. No analytical verification of the test substance concentration was conducted. The evaluation of the test was based on the nominal concentrations of the test material, assuming the test compound to be stable in water over 96 h. After 96 h of exposure a total of 3 and 1 of seven fish were dead at 1 and 100 mg/L, respectively. No mortality was observed at 10 mg/L. 1 fish died in the blank control after 96 h of exposure. Toxic effects other than mortality, e.g. loss of coordination, hypo- or hyperactivity and swimming on the back, were not observed. The no-observed-effect concentration (NOEC, LC0) was >100 mg/L since the one fish that died is considered not to represent a significant effect as defined by the validity criteria of the test. Since minor effects were observed at 100 mg/L, the three dead fish observed at 1 mg/L were rated to be not a substance related effect. 100 % mortality (LC100) could not be detected. Based on the binominal theory, the absence of mortality provides at least 99 % confidence that the LC50 of the formulation is greater than the highest applied nominal test concentration of 100 mg/L (LC50 recalculated for active ingredient = 6.3 mg/L).

Short-term toxicity to aquatic invertebrates:

The test item was evaluated for acute toxicity on Daphnia magma according to OECD guideline 202. Based on the results of a range finding study test item concentrations of 0.6, 1.3, 2.9, 6.4, 14.0 and 30.9 mg/L were tested along with untreated control and positive control (potassium dichromate). 5 Daphnids/dose were exposed to the test item by aqueous exposure (treatment) under static conditions. Signs of toxicity and immobility were recorded after 24 and 48 hours. No clinical signs of toxicity were observed in control and in the tested concentration of 0.6 mg/L during the 48 hour observation period. Immobilization and lethargy were observed in the tested concentrations of 1.3, 2.9, 6.4 and 14.0 mg/L during the 48 hour observation period. For immobility a percent of 15, 25, 40 and 65 % were observed in the tested concentrations of 1.3, 2.9, 6.4 and 14.0 mg/L. 100 % immobilization was observed in the highest concentration of 30.9 mg/L after 48 hours.

Based on these results, an EC50(48 h) of 6.6 mg/L (95 % CI: 4.778 to 9.116 mg/L) was determined. The No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) over the 48 hour exposure period were found to be 0.6 and 1.3 mg/L, respectively.

Toxicity to aquatic plants other than algae:

The Lemna sp. Growth Inhibition Test was performed with the test substance according to the OECD Guideline 221. This test was performed to determine ErC50 for % Inhibition of Growth, % Inhibition of yield EyC50 along with determination of Lowest Observed Effect Concentration (LOEC) and No Observed Effect Concentration (NOEC) for frond number and measurement variable (dry weight).

Lemna minor was exposed to the test item by aqueous exposure under static condition. Swedish Standard (SIS) growth medium was used to prepare test medium for exposure. Based on the results of range finding study, the main study was performed at the test concentration of 0.14, 0.41, 1.23, 3.7, 11.11, 33.33 and 100.0 mg/L. The ErC50 for % Inhibition of Growth, % Inhibition of yield EyC50 along with determination of LOEC and NOEC for frond number and measurement variable (dry weight) was determined. Lemna minor were observed for frond number on day 0, 4 and on day 7. Observation for fronds was made at beginning of the test and on day 3, 6 and at end of the test day 7. During main study, all fronds appeared normal on day 0, 3, 6 and on day 7 in control and in tested concentrations of 0.14, 0.41, 1.23 and 3.7 mg/L. Some fronds appeared normal and some fronds showed chlorosis on day 6 and 7 in the tested concentrations of 11.11 and 33.33 mg/L. Fronds showed chlorosis on day 6 and 7 in the tested concentration of 100 mg/L. The ErC50 and EyC50 values for growth rate and yield for frond number was found to be 30.982 and 9.411 mg/L respectively. With 95 % confidence limits for growth rate of 22.942 and 44.366 mg/L and  95 % confidence limits for yield 7.311 and 12.437 mg/L respectively. The ErC50 and EyC50 values for growth rate and yield for biomass (dry weight) was found to be 108.866 and 47.687 mg/L respectively. The NOEC and LOEC for frond number was found to be 1.230 and 0.410 mg/L. The NOEC and LOEC for dry weight (Biomass) was found to be 1.230 and 0.410 mg/L.