2,2'-vinylenebis[5-methylbenzoxazole]

Endpoint summary

Description of key information

Short term toxicity tests are available for all the three tropic levels (fish, invertebrates and aquatic plants).

In a key study with Daphnia magna, the 48-h EC50 of FAT 65004 was determined to be >100 mg/L. In the study conducted with fish, the TL50 of FAT 65004 was determined to be >1000 mg/L, while in studies with bacteria, the IC50 of the substance was determined to be >400 mg/L. Further, in a key study with Lemna, the EC50 for FAT 65004, was >100 mg/L.

Hence, based on the above results, FAT 65004 can be considered as not toxic to the aquatic ecosystem.

Additional information

Two acute fish toxicity test were performed according to a methodology similar to OECD Guideline 203 (CIBA method A-11). Zebra fishes were used in the experiment setup. Fish were tested at these different following concentrations: 100 and 1000.0 mg/L. In conclusion LC50 = >1000 mg/L was noted.

A study was performed to assess the acute toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphniasp., Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008. The acute toxicity of the test item to the freshwater invertebrate Daphnia magna has been investigated and based on the mean measured test concentrations gave a 48-Hour EC50 value of greater than 0.93 mg/L. The No Observed Effect Concentration was 0.93 mg/L. This study showed that there were no toxic effects at saturation.

Due to intrinsic properties of the substance (dark color), the study to determine the acute toxicity to aquatic algae and cyanobacteria cannot be performed. The dark coloration of the test medium and reduced light intensity in the medium modifying the conditions of test. Hence, to determine the toxicity to the aquatic plant Lemna minor, a semi-static growth inhibition test was performed.

A study was performed to assess the effect of the test item on the growth of the freshwater plant Lemna minor. The method followed that described in the OECD Guideline No. 221 “Lemna sp.Growth Inhibition Test (March 2006)”. The effect of the test item on the growth of Lemna minor has been investigated over a 7-Day period and based on the geometric mean measured test concentration showed Average Specific Growth Rate and Yield with respect to both Frond Number and Dry weight as EC50 > 0.092 mg/l and NOEC for the same endpoints was noted to be 0.092 mg/l. This study showed that there were no toxic effects at saturation.

In Bacterial toxicity tests,

both the available studies were performed following internal standard procedure B-21, which is similar to OECD method 209: “Activated Sludge, Respiration Inhibition Test". IC50 (3h) was determined to be > 400 mg/l.

Hence, based on the above results, FAT 65004 can be considered as not toxic to the aquatic ecosystem.