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Toxicity to aquatic algae and cyanobacteria

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Description of key information

In both available studies the test substance was not toxic under test conditions in the range of water solubility.

Key value for chemical safety assessment

Additional information

In the key study the inhibitory effect of 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters on the growth of the green alga Scenedesmus subspicatus, strain CHODAT (86.81 SAG) had been tested in accordance with OECD Guideline for Testing of Chemicals No.201 and EEC Methods for Determination of Ecotoxicity, Annex to Directive 92/69/EEC.

The test algae were exposed to 6 concentrations of 1,2,4-Benzenetricarboxylic acid, mixed decyl and octyl triesters, ranging from 0.24 to 3.5 mg/L. As the test substance was poorly soluble in water, a 1 g/L mixture with deionised water was prepared. This mixture was stirred for 18 hours and filtrated afterwards. The filtrate was analysed and showed an initial content of 3.9 mg/L DOC and was used as stock solution. The cultures were incubated on sterile ventilated Erlenmeyer flasks on light tables at 24±2 °C. Growth was monitored by determining the cell number photometrically at a wave length of 685 nm after 24, 48 and 72 hours. No inhibitory effects on the growth of the green alga were observed.

On the basis of cell growth, a mean effective concentration was calculated to be EbC50 (72 h) > 3.5 mg/L.

On the basis of the growth rate, a mean effective concentration was calculated to be ErC50 (0 -72 h) > 3.5 mg/L.

The NOEC value was >= 3.5 mg/L (on basis of cell growth).

In a supporting study the effect of the test item on the growth of Pseudokirchneriella subcapitata has been investigated and gave EL50 values of greater than 100 mg/L loading rate WAF. The No Observed Effect Loading Rate was 100 mg/L loading rate WAF.

Therefore in both tests the test substance was not toxic under test conditions in the range of water solubility.