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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

An IC50 of 574.98 mg/L was determined for glutaric acid, one of the constituent of the dicarboxylic acids, in a growth inhibition test with Tetrahymena pyriformis (Schultz, 1997).

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Additional information

Concerning the toxicity to microorganisms, there are tests with mixed inoculum and single species avaialbale using the dicarboxylic acids mixture as test substance as well as the single acids.

A test with activated sludge with a duration of 3 hours using a residue from adipic acid manufacturing is available. The test substance contains the following composition: 60 % adipic acid, 14 % glutaric acid, 6 % succinic acid, 10 % carbon, 6.5 % vanadium pentoxide, 3 % copper nitrate and 5 % copper (Bayer, 1988b). The result of EC50 = 7911 mg/l, shows that the compounds other than the dicarboxylic acids did not highly affect the microorganisms.

Another test with activated sludge with a duration of 0.5 hours was performed according to the ISO method 8192 using a dicarboxylic acids mixture without further specification as test substance. An EC20 of >100 mg/L was observed (BASF, 1988).

In a 17 hours test with the dicarboxylic acid mixture towards Pseudomonas putida according to the German standard method DIN-38412 Part 8 (Cell Multiplication Inhibition Test), an EC50 of 91 mg/l was observed (BASF AG 1990). But in this test the pH values in the test solutions ranged from 4.7 (125 mg/l) to 5.5 (3.91 mg/l). As at higher concentrations tested the pH was always <5, it cannot be excluded that the toxicity observed was due to pH effects. Therefore, the study is stated to be reliable, but should not be used for the hazard assessment.

Tests on growth impairment with Tetrahymena pyriformis (Schultz, 1997) using the single acids, adipic-, succinic- and glturaic acid as test substance, results in the following growth inhibitory

concentrations: an IC50 of 591.02 mg/L after 40 hours was found for adipic acid, for glutaric acid an IC50 of 574.98 mg/L was observed and an IC50 of 1027.32 mg/L was determined for succinic acid.