TCA

Endpoint summary

Additional information

Short-term toxicity to fish:

Key study: LC50 was greater than 1000 mg/L for Salmo gairdneri (test method according to German 'Biologische Bundesanstalt' (BBA)).

Long-term toxicity to fish:

Weight of evidence: NOEC lower than 7 ppm (63 days) for Cyprinus carpio. Other experimental data are reported from a different independent source where the LC0 (30 days) was 7370 mg/L for Cyprinus sp.

Short-term toxicity to aquatic invertebrates:

Weight of evidence: experimental results with the substance sodium trichloroacetate and read-across from trichloroacetic acid.

A study with sodium trichloroacetate shows a 24-h EC50 greater than 10000 mg/L.

The EC50 of trichloroacetic acid was higher than 100 mg/L for Daphnia magna based on results from several independent sources.

Read-across:

Based on published experimental data on the analogue trichloroacetic acid and the molecular weights, the read-across approach is applied and the EC50 values for sodium trichloroacetate are calculated to be greater than 100 mg/l.

Toxicity to aquatic algae and cyanobacteria:

Weight of evidence: Experimental results obtained with the substance sodium trichloroacetate in a non standardized test with several species and read-across from results obtained with the substance monochloroacetic acid in two independent studies according to OECD guideline 201 and DIN 38412, Part 9.

Sodium trichloroacetate:

Free trichloroacetic acid is a strong organic acid, which forms water-soluble salts with bases. In any medium at or near neutral pH the predominant form present is the trichloroacetate anion. The salts are therefore expected to be toxicologically equivalet to the free acid, except for the acute corrosive properties, which are at least partly determined by the very low pH of strong solutions of the acid.The strongest effects were recorded in a 14-day test with the species Chlorella pyrenoidosa and Chlorella mucosa with EC50 values of 0.3 and 0.46 mg/l, respectively.

Although these results are based on biomass after the exponential growth phase, an analysis of the growth curves reported in the publication shows that the effect concentrations derived from biomass during the exponential growth phase are of the same order as those reported after 14 days. From these results it is concluded that algae is very sensitive to sodium trichloroacetate.

Monochloroacetic acid:

Two studies with Scenedesmus subspicatus were independently performed at two different laboratories. The obtained results for biomass and growth were within the same range, i.e. 25-28 μg/l for biomass and 30-70 μg/l for growth (48-72 hour EC50-values). In the 72 -hour study, the NOEC is 0.0058 mg/l and in the 48 -hour study, the NOEC is 0.007 mg/l (based on biomass) and 0.014 mg/l (based on growth rate).

Based on these results and the molecular weights, the read-across approach is applied and the EC50 (based on growth rate) for sodium trichloroacetate is calculated to be between 0.065 and 0.14 mg/l.

These results, which are below 1 mg/l, support the classification of the substance sodium trichloroacetate as Hazardous for the Aquatic Environment, Acute Category 1.

The substance is already classified in the harmonised list of classification and labelling (CLP Regulation) as Hazardous for the Aquatic Environment, Acute Category 1.

Toxicity to microorganisms:

Weight of evidence: Experimental results obtained with the sodium trichloroacetate and read-across from the results obtained with trichloroacetic acid.

Trichloroacetic acid:

In an activated sludge respiration inhibition test, conducted with industrial activated sludge exposed to the substance trichloroacetic acid, the 24 -h EC20 was higher than 750 mg/l.

The luminiscent bacteria toxicity (LBT) test was performed on the marine phosphorescent bacterium Photobacterium phosphoreum. This test was conducted using the Microtox Toxicity Analyzer System. The EC50 for trichloroacetic acid in the LBT test was 35 mg/l. Single species test with Photobacterium phosphoreum (Vibrio fischeri) should be considered of low relevance for STPs (Sewage Treatment Plants).

Sodium trichloroacetate:

Free trichloroacetic acid is a strong organic acid, which forms water-soluble salts with bases. In any medium at or near neutral pH the predominant form present is the trichloroacetate anion. The salts are therefore expected to be toxicologically equivalet to the free acid, except for the acute corrosive properties, which are at least partly determined by the very low pH of strong solutions of the acid. Using analogous methods of the cell multiplication inhibition test, the toxicity threshold (TT) of sodium trichloroacetate was determined for model organisms. The toxicity threshold was greater than 1000 mg/l for the bacteria Pseudomonas putida and 800 mg/l for the protozoan species Entosiphon sulcatum.

The assimilation-depletion test (A-D test) was performed. The oxygen consumption of a natural bacterial population (depletion test) serves as measurement criteria. The 24 -h EC10 for sodium trichloroacetate for a mixture culture of heterotrophic bacteria was greater than 1000 mg/l.

A method of testing the toxicity of sodium trichloroacetate to bacterial organisms was performed at concentrations ranging from 10 to 1000 mg/l. After incubation of 24 hours at 30 ºC, the measurement of bacterial toxicity was carried out by determining the minimum inhibitory concentration (MIC) in mg/l of the test substance. The MIC was 1000 mg/l for the tested species Aeromonas hydrophila and Bacillus subtilis.

Read-across from trichloroacetic acid:

In an activated sludge respiration inhibition test, conducted with industrial activated sludge exposed to the substance trichloroacetic acid, the 24 -h EC20 was higher than 750 mg/l. The 24-h EC20 for sodium trichloroacetate is calculated to be higher than 850 mg/L.