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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Data of various reliability are available for seven freshwater species and three marine water species. Selenastrum capricornutum was the only specie showing toxic effect. Based on the geometric mean of the two reliable tests, an ErC50 of 8.5 mg/l and a NOEC of 0.2 mg/l were calculated for the freshwater algae. For marine algae no ErC50 can be derived and the lowest NOEC values correspond to the lowest tested concentrations (97 mg/L on the diatom Phaedactylum tricornutum).

Key value for chemical safety assessment

EC50 for freshwater algae:
8.5 mg/L
EC10 or NOEC for freshwater algae:
0.2 mg/L
EC10 or NOEC for marine water algae:
97 mg/L

Additional information

Acute and chronic data of various reliability, produced from international guidelines under GLP or not, are available for seven freshwater species and three marine water species (see Table below).

In aqueous solution, the pH of the substance is naturally low (pH<4) and for testing on organisms either the sodium salt (NaTFA) or pH adjustment were required. Two algae studies including chemical analysis were performed according to GLP and confirmed the stability of the test substance during freshwater and marine algae tests and therefore high stability during other algae tests was postulated.

Among all the species tested, a toxic effect (growth inhibition) was found only for Selenastrum capricornutum. Three tests were performed on this species.However one of the study showed a difference of one order of magnitude compared to the two others. The methodology of this test was further investigated and it was found that the growth in the control was probably limitated by the inorganic carbon (pH above 9.4 at the end of the test) resulting in a higher ErC50. Based on the geometric mean of the two remining tests, an ErC50 of 8.5 mg/l and a NOEC of 0.2 mg/l were calculated for the freshwater algae.

No toxicity was found for the three marine algae tested. Then no ErC50 can be derived and the lowest NOEC values correspond to the lowest tested concentrations (103 mg/L on Dunaliella tertiolecta, 97 mg/L on the diatom Phaedactylum tricornutum and 1997 mg/L on Skeletonema costatum).

Table: Growth inhibition effects of TFA on algae species

Organism

EC50/LC50 (mg/L)

NOEC (mg/L)

Flag

Reference in IUCLID 5

Aquatic algae

Freshwater

Selenastrum capricornutum

Growth rate 72h:11.4(TFA)

Growth rate72h*:0.10(TFA)

K

6.1.5 Alga tox., V2 1995 GROE

Selenastrum capricornutum

Growth rate 72h:6.4(TFA)

Growth rate72h*:0.42(TFA)

K

6.1.5 Alga tox., V2 1996 THIE

Selenastrum capricornutum

Growth rate 72h:133(TFA)

Growth rate 72h:0.30(TFA)

D

6.1.5 Alga tox., V2 1992 GROE

Scenedesmus subspicatus

Growth rate 72h:> 99.9(TFA)

Growth rate72h*:99.9(TFA)

K

6.1.5 Alga tox., V2 1995 BERE

Chlorella vulgaris

Growth rate 72h:> 999(TFA)

Growth rate 72h:999(TFA)

K

6.1.5 Alga tox., V1 1993 BERE

Chlamydomonas reinhardtii

Growth rate 72h:> 99.9(TFA)

Growth rate 72h:99.9(TFA)

K

6.1.5 Alga tox., V1 1996 BERE GROE

Microcystis aeruginosa

Growth rate 144h:> 97(TFA)

Growth rate 144h:97(TFA)

K

6.1.5 Alga tox., V2 1996 BERE 3

Navicula pelliculosa

Growth rate 96h:1997(TFA)

Growth rate 96h:499(TFA)

K

6.1.5 Alga tox., V2 1994 SMYT 1

Anabaena flos-aquae

Growth rate 120h:> 1997(TFA)

Growth rate 120h:499(TFA)

K

6.1.5 Alga tox., V1 1994 SMYT 3

Marine water

Dunaliella tertiolecta

Growth rate 72h:> 103(TFA)

Growth rate 72h:<103(TFA)

K

6.1.5 Alga tox., V1 1996 BERE 1

Phaeodactylum tricornutum

Growth rate 72h:> 97(TFA)

Growth rate 72h:97(TFA)

K

6.1.5 Alga tox., V1 1996 BERE 2

Skeletonema costatum

Growth rate 96h:> 1997(TFA)

Growth rate 96h:1997(TFA)

K

6.1.5 Alga tox., V1 1994 SMYT 2

* Recalculated values

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