Potassium trifluoroacetate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From May 17th 2017 to September 27th 2017.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Certificate No 2017/12

Analytical monitoring:

yes

Details on sampling:

Test concentrations were analyzed:
- at T0h, before algae addition
- at T72h with and without algae.
In order to remove algae at T72h, 50 mL of test concentration were sampled and centrifugated at 4000G during 10 minutes. Analyses were performed on the supernatant.
For test concentrations higher than 100 mg/L (maximum value of the working range) an appropriate dilution (factor 2 to factor 20) was applied.
All samples were analyzed immediately after sampling.

Vehicle:

no

Details on test solutions:

Preliminary experiments showed that pH of test concentrations higher than 60 mg/L were not appropriate to a suitable algal growth (pH < 6).

Therefore, the following steps were performed to prepare the range of test concentrations:
- preparation of a stock solution at 1 460 mg/L in growth medium,
- preparation of an intermediate solution at 58.4 mg/L by diluting stock solution in growth medium. This solution was used to prepare the lowest test concentrations (0.9 to 54.7 mg/L),
- adjustment of the stock solution pH with concentrated NaOH solution (10 M), to reach a pH consistent with suitable algal growth (≥ 6.5). This adjusted stock solution was used to prepare the highest test concentrations (153.1 to 1200.0 mg/L).

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

- Species: Pseudokirchneriella subcapitata, green alga belonging to the order of Chlorococcales; strain CCAP 278/4
- Origin: Liquid culture obtained from the Culture Center for Algae and Protozoa (CCAP) Institute of Freshwater Ecology, Ferry House, Ambleside, Cumbria, U.K.
- Sensitivity: controlled in May 2017 (See chapter IV - Reference item)
- Pre-culture : 4 days before the start of the test, cells from the algal stock culture were inoculated in culture medium.The pre-culture was maintained under the same conditions as used in the test. The cell density was measured immediately before use.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

21.7 – 22.2°C (continuous measurement during the study)

pH:

8.2 ± 0.1 (after equilibriation with air)

Nominal and measured concentrations:

Initial nominal concentrations: 0.9, 2.5, 7.0, 19.5, 54.7, 153.1, 428.6, 1 200.0 mg/L, corresponding to the following mean measured concentrations (geometric mean of measured concentration at T0h and at T72h): 0.9, 2.7, 7.2, 20.2, 55.6, 157.6, 438.0, 1207.0 mg/L

Details on test conditions:

- Test medium: OECD Growth medium as described in OECD guideline 201
- Vessels: 250 mL conical flasks with air permeable stoppers filled with 100 mL of test solutions
- Initial cell concentration: 10E4 cells/mL taken from an exponentially growing pre-culture
- Test concentrations: (initial nominal) (mg/L) 0.9 – 2.5 – 7.0 – 19.5 – 54.7– 153.1 – 428.6 – 1 200.0 This range of concentrations was selected, in agreement with the sponsor representative, after preliminary tests, to determine accurate EC50, EC10and NOEC values.
- Number of replicates: 6 for control conditions + 1 without algae (analysis) 3 per concentration with algae 1 per concentration, without algae (blank control and analysis)
- Incubation temperature: 21.7 – 22.2°C (continuous measurement during the study)
- Incubation illumination: 79 – 118 µE m-2s-1(obtained with plant growth light) corresponding to the range 2570 – 3790 lux.
- After equilibration with air, the pH of growth medium was 8.2 ± 0.1.
- Agitation: Orbital shaking 125 rpm
- Duration: 72h
- Renewal: None
- Determination of algal cells: Every 24 hours with a particle counter (Coulter counter Z2, BECKMAN COULTER Life Sciences)
- Algal cells microscopic observation: At the beginning of the test to verify the normal and healthy appearance of the inoculum culture. After 72h to observe any abnormal appearance of the algae (as may be caused by the exposure to the test item).

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

2.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: logarithmic increase of biomass (average specific growth rate) during the exposure period

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

5.59 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: logarithmic increase of biomass (average specific growth rate) during the exposure period

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

237.07 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: logarithmic increase of biomass (average specific growth rate) during the exposure period

Details on results:

- NOEC: 2.7 mg/L (measured concentration) corresponding to 2.5 mg/L in nominal concentration
- ErC10 (72h): 5.80 mg/L (3.36 – 10.06), corresponding to 5.59 mg/L (3.00 – 9.69) in nominal concentration.
- ErC50 (72h): 241.95 mg/L (195.45 – 292.66), corresponding to 237.07 mg/ (192.21 – 289.23) in nominal concentration.

Cell density measurements, performed with a particle counter at 0h, 24h, 48h and 72h are summarized in Table 1. Measurement done on blank controls, performed for all concentrations, demonstrated the lack of interference for measurements with particle counter. Microscopic observations were performed at T0h (inoculum) and at T72h for each test concentration. Some aggregations of algal cells were noticed at the highest test concentrations (mainly in the range between 153.1 and 1200 mg/L). On the other hand, no changes in color and cell shape was observed for any test concentration.
Averages specific growth rates calculated for tests concentrations and for control are summarized in Table 2. Effects on algal growth increased with increasing concentration of trifluoroacetic acid.

Analyses were performed on:
- the stock solution at 1460 mg/L and the intermediate solution 58.4 mg/L (dilution of the stock solution) at T0h (see Table 3).
- the test concentrations (including control) at T0h, before algae addition and at T72h with and without algae (See Table 4).
These results showed that:
- the concentrations of trifluoracetic acid were stable during the exposure period,
- results are comparable in test concentrations with and without algae demonstrating a lack of interaction between TFA and algae,
- the test item has been satisfactorily maintained within ± 20 % of the nominal concentration in all test conditions.
For each test concentration, an exposure concentration can be calculated by performing a geometric mean of measured values at T0h and T72h. Results are presented in Table 5.
According to these results, either nominal or measured concentrations can be used for toxicity values determination.

Results with reference substance (positive control):

Sensitivity of the strain of Pseudokirchneriella subcapitata was checked using potassium dichromate.
The test gave the following result: ErC50 (72h): 1.05 mg/L (0.99 – 1.14 mg/L)
This value was calculated using a log-logistic regression analysis with bootstrap estimation of the 95% confidence limits.
This value is included in the warning limits of the laboratory (mean ErC50±2 SD) on this species corresponding to two standard deviations from the historic geometric mean of themedian inhibitory concentration (0.75 – 1.19 mg/L).
This result confirmed the appropriate sensitivity of the algal strain.

Reported statistics and error estimates:

Statistics have been performed using Toxstat 3.5, Western Inc. and D. Gulley, University of Wyoming.
Normality and homogeneity of the data have been checked and the significance of the effect on growth was determined, by performing a two tailed ANOVA (α-value = 0.05) followed by the Bonferroni post-hoc test (α-value = 0.05). ErC10 and ErC50 (72 h) values have been calculated using log-logistic regression with bootstrap estimation of 95% confidence limits.

Table 1. Cell density measurements, performed with a particle counter at 0h, 24h, 48h and 72h

Test concentrations (initial nominal concentrations) in mg/L	Cell Density x 10^4cell/mL (particle counter)								pH
	T0	Mean	T24h	Mean	T48h	Mean	T72h	Mean	T0	T72h
Control	1.00 1.00 1.00 1.00 1.00 1.00	1.00	3.13 3.91 4.76 3.82 3.59 3.26	3.75	17.76 22.66 18.91 19.08 19.11 19.36	19.48	104.88 112.44 119.58 120.77 116.72 98.89	112.21	8.3	8.8
0.9	1.00 1.00 1.00	1.00	4.57 4.76 4.71	4.68	17.56 19.20 24.99	20.58	97.40 113.65 108.18	106.41	8.1	8.6
2.5	1.00 1.00 1.00	1.00	4.05 4.25 4.90	4.40	16.58 19.84 21.19	19.20	97.60 86.61 91.27	91.83	8.0	8.6
7.0	1.00 1.00 1.00	1.00	3.66 4.00 4.19	3.95	16.86 18.45 20.06	18.46	85.73 91.30 79.40	85.48	7.6	8.5
19.5	1.00 1.00 1.00	1.00	4.09 3.10 4.15	3.78	15.42 13.88 13.13	14.14	70.04 68.48 47.39	61.97	7.0	8.1
54.7	1.00 1.00 1.00	1.00	2.91 2.71 3.37	3.00	7.33 7.14 7.75	7.41	17.41 18.86 19.65	18.64	6.2	7.4
153.1	1.00 1.00 1.00	1.00	3.29 3.06 3.29	3.21	7.24 6.38 7.00	6.87	14.97 15.15 17.64	15.92	7.9	7.9
428.6	1.00 1.00 1.00	1.00	2.54 2.45 2.70	2.56	5.14 4.31 4.97	4.81	7.90 7.53 7.12	7.52	7.6	7.8
1200.0	1.00 1.00 1.00	1.00	2.81 2.60 2.28	2.56	3.37 3.13 3.35	3.28	4.08 4.19 4.20	4.16	7.1	7.7

Table 2. Average specific growth rates and growth rates inhibitions.

Test concentrations (nominal concentrations) in mg/L	Average specific growth rate (days^–1) - 0-72h	Mean	CV (%)	Growth rate inhibition (%)
Control	1.551 1.574 1.595 1.598 1.587 1.531	1.573	1.7	/
0.9	1.526 1.578 1.561	1.555	1.7	1.1
2.5	1.527 1.487 1.505	1.506	1.3	4.3
7.0	1.484 1.505 1.458	1.482	1.6	5.8
19.5	1.416 1.409 1.286	1.370	5.3	12.9
54.7	0.952 0.979 0.993	0.975	2.2	38.0
153.1	0.902 0.906 0.957	0.922	3.4	41.4
428.6	0.689 0.673 0.654	0.672	2.7	57.3
1200.0	0.469 0.478 0.478	0.475	1.1	69.8

Table 3. Stock solution and intermediate solution analysis

	Nominal concentration (mg/L)	Measured concentration (mg/L)
Stock solution	1 460	1 448.0
Intermediate solution	58.4	59.8

Table 4. Concentrations of TFA measured during the test

Nominal concentration (mg/L)	T0h		T72h with algae		T72h without algae
	Measured concentration (µg/L)	% Nominal concentration	Measured concentration (µg/L)	% Nominal concentration	Measured concentration (µg/L)	% Nominal concentration
Control	ND	/	ND	/	ND	/
0.9	1.0	113	0.9	99	0.9	103
2.5	2.7	108	2.7	106	2.7	108
7.0	7.3	105	7.2	103	7.2	103
19.5	20.2	103	20.1	103	19.8	101
54.7	55.7	102	55.5	101	55.0	101
153.1	157.1	103	158.0	103	158.1	103
428.6	436.7	102	439.3	103	438.9	102
1200.0	1208.7	101	1205.4	100	1208.4	101

Table 5. Mean measured concentration of trifluoroacetic acid in test concentrations

Nominal concentration (mg/L)	Mean measured concentration (mg/L)	% of nominal concentration
0.9	0.94	106
2.5	2.66	107
7.0	7.23	104
19.5	20.15	103
54.7	55.60	102
153.1	157.57	103
428.6	437.98	102
1200.0	1207.04	101

Validity criteria fulfilled:

yes

Remarks:

biomass of controls increased by a factor > 16, mean CV for section by section specific growth rates for control < 35% (mean CV: 14.7%), CV of average specific growth rates during the whole test period in replicate control cultures < 7% (CV: 1.7%)

Conclusions:

In a GLP-compliant and OECD guideline 201 toxicity study on the growth of the unicellular alga Pseudokirchneriella subcapitata, the following toxicity values have been determined for the test item trifluoroacetic acid based on nominal concentrations:
- NOEC: 2.5 mg/L
- ErC10 (72h): 5.59 mg/L
- ErC50 (72h): 237.07 mg/L

Executive summary:

In a GLP-compliant study conducted according to the procedure described in the OECD Guideline 201 “Freshwater Alga and Cyanobacteria, Growth Inhibition Test", the effects of the test item trifluoroacetic acid on the growth of the unicellular green algal species Pseudokirchneriella subcapitata was investigated.

Green algae were exposed during 72h to the test item in static conditions. The initial nominal concentrations were 0.9 – 2.5 – 7.0 – 19.5 – 54.7 – 153.1 – 428.6 – 1200.0 mg/L (corresponding to the following geometric mean of measured concentration at T0h and at T72h: 0.9 – 2.7 – 7.2 – 20.2 – 55.6 – 157.6 – 438.0 – 1207.0 mg/L). The test concentrations were analytically monitored by ion-exchange chromatography with gradient elution and conductimetric detection. The test item has been satisfactorily maintained within ± 20 % of the nominal concentration in all test conditions. The endpoint was inhibition of growth, expressed as logarithmic increase of biomass (average specific growth rate) during the exposure period.

All validity criteria were fulfilled. In conclusion, the following toxicity values have been determined for the test item trifluoroacetic acid based on nominal concentrations:

- NOEC (72h): 2.5 mg/L

- ErC10 (72h): 5.59 mg/L

- ErC50 (72h): 237.07 mg/L

Description of key information

No data on potassium trifluoroacetate is available for this endpoint. However, a reliable key study is available for trifluoroacetic acid (adjusted to neutral pH) which is used in a read-across approach. Data of various reliability are available for seven freshwater species and three marine water species. Pseudokirchneriella subcapitata was the only species showing adverse effects resulting in a 72h-ErC50 of 237 mg/L (Chabot, 2017). For marine algae no ErC50 can be derived and the lowest NOEC value of 97 mg/l was defined for Phaedactylum tricornutum.

Key value for chemical safety assessment

EC50 for freshwater algae:

237 mg/L

EC10 or NOEC for freshwater algae:

5.6 mg/L

EC10 or NOEC for marine water algae:

97 mg/L

Additional information

Algal toxicity 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.

Not all studies were performed with analytical monitoring. But the studies including chemical analysis 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 Pseudokirchneriella subcapitata, (formerly known as Selenastrum capricornutum). These effects have been demonstrated in several studies giving ErC50 in a range of 6.4 – 237 mg/L. Due to the high variability of the toxicity results, the available data have been closely assessed in line with the validity criteria of the OECD TG 201 (OECD Testing Guideline 201, last version adopted on the 23 March 2006) and using the CRED (Criteria for Reporting and Evaluating Ecotoxicity Data) evaluation method (Moermond et al., 2016).

The study of Groeneveld A.H.C., de Kok H.A.M. and van den Berg G. (1992) was performed in 1992 with a GLP statement and according to the OECD TG 201 adopted in 1984. The experiment was scheduled for a duration of 4 days, but due to unexpectedly high growth of the algae in the control, the pH had increased from 7.3 at the start of the test to 9.4 after 3 days and therefore the study was not continued after 3 days. This high increase of pH observed in the control medium has also been observed in the lowest tested concentration (i.e. from 7.3 to 9.2). On one hand, a high pH could limit the growth of algae and therefore can mask the potential effect of the substance. On the other hand, a high increase of pH can be the result of an insufficient aeration demonstrating the absence of optimal growth conditions and therefore can enhance the stress generated by the test substance. Even if this criterion is not reported in the performance criteria of the guideline, it is however indicated that “The pH of the control medium should not increase by more than 1.5 units during the test”. Therefore, there are uncertainties on the reliability of this study which showed an EC 50 of 133 mg/L based on growth rate inhibition.

The study of Berends A.G. and Molenaar J.A. (1993) was performed in 1992 with a GLP statement and according to the OECD TG 201 adopted in 1984. The objective of this study was to determine the effects of TFA at low concentrations in order to clarify the results of the previous study performed in the same laboratory (i.e. Groeneveld et al., 1992, discussed above) which showed 11% of the inhibition of the biomass at the lowest tested concentration of 0.3 mg/L. This additional study was performed at concentrations ranging from 0.03 to 1 mg/L in order to determine the NOEC based on biomass inhibition. The highest concentration tested resulted in an inhibition of only 6% of the growth rate which doesn't allow the derivation of robust NOEC, EC10 or EC50 values for growth rate. It is noted that no NOEC and EC10 based on the growth rate inhibition were reported in the study. This study can be considered as not relevant for the derivation of PNECwater because no results on the growth rate can be derived.

The study of Groeneveld A.H.C. and Berends A.G. (1995) was performed in 1995 with a GLP statement and according to the OECD TG 201 adopted in 1984. The objective of this study was to compare the toxicity of sodium trifluoroacetate, difluoroacetic acid, sodium monofluoroacetate and sodium fluoride to the alga Pseudokirchneriella subcapitata by comparison of rough estimation of EC50. Therefore, even if this study complies with the validity criteria of the OECD TG 201 published in 1984, its objective was not to determine NOEC or EC10 value, and the study design may not be adequate for this determination. This is supported by the fact that only 4 concentrations were tested and separated by a large ratio of 10, although the OECD TG 201 indicates at least 5 concentrations arranged in a geometric series with a factor not exceeding 3.2. Additionally, only 2 replicates were performed per test concentration while the OECD TG 201 requests 3 replicates. These elements show that the study design is not appropriate to obtain statistically reliable results, what is also indicated in the study report itself as follows: “Due to the large ratio between the test concentrations (10) and the low number of replicates (only 2 erlenmeyers per concentration) the EC50 values can only be considered as rough estimates”. It is also noted that the reliability criterion of the current version of the OECD TG 201 on low variability of the growth rate for section-by-section in the control is not fulfilled. This indicates that there are uncertainties on the reliability of this study which is not appropriate for the derivation of PNECwater because no robust EC10 or NOEC on the growth rate can be derived.

The study of Thiebaud H. (1996) was performed in 1996 according to the OECD TG 201 adopted in 1984. However, 6 concentrations were tested with a non constant separating factor ranging from 2 to 10 and only 3 replicates were performed for the control. These elements show that the study design may not be appropriate to obtain statistically reliable results. Similarly to the previous study, the reliability criterion of the current version of the OECD TG 201 on low variability of the growth rate for section-by-section in the control is not fulfilled. Therefore, there are uncertainties on the reliability of this study which showed an EC50 and an EC10 based on the growth rate inhibition of 6.4 mg/l an 1 mg/L respectively. 

 The study of Barthel Y. (2008) was performed in 2008 according to the norm NF EN ISO 8692 2005. Although some information is lacking to enable a full reliability assessment (i.e. source of the inoculum) and the number of replicates in the control is 5 instead of 6 recommended in the OECD TG 201, it can still be assumed with reasonable certainty that the results are reliable. The EC50 and EC10 based on the growth rate inhibition were determined to be 145 mg/l and 15.4 mg/L respectively. It is recognized that these results being more than 10 times higher than the results of the study of Thiebaud H. (1996), they need to be confirmed, what was done in the study of INERIS (2017).

A new GLP study has been performed at INERIS in 2017 (Chabot L., 2017), in compliance with the most recent version of the OECD TG 201 (OECD Testing Guideline 201, last version adopted on the 23 March 2006). In pre-tests, the following parameters of the test conditions have been varied to check if they can explain the difference of results observed between the available studies :

• the method of pH adjustment to reach relevant pH for algae growth,

• the composition of the test medium by comparing two different growth media,

• the method applied for algae cells counting: fluorimetry or particle counter.

None of the above parameters influenced significantly the effects observed and the preliminary results were as follows :72h-ErC50 = 604.8 mg/L; 72h-ErC10 = 22.7 mg/L; 72h-NOEC = 10 mg/L

 

Based on these preliminary results, the final study was performed with 8 test concentrations ranging from 0.9 to 1200 mg/L. The pH of the test solutions from 0.9 to 54.7 mg/L was above 6 and therefore was not adjusted. The test solutions of concentrations from 153.1 to 1200 mg/L were prepared using a pH adjusted stock solution of 1460 mg/L. Analytical verification showed a good correlation between the nominal and the measured concentrations. Therefore, the results were based on nominal concentrations.

The following results were determined based on the inhibition of the growth rate of the algal cells: 72h-ErC50 = 237 mg/L; 72h-ErC10 = 5.6 mg/L; 72h-NOEC = 2.5 mg/L

All validity criteria were met, therefore the test is considered to be reliable without restrictions. This study confirms that Pseudokirchneriella subcapitata is the most sensitive species tested to TFA.

This new study being assessed as reliable without restrictions is considered as the key study. The studies of Thiebaud H. (1996) and Barthel Y. (2008) provide ErC10 values of 1 mg/L and 15.4 mg/L respectively. Although of lower reliability, the mean value of these results is 8.2 mg/L which is consistent with the ErC10 value of the key study. Therefore it can be concluded that the results of the key study are relevant for the determination of the aquatic PNEC.

Concerning the remaining studies, although they are supporting the conclusion that TFA has toxic effects on the growth of Pseudokirchneriella subcapitata, their design do not enable the determination of ErC10 values. They are therefore not considered for the derivation of the PNEC.

No toxicity (at concentration up to 2 g/l) was found for the three marine algae tested. Then no ErC50 can be derived and the lowest NOEC value corresponds to the lowest tested concentration of 97 mg/l on the diatom Phaedactylum tricornutum.

Several supporting studies investigate the mode of action of TFA on Selenastrum capricornutum. An effect on the chlorophyll content was found but it is unknown if this is a primary or secondary effect. Another study showed that the exposure to high concentrations (up to 999 mg/l) of TFA does not result in mortality of the algae because a recovery of the growth was observed when the substance was removed from the test solutions. Further, it is hypothesised that the activated products of TFA could result in inhibition of the citric acid cycle according to two possible routes: the defluorination to monofluoroacetate (MFA) which is highly toxic to the algae and/or a direct effect on acetyl CoA which would result in the formation of difluorocitrate, that could inhibit aconitase. If activated products of TFA are inhibitors of the citric acid cycle, the enzymatic differences could explain the variation in toxicity of TFA between species. But there is only some evidence that the mode of action of TFA is inhibition aconitase. Moreover, possible accumulation of TFA in the algae cells from the media and conversion of TFA to DFA or MFA are not clearly demonstrated.

Freshwater species
Species	NOEC growth rate	EC10 growth rate	EC50 growth rate	Method	Reference	ESR name
Pseudokirchneriella subcapitata	2.5 mg/L	5.6 mg/L	237 mg/L	OECD TG 201 (2006)	Chabot L. 2017	P.suba.V1 2017INERIS
Pseudokirchneriella subcapitata	6 mg/L	15.4 mg/L	145 mg/L	NF-EN-ISO 8692 (2005)	Barthel Y. 2008	P.suba.V2 2008IPL
Pseudokirchneriella subcapitata	n.d.	1 mg/L	6.4 mg/L	OECD TG 201 (1984)	Thiebaud H. 1996	P.suba.V2 1996ElfAto
Pseudokirchneriella subcapitata	n.d.	n.d.	11.4 mg/L	OECD TG 201 (1984)	Groeneveld A.H.C., Berends A.G. 1995	P.suba.V2 1995Solvay
Pseudokirchneriella subcapitata	n.d.	n.d.	n.d.	OECD TG 201 (1984)	Berends A.G. and Molenaar J.A. 1993	P.suba.V2 1993Solvay
Pseudokirchneriella subcapitata	n.d.	n.d.	133 mg/L	OECD TG 201 (1984)	Groeneveld AHC et al. 1992	P.suba.V2 1992Solvay
Chlorella vulgaris	≥ 999 mg/L	n.d.	> 999 mg/L	OECD TG 201 (1984)	Berends A.G. 1993	C.vulga. V2 1993Solvay
Desmodesmus subspicatus	n.d.	n.d.	> 99.9 mg/L	OECD TG 201 (1984)	Berends A.G. et al. 1995	D.subspi. V2 1995Solvay
Clamydomonas reinhardtii	≥ 99.9 mg/L	n.d.	> 99.9 mg/L	OECD TG 201 (1984)	Berends A.G. 1995 and Groeneveld A.H.C., 1996	C.reinhard. V1 1996Solvay
Microcystis aeruginosa	≥ 97 mg/L	n.d.	> 97 mg/L	OECD TG 201 (1984)	Berends A.G. 1995 and Groeneveld A.H.C., 1996	M.aerugi. V2 1996Solvay
Navicula pelliculosa	499 mg/L	n.d.	1997 mg/L	OECD TG 201 (1984)	Smyth D.V. et al., 1994	N.pellic. V2 1994Zeneca
Anabaena flos-aquae	499 mg/L	n.d.	> 1997 mg/L	OECD TG 201 (1984)	Smyth D.V. et al., 1994	A.flos-a. V1 1994Zeneca
Marine species
Species	NOEC growth rate	EC10 growth rate	EC50 growth rate	Method	Reference	ESR name
Dunaliella tertiolecta	< 103 mg/L	n.d.	> 103 mg/L	OECD TG 201 (1984)	Berends A.G. 1996	D.tertiolecta. V1 1996Solvay
Phaeodactylum tricornutum	≥ 97 mg/L	n.d.	> 97 mg/L	OECD TG 201 (1984)	Berends A.G. 1996	Ph.tricor. V1 1996Solvay
Skeletonema costatum	≥ 1997 mg/L	n.d.	> 1997 mg/L	OECD TG 201 (1984)	Smyth D.V. et al., 1994	S.costa. V1 1994Zeneca

Barthel Y. (2008). Evalutation de l'écotoxicité d'une substance référence: "acide trifluoroacétique".Testing laboratory: IPL santé. Report no.: RPRK08YBA17 rev1. Owner company: Rhodia organique. Report date: 2008-03-07.

Berends A.G. and J. A. Molenaar (1993). The toxicity of sodium trifluoroacetate to the alga selenastrum capricornutum at low concentrations. Testing laboratory: SOLVAY DUPHAR B. V., Environmental Research Department, Noordereinde 56, 1243 JJ 's-Graveland, The Netherlands. Report no.: 56635/61/92. Owner company: SOLVAY DUPHAR B. V. Study number: C. SOL.51.045. Report date: 1993-04-15.

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