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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2010
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Test item name:Fatty acid, tall-oil, reaction products with diethylenetriamine, maleic anhydride, tetraethylenepentamine and triethylenetetramine
Batch number: TEE3316/22
Molecular weight: > 700
Declared purity: 97 %
Storage conditions: Room temperature/dark conditions
Stability under storage conditions: Stable

Sampling and analysis

Analytical monitoring:
not specified

Test solutions

Vehicle:
not specified

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
The study was performed with the unicellular, fresh-water green algae Pseudokirchneriella subcapitata strain, Sele-IRSA, cultured in the ChemService laboratory and originally obtained from the IRSA-CNR (Water Research Institute-Italian Research Council), Brugherio, Milano.
The algae have been cultured in a temperature controlled room at 24.0 °C ± 2.0 °C under continuous uniform illumination of approximately 6000 Lux in the spectral range 400-700 nm. The culture medium was the same of the test medium; the stock culture were weekly transferred to fresh medium and maintained in continuous shaking to ensure the necessary amount of CO2 and to keep algae in suspension. Cultures containing deformed or abnormal cells were discarded. Only exponentially growing algal cultures were used to start the test.

Study design

Test type:
not specified
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h

Test conditions

Test temperature:
23.4– 27.0 °C
pH:
Immediately after preparation, the pH in test solution was 7.91 for the test item and 7.99 for the control and the pH did not vary more than 1.5 unit during the test

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC20
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate

Any other information on results incl. tables

A limit test was performed to evaluate the effect of the test item onPseudokirchneriella subcapitata.

Cell density was measured every 24 hours by fluorescent reading with a spectrofluorophotometer in few millilitre samples taken from each test concentration replicate and from controls. The obtained cell densities for each replicate are reported in Table 1.

Tab. 1 

Effect of Fatty acid, tall-oil, reaction products with diethylenetriamine, maleic anhydride, tetraethylenepentamine on the growth ofPseudokirchneriella subcapitata

 

Nominal

test item concentration [mg/L]

replicate

Cell density (n. cells x 104/mL)

0 h

24 h

48 h

72 h

Negative control

A

B

C

D

E

F

Average value

1

1

1

1

1

1

1

6.4208

6.9100

7.9582

8.2149

6.5681

5.4908

6.9271

61.6703

57.4623

55.5053

66.5773

65.6403

62.1813

61.5061

257.2394

235.1594

267.1994

269.5994

221.8594

248.7794

249.9727

100.0

A

B

C

D

E

F

Average value

1

1

1

1

1

1

1

5.7440

6.1722

6.6641

7.3959

6.3474

6.1554

6.4132

84.0450

69.5310

86.1350

81.8110

87.4370

84.9750

82.3223

341.4841

259.6641

329.7641

324.1441

335.6241

340.7841

321.9108

At the end of the test the cell density in the negative control was increased on average by a factor of 250. This value complies with the validity criteria of the test, according to the mentioned guidelines, which indicate a minimum increase factor of 16.The negative control met also the other validity criteria, with a coefficient of variation of daily growth rates of 21.7% and a coefficient of variation of average growth in replicates control cultures during the test period of 5.5%.

In the test item solution the algal growth rate (r) and the yield (y) after 72 hours of exposure did not show any significant effects in comparison with negative control (Equal Variance test).

 

The percentages of growth inhibition for the tested concentration are reported in Table 2, while the percentages of growth inhibition in terms of biomass for the tested concentration are reported in the Table 3.

Tab. 2 

Algal growth rate and inhibition caused by Fatty acid, tall-oil, reaction products with diethylenetriamine, maleic anhydride, tetraethylenepentamine over 72 hours of exposure in comparison with control.

Nominal

test item

concentration

[mg/L]

24 h

48 h

72h

Mean growth rate

(x10-3)

Mean inhibition

%

Mean growth rate

(x10-3)

Mean inhibition

%

Mean growth rate

(x10-3)

Mean inhibition

%

0

(negative control)

80.3

-----

85.8

-----

76.7

-----

100.0

77.3

3.7

91.8

-7.1

80.1

-4.5

Tab. 3

Algal yield and growth inhibition caused by Fatty acid, tall-oil, reaction products with diethylenetriamine, maleic anhydride, tetraethylenepentamine over 72 hours of exposure in comparison with negative control.

Nominal test item concentration

(mg/L)

Mean biomass at 72h

(cell/ml)

Mean growth inhibition

%

0

(Negative control)

2499727

-----

100.0

3219108

-28.9

The EYCxand ErCxcalculations were carried out using a Linear Interpolation analysis.

The EC10, the EC20and the EC50for each observation time and for both endpoints could not be determined, but they could be assessed as greater than 100 mg/L.

The temperature under the test light was in the range 23.4 –27.0°C during the exposure period, with a mean value ofand a standard deviation of 0.8; these values exceeded the OECD’s recommended range ( 24°C±2).

the pH in test solution was 7.91 for the test item and 7.99 for the control and the pH did not vary more than 1.5 unit during the test, as required by the mentioned guidelines

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The acute toxicity of test item Fatty acid, tall-oil, reaction products with diethylenetriamine, maleic anhydride, tetraethylenepentamine was tested on Pseudokirchneriella subcapitata. The EC10, EC20 and EC50 for growth rate and for yield were determined to be greater than the nominal tested concentration of product 100.0 mg/L.
Executive summary:

The influence of the test item “Fatty acid, tall-oil, reaction products with diethylenetriamine, maleic anhydride, tetraethylenepentamine and triethylenetetramine” on the growth of the green algal speciesPseudokirchneriella subcapitata, formerly known asSelenastrum capricornutum, was investigated in a 72-hour limit test according to the OECD Guideline No. 201, 2006.

 

For this purpose, exponentially growing test algae were exposed for 72 hours to an aqueous test medium solution at the only nominal concentration of 100.0 mg/L, under defined conditions. Besides this concentration, a negative control without the test item was prepared to check the acceptability of the algal inoculum.

 

Algal cell density was measured every 24 hours by fluorescent reading with a spectrofluorophotometer in few millilitre samples taken from each test concentration replicate and from controls.

The pH of the test medium after preparation was 7.91 for test item and 7.99 for control.

 

The room temperature was in the range 23.4 –during the test period; the maximum value exceeded the OECD’s recommended range (24 ±), however this deviation did not affect the results of the study as showed by the inhibition data in the control.

 

Light intensity at test initiation was 5931 Lux as mean value measured under the light, according to the mentioned guideline (approximately 6000 Lux).

 

In the negative control the cell density increased on average by a factor of 250. This value complies with the validity criteria of the test according to the mentioned guidelines, such as the coefficient of variation of daily growth rates (21.7%) and the coefficient of variation of average growth in replicates control cultures during the test period (5.5%).

 

In the test solution, at the only nominal concentration of 100.0 mg/L of product, no significant effect was shown in comparison with negative control for both the endpoints, yield and growth rate, after 72 hours of exposure (Equal Variance test).

The 72-h ExC10ExC20ExC50were determined to be greater than the nominal concentration tested (100 mg/L).