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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:
From 23 March 2010 to 15 April 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: According to the OECD 201 and it is GLP

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)
Deviations:
no
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Amines, C20-22-alkyldimethyl
EC Number:
296-866-4
EC Name:
Amines, C20-22-alkyldimethyl
Cas Number:
93164-85-3
Molecular formula:
CnH2nN(CH3)2 n: from 18 to 22
IUPAC Name:
Amines, C20-22-alkyldimethyl
Details on test material:
- Physical state: white solid
- Storage: at room temperature in the dark under nitrogen
- Stability under storage conditions: stable

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Preparation of test solution started with an aqueous mixture at a loading rate of 100 mg/L. This mixture was magnetically stirred for 21 hours (final test) or 22 hours (combined limit/range-finding) after which the resulting dispersion was left to settle for 4 hours. After settlement a clear solution with a floating layer was obtained. The Water Soluble Fraction (WSF) was collected by siphoning the middle fration through glass wool after it was used for testing. The control received similar treatment related effects. The lower test concnetration were prepared by subsequent dilution of the WSF in test medium. All final test solution were clear and colourless.

Test solutions

Vehicle:
no
Details on test solutions:
Volumes of 50mL were added to each replicates of the respective test concentration. Subsequently, 1 mL of an algal suspension was added to each replicate providing a cell density of 10^4 cells/mL.

Test organisms

Test organisms (species):
Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata, strain NIVA CHL 1
- Source (laboratory, culture collection): in-house laboratory culture

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

pH:
8.1
Nominal and measured concentrations:
0.10, 0.32, 1.0, 3.2, 10 and 32% of a WSF prepared at a loading rate of 100 mg/L
Details on test conditions:
-Test vessels: 100mL, all-glass, containing 50 mL of the test solution
Replicates
3 replicates of each test concnetration
6 repliactes of the control
2 replicates of the highest concentration without algae
1 replicate of each test concentration for sampling purposes.
Controls: test medium without test substance or other additives
Reference substance (positive control):
yes

Results and discussion

Effect concentrationsopen allclose all
Dose descriptor:
NOEC
Effect conc.:
0.16 µg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
0.26 µg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 0.02-3.2
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
1.7 µg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 0.15-20
Dose descriptor:
NOEC
Effect conc.:
0.16 µg/L
Conc. based on:
test mat.
Basis for effect:
other: yield
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
0.26 µg/L
Conc. based on:
test mat.
Basis for effect:
other: yield
Remarks on result:
other: 0.04-0.76
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
0.62 µg/L
Conc. based on:
test mat.
Basis for effect:
other: yield
Remarks on result:
other: 0.16-2.4

Any other information on results incl. tables

Mean cell densities (x10^4 cellss/mL) during the combined limit/range-finding test

 Test substance  Exposure  time  (hours)  
 %WSF / initial µg/L  0  24*  48*  72*
 control  1.0  4.1  24.2  115.2
 0.10 / 0.6  1.0  4.5  24.0  114.4
 1.0 / 6.0  1.0  4.1  20.0  92.5
 10 / 60  1.0  1.0  1.0  1.0
 100 / 600  1.0  1.0  1.0  1.0

* Droplets were observed against wall of test vessels. These disappeared when shaking the vessels

Percentage reduction of growth rate and inhibition of yield during the combined limit/range-finding test

 Test substance  Mean growth rate  Mean growth rate  Yield (0 -72h)  Yield (0 -72h)
 %WSF / initial µg/L  µ (0 -72h)  Reduction (%)  x10^4 cells/mL  inhibition (%)
 control  0.06589   114.18   
 0.10 / 0.6  0.06583  0.1  113.43  0.7
 1.0 / 6.0  0.06272  4.8  91.46  19.9
 10 / 60  0.00000  100.0  0.00  100.0
 100 / 600  0.00000  100.0  0.00  100.0

Measured concentrations versus nominal concentrations

 % WSF  Measured conc. t= 0 h (µg/L)  Measured conc. t= 24 h (µg/L)  Mesured conc. t=72 h (µg/L)  TWA conc. (µg/L)
 0.10  0.139  0.045*  0.045*  0.06
 0.32  0.443  0.045*  0.045*  0.08
 1.0  3.23  0.045*  0.045*  0.16
 3.2  8.53  0.174  0.161  0.52
 10  30.9  1.10  0.587  2.48
 32  101  0.412  0.316  2.39

*Concentration used is half the LOD (LOD=0.090µg/L)

Mean cell density (x10^4 cells/mL) during the final test

 %WSF / TWA µg/L  Exposure  time  (hours)  
   0  24  48  72
 control  1.0  9.4 31.6   160.4
 0.10 / 0.06  1.0  9.7  33.6  161.2
 0.32 / 0.08  1.0  9.4  30.5  161.1
 1.0 / 0.16  1.0  10.2  33.4  163.7
 3.2 / 0.52  1.0  6.5  14.1  65.1
 10 / 2.48  1.0  3.7  7.3  30.1
 32 / 2.39  1.0  1.4  1.0  2.6

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the conditions of the present study Pseudokirchneriella subcapitata, reduce growth rate and inhibited the yield of this fresh water algae species significantly at TWA concentrations of 0.52µg/L and higher.
the EC50 for growth rate reduction (ErC50:0-72h) was estimated to be 1.7 µg/L with a 95% confidence interval ranging from 0.15 to 20µg/L.
The EC50 for yield inhibition (E γC50:0 -72h) was 0.62µg/L with a 95% confidence interval ranging from 0.16 to 2.4µg/L. The NOEC for both growth rate reduction and yield inhibition was 0.16µg/L.
Executive summary:

The study procedures described in this report were based on the OECD Guideline No.201.

Analyses of samples taken at the start of the test showed measured concentrations of 0.139, 0.443, 3.23, 8.53, 30.9 and 101µg/L in The test solution containing 0.10, 0.32, 1.0, 3.2, 10 and 32% of the WSF, respectively. The study met the acceptability criteria prescribed by the protocol and was considered valid. the substance reduced growth rate and inhibited the yield of this fresh water algae especies significantly at TWA concentrations of 0.52µg/L and higher. The EC50 for growth rate reduction (ERC50:0 -72h) was estimated to be 1.7µg/L with a 95% confidence interval ranging from 0.15 to 20µg/L. The EC50 for yield inhibition (E γC50:0 -72h) was 0.62µg/L with a 95% confidence interval ranging from 0.16 to 2.4µg/L. The NOEC for both growth rate reduction and yield inhibition was 0.16µg/L.