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Toxicity to aquatic algae and cyanobacteria

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Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Remarks:
This data has been collected as part of the EU Risk Assessment Report on Hydrogen Fluoride
Qualifier:
no guideline followed
Principles of method if other than guideline:
Methods not detailed in the review.
GLP compliance:
not specified
Analytical monitoring:
not specified
Details on sampling:
No details of sampling given in review.
Vehicle:
not specified
Details on test solutions:
No details of test solution in review.
Test organisms (species):
other: Various algae species are described in the review.
Details on test organisms:
Algae species included in the review:
fresh water: Scenedesmus sp., Selenastrum capricornutum.
marine: Ankistrodesmus braunii, Cyclotella meneghiniana, Oscillatoria limnetica, Scenedesmus quadricauda, Stephanodiscus minutus, Synechococcus leopoldiensis.
Test type:
static
Limit test:
no
Total exposure duration:
96 h
Details on test conditions:
No details are provided in the review.
Reference substance (positive control):
not specified
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
43 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Remarks:
Fluoride ion
Basis for effect:
biomass
Remarks on result:
other: freshwater: Scenedesmus sp.
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
122 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Remarks:
Fluoride ion
Basis for effect:
biomass
Remarks on result:
other: freshwater: Selenastrum capricornutum
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
81 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Remarks:
Fluoride ion
Basis for effect:
biomass
Remarks on result:
other: marine: Skeletonema costatum
Duration:
7 d
Dose descriptor:
NOEC
Effect conc.:
50 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Remarks:
Fluoride ion
Basis for effect:
biomass
Remarks on result:
other: marine: Ankistridesmus braunii, Cyclotella menghiniana, Oscillatoria limnetica, Scenedesmus quadricauda, Stephanodiscus minutus, Synechococcus leopoldiensis
Duration:
8 d
Dose descriptor:
NOEC
Effect conc.:
249 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Remarks:
Fluoride ion
Basis for effect:
biomass
Remarks on result:
other: marine: Scenedesmus quadricauda
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
>= 50 - <= 200 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Remarks:
Fluoride ion
Basis for effect:
biomass
Remarks on result:
other: marine: Amphidnium carteri, Chaetoceros gracilis, Dunaliella tertiolecta, Pvlova lutheri
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
>= 50 - <= 200 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Remarks:
Fluoride ion
Basis for effect:
biomass
Remarks on result:
other: marine: Amphidnium carteri, Chaetoceros gracilis, Dunaliella tertiolecta, Pvlova lutheri
Details on results:
The EC50 values for freshwater algae ranged from 43 to 122 mg/L. For marine algae the EC50 was 81 mg/L for Skeletonema costatum.

Expressed in terms of fluoride ion (F-), EC50 values for freshwater algae range from 43 to 122 mg/L, with NOEC values of 50 -249 mg/L. For marine algae the only reported EC50 value was 81 mg/L.

NOEC values of 50 -200 mg/L are reported however the EU Risk Assessment Report states that these values should be used with caution due to the relatively long exposure time of 14 -21 days.

Validity criteria fulfilled:
not specified
Conclusions:
In the EU Risk assessment report for hydrogen fluoride, EC50 values are reported for freshwater algae ranging from 43 to 122 mg/L. For marine algae, an EC50 of 81 mg/L was reported.
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study according to International guidelines. Total and dissolved Ba-levels were reported
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Details on sampling:
Chemical analysis of test concentrations at start and end of exposure
- at the beginning of the test, duplicate samples of each of the test solutions and the control were taken.
- at the end of the test, immediately after determination of the biological and physico-chemical parameters, the test solutions of the replicates of each treatment were mixed. Duplicate samples were taken from the control, each of the test solutions and from the test vessels without algae with the highest test item concentration.
Details on test solutions:
The algal medium (Kuhl and Lorenzen, 1964) consists of trace elements and macronutrients in the following final concentrations:
KNO3: 1011.1 mg/L
NaH2PO4 * 1 H2O: 621.0 mg/L
Na2HPO4 * 2 H2O: 89.0 mg/L
MgSO4 * 7 H2O: 246.5 mg/L
CaCl2 * 2 H2O: 14.7 mg/L
FeSO4 * 7 H2O: 6.9 mg/L
Titriercomplex III: 9.3 mg/L
H3BO3: 0.061 mg/L
MnSO4 * 1 H2O: 0.169 mg/L
ZnSO4 * 7 H2O: 0.287 mg/L
CuSO4 * 5 H2O: 0.00249 mg/L
(NH4)6Mo7O24 * 4 H2O: 0.01235 mg/L
100 mg of the test item was mixed into 1,000 mL algal medium in a 1,000 mL measuring flask, resulting in a nominal concentration of 100 mg test item/L. The solution was shaken for 3 minutes at room temperature.
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
Pseudokirchneriella subcapitata (SAG 61.81) was supplied by Georg-August-Universität Göttingen, D-37073 Göttingen, Germany (Date of receipt: December 18, 2009)
Amount of liquid stock culture per pre-culture vessel: 100 mL
Pre-culture vessels: 300 mL Erlenmeyer flasks
Number of cells per mL in the pre-culture before inoculating the test solution: 88.5E4
Number of replicates: 2
Light: light/dark (24/0 h); fluorescent tubes of universal white type
Light intensity: 60 – 120 µE/m2 * s
Shaker: 100 ± 5 oscillations/min
Temperature in the test room: 21 - 24°C, controlled at ± 2°C
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
22.9 +/- 0.6 degrees Celcius (mean +/- SD)
pH:
start of test: 5.8-5.9 (all test concentrations)
end of test: 6.0-6.1 (all test concentrations)
Dissolved oxygen:
not relevant for algal testing
Nominal and measured concentrations:
nominal: 0, 1.0, 2.2, 10, 31.6 and 100 mg test item/L
dissolved Ba at t=0: below detection limit, 0.139, 0.213, 0.65, 1.92, 1.33 mg Ba/L; expressed as BaCl2: below detection limit, 0.247, 0.376, 1.15, 3.42, 2.37 mg test item/L
dissolved Ba at t=72h: below detection limit, 0.054, 0.111, 0.359, 0.839, 0.999/1.12 (double determination) mg Ba/L; expressed as BaCl2: below detection limit, 0.096, 0.20, 0.64, 1.49, 1.78/1.99 (double determination) mg test item/L
total Ba at t=0: below detection limit, 0.312, 0.211, 3.65, 2.18, 26.32 mg Ba/L; expressed as BaCl2: below detection limit, 0.555, 0.376, 6.49, 3.88, 46.83 mg test item/L
total Ba at t=72h: below detection limit, 0.196, 0.271, 3.21, 8.67, 34.31/30.10 (double determination) mg Ba/L; expressed as BaCl2: below detection limit, 0.348, 0.481, 5.70, 15.43, 61.05/53.56 (double determination) mg test item/L
Details on test conditions:
Test units: 300 mL Erlenmeyer flasks
Volume of test solution per test vessel: 100 ml
No. of test concentrations (incl. control): 6
No. of replicates in the control: 6
No. of replicats per test concentration: 3
Test medium: Algal medium (Kuhl & Lorenzen, 1964)
The concentration of the algal cells in the test solutions at the beginning of exposure was approximately 0.5 * 1E4 cells per mL.
Endpoints: EC50, NOEC, LOEC
Biological parameters: Inhibition of growth in relation to control (growth rate & yield)
Light regime: permanent at 93.6 µE/m2 * s (mean; required is 60-120 µE/m2 * s).
Types of light: fluorescent tubes of universal white type (Osram Lumilux 58W/865)
For chemical analysis at the end of the test, two additional test vessels without algae were prepared at the highest test item concentration in order to assess test item stability during exposure without the presence of algae (stability samples).
Determination of cell number: THOMA Counting Chamber with Microscope Ortholux II, Ernst Leitz KG, Wetzlar, Germany; Multiple Reader Tecan ULTRA, Tecan Deutschland GmbH, Crailsheim, Germany

After 24, 48 and 72 hours, the cell numbers were determined by measuring the fluorescence intensity in 4 samples of 200 µL of test solution per replicate using a fluorometer (Multiple Reader Tecan ULTRA). The results [RFU, relative fluorescence units] were converted into biomass concentration [cells/mL] using a calibration line. A dilution series of the pre-culture was used to determine the calibration line by comparison of cell numbers (counted using a microscope) and fluorescence intensity (measured using a fluorometer) in consideration of background fluorescence of the blank algal medium.
Reference substance (positive control):
yes
Remarks:
K2Cr2O7 (potassium dichromate)
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 1.92 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
dissolved
Remarks:
Ba
Basis for effect:
growth rate
Remarks on result:
other: highest measured level
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 1.92 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
dissolved
Remarks:
Ba
Basis for effect:
growth rate
Remarks on result:
other: highest measured level
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 34.31 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Remarks:
total Ba
Basis for effect:
growth rate
Remarks on result:
other: highest measured level
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 34.31 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Remarks:
total Ba
Basis for effect:
growth rate
Remarks on result:
other: highest measured level
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
No statistically significant differences (Table 1) were found between the control and the test item concentrations up to 100 mg test item/L. The EC50 (72 h) based on nominal concentrations was therefore determined to be higher than the highest concentration of 100 mg test item/L. The results of the study demonstrate that the no-observed effect concentration for Pseudokirchneriella subcapitata for the parameters yield and growth rate is ≥ 100 mg test item/L (nominal concentration).

Samples from the test solutions were analysed to determine the actual test item concentration in comparison to the nominally applied concentration. Measured concentrations of dissolved test item in 0.45 µm-filtered test solutions were between 2 and 25% of the nominal concentrations. Analysis of total Barium in non-filtered, acidified test solutions resulted in recoveries of 12 and 61% of the nominal concentrations.
Considering the measured concentrations as based on total measured Barium content, the EC50 for Pseudokirchneriella subcapitata is > 61.1 mg test item/L (measured in the highest concentration at test end). The no-observed effect concentration (NOEC) is ≥ 61.1 mg/L Barium Chloride Dihydrated
Results with reference substance (positive control):
The reference item potassium dichromate (K2Cr2O7) is tested at least twice a year in order to determine the sensitivity of the organisms from the culture, and to demonstrate that the test conditions are appropriate. Results of the reference test performed in January 2010:
- EbC50: 0.23 mg/L
- ErC50: 0.85 mg/L
Based on an international ring test (ISO 2004) mentioned in OECD guideline 201, the ErC50 (72h)-values for potassium dichromate obtained from different laboratories should be 1.19 mg/L with a standard deviation of 0.27 mg/L.
The EC50 value for the toxic reference item, potassium dichromate, was determined as 0.85 mg/L. This value is within the historical range of the results of our laboratory (mean EC50 value = 1.15 ± 0.42 mg/L) and within the upper (2.54 mg/L) and lower (0.44 mg/L) warning limit. The warning limits were calculated as two standard deviations from the historical mean of the EC50 (all calculated using the log concentration; according to Environment Canada 2005). Furthermore, the EC50 value is within the refined range of 1.10 ± 0.48 mg/L, recommended based on an international ring test (Pattard et al. 2009). Therefore, the results of this reference test are acceptable and the test conditions are reliable.

Reported statistics and error estimates:
Range-to-standard-deviation-ratio Test on Normal Distribution; Cochran´s Test on Variance Homogeneity; One-way Analysis of Variance (ANOVA)
The statistical software package ToxRat 2.10 Professional (ToxRat Solutions GmbH, Naheweg 15, D-52477 Alsdorf) was used for these calculations.

Summary of tests results based on statistical evaluation of biological results and nominal concentrations of the test item.

 Treatment [mg test item/L]

 %Inhibition of Yield (72 h)  Significant difference to control (p≤0.05)  %Inhibition of Growth Rate (72 h) Significant difference to control (p≤0.05
 Control 0.0  No  0.0  No 
 1.0 0.6    No  0.1   No
 3.2 6.9   No    1.3  No  
 10.0 17.3    No  4.6    No 
 31.6 4.6   No   0.9   No  
 100 5.9   No   1.1 

 No  

 EC50 > 100.0 > 100.0    >100.0    
 NOEC  >= 100.0    >= 100.0    
 LOEC > 100.0     > 100.0    

Validiy of test:

- Mean biomass increase in the control cultures: 252.0 (required: factor of at least 16 within the 72h test period

- Mean coefficient of variation for section-by-section specific growth rates in the control cultures: 22.8% (required: up to 35%)

- Coefficient of variation of average specific growth rates during test period in replicate control cultures: 1.4% (required: up to 7%)

Validity criteria fulfilled:
yes
Conclusions:
No statistically significant differences were found between the control and any test item concentration up to and including 100 mg test item/L. The results of the study demonstrate that the EC50 for Pseudokirchneriella subcapitata is >100 mg test item/L. The no-observed effect concentration (NOEC) is ≥100 mg/L Barium Chloride Dihydrated based on nominal concentrations. Considering the measured concentrations, the EC50 for Pseudokirchneriella subcapitata is > 61.1 mg test item/L (measured in the highest concentration at test end). The no-observed effect concentration (NOEC) is ≥ 61.1 mg/L Barium Chloride Dihydrated.
These data can be used for hazard and risk assessment purposes (classification; PNEC-derivation)
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Test conducted under GLP according to standard OECD guidelines
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
Samples for possible analysis were taken from all test concentrations and the control:
- frequency: at t=0, t=24h and t=72h
- volume: 4.8 mL
- storage: samples were stored in a freezer until analysis
At the end of the exposure period, the replicates with algae were pooled at each concentration before sampling
Details on test solutions:
Pre-culture medium: M2; according to OECD 201 Guideline, formulated using MilliQ tap water and subsequently passed over activated carbon and ion-exchange cartridges
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
In-house laboratory culture; strain NIVA CHL 1
Stock culture: Algae stock cultures were started by inoculating growrth medium with algal cells from a pure culture on agar. The suspensions were continuously aerated and exposed to light in a climate room at a temperature of 21-24 degrees Celcius.
Pre-culture: 4 days before the start of the test, cells from the algal stock culture were inoculated in culture medium at a cell density of 10,000 cells/mL. The pre-culture was maintained under the same conditions as used in the test. Te cell density was measured immediately before use.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Hardness:
test medium (m2): 24 mg/L as CaCO3
pH:
test medium (M2): 8.1 +/- 0.2
Nominal and measured concentrations:
nominal: 0.1, 1, 10 and 100 mg/L of strontium nitrate
Measured 100 mg/L: 102.5 mg/L strontium nitrate (t=0)
Measured 100 mg/L: 104 mg/L strontium nitrate (t=24h)
Measured 100 mg/L: 107.5 mg/L strontium nitrate (t=72h)
Measured 100 mg/L (mean): 104.7 mg/L strontium nitrate, i.e., 43.3 mg Sr/L
Details on test conditions:
Vigorous shaking was sufficient to completely dissolve the test substance in medium
Test vessels: 100 mL; all glass - vessels were distributed at random in the incubator
Test volume per replicate: 50 mL
Control: test medium without test substance or other additives
No of replicates for control and highest test concentration: 6
No. of replicates for remaining test concentrations: 3
1 or 2 replicates of each test concentration without algae
1 replicate of each concentration for sampling purposes
Cell concentration at start: 10,000 cells/mL
Illumination: continuously using TLD-lamps of the type 'Cool-white' of 30 Watt, with a light intensity within the range off 66 to 77 uE/m2/s
Algal cells were kept in suspension by continuous shaking

- pH was measured at the beginnig and end of the test period, and was not supposed to deviate by more tan 1.5 units during the test
- at the end of the final test microscopic observations were performed on the limit and one lower concenration to verify a normal and healthy appearance of the inoculum algae and to observe for any abnormal appearance of algae.
- Cells were counted using a microscope and a counting chamber at the beginning of the test; thereafter cell densities were determined by spectrophotometric measurement of samples at 720 nm using a Varian Cary 50 single beam spectrophotometer with a cuvette (pathlength : 10 mm). Quantification of cell density was based on a calibration curve.
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 43.3 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 104.7 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 43.3 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 104.7 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 43.3 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 104.7 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 43.3 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
element
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 104.7 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Details on results:
No significant differences were recorded between the values for growth rate or yield at the limit concentration, i.e., 100 mg/L when compared to the control group. The growth and yield in lower test concentrations were stimulated rather than reduced/inhibited by the test substance. Microscopic observations at the end of the test revealed a normal and healthy appearance of the exposed cells when compared to the control.
Compliance with the Quality criteria regarding mainenance of actual concentrations was demonstrated by running a test vessel at the highest substance concentrartion but without algae, and samples for analysis were taken at the start, after 24 hours of exposure and at the end of the test period.
Test results were in compliance with all validity criteria (minimum increase in cell density, criteria on variation (growt rates, section-by-section specific growth rates) were not exceeded.
Results with reference substance (positive control):
The 72h-EC50 for growth reduction was 1.2 mg/L (95%CL: 0.77-2.0 mg/L).
The historical range of this value lie between 0.82 and 2.3 mg/L.
Reported statistics and error estimates:
Recorded effects were not significant (< 10%); EC50 values could not be calculated because the test substance proved to be non-toxic within the tested concentration range.
For determination of the NOEC and the EC50 the approaches recommended in the OECD guideline 201 are used. An effect was considered to be significant if statistical analysis of the data obtained for the test concentrations compared with those obtained in the negative control revealed significant reduction of growth rate or yield inhibition (ANOVA, Tukey test, Bonferroni t-test, TOXSTAT Release 3.5, 1996, D.D. Gulley et al).

Percentage reduction of growth rate (total test period)

 Nominal Concentration Strontium nitrate (mg/L Mean growth rate - u (0 -72h)  Mean growth rate - reduction (%) 
Control  0.05924   
0.10  0.06675  - 12.7 
1.0  0.06704  -13.2 
10  0.06628  -11.9 
100  0.05931  -0.1 
     
Validity criteria fulfilled:
yes
Conclusions:
No statistically significant differences were found between the control and any test item concentration up to and including 100 mg test item/L. The results of the study demonstrate that the EC50 for Pseudokirchneriella subcapitata is >100 mg test item/L. The no-observed effect concentration (NOEC) is ≥104.5 mg/L strontium nitrate (based on measured concentrations). Considering the measured concentrations, the EC50 for Pseudokirchneriella subcapitata is > 43.3 mg Sr/L (measured in the highest concentration at test end). The no-observed effect concentration (NOEC) is ≥ 43.3 mg/L Sr.
These data can be used for hazard and risk assessment purposes (classification; PNEC-derivation)
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
See the read-across document provided under section 13 for the justification of the read-across approach.
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
GLP compliance:
yes (incl. QA statement)
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 2.45 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
dissolved
Remarks:
Ba
Basis for effect:
growth rate
Remarks on result:
other: highest measured level
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 2.45 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
dissolved
Remarks:
Ba
Basis for effect:
growth rate
Remarks on result:
other: highest measured level
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 43.8 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Remarks:
total Ba
Basis for effect:
growth rate
Remarks on result:
other: highest measured level
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 43.8 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
element
Remarks:
total Ba
Basis for effect:
growth rate
Remarks on result:
other: highest measured level
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 127.67 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 127.67 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Results with reference substance (positive control):
The reference item potassium dichromate (K2Cr2O7) is tested at least twice a year in order to determine the sensitivity of the organisms from the culture, and to demonstrate that the test conditions are appropriate. Results of the reference test performed in January 2010:
- EbC50: 0.23 mg/L
- ErC50: 0.85 mg/L
Based on an international ring test (ISO 2004) mentioned in OECD guideline 201, the ErC50 (72h)-values for potassium dichromate obtained from different laboratories should be 1.19 mg/L with a standard deviation of 0.27 mg/L.
The EC50 value for the toxic reference item, potassium dichromate, was determined as 0.85 mg/L. This value is within the historical range of the results of our laboratory (mean EC50 value = 1.15 ± 0.42 mg/L) and within the upper (2.54 mg/L) and lower (0.44 mg/L) warning limit. The warning limits were calculated as two standard deviations from the historical mean of the EC50 (all calculated using the log concentration; according to Environment Canada 2005). Furthermore, the EC50 value is within the refined range of 1.10 ± 0.48 mg/L, recommended based on an international ring test (Pattard et al. 2009). Therefore, the results of this reference test are acceptable and the test conditions are reliable.

Conclusions:
Based on read-across and a worst-case approach, the toxicity of CH02886 to aquatic algae was determined: NOEC >= 2.45 mg/L. Following CLP rules, no classification is required for the substance.

Description of key information

Key value for chemical safety assessment

Additional information