Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

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:
September 2015 to January 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed to OECD guideline 201 and in accordance with GLP.
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
2011
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Specific details on test material used for the study:
Chemical name: Pentaerythritol
EC number: 204-104-9
CAS number: 115-77-5
Supplier: Perstorp
Batch No.: 4410102701
Purity: 98.8%
Appearance: Crystalline solid
Analytical monitoring:
yes
Details on sampling:
No samples for analysis were taken during the range-finding tests. For the purpose of chemical analysis during the limit test, duplicate aliquots (ca. 20 mL) were removed from each prepared concentration at the commencement of the test as 0 h samples. At test termination, an aliquot (8 mL) was removed from each replicate vessel and combined for each concentration. Duplicate aliquots (ca. 20 mL) were removed from the combined solutions as 72 h samples.

An additional flask was prepared at 1000 mg/L pentaerythritol concentration and this was incubated (without algal cells) along with the test and control flasks. At 72 h, duplicate aliquots (ca. 20 mL) were removed from this flask for analysis, to determine any differences in measured concentrations of pentaerythritol between inoculated and cell-free medium.
Vehicle:
no
Details on test solutions:
A 1000 mg/L nominal pentaerythritol stock solution was prepared by adding pentaerythritol (1.00003 g) to algae medium (1000 mL). The solution was then sonicated for ca 5 mins to aid dissolution.
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
The freshwater green alga Pseudokirchneriella subcapitata (CCAP 278/4) was used for this study. A starter culture was obtained from the Culture Collection of Algae and Protozoa (CCAP), Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, Argyll, UK on 06 May 2015 for the range finding test and 16 Dec 2015 for the limit test.

Test flasks were inoculated from an algal stock culture at a cell density of ca 10000 cells/mL. The stock 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:
yes
Total exposure duration:
72 h
Hardness:
Not applicable
Test temperature:
22.5 to 23.2°C in the limit test
pH:
pH range 7.93 to 8.09 at the start of the exposure period. 7.86 - 8.62 at the end of the exposure period in the limit test. The pH did not deviate by more than 1.5 units throughout the limit test
Dissolved oxygen:
Not applicable
Salinity:
Not applicable
Conductivity:
Not applicable
Nominal and measured concentrations:
Nominal exposure concentrations were 0 (control) and 1000 mg/L.
The measured exposure concentrations at 1000 mg/L were 1070 mg/L at the start of the exposure period and 932 mg/L after 72 hours.
Details on test conditions:
The algae were provided with continuous uniform illumination in the spectral range 400-700nm obtained with universal white-type fluorescent lamps (light intensity range 4440-8800 lux).
Culture vessels were all of glass construction and test vessels were Erlenmeyer glass flasks of 250mL nominal capacity. Six replicate flasks were prepared for the control and test concentration. Each flask contained 100 mL of test solution and was inoculated with ca 1.00 x 104 cells/mL P. subcapitata. Vessels were covered with aluminium foil caps.

For the limit test measurements, aliquots (5 mL) were taken from each flask, at each timepoint and Lugol solution (100 μL) was added to each to preserve the sample for storage. Aliquots were stored in a refrigerator set to maintain ca 4°C until cell concentrations were determined. Cell concentrations were determined using a compound Leica light microscope and Improved Neubauer ruling counting chambers. Cell concentrations were determined within 3 days of sampling.
Reference substance (positive control):
no
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Details on results:
The 72 h EC10, EC20and EC50for average specific growth rate and yield could not be calculated due to the lack of algae inhibition during the test. The 72 h EC10, EC20, EC50and LOEC for average specific growth rate and yield are therefore estimated to be > 1000 mg/L. The NOEC was estimated to be 1000 mg/L under the test conditions.
Results with reference substance (positive control):
Not applicable
Reported statistics and error estimates:
The average specific growth rate and the percent inhibition in yield (% Iy) was calculated as described in the test guideline.

No statistical analysis was conducted due to the lack of algae inhibition during the test

Analysis

Nominal Concentration of Pentaerythritol (mg/L)

Time

(h)

Mean Measured Concentration of Pentaerythritol (mg/L)

Mean Measured Concentration of Pentaerythritol during the test period

(mg/L)

Deviation of 72 h Measured Concentration from 0 h Measured Concentration

(%)

Deviation from Nominal

(%)

Control

0

ND

ND

NC

NC

72

ND

1000

0

1070

1001

-13

0

72

932

72

(Not Inoculated)

992

1031*

-7

3

* Calculated using the mean measured concentrations determined at Day 0 and the non-inoculated value determined at 72h.

Not Inoculated = Vessel not inoculated to establish any differences in measured concentrations between cell-free medium and medium containing cells over the test period.

ND = Not Detected

NC = Not Calculated

Mean Cell Concentrations at 0 and 72 h during the Limit Test

  

Nominal Concentration of Pentaerythritol (mg/L)

Replicate Flask

Mean Cell Concentration (x105cells/mL)

Mean Percentage Inhibition compared with the Control

(%)

0 hr

(Inoculum)

24 h

48 h

72 h

Control

A

0.10

0.70

2.55

11.10

NA

B

0.10

0.78

2.63

9.25

C

0.10

0.65

2.53

9.23

D

0.10

0.53

2.65

11.43

E

0.10

0.50

2.58

8.60

F

0.10

0.98

2.23

10.03

Mean

0.10

0.69

2.53

9.94

1000

A

0.10

0.65

2.60

11.12

0.00

B

0.10

0.80

2.65

10.00

C

0.10

0.65

3.10

11.75

D

0.10

0.80

2.48

10.70

E

0.10

0.85

2.78

11.68

F

0.10

0.65

2.73

10.58

Mean

0.10

0.73

2.72

10.97

Cell Growth Group Mean Values Determined from Daily Cell Counts During the Limit Test

 

Growth Function

Time Interval
(h)

Nominal Concentration of Pentaerythritol (mg/L)

Control

1000

Average Specific Growth Rate

(Day)

0-24

1.93

1.99

0-48

1.62

1.65

0-72

1.53

1.57

24-48

1.30

1.31

48-72

1.37

1.39

Yield

0-24

1.48

1.58

0-48

6.08

6.55

0-72

24.60

27.18

 


Validity criteria fulfilled:
yes
Conclusions:
The 72 h EC10, EC20and EC50for average specific growth rate and yield could not be calculated due to the lack of algae inhibition during the test. The 72 h EC10, EC20, EC50and LOEC for average specific growth rate and yield are therefore estimated to be > 1000 mg/L. The NOEC was estimated to be 1000 mg/L under the test conditions.
Executive summary:

The inhibition of growth of pentaerythritol to the green algae Pseudokirchneriella subcapitata was determined. The study was carried out according to OECD test guideline 201 – Freshwater Alga and Cyanobacteria, Growth Inhibition Test. The test material was dissolved in algal medium, nominal exposure concentrations were 0 (control) and 1000 mg/L.  The overall (0 and 72 h) mean measured concentration of pentaerythritol was determined to be 1001 mg/L. The results of the study were therefore based on the nominal concentration.

The 72 h EC10, EC20and EC50for average specific growth rate and yield could not be calculated due to the lack of algae inhibition during the test. The 72 h EC10, EC20, EC50and LOEC for average specific growth rate and yield are therefore estimated to be > 1000 mg/L. The NOEC was estimated to be 1000 mg/L under the test conditions.

Description of key information

A 72 hour algal growth inhibition study on the freshwater alga Selenastrum capricornutum was conducted according to the OECD test guideline 201 and performed to GLP. A limit test was conducted at a nominal pentaerythritol concentration of 1000 mg/L which resulted in no algae inhibition. The 72 h EC10, EC20, EC50 and LOEC for average specific growth rate and yield are therefore estimated to be > 1000 mg/L, and the NOEC was estimated to be 1000 mg/L (Hugill, 2016).

Key value for chemical safety assessment

EC50 for freshwater algae:
1 000 mg/L
EC10 or NOEC for freshwater algae:
1 000 mg/L

Additional information