Fatty acids, linseed-oil, reaction products with bisphenol A-epichlorohydrin polymer and glycidyl neodecanoate

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 23, 2016 to May 27, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Qualifier:

according to guideline

Guideline:

other: OECD guidance document no.43

Version / remarks:

Guidance document on aquatic toxicity testing of difficult substances and mixtures (adopted Dec. 2000)

Principles of method if other than guideline:

NB. The following deviation from the guideline was documented:
- The temperature in the experiment was slightly higher than stated in the guidelines. Because normal growth was observed, this can be stated as uncritical. The deviation was signed and assessed by the study director on 09. June 2016.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch no.: #210162718
Composition: Reaction products of linseed-oil fatty acids, 4,4'-methylendiphenyldiglycidylether with neodecanoic fatty acid, oxiranylmethylester
Purity: 100 % as per definition of UVCB
Appearance: brown liquid

Analytical monitoring:

yes

Details on sampling:

The water-accommodated fraction (WAF) was prepared for the test. This was done mixing the nominal load 100.1 mg/L with the corresponding amount of algal medium (demineralised water enriched with minerals but without algae) and shaking vigorously for 24 hours. The resulting solution was filtrated through 0.45 μm nylon filters. The lower treatments were prepared by dilution of this WAF with nutrient medium.

Vehicle:

no

Details on test solutions:

At the start and at the end of the test, the content of the test substance in the test solutions was determined using measurement of dissolved organic carbon (DOC). The measured concentration based on DOC measurement was very low and is caused by the low water solubility of the test substance. Nevertheless, the increase of DOC showed the presence of the test substance in the test solutions. Therefore, the determination of the results was based on the mean of the measured concentrations which represent the limit of solubility during the conditions of this study. Additionally the effect-levels based on the nominal concentrations were further calculated.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

- The culture of Desmodesmus subspicatus was obtained in January 2016 by MBM Sciencebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen). The algae were kept as stock culture on solid agar at 2 - 8 °C. From the stock culture, a permanent culture was prepared. From an aliquot of the permanent culture, the pre-culture was prepared.
- Four days before the start of each test, an aliquot of the permanent culture was brought into nutrient medium and incubated under continuous lighting for 96 hours. The resulting culture grew exponentially. Before usage, the pre-culture was checked for the absence of cell aggregates and the cell number of culture was determined.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23.0 – 24.3 °C

pH:

7.5-7.7

Salinity:

-

Conductivity:

-

Nominal and measured concentrations:

Treatments tested: 1.0, 3.2, 10, 32 and 100 mg/L (nominal concentration)

Details on test conditions:

Number of replicates: 6 replicates for the control and 3 replicates for each treatment
Vessels: glass flasks total volume 65 mL
Lighting: 5300 Lux
- Blank control: deionised water with nutrient medium and algae
- Treatments: test solution and algae

Reference substance (positive control):

yes

Remarks:

Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9)

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

13 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 100 mg/L (nominal)

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

4.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 32 mg/L (nominal)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

12 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 91 mg/L (nominal)

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

5.5 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 43 mg/L (nominal)

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

13 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Remarks on result:

other: 100 mg/L (nominal)

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

4.2 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Remarks on result:

other: 32 mg/L (nominal)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

6.5 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Remarks on result:

other: 50 mg/L (nominal)

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

3.6 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Remarks on result:

other: 28 mg/L (nominal)

Details on results:

One valid experiment was performed. The study was performed using 5 concentrations ranging from 1.0 to 100 mg/L nominal concentrations. Significant inhibition of algal growth was observed at the highest concentration of 100 mg/L nominal concentration only.

Results with reference substance (positive control):

The 72h-EC50s of potassium dichromate (K2Cr2O7, CAS No. 7778-50-9) were determined in a separate reference test. The values lay within the range of the laboratory (growth rate 0.73 - 1.10 mg/L, yield 0.21 – 0.66 mg/L).

Analytical Determination:

At the start and at the end of the test, the content of the test substance in the test solutions was determined using measurement of dissolved organic carbon (DOC). The measured DOC in the blank control at the end of the test was unexpected high, probably caused by contamination. Therefore, the measured DOC in the blank control at the start of the test was subtracted from the measured DOC values in the test item solutions at the end of the test. As the measured DOC concentrations in the two lowest treatments were below the blank control at the start of the test, no evaluation of test item concentrations was done for these concentrations. The measured concentration based on DOC measurement was very low and is caused by the low water solubility of the test substance. Nevertheless, the increase of DOC showed the presence of the test substance in the test solutions. Therefore, the determination of the biological results was based on the geometric mean of the measured concentrations. Geometric mean is calculated by multiplication of the n participating concentrations and taking the nth root. Additionally, the determination of the biological results was based on nominal concentration.

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the 72h ErC50 (growth rate) and EYC50 (yield inhibition) for Desmodesmus subspicatus based on measured concentrations were determined to be 12 and 6.5 mg/L respectively (i.e., corresponding to 91 and 50 mg/L nominal concentration), while the NOEC for both the parameters was 4.2 mg/L (i.e., corresponding to 32 mg/L nominal concentration). Further, the 72 h ErC10 and EbC10 were determined to be at 5.5 and 3.6 mg/L respectively (i.e., corresponding to 43 and 28 mg/L nominal concentrations) respectively (Muckle, 2016).

Executive summary:

A study was conducted to determine the toxicity to aquatic algae and cyanobacteria of the test substance according to OECD Guideline 201 and EU Method C.3. Algae were exposed to Water Accomodated Fractions (WAF; using an orbital shaker) of the substance at loading rates of 0, 1, 3.2, 10, 32 and 100 mg/L (loading rate) and incubated in open (covered with perforated plastic foil) for 72 hours in triplicates. The cell concentration of each replicate was determined by measuring the cell numbers every 24 h with an electronic particle counter. Growth rate and the yield were determined from the cell number at the respective observation times (i.e., at 0, 24, 48 and 72 h). Samples were collected for analytical dose verification at the start and at the end of the test. Analysis of the samples indicated very low dissolved organic carbon (DOC) concentrations, due to low water solubility, which was found to increase after 72 h. Therefore, the determination of the results was based on the geometric mean of the measured concentrations.Significant inhibition of algal growth was observed at the highest concentration of 100 mg/L nominal concentration only. The 72 h EC50 of positive control (potassium dichromate) were determined to be within the range of the laboratory (growth rate: 0.73 - 1.10 mg/L; yield: 0.21–0.66 mg/L). All validity criteria were met. Under the study conditions, the 72h ErC50 (growth rate) and EYC50 (yield inhibition) forDesmodesmus subspicatusbased on measured concentrations were determined to be12 and 6.5 mg/L respectively (i.e., corresponding to 91 and 50 mg/L nominal concentration), while the NOEC for both the parameters was 4.2 mg/L (i.e., corresponding to 32 mg/L nominal concentration). Further, the 72 h ErC10 and EbC10 were determined to be at 5.5 and 3.6 mg/L respectively (i.e., corresponding to 43 and 28 mg/L nominal concentrations) respectively (Muckle, 2016).

Description of key information

The 72 h ErC50 and ErC10 for Desmodesmus subspicatus were established at 12 and 5.5 mg/L, based on mean measured concentrations.

Key value for chemical safety assessment

EC50 for freshwater algae:

12 mg/L

EC10 or NOEC for freshwater algae:

5.5 mg/L

Additional information

A study was conducted to determine the toxicity to aquatic algae and cyanobacteria of the test substance according to OECD Guideline 201 and EU Method C.3. Algae were exposed to Water Accomodated Fractions (WAF; using an orbital shaker) of the substance at loading rates of 0, 1, 3.2, 10, 32 and 100 mg/L (loading rate) and incubated in open (covered with perforated plastic foil) for 72 h in triplicates. The cell concentration of each replicate was determined by measuring the cell numbers every 24 h with an electronic particle counter. Growth rate and the yield were determined from the cell number at the respective observation times (i.e., at 0, 24, 48 and 72 h). Samples were collected for analytical dose verification at the start and at the end of the test. Analysis of the samples indicated very low dissolved organic carbon (DOC) concentrations, due to low water solubility, which was found to increase after 72 h. Therefore, the determination of the results was based on the geometric mean of the measured concentrations. Significant inhibition of algal growth was observed at the highest concentration of 100 mg/L nominal concentration only. The 72 h EC50 of positive control (potassium dichromate) were determined to be within the range of the laboratory (growth rate: 0.73 - 1.10 mg/L; yield: 0.21–0.66 mg/L). All validity criteria were met. Under the study conditions, the 72h ErC50 (growth rate) and EYC50 (yield inhibition) for Desmodesmus subspicatus based on measured concentrations were determined to be 12 and 6.5 mg/L respectively (i.e., corresponding to 91 and 50 mg/L nominal concentration), while the NOEC for both the parameters was 4.2 mg/L (i.e., corresponding to 32 mg/L nominal concentration). Further, the 72 h ErC10 and EbC10 were determined to be 5.5 and 3.6 mg/L respectively (i.e., corresponding to 43 and 28 mg/L nominal concentrations) (Muckle, 2016).