Amides, from C8-10-fatty acids and tetraethylenepentamine

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:

13th June 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Study conducted according to OECD guideline under GLP conditions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

adopted 23 March 2006, Annex 5 corrected 28 July 2011

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: In-house manufactured material. Bx. BBD02611V1-1.STEP
- Expiration date of the lot/batch: 06 - 12 - 2017

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The dilution media used was EC medium, as described in the OECD 201 Test Guideline.
At the start of the definitive test, the 10 mg/L stock medium was prepared by weighing ca 10 mg of test substance and adding to 1000 mL of EC medium, a serial dilution was then performed to give the test concentrations. Control and all stock and media were observed to be colourless solutions. A control treatment was prepared by adding EC medium only to the control vessels.

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

The test organism, Pseudokirchneriella subcapitata (Strain 278/4), was originally obtained from the Culture Collection of Algae and Protozoa (CCAP) and is a representative species of the freshwater aquatic phytoplankton. This species is recommended for testing in accordance with the OECD regulatory guidelines.
Prior to testing, duplicate starter cultures were prepared and incubated under test conditions (as detailed in Appendix1) to obtain sufficient algal cells in exponential growth and to achieve a starting alga cell density of 1 × 104 cells/mL.

Test type:

static

Water media type:

other: EC Medium

Limit test:

no

Total exposure duration:

72 h

Test temperature:

21 to 24°C +/- 2°C

pH:

7.75 - 8.65 after 72 hours

Details on test conditions:

Nominal Concentrations 0.032, 0.1, 0.32 and 1.0mg/l

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 0.538 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 0.342 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

ca. 0.325 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

After 72 hours the ErC50 for the test substance was determined to be 0.538mg/L

Parameter		Toxicity Values (mg/L)		Statistical Test
		72 hours	Confidence limits (LCL-UCL)*
Yield	EyC10	0.145	NC – 0.214	Linear Interpolation (ICPIN)
	EyC20	0.218	0.0307 – 0.3237
	EyC50	0.464	0.297 – 0.564
	NOEC	0.1	NC	Parametric-Multiple Comparison
Biomass	EbC10	0.108	NC – 0.181	Linear Interpolation (ICPIN)
	EbC20	0.160	0.0827 – 0.224
	EbC50	0.342	0.244 – 0.469
	NOEC	0.1	NC	Parametric-Multiple Comparison
Growth Rate	ErC10	0.325	0.202 – 0.345	Linear Interpolation (ICPIN)
	ErC20	0.375	0.346 – 0.394
	ErC50	0.538	0.514 – 0.557
	NOEC	0.1	NC	Parametric-Multiple Comparison
*	LCL = lower confidence limit, CL = upper confidence limit
NC	Not calculated

Validity criteria fulfilled:

yes

Conclusions:

The effects of TEPA C8-10 FA on the growth of the unicellular green alga, Pseudokirchneriella subcapitata, were determined during a 72-hour growth inhibition test conducted in accordance with OECD Chemicals Testing Guideline No. 201 Alga, Growth Inhibition Test (adopted 23 March 2006) (Annex 5 corrected 28 July 2011) (Reference 1).

All validity criteria were met therefore the test was considered valid.

As measured concentrations were determined using TOC analysis results are based on nominal concentrations, at the request of the study monitor results are also presented in terms of initial measured concentrations.

Based on nominal concentrations, the 72-hour EyC50, EbC50 and ErC50 values were calculated to be 0.464, 0.342 and 0.538 mg/L, respectively.

Based on nominal concentrations the corresponding NOEC values for yield, biomass and specific growth rate after 72 hours were 0.1, 0.1 and 0.32 mg/L, respectively.

Executive summary:

The objective of the study was to determine the effects of TEPA C8-10 FA against algal growth by exposing the green alga, Pseudokirchneriella subcapitata, at the exponential growth phase to the test substance during a 72-hour test period.

The test was conducted in accordance with OECD Chemicals Testing Guideline No.201.

Based on the results of a range-finding test, for which only the key findings have been reported, the definitive test was conducted at nominal test concentrations of 0.01, 0.032, 0.1, 0.32 and 1.0 mg/L.

Test vessels (250 mL conical flasks) were prepared containing 100 mL of the appropriate test or control medium. Each test vessel was inoculated with 1 × 104 alga cells/mL and incubated at 21 - 24°C (under 4440 - 8880 Lux light intensity) for 72 hours with cell counts at 24-hour intervals.

Total organic carbon (TOC) concentrations were determined from samples of test solution from each treatment and control group at the beginning (0 hours) and end (72 hours) of the test. Due to the sensitivity issues with TOC analysis below 1.0 mg/L, it was considered justifiable to base the results on nominal and initial test concentrations.

Analysis of the test samples at 0 hours showed TOC concentrations to range from 2.27 to 23.83 ppm TOC. Due to the sensitivity of TOC analyser, the stock medium was also analysed, this showed a TOC concentration of 30.23 ppm TOC. Samples at 72 hours showed TOC concentrations to range from 0.0 to 1.98 ppm TOC. Analysis of the 72 hours centrifuged samples showed TOC concentration to range from 0.0 to 3.09 ppm TOC.

Based on nominal concentrations, the 72-hour EyC50, EbC50 and ErC50 values were calculated to be 0.464, 0.342 and 0.538 mg/L, respectively.

The corresponding NOEC values for yield, biomass and specific growth rate after 72 hours were 0.1mg/L. (ErC10 0.325mg/l)

All validity criteria were met therefore the test was considered valid.

Description of key information

The inhibition to algal growth rate was determined in a study undertaken according to OECD test guideline 201 and conducted according to GLP.

The resulting EC50 based on growth rate was determined to be 0.538mg/l and the NOEC, also based on growth rate, was determined to be 0.1mg/l

Key value for chemical safety assessment

EC50 for freshwater algae:

0.538 mg/L

EC10 or NOEC for freshwater algae:

0.325 mg/L