Thiophene-2-ethylamine

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Guideline study to GLP certification with no deviations.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

The temperature during the test ranged from 22.7 to 24.2ºC. This was a deviation to the protocol which stated that the temperature should remain within the 21 - 24ºC. This deviation was considered not to affect the validity of the test given that the cont

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Thiophene-2-ethylamine

EC Number:

250-196-9

EC Name:

Thiophene-2-ethylamine

Cas Number:

30433-91-1

Molecular formula:

C6H9NS

IUPAC Name:

2-(2-thienyl)ethanamine

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
Source and lot/batch number of test material:
Thienylethylamine (CAS-No.: 30433-91-1) Batch number 6U098
- Purity: 98.1%

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations:
Nominal concentrations were 1.0, 3.2, 10, 32 and 100 mg/L
0 hour measured concentrations were 0.975, 3.19, 10.4, 32.8 and 105 mg/L
72 hour measured concentrations were 0.597, 2.58, 8.63, 29.4 and 95.9 mg/L

- Sampling method:
Samples collected from all test concentrations for analysis at 0 and 72 hours.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
Test concentrations were created through the creation of a master stock and serially diluting to lower concentration. A control treatment was prepared by adding test medium only to the control vessels. A media blank was also prepared by adding test medium only to a vessel; this was not inoculated with algae.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Green algae
- Strain: 278/4
- Age of inoculum (at test initiation): At least 72 hours

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

None

Post exposure observation period:

None

Test conditions

Hardness:

Not stated

Test temperature:

21-24 °C (± 2°C)

pH:

7.99 - 9.79 at test start and 8.00 - 10.15 after 72 hours

Dissolved oxygen:

Not data (OECD TG 201 medium)

Salinity:

Not applicable

Conductivity:

No data (OECD TG 201 medium)

Nominal and measured concentrations:

Nominal concentrations were 1.0, 3.2, 10, 32 and 100 mg/L
Analysis of the test samples at 0 hours showed measured concentrations of 0.975, 3.19, 10.4, 32.8 and 105 mg/L (equivalent to 98% to 105% of nominal value). Samples at 72 hours showed measured concentrations of 0.597, 2.58, 8.63, 29.4 and 95.9 mg/L. Measured concentrations at 72 hours ranged from 81% to 96% of nominal value with the exception of the lowest concentration which resulted in a measured concentration of 60% of nominal. Given that the lowest concentration was below the No Observed Effect Concentration (NOEC), and all other measured concentrations were within the required 80% to 120% of nominal acceptance criteria, results have been based on nominal test concentrations.

Details on test conditions:

TEST SYSTEM
- Initial cells density: 1 × 104 cells/mL
- Control end cells density: 1.53 × 106 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Photoperiod: constant light

Reference substance (positive control):

yes

Remarks:

Potassium dichromate, Batch No. 13D290030, Purity: 100%, expiry date: 31 Jan 2018

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

7.09 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

11.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

18.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

yield

Effect concentrations 5

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

6.64 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 6

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

11.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 7

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

18.9 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 8

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 9

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

13.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 10

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

18.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 11

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

43.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 12

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: 1.93 mg/l

Reported statistics and error estimates:

Statistical analysis was performed using the CETIS program v 1.8.6.8.
To distinguish between ExC50 values, estimated using areas under the growth curve, final yield and growth rates, the symbols EbC50, EyC50 and ErC50 were used, respectively.
The EC10, EC20 and EC50 are defined as the concentrations that result in a 10%, 20% and 50% mean reduction, respectively, relative to the control.
The area under the growth curve (A), the average specific growth rate (μ) and the final yield over specified time intervals were analysed using Bonferoni Adj t Test to determine the no observed effect concentration (NOEC).
Linear interpolation analysis was performed in order to estimate EC10, EC20 and EC50 values. Where possible, 95% confidence limits were calculated for the EC10, EC20 and EC50 values.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The reliable (Klimisch 1) OECD 201 Guideline study on the effect of thienylethylamine on algal growth inhibition reported a 72-hr EC50 of 43.6 mg/l, an EC10 of 13.1 mg/l and a NOEC of 10 mg/l based on growth of Pseudokirchneriella subcapitata (nominal concentrations, calculated).

Executive summary:

The objective of the study was to determine the effects of the test substance 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.
Measured test concentrations were determined from samples of test solution from each treatment and control group at the beginning and end of the test. All measured concentrations were within the required 80% to 120% of nominal acceptance criteria, except the lowest concentration which resulted in a measured concentration of 60% of nominal. Given that the lowest concentration was below the No Observed Effect Concentration (NOEC), and all other measured concentrations were within the required acceptance criteria, results have been based on nominal test concentrations.
The 72-hour yield (EyCx), area under the growth curve (EbCx) and growth rate (ErCx) toxicity values, with corresponding no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) values, are presented in the table below:

		72 hour (mg/l)	Confidence limits (LCU-UCL)*
Yield	EyC10	7.09	NC – 15.8
	EyC20	11.3	NC – 15.0
	EyC50	18.6	14.3 – 22.1
	NOEC	10	NC
Biomass	EbC10	6.64	NC – 14.8
	EbC20	11.2	4.94 – 13.7
	EbC50	18.9	15.4 – 21.6
	NOEC	10	NC
Growth Rate	ErC10	13.1	10.7 – 15.1
	ErC20	18.6	15.1 – 21.8
	ErC50	43.6	38.0 – 48.7
	NOEC	10	NC

*LCL = lower 95% confidence limit, UCL = upper 95% confidence limit
NC = Not calculated

 

Based on nominal concentrations, the 72-hour EyC50, EbC50 and ErC50 values were calculated to be 18.6, 18.9 and 43.6 mg/L, respectively.
Based on nominal concentrations, the corresponding NOEC values for yield, biomass and specific growth rate after 72 hours were 10 mg/L, respectively.
All validity criteria were met therefore the test was considered valid.