2-Thiophenecarboxylic acid, 3-amino-2,5-dihydro-4-methyl-, methyl ester, 1-oxide

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

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

Section 2, No. 201: "Freshwater Alga and Cyanobacteria, Growth Inhibition Test", adopted March 23, 2006, corrected July 28, 2011

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Commission Regulation (EC) No 761/2009, Annex, Part C, C.3.: "Freshwater Algae and Cyanobacteria, Growth Inhibition Test", Official Journal of the European Union (EN), dated August 24, 2009

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: SANCO/3029/99 rev.4 11/07/00: Residues: Guidance for generating and reporting methods of analysis in support of pre-registration data requirements for Annex II (part A; Section 4) and Annex III (part A; Section 5) of directive 91/414

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-Thiophenecarboxylic acid, 3-amino-2,5-dihydro-4-methyl-, methyl ester, 1-oxide

EC Number:

603-029-2

Cas Number:

125088-75-7

Molecular formula:

C7H11NO3S

IUPAC Name:

2-Thiophenecarboxylic acid, 3-amino-2,5-dihydro-4-methyl-, methyl ester, 1-oxide

Test material form:

solid: crystalline

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: The test item and the information concerning the test item were provided by the Sponsor.Batch N. 140098
- Expiration date of the lot/batch: 05/05/2016

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: After receipt at the test facility from November 20 – 30, 2015 at 4 ± 4°C until storage recommendations were provided; thereafter at 20 ± 5 °C in the dark

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

The test medium of the only test item concentration of nominal 100 mg/L was prepared by dissolving 46.2 mg test item into 462 mL test water by intense stirring for 25 minutes. The test medium was freshly prepared just before the start of the test (= introduction of algae).

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Selenastrum capricornutum
- Strain: Strain No. 61.81 SAG
- Source (laboratory, culture collection): The algae were supplied by the „Sammlung von Algenkulturen, Albrecht-von-Haller-Institut für Pflanzenwissenschaften, Universität Göttingen", 37073 Göttingen, Germany
- Method of cultivation: The algae were cultivated in the laboratories of ibacon under standardised conditions according to the test guidelines.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield and growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield and growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield and growth rate

Effect concentrations 4

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Yield and growth rate

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The influence of Dihydrothiophene Ester Sulfoxide on the growth of the freshwater green algae Pseudokirchneriella subcapitata was assessed in a static limit test. There was no statistically significant effect of the only test item concentration on the freshwater green algae Pseudokirchneriella subcapitata. The 72-hour NOEyC and NOErC were determined to be ≥100 mg test item/L. The 72-hour LOEyC and LOErC were determined to be > 100 mg test item/L. The 72-hour EyC50 and ErC50 were determined to be > 100 mg test item/L.

Executive summary:

The purpose of this test was to determine the inhibitory effect of the test item Dihydrothiophene Ester Sulfoxide on the growth of the freshwater green algaePseudokirchneriella subcapitata.

Exponentially growing cultures of this unicellular green algal species were exposed to the only test item concentration of nominal 100 mg/L under defined conditions. The inhibition of growth in relation to control cultures was determined over a test period of 72 hours, and thus over several algal generations. This limit test was performed in compliance with the test guidelines to demonstrate that the test item has no toxic effect onPseudokirchneriella subcapitataup to at least this concentration.

The test method of application and the test system are recommended by the test guidelines andPseudokirchneriella subcapitatais one of the recommended test species.

The purpose of the analytical part of this study was to verify the concentration of the test item in the test medium.

This study encompassed 2 treatment groups (1 dose rate of the test item and a control) with six replicates of the only test concentration and six replicates of the control. At test start 50 mL of the test concentration was inoculated with 5000 algal cells per mL test medium and defined volumes of the algal suspensions were sampled after 24, 48 and 72 hours for determination of cell densities by spectrophotometrical measurement.

At the start of the test 99 % of the nominal test concentration was found (average of the only test concentration). After 72 hours test duration, 97 % of the nominal value was determined (average of the only test concentration). During the test the algae were exposed to a mean of 98 % of nominal. Therefore, all reported results refer to nominal concentration.

The influence of Dihydrothiophene Ester Sulfoxide on the growth of the freshwater green algaePseudokirchneriella subcapitatawas assessed in a static limit test. There was no statistically significant effect of the only test item concentration on the freshwater green algaePseudokirchneriella subcapitata. The 72-hour NOEyC and NOErC were determined to be ≥100 mg test item/L. The 72-hour LOEyC and LOErC were determined to be > 100 mg test item/L. The 72-hour EyC50and ErC50were determined to be > 100 mg test item/L.