Ethyl 9-oxo-9H-thioxanthene-2-carboxylate

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 Jun - 11 Jul 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 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

2008

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: OECD Series on Testing and Assessment, No. 23, "Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures"

Version / remarks:

2000

Test guideline 4

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 (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Klimaschutz, Landwirtschaft und Verbraucherschutz, Germany

Test material

Test material information

Constituent 1

Reference substance name:

Ethyl 9-oxo-9H-thioxanthene-2-carboxylate

EC Number:

280-960-7

EC Name:

Ethyl 9-oxo-9H-thioxanthene-2-carboxylate

Cas Number:

83817-60-1

Molecular formula:

C16H12O3S

IUPAC Name:

ethyl 9-oxo-9H-thioxanthene-2-carboxylate

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations and method: duplicate samples from the freshly prepared test media filtrate and from the control were taken at the start of the test. Duplicate samples from the test media filtrates of the 100 mg/L test concentrations and the control were taken also at the end of the test by pooling the replicates. Additional samples of the control blank and the dilution solvent were taken at test start and test end without any sample treatment.
- Sample storage conditions before analysis: all samples were diluted by a factor of 2 with acetonitrile and stored at ≤ - 20 °C, protected from light

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: a stock suspension of 100 mg test item/L was prepared by suspending 110.5 mg
test item in 1105 mL test water. The supersaturated stock suspension was mixed for 48 h at room temperature by overhead shaking. Then, medium was filtrated (0.45 μm cellulose acetate filter) and the filtrate was used as test medium.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Clone: 5
- Source: in-house culture
- Age of parental stock: 6.75 to 23 h old
- Breeding: in Elendt M4 medium, fed with green algae (Desmodesmus subspicatus) freshly grown in the laboratory

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

2.5 mmol/L (= 250 mg/L) as CaCO3

Test temperature:

20.5 - 20.6 °C

pH:

7.9 - 8.3

Dissolved oxygen:

6.4 - 8.9 mg/L

Salinity:

-

Conductivity:

-

Nominal and measured concentrations:

Nominal test concentrations: 0 (control) and 100 mg/L (filtrate of a supersaturated stock suspension)

Details on test conditions:

TEST SYSTEM
- Fill volume: 60 mL
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline
- Alkalinity: 0.9 mmol/L
- Culture medium different from test medium: no
- Intervals of water quality measurement: water temperature, pH-values and dissolved oxygen concentrations were determined at test start and test end in each treatment group

OTHER TEST CONDITIONS
- Photoperiod: 16 h light - 8 h dark
- Light intensity: 300 - 340 lux

EFFECT PARAMETERS MEASURED: mobility of the Daphnia was determined by visual observation after 24 and 48 h

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Behavioural abnormalities: no
- Mortality of control: no

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50 (48 h): 0.986 mg potassium dichromate/L

Reported statistics and error estimates:

No statistical analysis was performed. The NOEC, LOEC and ECx after 24 and 48 h were determined directly from the raw data.

Any other information on results incl. tables

Table 1: Summary of further biological results after 48 h exposure.

	Effect Concentration in mg/L
EC20	> 100
EC10	> 100
NOEC	≥ 100
LOEC	> 100

The concentration analysed at the beginning of the test in the only test concentration of nominal 100 mg test item/L was below the LOQ. After 48 h test duration, no test item could be detected.

All reported results refer to nominal concentrations.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes