N,2-dimethyl-N-phenylbutyramide

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-ethyl-N-methyl-N-(3-methylphenyl) butanamide

EC Number:

446-190-2

EC Name:

2-ethyl-N-methyl-N-(3-methylphenyl) butanamide

IUPAC Name:

446-190-2

Constituent 2

Reference substance name:

406488-30-0

Cas Number:

406488-30-0

IUPAC Name:

406488-30-0

Test material form:

other: liquid

Details on test material:

Sponsor's identification: M 019087
Description: clear colourless liquid
Batch No.: 01/02
Date received: 30 May 2002
Storage conditions: approximately 4 °C, in the dark

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

The test samples were analysed directly without further treatment.
A volume of saturated solution of was diluted with test medium to give a final theoretical concentration of 40 mg/L.

Test solutions

Vehicle:

yes

Details on test solutions:

A modification of the standard method for the preparation of aqueous media was performed. An approach endorsed by several important regulatory authorities in the EU and elsewhere (ECETOC 1996 and OECD 2000), is to expose organisms to a saturated solution of the test material in cases where the test material is of high purity and is poorly soluble in water.
The test material solutions were prepared by shaking an excess (2000mg/l) of test material in reconstituted water at 300 rpm at a temperature of 30'C for 24 hours prior to removing any undissolved test material by filtration through a pre-conditioned filter to produce a saturated solution. This saturated solution was then further diluted as necessary to prepare the required test concentrations.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

The test was carried out using 1st instar Daphnia Magna derived from in-house laboratory cultures.
Adult Daphnia were maintained in polypropylene vessels containing approximately 2 litres of reconstituted water in a temperature controlled room at 21 °C. The lighting cycle was controlled to give a 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods. Each culture was fed daily with a suspension of algae (Chorella spp.). Culture conditions ensured that reproduction was by parthenogenesis. Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing. The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

None.

Test conditions

Hardness:

The reconstituted water had an approximate theoretical total hardness of 250 mg/L as CaCO3

Test temperature:

The test vessels were maintained in a temperature controlled room at 21 °C

pH:

pH concentrations were recorded at the start and termination of the test using a WTW pH 330 pH meter.

Dissolved oxygen:

Disolved oxygen concentrations were recorded at the start and termination of the test using a YSI 54A dissolved oxygen meter.

Nominal and measured concentrations:

Nominal concentrations
Range-finding test: 0.8, 8.0 and 80 mg/L
Definitive test: 1.0, 1.8, 3.2, 5.6, 10, 18, 32, 56 and 100 mg/L

Measured concentrations at 0 h:
1.0, 1.77, 3.13, 5.41, 9.79, 18.0, 31.4, 54.4, 97.0 mg/L

Reference substance (positive control):

not specified

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

74 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 53 - 130 mg/L

Effect concentrations 2

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

22 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 18 - 26 mg/L

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Analysis of the solutions at 0 and 48 hours showed the measured test concentrations to be near nominal and so the results are based on nominal test concentrations only.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In a guideline study, conducted according to GLP, Paradisamide was found to have an EC50 (48 hr) of 22 mg/L. The No Observed Effect Concentration at 48 hours was 10 mg/L.

Executive summary:

Paradisamide was evaluated for its acute toxicity to aquatic invertebrates (Daphnia magna) in a study conducted according to OECD Guideline 202 and EU method C.2 of EC Directive 92/69/EEC (1992), and performed to GLP. Paradisamide was tested at nominal concentrations of 0, 0.63, 1.25, 2.5 and 5 mg/L for 48 hr in a static system. Mobility of Daphnia magna was assessed at 0, 24 and 48 hr. No effects on the mobility of the test organisms were observed at nominal concentrations up to 10 mg/L; this concentration is considered the NOEC. Based on nominal concentrations, the EC50 (48 hr) was determined to be 22 mg/L with 95% confidence limits of 18 - 26 mg/L.

Analysis of the solutions at 0 and 48 hours showed the measured test concentrations to be near nominal and so the results are based on nominal test concentrations only.