4'-chloro-2',5'-dimethoxyacetoacetanilide

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:

2008 to 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study fully followed the guideline, no deviation,validity criteria fullfilled

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

4'-chloro-2',5'-dimethoxyacetoacetanilide

EC Number:

224-638-6

EC Name:

4'-chloro-2',5'-dimethoxyacetoacetanilide

Cas Number:

4433-79-8

Molecular formula:

C12H14ClNO4

IUPAC Name:

N-(4-chloro-2,5-dimethoxyphenyl)-3-oxobutanamide

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Source: Sammlung von Algenkulturen (SAG), Pflanzenbiologisches Institut der Universität Göttingen, Nikolausberger Weg 18, D-37073 Göttingen
Method of cultivation: Fresh stocks were prepared every month on Z-Agar.
Culture medium: Nutrient medium Z according to Lüttge et al (1994)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

0.24 mmol Ca+Mg /L

Test temperature:

Nominal range: 21 - 24 °C, controlled at +/- 2°C

pH:

8.1 +/- 0.2

Salinity:

0,24 mmol Ca+Mg/l

Nominal and measured concentrations:

Nominal - Test start (measured) - Test end (measured); values in mg/L
100 - 101 - 96.6
32 - 33.2 - 30.4
10 - 10.3 - 9.21
3.2 - 3.28 - 2.65
1.0 - 0.988 - 0.801

Details on test conditions:

- Initial cells density:4884 and 4878 cells/ml
- replicates test concentrations: 3
- replicates control: 6
- test container: erlenmeyer flasks sterile, 250 ml, sealed (cooton woll)
- dilution water: acc to OECD 201 medium
- reference: potassium dichromate
- illumination: 24 h/d
- brightness (mean): 64.8 µE * m^(-2) * s^(-1); cv [%]: 3.4
- standard medium according to OECD 201

Reference substance (positive control):

yes

Remarks:

Potassium dichromate p.a. (CAS No 7778-50-9), Purity: 99.5%

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Rate-related inhibition

Effect concentrations 2

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Rate-related inhibition

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

33 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Rate-related inhibition

Remarks on result:

other: 95% CI: 26.6-39.8

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Inhibition of Yield

Effect concentrations 5

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Inhibition of Yield

Effect concentrations 6

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

5.66 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Inhibition of Yield

Remarks on result:

other: 95% CI: 4.76-6.69

Details on results:

All given effect levels given are based on onimal concentration of the test item

Results with reference substance (positive control):

Rate-related Inhibition: EC50: 0.69 mg/L (95% CI: 0.64 - 0.74 mg/L) - Valid range: 0.828 +/- 0.399 mg/L
Inhibition of Yield: EC50: 0.31 mg/L (95% CI: 0.30 - 0.32 mg/L) - Valid range: 0.352 +/- 0.143 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The aim of the study was to assess the effects of the test substance on on growth rate and yield on the algae Desmodesmus subspicatus over a period of 72 h, the study was performed following the guideline OECD 201. At the start of the test a HPLC-DAD analysis revelaed 99 - 104 % and at the end of the test the active ingredient gave recoveries of 80 - 97 % of the nomimal values.
In the 72 h test intervall for the rate related inhibition the NOEC was determined with 3.20 and the LOEC with 10 mg/ l, whereas the EC 10 and EC 50 were in the range of 2.53 - 6.48 (mean 4.34) and 26.6 - 39.8 (mean 33.0) respectively.
The Inhibition of the Yield at the end of the study were as followed. NOEC: 1.0, LOEC 3.20, EC 10 and EC 50 2.28 - 3.37 (mean 2.78) and 4.76 - 6.69 (mean 5.66) respectively.

Executive summary:

The aim of the study was to assess the effects of the test substance on on growth rate and yield on the algae Desmodesmus subspicatus over a period of 72 h, the study was performed following the guideline OECD 201. At the start of the test a HPLC-DAD analysis revealed 99 - 104 % of the active ingredient and at the end the analysis revealed recoveries of 80 - 97 % of the nomimal value.

In the 72 h test intervall for the rate related inhibition the NOEC was determined with 3.20 and the LOEC with 10 mg/ l, whereas the EC 10 and EC 50 were in the range of 2.53 - 6.48 (mean 4.34) and 26.6 - 39.8 (mean 33.0) respectively.

The Inhibition of the Yield at the end of the study were as followed. NOEC: 1.0, LOEC 3.20, EC 10 and EC 50 2.28 - 3.37 (mean 2.78) and 4.76 - 6.69 (mean 5.66) respectively.