2-chloro-N,N-dimethyl-3-oxobutyramide

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:

other: OECD Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-chloro-N,N-dimethyl-3-oxobutyramide

EC Number:

227-372-9

EC Name:

2-chloro-N,N-dimethyl-3-oxobutyramide

Cas Number:

5810-11-7

Molecular formula:

C6H10ClNO2

IUPAC Name:

2-chloro-N,N-dimethyl-3-oxobutanamide

Details on test material:

Batch Number: 502001
Certificate of analysis: April 06, 1995
CAS-No.: 005810-11-7
Colour and condition: brown liquid
Solubility in water: unlimited
logPow: -0.27 (25°C)
Density: 1.204 g/cm3
Vapour pressure: 1 hPa (20°C)
Storage conditions: room temperature (frost free, max. 25°C), dark, keep container dry and tightly closed

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

20 mL samples for the chemical analysis were taken from the freshly prepared test solutions at t = 0 h and from the aged solutions at t = 48 h. The samples were immediately fast frozen and transferred to sponsor at the end of the test.

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna STRAUS was used as test organism. The animals were originally purchased in a healthy condition from the Bundesanstalt fur Ernährung in D-76131, Karlsruhe.
Daphnia magna is a part of the zooplankton of stagnant inland waters and feeds on particular organic matter by filtration. As a consument of low order this species ranges in its ecological function in the aquatic consumption chain between the destruents and the primary producers on the one hand and the consumers of high order on the other hand. Daphnia magna is continuously bred in the laboratory by feeding on single cell green algae (Scenedesmus subspicatus), whereby only as much food is added as is consumed within one day. The animals are kept in M 4-Medium (Elendt & Bias, 1990), the test was performed in the same medium.
The animals are reared at 20 +/- 2 °C in 1 L beakers in a RUMED light chamber with 18 hrs of illumination and 6 hrs of darkness. Per one litre, about 50 adults are kept. The dilution water is renewed three times per week, separating the young from the adults with sieves at the same time of two different meshes (ISO 3310-1). The adults remain on the upper sieve (0.710 mm) and the young on the lower one (0.200 mm). Adult animals are transferred without air contact into the freshly prepared breeding vessels. For the test, daphnids of an age between 6 and 24 hours have been used. They were collected by sieving the culture twice within 18 h. After sieving the first time, the adults re-mained on the coarse sieve. They were transferred with a special pipette into a vessel with fresh medium and separated after 18 hrs a second time, whereby only the mean-while hatched animals could pass the coarse sieve and remained on the finemeshed sieve. Young animals were transferred without air contact into a small vessel (50 mL).
4 vessels with each 5 daphnids were used for each concentration tested.

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:

14.5 °dH (250 ppm CaC03)

Test temperature:

20 +/- 2 °C

pH:

7.2 -8.1

Dissolved oxygen:

98 % saturation

Salinity:

n.a.

Nominal and measured concentrations:

0, 29.6 ,44.4, 66.7, 100, 150, 225 mg/l (nominal)
(0, 6.94, 15.63, 43.75, 53.22 mg/l (measured)

Details on test conditions:

The test was performed with concentrations differing with a dilution factor of 1.5. The
highest test concentration was 225 mg/L Dimethyl-2-chloracetoacetamid. The following concentrations were tested: 0, 29.6, 44.4, 66.7, 100, 150, and 225 mg/L Dimethyl-2-chloracetoacetamid. The concentrations to be tested were made up with test substance and M 4-medium and transferred to 25 mL graduated cylinders with 10 mL portions each. For each test concentration, 20 animals/40 mL were used. Per 10 mL of test solu-tion 5 daphnids were added. A control with dilution water and without test substance was run concurrently.
Additionally, two concentrations (0.9 mg/L and 1.9 mg/L) of the reference substance potassium dichromate were tested. After 24 h and 48, the immobilised daphnids were counted. All daphnids not able to swim after gentle agitation of the test vessel were con-sidered to be immobile, and the percentage of immobilised daphnids was calculated.

Reference substance (positive control):

yes

Remarks:

potassium chromate

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

28.36 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mobility

Details on results:

The highest concentration at which all daphnids were still able to swim (EC0) was 44.4 mg/L.
The lowest concentration (EC100) at which all daphnids are immobilised was 150 mg/L.

Results with reference substance (positive control):

The EC50 value of potassium dichromate ranged between 0.9 and 1.9mg/L and was determined at 1.4mg/L

Reported statistics and error estimates:

The results of the test can be regarded as valid, since
• in the control not more than 10 % of animals were immobilised
• the dissolved oxygen concentration at the end of the test was> 60 % of the air saturation value (9.08 mg/L at 20°C) at the temperature used
• the EC50 value of the reference substance ranged between 0.9 and 1.9 mg/L and was determined at 1.4 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The substance is harmful to daphnids under the conditions of this study.

Executive summary:

The immobilisation test according to OECD Guideline 202 with Daphnia magna was carried out at concentrations between 29.6 and 225 mg/L Dimethyl-2-chloracetoacetamid (97.3% pure)for a period of 48 h. One control without test substance and two reference groups with potassium dichromate were tested as well. The EC50 value of Dimethyl-2-chloracetoacetamid (nominal concentration) was determined at 86.8 mg/L after 48 h and was derived by the method of Spearman-Karber (Sachs, 1984). The highest concentration at which all daphnids were still able to swim (EC0) was 44.4 mg/L. The lowest concentration (EC100) at which all daphnids are immobilised was 150 mg/L. The concentrations of Dimethyl-2-chloracetoacetamid during the test were analysed at t = 0 h and t = 48 h. Since there were strong deviations between the nominal and the analysed initial and final concentrations, the nominal values were not taken into consideration. The averages of the analysed values of Dimethyl-2-chloracetoacetamid at t = 0 h and t = 48 h were taken for the evaluation of its effects. The calculation of the EC values was performed by probit analysis, because the concentration values of Dimethyl-2-chloracetoacetamid did not differ by a constant factor. The EC50 value for the analysed concentration was determined at 28.36 mg/L.