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

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

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:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle 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:

Designation: Dimethyl- 2-ch10racetoac etamid
CAS no.: 5810-11-7
Batch no. : 10C202009
Receipt no. : 24650 a
Characteristics: brown, liquid
Storage conditions: at room temperature, dark, tightly closed
Stability under storage conditions: < 1 year at + 25°C
Stability in water: > 1 day at + 4 °C in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Inoculation was made using a secondary effluent of good quality collected from a treatment plant dealing with predominantly domestic sewage. The effluent was kept under aerobic conditions in the period be-tween sampling and application. To prepare the inoculum the sample was filtered through a coarse filter, the first 200 mL being discarded. The rest of the filtrate was kept aerobic until use. The inoculum was used on the day of collection. The number of bacteria was determined with Easicult TTC. There were 2 x 108 bacteria per litre of final volume of the test medium.

Duration of test (contact time):

28

Initial test substance concentration

Initial conc.:

3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Nutrient medium
Solution 1: 0.850 g KH2P04, 2.850 g K2HP04 . 3H20, 3.340 g Na2HP04 . 2H20; 0.050 g NH4CI were dissolved in distilled water' and made up to 100 mL.The pH was determined as pH 7.36.
Solution 2:2.25 g MgS04 . 7H20 were dissolved in distilled water and made up to 100 mL.
Solution 3:3.64 g CaCI2 • 2H20 were dissolved in distilled water and made up to 100 mL.
Solution 4:0.025 9 FeCI3 • 6H20 were dissolved in distilled water and made up to 100 mL.
1 mL each of solutions 1 to 4 was added to 1 L of distilled water.
A volume of the medium as needed for the day, 65 L was aerated strongly for 20 minutes with com-pressed air at room temperature (as close as possible to 20°C). Generally, the medium was ready for use after standing for 20 hours at 20°C. The dissolved oxygen concentration was determined for control pur-poses. The concentration at 19.8°C was about 8.84 mg O2/L. All transfer and filling operations of the
air saturated water were conducted bubble-free by siphon.

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

Preliminary study:

A predetermined amount of the test compound was dissolved in an inorganic medium (mineral nutrient solution), providing a concentration of 3 mg active substance per litre (AS/l). The solution was inoculated with a small number of microorganisms from a mixed population and kept in closed bottles in the dark in a constant temperature bath at 20°C +/- 1°C. The degradation was monitored by oxygen analysis during a 28-day period. A positive control (sodium acetate), a negative control with inoculum but without test mate-rial for the determination of oxygen blanks, and a toxicity control were run in parallel.

Test performance:

Parallel groups of BOD bottles (300 mL) were prepared for the determination of the test and reference chemicals including the toxicity control in simultaneous experimental series, including inoculum blanks. The following times were used: 0, 3, 7, 10,14,17,21,24 and 28 days. The test was conducted in duplicate in a parallel series. Fully aerated mineral nutrient medium was added to large bottles so that they were about one-third full. Then sufficient amounts of the stock solutions of the test chemical and control sub-stance were added to separate large bottles so that the final concentration of the test chemical was 3 mg/L or 4 mg/L for sodium acetate. No chemicals were added to the blank control medium contained in a further large bottle.
The solutions were inoculated from a pointed pipette with 2000 µL (13 mL/6.5 L) secondary effluent per litre test medium. The solutions were made up to volume with aerated mineral nutrient medium using a hose which reaches down to the bottom of the bottle to achieve adequate mixing. Subsequently each prepared solution was dispensed into the respective group of BOD bottles (300 mL) by hose from the lower quarter (not the bottom) of the appropriate large bottle so that all the BOD bottles were completely filled. The bottles were gently tapped to remove any air bubbles. Two bottles were immediately analysed for dissolved oxygen. The remaining replicate bottles were stoppered ensuring that no air bubbles were enclosed and placed in a water bath at 19.8 - 20.3°C, kept in the dark and removed in duplicate after 3,7,10,14,17,21,24 and 28 days for immediate dissolved oxygen analysis. For the toxicity control bottles were analysed after 7 and 14 days.

% Degradation

% Degradation 1

Parameter:

% degradation (O2 consumption)

Value:

6

St. dev.:

3

Sampling time:

7 d

% Degradation 2

Parameter:

% degradation (O2 consumption)

Value:

7

St. dev.:

1

Sampling time:

14 d

% Degradation 3

Parameter:

% degradation (O2 consumption)

Value:

8

St. dev.:

1

Sampling time:

17 d

% Degradation 4

Parameter:

% degradation (O2 consumption)

Value:

8

St. dev.:

1

Sampling time:

21 d

% Degradation 5

Parameter:

% degradation (O2 consumption)

Value:

8

St. dev.:

2

Sampling time:

28 d

Details on results:

The difference of duplicate values for the degradation of the test article was less than 20% at the end of the test. Dimethyl-2-chloracetoacetamid was only slightly biodegradable under the conditions of the 'Closed Bottle Test' presently performed. The criterion for ready biodegradability (at least 60% biodegra-dation was not reached within ten days of biodegradation exceeding 10%) was not met.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

Dimethyl-2-chloracetoacetamid was not readily biodegradable under the conditions of the' Closed Bottle Test' presently performed.

Executive summary:

Dimethyl-2-chloracetoacetamid was assessed for its biodegradability in a Closed Bottle Test according to OECD Guideline 301 D. The ThOD of test material is 1.271 mg 02/mg. The residual oxygen concentration in the test flasks was >0.5 mg/L at any time. Oxygen depletion in the inoculum control was 0.40 mg 02/L after 28 days, and did not exceed 1.5 mg 02/L over the 28-day exposure period.

The substance reached a degradation of 7.7% after 28 days: The difference of duplicate values for the degradation of the test article was less than 20% at the end of the test. Dimethyl-2-chloracetoacetamid was only slightly biodegradable under the conditions of the 'Closed Bottle Test' presently performed.

The criterion for ready biodegradability (at least 60% biodegradation was not reached within ten days of biodegradation exceeding 10%) was not met. Sodium acetate as a positive control reached a degradation of average of 75.3% by exposure day 14 and 84.9%after 28 days.

Degradation toxicity control of sodium acetateandDimethyl-2-chloracetoacetamid reached a degradation of 31.7% after 14 days. Since 31.7 % degradation (based on ThOD added as test material and reference compound) was noted in the toxicity control within 14 days of exposure, it can be excluded that Dimethyl-2-chloracetoacetamid was inhibitory to the microorganisms.

Dimethyl-2-chloracetoacetamid was not readily biodegradable under the conditions of the' Closed Bottle Test' presently performed.