Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2nd January - 21st March 2002
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP study conducted to an appropriate guideline with no or minor deviations but not conducted on the substance to be registered.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
The test item, 1,3-dichloropropene, was received from Dow AgroSciences, LLC on 03-Dec- 2001.

Chemical Name (IUPAC): 1,3- Dichloropropene
Cornmon Name: 1,3-D, Telone II
Code Number: TSN 10240 1
Batch: TEL 102300
CAS RN: 542-75-6
Molecular Formula: C3H4Cl2
Molecular Weight: 110.97 g/mol
Isomers: cis-l,3-dichloropropene
trans-I,3-dichloropropene
Isomeric Ratio: 51:49, cis.trans
Appearance: Clear colorless liquid
Chemical Purity: 98.7 %, w/w
Storage Conditions: Refrigerator (approximately 4°C)
Quantity Received: 1 gram
Expiration Date: November 10, 2002
Solubility: water: 2180 ppm cis; 2320 ppm trans
Vapor Pressure (25°C): 34.3 torr (cis); 23.0 torr (trans)

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
sewage, predominantly industrial (adaptation not specified)
Details on inoculum:
Inoculum from Secondary Effluent
The effluent from a sewage plant working predominantly with domestic sewage (sewage plant at D-65232 Taunusstein-Bleidenstadt) was filtered through folded paper filter. The first 200 mL were rejected.

Inoculum from Soil
A mixture of 100 g soil of the Institut Fresenius area at D-65232 Taunusstein was suspended in 1000 mL drinking water and stirred on a shaking machine for approximately 30 minutes. The suspension was filtered through folded paper filter. The first 200 mL were rejected.

Same volumes of the two inocula were mixed together and used for the test. 5000 mL of the test solutions were inoculated with 2 mL of the mixed inoculum.
Duration of test (contact time):
28 d
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium:

1) 8.50 g KH2PO4
21.75 g K2HPO4
33.40 g Na2HPO4 x 2 H2O
0.50 g NH4Cl
were diluted in 1 L ultrapure water (this solution may be stored for at least 3 month at + 4°C)

2) 36.40 g CaCl2 x 2H20
were diluted in lL ultrapure water (this solution may be stored for at least 3 month at + 4°C)

3) 22.50 g MgSO4 X 7 H20
were diluted in lL ultrapure water (this solution may be stored for at least 3 month at + 4°C)

4) 0.25 g FeCl3 x 6 H20
were diluted in 1L ultrapure water (this solution has to be prepared freshly before use in the test series)

- Additional substrate: NDA
- Solubilising agent (type and concentration if used): No
- Test temperature: 19.4 and 22.2 °C with a mean value of 20.6 °C.
- pH: NDA
- pH adjusted: NDA
- CEC (meq/100 g): NDA
- Aeration of dilution water: NDA
- Suspended solids concentration:NDA
- Continuous darkness: yes
- Other: oxygen content of that water was 9.23 mg 02/L,

TEST SYSTEM
At time to the test solutions were prepared. For this purpose approximately 1 L water was given in a 2 L-measuring flask. Thereafter, 5 mL of each of the following nutrient mineral solutions were added. For the test series with control item and the toxicity control, 15 mL of the stock solution with Na-benzoate were added. For the test series with test 10 mL of the stock solution, containing 0.1171 g test item in 100 mL were added. For the test series with the toxicity control, 10 mL of a stock solution of the test item with 0.1171 g/100 mL and 15 mL of the stock solution with 0.1000 g Sodium benzoate/ 100 mL ultrapure water were used in 5L of final volume. The respective measuring flask was filled up to 2 L and filled in a 5 L narrow neck flask. The 2 L measuring flask was filled twice with 2 L water for rinsing purpose and transferred also in the 5 L narrow neck flask. A second measuring flask with a volume of 1 L was also filled with deionized water and completed the test solution. Thereafter the test solution was inoculated with 2 mL of the mixed inoculum and stirred for nearly one minute to get a homogenous solution. This solution was filled into 15 glass flasks with a volume of approximately 290 mL and stoppered bubble free with glass stoppers. These flasks were incubated for 28 days in the dark at a mean temperature of 20.6 ºC. At time to (start), 2 flasks were taken and the oxygen content was measured with an oxygen electrode. At times t7d, t14d and t21d, 3 flasks were taken and the oxygen content was measured with an oxygen electrode. At time t28d,4 flasks were taken and the oxygen content was measured with an oxygen electrode. From the difference between the oxygen content at to to each other measuring time (t7d, t14d, t21d and t28d) the BOD was calculated.
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

Preliminary study:
NDA
Test performance:
The control item sodium benzoate was degraded 82% within 28d. The threshold of ready biodegradability of ~ 60 % was met within 7d of incubation (70 %). There was a net oxygen demand of 0.56 mg O2 /L of the blank. The BOD of the toxicity control indicates, that more than the sodium benzoate was degraded in that test solution and thus, there was no bacterial toxicity detectable at the used concentration. These factors show that the systems were appropriate for evaluation of 1,3-dichloropropene.
% Degradation
Parameter:
% degradation (O2 consumption)
Value:
4.9
Sampling time:
28 d
Details on results:
1,3-Dichloropropene was tested for ready biodegradability according to OECD 301 D Closed Bottle Test. Under the chosen conditions, degradation equal to 5% of the calculated biological demand was measured after 28d. The threshold for ready biodegradability as well as the 14-days-window, as required by the OECD guideline 301 D, were not met. Therefore the test item must be considered not readily biodegradable.

BOD5 / COD results

Results with reference substance:
82 % biodegradation after 28 days.

Any other information on results incl. tables

The control item sodium benzoate was degraded 82% within 28d. The threshold of ready biodegradability of 60 % was met within 7d of incubation (70 %). There was a net oxygen demand of 0.56 mg O2 /L of the blank. The BOD of the toxicity control indicates, that more than the sodium benzoate was degraded in that test solution and thus, there was no bacterial toxicity detectable at the used concentration. These factors show that the systems were appropriate for evaluation of 1,3-dichloropropene.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: not readily biodegradable
Conclusions:
Under the chosen conditions, degradation equal to 5% of the calculated biological demand was measured after 28d. The threshold for ready biodegradability as well as the 14-days window, as required by the OECD guideline 301 D were not met. Therefore the test item must be considered not readily biodegradable.
This study was conducted on a mixture of cis and trans isomers (ratio 51:49). The results show a very low level of biodegradation and so it is considered reasonable to conclude that the cis isomer (the substance to be registered) is not readily biodegradable.
Executive summary:

1,3-Dichloropropene was tested for ready biodegradability according to OECD 301 D Closed Bottle Test. The performance of the test was done according to the study plan dated January 2, 2002. Under the chosen conditions, degradation equal to 5% of the calculated biological demand was measured after 28d. The threshold for ready biodegradability as well as the 14-days window, as required by the OECD guideline 301 D were not met. Therefore the test item must be considered not readily biodegradable.

This study was conducted on a mixture of cis and trans isomers (ratio 51:49). The results show a very low level of biodegradation and so it is considered reasonable to conclude that the cis isomer (the substance to be registered) is not readily biodegradable.