Bis(2-chloroethyl) ether

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

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:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

TEST MATERIAL:
- Name (as cited): 2,2’- Dichlorodiethyl ether
- Purity: 99.5%

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: batch n°20150706
- Expiration date of the lot/batch: 01 June 2016
- Purity test date: 28 August 2015

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: controlled room temperature (15-25°C, below 70 RH%), protected from light
- Stability under test conditions: considered to be stable

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: domestic sewage in Veszprém, Hungary
- Preparation of inoculum for exposure: settle for 30 minutes, then the decanted effluent was aerated until use (not later than an hour)

Duration of test (contact time):

28 d

Initial conc.:

5.4 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: as described in the guideline
- Test temperature: 22 +/- 2°C
- pH: 7.35
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: BOD bottles (300 ml) with special neck and glass stoppers.
- Number of culture flasks/concentration: 10
- Measuring equipment: oxygen meter with a stirring O2 electrode
- Oxygen concentration: 9.0 mg/L at the start of the test

SAMPLING
- Sampling frequency: 0, 7, 14, 21 and 28 days

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

15.7

Sampling time:

28 d

Validity criteria fulfilled:

yes

Interpretation of results:

not inherently biodegradable

Conclusions:

Under the test conditions the percentage biodegradation of Bis(2-chloroethyl) ether reached a mean of 15.7 % after 28 days based on measured ThOD. Therefore, the test item is considered to be not readily biodegradable.

Executive summary:

The test item Bis(2-chloroethyl) ether was investigated for its ready biodegradability in a Closed Bottle Test over a period of 28 days according to OECD Guideline No. 301D under GLP. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item, Sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. The test system was a microbial inoculum of good quality, collected from a sewage plant for domestic sewage. The sludge was allowed to settle and was then aerated until use.

Under the test conditions the percentage biodegradation of Bis(2-chloroethyl) ether reached a mean of 15.7 % after 28 days based on the measured ThOD of the test item.Therefore, the test item is considered not readily biodegradable According to the test guidelines the pass level for ready biodegradability is removal of 60 % ThOD. The reference item Sodium benzoate was sufficiently degraded to a mean of 83.3 % after 14 days, and to a mean of 84.2 % after 28 days of incubation, based on ThOD, thus confirming the suitability of the used inoculum. In the toxicity control containing both, the test item and the reference item Sodium benzoate, a mean of 42.7 % biodegradation was noted within 14 days and 41.1 % biodegradation after 28 days of incubation. According to the test guidelines, the test item was not inhibitory at the applied concentration level of 5.4 mg/L on the activated sludge microorganisms as degradation was >25 % within 14 days.

Conclusion:

The study met the validity criteria. The test item was not considered to have significant inhibitory effects on the secondary effluent microorganisms. Based on the results of this study, the test item is considered not readily biodegradable.

Reference 2

Endpoint:

biodegradation in water: screening test, other

Remarks:

Static-culture-flask biodegradation screening test

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

This study is based on a static culture biodegradability screening procedure and, a culture enrichment technology utilizing a synthetic medium, containing 5 mg yeast extract per litre, a 7-day static incubation at 25ºC in the dark, followed by 3 weekly subcultures and settled domestic wastewater as microbial inoculum.

GLP compliance:

no

Specific details on test material used for the study:

TEST MATERIAL:
- Name (as cited): Bis-(2-chloroethyl) ether
- Purity: not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Settled domestic wastewater was used as microbial inoculum. Adaptation of the inoculum is not specified.

Duration of test (contact time):

28 d

Initial conc.:

5 mg/L

Based on:

test mat.

Initial conc.:

10 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Parameter followed for biodegradation estimation:

TOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: biochemical oxygen demand (BOD) dilution water containing 5 mg of yeast extract per litre
- Solubilising agent: absolute ethanol (10% concentration of test substance)
- Test temperature: 25°C
- pH: not specified
- Continuous darkness: yes
- Sub-culturing: 7-day static incubation followed by three weekly subcultures (totaling 28 days of incubation),

TEST SYSTEM
- Culturing apparatus: BOD bottles (250 mL) with glass stoppers
- Number of culture flasks/concentration: not specified
- Test performed in closed vessels: yes

SAMPLING
- Sampling frequency: weekly
- Sample storage before analysis: not specified


CONTROL AND BLANK SYSTEM
- Volatility control: yes
- Abiotic sterile control: yes
- Toxicity control: yes (reference substance: phenol)

Reference substance:

other: phenol

Parameter:

not specified

Value:

100

Sampling time:

7 d

Results with reference substance:

Not specified

Biodegradability of Bis(2 -chloroethyl) ether by the static screening flask method:

	Biodegradation of test compound in 7 days in % (Average of at least 3 test flasks)
Concentration of test item (mg/L)	Original culture	First subculture	Second subculture	Third subculture
5	100	100	100	100
10	100	100	100	100

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

Under the conditions of this test, Bis(2-chloroethyl) ether was 100% biodegradable in 7 days. The absence of the test item in the culture medium at the end of the incubation period was checked using GC. The minimum sensitivity of the GC procedures used was about 0.1 mg/L.

Executive summary:

This published study by the Municipal Environmental Research Laboratory of EPA (Cincinnati, Ohio) report the results from a 28-days biodegradability screening procedure (as described by Bunch & Chambers, 1967). The method was based on a static biodegradability screening procedure using enriched cultures. A synthetic medium, containing 5 mg yeast extract per litre was used, was incubated for 7-day static at 25ºC in the dark. This first ioncubation period was followed by 3 weekly subcultures. The test was performed in static culture flask. 5 and 10 mg/l concentrations of Bis(2-chloroethyl) ether were used as test compound. Following the first 7-days incubation period, Bis(2-chloroethyl) ether was found to undergo 100% biodegradation.

The publication used a non-standard biodegradability test method. In addition, it reports the results of biodegradability test for various organic priorirty pollulants and the results are presented in a very synthetic form with no access to raw data. The study has been conducted by a laboratory from a reciognised institution (U.S. EPA), the methodlogy is described in sufficient details and the publication has beeb subject to peer-review. The data are thus considered acceptable (Reliability score of 2).

Description of key information

The test item Bis(2-chloroethyl) ether was investigated for its ready biodegradability in a Closed Bottle Test over a period of 28 days based on OECD Guideline No. 301D under GLP. Under the test conditions the percentage biodegradation of Bis(2-chloroethyl)

ether reached a mean of 15.7 % after 28 days based on the measured ThOD of the test item.Therefore, the test item is considered not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Two studies were available to assess the biodegradability of Bis(2-chloroethyl) ether.

The test item Bis(2-chloroethyl) ether was investigated for its ready biodegradability in a Closed Bottle Test over a period of 28 days according to OECD Guideline No. 301D under GLP. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item, Sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. The test system was a microbial inoculum of good quality, collected from a sewage plant for domestic sewage. The sludge was allowed to settle and was then aerated until use. Under the test conditions the percentage biodegradation ofBis(2-chloroethyl) ether reached a mean of 15.7 % after 28 days based on the measured ThOD of the test item. Therefore, the test item is considered not readily biodegradable. The reference item Sodium benzoate was sufficiently degraded to a mean of 83.3 % after 14 days, and to a mean of 84.2 % after 28 days of incubation, based on ThOD, thus confirming the suitability of the used inoculum. In the toxicity control containing both, the test item and the reference item Sodium benzoate, a mean of 42.7 % biodegradation was noted within 14 days and 41.1 % biodegradation after 28 days of incubation. According to the test guidelines, the test item was not inhibitory at the applied concentration level of 5.4 mg/L on the activated sludge microorganisms as degradation was >25 % within 14 days. Under the conditions of this test, Bis(2-chloroethyl) ether did not have significant inhibitory effects on the secondary effluent microorganisms and did not pass the criteria to be cosnidered readily biodegradable. The results of this study are considered reliable withotu restriction (reliability 1).

The publication of Tabak et al.(JWPCF, 1981, 53(10):1503-1518) from the Municipal Environmental Research Laboratory of EPA (Cincinnati, Ohio) report the results from a 28-days biodegradability screening procedure (as described by Bunch & Chambers, 1967). The method was based on a static biodegradability screening procedure using enriched cultures. A synthetic medium, containing 5 mg yeast extract per litre was used, was incubated for 7-day static at 25ºC in the dark. This first ioncubation period was followed by 3 weekly subcultures. The test was performed in static culture flask. 5 and 10 mg/l concentrations of Bis(2-chloroethyl) ether were used as test compound. Following the first 7-days incubation period, Bis(2-chloroethyl) ether was found to undergo 100% biodegradation. The publication used a non-standard biodegradability test method. In addition, it reports the results of biodegradability test for various organic priorirty pollulants and the results are presented in a very synthetic form with no access to raw data. The study has been conducted by a laboratory from a reciognised institution (U.S. EPA), the methodlogy is described in sufficient details and the publication has beeb subject to peer-review. The data are thus considered acceptable (Reliability score of 2).

The study of Tabak et al. (1981) contradicts the data reported as key data. Considering that the methodology used in this study differs from guidelines, that raw data on Bis(2-chloroethyl) ether are not available in the original publication and thqat the validity criteria for this test are unclear, priority was given to the guideline study. Accordingly, Bis(2-chlorethyl) ether shall be assumed to be not readily biodegradable and, in the absence of additional data, not inherently biodegradable.