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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
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:
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
GLP compliance:
yes (incl. QA statement)
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Type: mixed population of aquatic microorganisms (activated sludge)
- Origin: aeration tank of a waste water plant treating predominantly domestic sewage (Wupper area water authority)
- Date of collection: 2004-08-17
- Pretreatment: none
- Concentration of inoculum: 30mg/L ss

Pretreatment of the test item
25 mg test item were weighed out on aluminium foil. This substance inclusive the aluminium foil was added to the test vessels to give a test concentration of 100 mg test item/L.
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
Exposure conditions
- Test volume: 205 mL
- Test apparatus: Voith Sapromat
- Mixing: 1 magnetic stirrer per test vessel
- Incubation time: 28 d
- Incubation temperature: 22 ± 2°C
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
8 d
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
16 d
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
22 d
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
2-Chloro-5-chloromethylpyridine showed 0 % degradation after 28 days. Therefore 2-chloro-5-chloromethylpyridin has to be classified as "Not Readily Biodegradable".
Executive summary:

A study was performed to assess the ready biodegradability of 2 -chloro-5 -chloromethylpyridine. The study was conducted in accordance with the Council Directive 92/69/EEC Method C.4-D "Manometric Respirometry Test". This test method is in all essential parts identical with OECD Guideline 301 F.

A suspension of 100 mg/L test item in a mineral medium is inoculated and incubated under aerobic conditions in the dark at a constant temperature (22 ± 2°C) for up to 28 days under aerobic conditions.

Allowance is made for the endogenous activity of the inoculum by running parallel blanks with inoculum but without test item. A reference compound (sodium benzoate) is run in parallel to check the operation of the procedures. Furthermore, a toxicity test (test item and reference compound mixed) is run in parallel. Because of the nature of biodegradation and of the mixed bacterial populations used as inocula, determinations are carried out at least in duplicate.

The consumption of oxygen is determined by measuring the quantity of oxygen (produced electrolytically) required to maintain constant gas volume in the respirometer flask. Evolved carbon dioxide is absorbed in a solution of potassium hydroxide. The amount of oxygen taken up by the test chemical (corrected for uptake by blank inoculum, run in parallel) is expressed as a percentage of theoretical oxygen demand (ThOD) or chemical oxygen demand (COD).

2-Chlor-5 -chloromethylpyridine showed 0 % degradation after 28 days. Therefore 2 -chloro-5 -chloromethylpyridine has to be classified as "Not Readily Biodegradable".

The reference compound showed 92 % degradation after 14 days.

Description of key information

A study was performed to assess the ready biodegradability of 2 -chloro-5 -chloromethylpyridine. The study was conducted in accordance with the Council Directive 92/69/EEC Method C.4-D "Manometric Respirometry Test". This test method is in all essential parts identical with OECD Guideline 301 F.

A suspension of 100 mg/L test item in a mineral medium is inoculated and incubated under aerobic conditions in the dark at a constant temperature (22 ± 2°C) for up to 28 days under aerobic conditions.

Allowance is made for the endogenous activity of the inoculum by running parallel blanks with inoculum but without test item. A reference compound (sodium benzoate) is run in parallel to check the operation of the procedures. Furthermore, a toxicity test (test item and reference compound mixed) is run in parallel. Because of the nature of biodegradation and of the mixed bacterial populations used as inocula, determinations are carried out at least in duplicate.

2-Chloro-5-chloromethylpyridine showed 0 % degradation after 28 days. Therefore 2-chloro-5-chloromethylpyridine has to be classified as "Not Readily Biodegradable".

The reference compound showed 92 % degradation after 14 days.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed
Type of water:
freshwater

Additional information