O-(4-bromo-2-chlorophenyl) O-ethyl S-propyl phosphorothioate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, adapted

Details on inoculum:

Obtained from local municiple waste water treatment plant. Sludge was seived (2mm) and concentrated by centrifugation and supernatant discarded. Sludge washed with mineral medium, centrifuged and supernatant discarded. Moisture content of sludge determined by drying. A sludge sloution containing 4.0g solids/L mineral medium prepared one day prior to test initiation. Inoculum solution stored in an environmental chamber under aeration.

Duration of test (contact time):

28 d

Initial conc.:

108.5 mg/L

Based on:

test mat.

Initial conc.:

134.89 mg/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

7 vessels were set up: 2 test suspension vessels, 2 inoculum blank vessels, 1 procedural control, 1 abiotic sterile control (no inoculum), 1 toxicity control.

Reference substance:

other: Sodium benzoate

Test performance:

BOD in inoculum blanks were 47.8 and 50.6 mg O2/L at 28 days (for valididty should not exceed 60 mg/L) so validity fulfilled. Difference in blanks did not exceed 5% at any timepoint.Rapid degradation of sodium benzoate confirmed presence of an active microbial population and system integrity. Toxicity control compared to procedural control. 95.2% degradation was observed so the test item was not inhibitory to the inoculum.The abiotic sterile control showed neither degradation nor adsorption to the reaction vessel.

Parameter:

% degradation (O2 consumption)

Value:

8.4

Sampling time:

28 d

Details on results:

Difference between the two replicates was 2% at test completion.

Results with reference substance:

61.6% in 4 days

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Since less than 10% degradation was observed for Profenofos at 28 days, Profenofos cannot be classified as readily biodegradable under the conditions of this test.

Executive summary:

The ready biodegradability of profenofos was carried out to OECD 301F at 22 +/- 1 degree C.

All the validity criteria was fulfilled.

Less than 10% degradation was observed at 28 days. Therefore profenofos cannot be classified as readily biodegradable under the conditions of the test.

Description of key information

Less than 10% degradation was observed at 28 days. Therefore profenofos cannot be classified as readily biodegradable under the conditions of the test.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

The ready biodegradability of profenofos was carried out to OECD 301F at 22 +/- 1 degree C.

All the validity criteria was fulfilled.

Less than 10% degradation was observed at 28 days. Therefore profenofos cannot be classified as readily biodegradable under the conditions of the test.