Fatty acids, C16 and C18-unsaturated, methyl esters, chlorinated

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

Study period:

From 3-10-2019 to 01-11-2019

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)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Organo chlorinated compound 35 wt% Cl, corresponding to fatty acids, C16-C18 methyl ester
CAS: 95009-45-3
Name in the study report is different since the study report has been reported in 2019 when CAS number was not assigned yet.
Batch: R4003190123

Oxygen conditions:

aerobic

Inoculum or test system:

natural water

Remarks:

river water

Details on inoculum:

River water was sampled from the Rhine near Heveadorp, The Netherlands (26-09-2019). The nearest plant (Arnhem-Zuid) treating domestic wastewater biologically was 3 km upstream. The river water was aerated for 7 days before use to reduce the endogenous respiration (van Ginkel and Stroo, 1992). River water without particles was used as inoculum. The particles were removed by sedimentation after 1 day while moderately aerating.

Duration of test (contact time):

ca. 0 - ca. 28 d

Initial conc.:

ca. 0 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

acetic acid, sodium salt

Test performance:

The test was performed in 0.30 L BOD (biological oxygen demand) bottles with glass stoppers.

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 66

Sampling time:

28 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 65

Sampling time:

21 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 54

Sampling time:

14 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 15

Sampling time:

7 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 0 ca.

Sampling time:

0 d

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test item was biodegraded by 66% at day 28 in the OECD 301D Closed Bottle test. Over 60% biodegradation was not achieved within a period of 10 days (14 days for the Closed Bottle test) immediately following the attainment of 10% biodegradation. The time window criterion should however not be applied because organo chlorinated compound 35 wt% Cl is a mixture of constituents (UVCB). The biodegradation of organo chlorinated compound 35 wt% is therefore an addition of different biodegradation curves and the time window should therefore not be used as a pass/fail criterion. Organo chlorinated compound 35 wt% is therefore classified as readily biodegradable based on the >60% biodegradation reached at day 28.
The test is valid as shown by an endogenous respiration of 0.75 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded by 83% of its theoretical oxygen demand after 14 days. Finally, the most important criterion was met by oxygen concentrations >0.5 mg/L in all bottles during the test period

Executive summary:

To assess the biotic degradation of organo chlorinated compound 35 wt% Cl, a ready biodegradability test was performed which allows the biodegradability to be measured in an aerobic aqueous medium. The ready biodegradability was determined in the Closed Bottle test performed according to slightly modified OECD, EU and ISO Test Guidelines, and in compliance with the OECD principles of Good Laboratory Practice.
The test item (2.0 mg/L) was exposed to river water which was spiked with nutrients, dosed in closed bottles and incubated in the dark at 22.4-22.9°C for 28 days. The degradation of the test item was assessed by measuring oxygen consumption. According to the results of this study, the test item did not cause a reduction in the endogenous respiration at day 7.
The test substance is therefore considered to be non-inhibitory to the inoculum.
The test item was biodegraded by 66% at day 28 in the OECD 301D Closed Bottle test. Over 60% biodegradation was not achieved within a period of 10 days (14 days for the Closed Bottle test) immediately following the attainment of 10% biodegradation. The time window criterion should however not be applied because organo chlorinated compound 35 wt% Cl is a mixture of constituents (UVCB). The biodegradation of organo chlorinated compound 35 wt% is therefore an addition of different biodegradation curves and the time window should therefore not be used as a pass/fail criterion. Organo chlorinated compound 35 wt% is therefore classified as readily biodegradable based on the >60% biodegradation reached at day 28.
The test is valid as shown by an endogenous respiration of 0.75 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded by 83% of its theoretical oxygen demand after 14 days. Finally, the most important criterion was met by oxygen concentrations >0.5 mg/L in all bottles during the test period.

Description of key information

The substance is readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater