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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Endpoint:
biodegradation in water: simulation testing on ultimate degradation in surface water
Type of information:
experimental study
Adequacy of study:
key study
Study period:
April to May 2004
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to a standard guideline without deviations from the protocol, but it was not conducted under GLP guidelines.
Justification for type of information:
A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
according to guideline
Guideline:
OECD Guideline 306 (Biodegradability in Seawater)
Deviations:
no
GLP compliance:
no
Radiolabelling:
no
Oxygen conditions:
aerobic
Inoculum or test system:
other: Seawater
Details on source and properties of surface water:
The medium was prepared using seawater collected on April 5, 2004 from the Manasquan Inlet, New Jersey, USA, a designated New Jersey Department of Environmental Protection collection site, the salinity was 32 ppt and the DOC was 0.6 ppm C. The collected seawater was aerated and stored in an environmental chamber at 20 degrees C. On Day -1 of the test, mineral salts were added to the seawater and it was aerated.
Details on inoculum:
The inoculum included only the indigenous microorganisms present in the seawater sample.
Duration of test (contact time):
28 d
Details on study design:
The amount of oxygen consumed by the microorganisms from oxidation of the test substance was monitored by an automated respirometer during a 28-day testing period. The control, sodium benzoate, and the test substance were evaluated in duplicate test systems. The amount of oxygen reported for each test system was corrected for oxygen consumption due to endogenous respiration in blank test systems. Temperature range for the 28 day testing period was 22 ± 1 degrees C.

Biodegradation results were calculated by the respirometer software using the theoretical oxygen demand (ThOD) and the mass of the test or positive control substance added. The ThOD was calculated using the empirical formula of each substance and the caclulations as defined in the OECD guideline.
% Degr.:
6.2
St. dev.:
0.5
Parameter:
O2 consumption
Sampling time:
4 d
% Degr.:
11.6
St. dev.:
1.2
Parameter:
O2 consumption
Sampling time:
5 d
% Degr.:
51.6
St. dev.:
5.9
Parameter:
O2 consumption
Sampling time:
11 d
% Degr.:
61
St. dev.:
5.1
Parameter:
O2 consumption
Sampling time:
17 d
% Degr.:
68.8
St. dev.:
3.3
Parameter:
O2 consumption
Sampling time:
28 d
Remarks on result:
other: The test substance biodegradation was still increasing, albeit slowly, on day 28.
Compartment:
water
DT50:
ca. 10 d
Type:
not specified
Remarks on result:
other: Temperature not specified
Transformation products:
not measured
Evaporation of parent compound:
no
Volatile metabolites:
not measured
Residues:
not measured
Validity criteria fulfilled:
yes
Conclusions:
Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics, biodegraded to an extent of 69% after 28 days in seawater that used the indigenous microorganisms in the seawater sample as a sole source of the inoculum.
Executive summary:

Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics, demonstrated a high extent of biodegradation in seawater following a standard OECD test guideline, which suggests that it has the potential to rapidly biodegrade in the marine environment. The test substance biodegraded to an extent of 69% after 28 days in seawater that used the indigenous microorganisms in the seawater sample as a sole source of the inoculum.

Endpoint:
biodegradation in water: simulation testing on ultimate degradation in surface water
Type of information:
experimental study
Adequacy of study:
key study
Study period:
March to April 2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This robust summary has a reliability rating of 1 because the study followed a standard guideline, followed GLP guidelines, and was conducted without deviations that would invalidate the study.
Justification for type of information:
A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
according to guideline
Guideline:
OECD Guideline 306 (Biodegradability in Seawater)
Deviations:
no
GLP compliance:
yes
Radiolabelling:
no
Oxygen conditions:
aerobic
Inoculum or test system:
other: Natural seawater
Details on source and properties of surface water:
Seawater was collected from the Burnham-on-Crouch estuary at high tide. The estuary has no industrial input.
Details on inoculum:
Indigenous microorganisms contined in natural seawater.
Duration of test (contact time):
28 d
Initial conc.:
1.21 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
A surfactant (Nonidet P40) was used to emulsify the test substance. Background BOD for the surfactant was determined by evaluating the BOD of the surfactant alone in parallel test systems.
Reference substance:
acetic acid, sodium salt
% Degr.:
0
Parameter:
O2 consumption
Sampling time:
7 d
% Degr.:
5
Parameter:
O2 consumption
Sampling time:
14 d
% Degr.:
4
Parameter:
O2 consumption
Sampling time:
21 d
% Degr.:
11
Parameter:
O2 consumption
Sampling time:
28 d
Transformation products:
not measured
Evaporation of parent compound:
not measured
Volatile metabolites:
not measured
Residues:
not measured
Validity criteria fulfilled:
yes
Conclusions:
The test substance biodegraded to an extent of 11% after 28 days.
Executive summary:

The test substance biodegraded to an extent of 11% after 28 days.

Endpoint:
biodegradation in water: sediment simulation testing
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the substance is readily biodegradable

Description of key information

Biodegradation in water

Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics, biodegraded to an extent of 69% after 28 days in seawater that used the indigenous microorganisms in the seawater sample as a sole source of the inoculum. These data are used as read-across data for C9-14 Aliphatics (≤ 2% aromatic).

Hydrocarbons, C12-C14, isoalkanes, <2% aromatics biodegraded to an extent of 11% in sea water after 28 days. These data are used as read-across data for C9-14 Aliphatics (≤ 2% aromatic).

Biodegradation in sediment

C9-14 Aliphatics (≤ 2% aromatics) are readily biodegradable. Therefore, simulation tests in sediment are not required.

Key value for chemical safety assessment

Additional information