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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:
weight of evidence
Study period:
15 April 1996 to 13 May 1996
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Proprietary GLP study
Qualifier:
according to
Guideline:
OECD Guideline 306 (Biodegradability in Seawater)
GLP compliance:
yes
Radiolabelling:
no
Oxygen conditions:
not specified
Inoculum or test system:
not specified
Details on source and properties of surface water:
The source of the seawater was the east coast of Scotland (Eyemouth), a surface sample (0.5-1 foot) being taken. The sample was aged for 6 days before use.
Details on source and properties of sediment:
Not applicable
Details on inoculum:
No information
Duration of test (contact time):
28 d
Initial conc.:
2.45 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
not specified
Details on study design:
Closed bottle test: a predetermined amount of the test material was introduced to a seawater medium providing a final concentration of ca 2 mg/l. The solutions were kept in closed bottles (by using ground glass stoppered bottles to provide an air tight seal) in the dark at a temperature of 15-20°C. The biodegredation was followed by oxygen analysis over a 28 d period. As a control, a seawater medium without any test material was run in parallel for determination of the baseline oxygen consumption. An inhibition check was also performed using equal volumes of reference and test material at ca 1.5 mg/l and 2 mg/l, respectively.
Reference substance:
benzoic acid, sodium salt
Remarks:
1.54mg/l
Test performance:
No information
Compartment:
other: water / sediment, material (mass) balance
Remarks on result:
other: No information
% Degr.:
78.9
Parameter:
O2 consumption
Sampling time:
28 d
Transformation products:
not specified
Details on transformation products:
No information
Evaporation of parent compound:
not specified
Volatile metabolites:
not specified
Residues:
not specified
Details on results:
Acrylonitrile showed degredation over the 28 day test period, based on oxygen consumption in the test system. At the end of the 28 day test period, when compared against the oxygen removal by the blank, a calculated biodegredation of 78.91% was determined.
An inhibition test confirmed that acrylonitrile was non-inhibitory to bacteria.
Results with reference substance:
97.4% degredation of the sodium benzoate control occurred by day 4 of the study.

78.9% degredation of acrylonitrile was achieved over the 28 day period indicating a high degree of degradability in seawater.

Validity criteria fulfilled:
not specified
Conclusions:
78.9% degredation of acrylonitrile was achieved over the 28 day period indicating a high degree of degradability in seawater.
Executive summary:

The ready biodegradability of acrylonitrile in seawater was determined using OECD Test Guideline 306, (closed bottle test) and a test concentration of 2.45 mg/l acrylonitrile. 78.9% degradation of acrylonitrile was achieved over the 28 day period indicating a high degree of degradability in seawater. An estimated 45% degradation was achieved within a 10-day period following start of degradation (10% on day 3).

Endpoint:
biodegradation in water: sewage treatment simulation testing
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
Published studies
Principles of method if other than guideline:
Simulation tests; laboratory scale, continuous flow, activated sludge systems
GLP compliance:
not specified
Radiolabelling:
not specified
Oxygen conditions:
not specified
Inoculum or test system:
activated sludge (adaptation not specified)
Details on source and properties of surface water:
No information available
Details on source and properties of sediment:
No information available
Details on inoculum:
Municipal activated sludge
Duration of test (contact time):
60 d
Details on study design:
Kincannon and his group used 3 litre internal recycle reactor system initially seeded with municipal activated sludge and operated at mean residence times of 2, 4 or 6 days, with hydraulic retention time being maintained at 8 hours. Following acclimation, influent, effluent, mixed liquor and off-gas samples were collected over a 60-day testing period.
Test performance:
No information available
% Degr.:
99.9
Sampling time:
60 d
Remarks on result:
other: Based on specific compound analysis
Transformation products:
not measured
Details on results:
Kincannon and group showed a 96.6 to 98.1% treatment efficiency based on BOD5 and 99.9% based on specific compound analysis. They also showed no stripping of acrylonitrile from the test system in the absence of biological activity.
Results with reference substance:
No information available

Kincannon and group showed a 96.6 to 98.1% treatment efficiency based on BOD5 and 99.9% based on specific compound analysis. They also showed no stripping of acrylonitrile from the test system in the absence of biological activity.

Validity criteria fulfilled:
not specified
Conclusions:
Kincannon and group showed a 96.6 to 98.1% treatment efficiency based on BOD5 and 99.9% based on specific compound analysis. They also showed no stripping of acrylonitrile from the test system in the absence of biological activity.
Executive summary:

Kincannon and group showed a 96.6 to 98.1% treatment efficiency based on BOD5 and 99.9% based on specific compound analysis. They also showed no stripping of acrylonitrile from the test system in the absence of biological activity.

Endpoint:
biodegradation in water: sediment simulation testing
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
Published study
Principles of method if other than guideline:
Simulation test with recycle sludge
GLP compliance:
not specified
Radiolabelling:
not specified
Oxygen conditions:
aerobic
Inoculum or test system:
other: recycle sludge
Details on source and properties of surface water:
No information available
Details on source and properties of sediment:
No information available
Details on inoculum:
Recycle sludge obtained from Monsanto's Port Plastics plant in Addyston, Ohio. The sludge had already been acclimated to the plant wastewater containing acrylonitrile, phenol and styrene.
Duration of test (contact time):
45 d
Initial conc.:
200 mg/L
Details on study design:
A continuous flow bench scale oxidation system operated over 45 days. The systems were designed to operate at 50%, 100% or 150% recycle rates at an influent water flow rate of 10 ml/min and were initially seeded with recycle sludge obtained from Monsanto's Port Plastics plant in Addyston, Ohio. The sludge had already been acclimated to the plant wastewater containing acrylonitrile, phenol and styrene. The reactor was initially spiked with 200 mg/l acrylonitrile and then fed over a 4-week period with acrylonitrile at 0.284 g/hr. Sludge was periodically wasted to maintain steady Mixed Liquor Volatile Suspended Solid (MLVSS) concentrations, which averaged 1,715 mg/l over the period of the experiment. Dissolved Oxygen Concentrations were generally maintained at 2 mg/l, and acrylonitrile was analysed in both the aqueous and atmospheric phases.
Test performance:
No information available
% Degr.:
99.9
Parameter:
not specified
Remarks:
Removal by biological action
Sampling time:
45 d
Transformation products:
not specified
Details on results:
The authors reported over 99.9% removal by biological action in a continuous flow bench scale oxidation system operated over 45 days.
Results with reference substance:
No information available.

The results of the study showed greater than 99.97% removal of acrylonitrile by biological action at the earliest sampling period (2 days) and thereafter throughout the 4-week period of the study. There was little (0.01%) stripping of acrylonitrile to air in the biological system. In all cases acrylonitrile concentrations in the effluent from the system was less than the detection limit for the system of 0.5 mg/l. Freeman used a mathematical computation of the equilibrium relationship between the liquid concentration and the concentration in the aeration bubbles to derive the actual concentration of acrylonitrile in the effluent phase. The study also included a sterile system operated over a 5-day period under similar conditions but with no seed sludge. Acrylonitrile concentrations in the reactor were analysed at 367 mg/l on day 5. The material balance for the sterile system (3.2% error) showed 18% stripping to air of the acrylonitrile entering the reactor.

Conclusions:
The authors reported over 99.9% removal by biological action in a continuous flow bench scale oxidation system operated over 45 days.
Executive summary:

The authors reported over 99.9% removal by biological action in a continuous flow bench scale oxidation system operated over 45 days.

Endpoint:
biodegradation in water: sewage treatment simulation testing
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
Published study
Principles of method if other than guideline:
Simulation test; benchscale activated sludge unit
GLP compliance:
no
Radiolabelling:
not specified
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on source and properties of surface water:
No information available
Details on source and properties of sediment:
No information available
Details on inoculum:
Weak settled sewage (BOD 50-75 mg/l)
Duration of test (contact time):
42 d
Initial conc.:
22 mg/L
Details on study design:
The authors examined the effect of increased concentrations of acrylonitrile in a benchscale activated sludge unit (5.5 L) seeded with weak settled sewage (BOD 50-75 mg/l). A semicontinuous flow system was used with compensatory removal of sludge solids in addition to aqueous effluent. Gradually increasing concentrations of acrylonitrile (22-89 mg/l) were used.
Test performance:
No information available
% Degr.:
90 - 97
Parameter:
other: theoretical BOD
Sampling time:
42 d
Transformation products:
not measured
Details on results:
Gradually increasing concentrations of acrylonitrile (22-89 mg/l) during the acclimation period showed 40% of influent nitrogen detectable as effluent ammonia during days 1-4. By days 10-13, 90% influent nitrogen was detectable as effluent oxidised material, and during four subsequent weeks of normal operation 90%-97% of the acrylonitrile theoretical BOD was removed. Efficiency decreased on acrylonitrile overload with 177 mg/l and was materially reduced at 266 mg/l.
Results with reference substance:
Not examined

Gradually increasing concentrations of acrylonitrile (22-89 mg/l) during the acclimation period showed 40% of influent nitrogen detectable as effluent ammonia during days 1-4. By days 10-13, 90% influent nitrogen was detectable as effluent oxidised material, and during four subsequent weeks of normal operation 90%-97% of the acrylonitrile theoretical BOD was removed. Efficiency decreased on acrylonitrile overload with 177 mg/l and was materially reduced at 266 mg/l.

Executive summary:

Gradually increasing concentrations of acrylonitrile (22-89 mg/l) during the acclimation period showed 40% of influent nitrogen detectable as effluent ammonia during days 1-4. By days 10-13, 90% influent nitrogen was detectable as effluent oxidised material, and during four subsequent weeks of normal operation 90%-97% of the acrylonitrile theoretical BOD was removed. Efficiency decreased on acrylonitrile overload with 177 mg/l and was materially reduced at 266 mg/l.

Endpoint:
biodegradation in water: sewage treatment simulation testing
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
Published study
Principles of method if other than guideline:
Simulation test; anaerobic sewage digesters
GLP compliance:
no
Radiolabelling:
not specified
Oxygen conditions:
anaerobic
Inoculum or test system:
other: raw sludge from a municipal treatment plant
Details on source and properties of surface water:
No information available
Details on source and properties of sediment:
No information available
Details on inoculum:
Raw sludge from a municipal treatment plant
Duration of test (contact time):
20 d
Initial conc.:
1 mg/L
Details on study design:
The effect of acrylonitrile on anaerobic sewage digesters was examined, using a controlled residence 10 l working volume digester system fed on a daily basis with acrylonitrile and raw sludge from a municipal treatment plant, spent sludge being wasted from the system to maintain steady state sludge concentrations. Hydraulic residence time was 20 days. Gradually increasing dosages of acrylonitrile (1, 2, 4, 10, 20 mg/l) were fed and the performance of the digester was compared with a control digester operated under identical conditions but without acrylonitrile feed.
Test performance:
No information available
Remarks on result:
other: No effect on effluent COD was detected at the highest concentrations, indicating that at these concentrations acrylonitrile was not harmful to an anaerobic digester.
Transformation products:
not measured
Details on results:
No effect on effluent COD was detected at the highest concentrations, indicating that at these concentrations acrylonitrile was not harmful to an anaerobic digester.

No effect on effluent COD was detected at the highest concentrations, indicating that at these concentrations acrylonitrile was not harmful to an anaerobic digester.

Conclusions:
No effect on effluent COD was detected at the highest concentrations, indicating that at these concentrations acrylonitrile was not harmful to an anaerobic digester.
Executive summary:

No effect on effluent COD was detected at the highest concentrations, indicating that at these concentrations acrylonitrile was not harmful to an anaerobic digester.

Description of key information

Acrylonitrile is considered to be inherently biodegradable.

Key value for chemical safety assessment

Additional information

The ready biodegradability of acrylonitrile in seawater was determined using OECD Test Guideline 306, (closed bottle test) and a test concentration of 2.45 mg/l acrylonitrile. 78.9% degradation of acrylonitrile was achieved over the 28 day period indicating a high degree of degradability in seawater. An estimated 45% degradation was achieved within a 10-day period following start of degradation (10% on day 3) (AN Group, 1996). Kincannon and group showed a 96.6 to 98.1% treatment efficiency based on BOD5 and 99.9% based on specific compound analysis. They also showed no stripping of acrylonitrile from the test system in the absence of biological activity (Kincannon et al, 1983; Stiver & Kincannon, 1983). Freeman & Schroy (1984) report over 99.9% removal by biological action in a continuous flow bench scale oxidation system operated over 45 days. In a further study (Ludzak, 1961), gradually increasing concentrations of acrylonitrile (22-89 mg/l) during the acclimation period showed 40% of influent nitrogen detectable as effluent ammonia during days 1-4. By days 10-13, 90% influent nitrogen was detectable as effluent oxidised material, and during four subsequent weeks of normal operation 90%-97% of the acrylonitrile theoretical BOD was removed. Efficiency decreased on acrylonitrile overload with 177 mg/l and was materially reduced at 266 mg/l.