Reaction mass of N-(2-hydroxypropyl)decan-1-amide and N-(2-hydroxypropyl)octanamide

Hydrolysis

Administrative data

Endpoint:

hydrolysis

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

Cross-reference

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

supporting study

Study period:

From March 10, 1997 to April 9, 1997

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

KL2 due to RA

Justification for type of information:

Refer to the section 13 for details on the read across justification.

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

yes

Remarks:

; no abiotic control was taken as previous experience has shown that abiotic degradation under the test conditions does not occur; no toxicity control taken as test material was found to be non-toxic at tested concentration in a preliminary study.

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Deviations:

yes

Remarks:

; no abiotic control was taken as previous experience has shown that abiotic degradation under the test conditions does not occur; no toxicity control taken as test material was found to be non-toxic at tested concentration in a preliminary study.

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Stage and source of inoculum/activated sludge: A mixed population of activated sludge micro-organisms from the aeration stage of the Severn Trent Water plc sewage treatment plant at Belper, Derbyshire, treating predominantly domestic sewage.
- Pretreatment: Sample washed 3 times by settlement and resuspension in culture medium.
- Concentration of sludge: 49.7 mL of sludge added to each test vessel to give concentration of 30 mg suspended solids/L.
- Storage conditions: Sample maintained on aeration at 21°C prior to use.

Duration of test (contact time):

ca. 28 d

Initial conc.:

ca. 20 mg/L

Based on:

other: Elemental carbon

Initial conc.:

ca. 28.6 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

inorg. C analysis

Details on study design:

TEST CONDITIONS
- Composition of medium:
Solution A: KH2PO4 - 8.50 g/L; K2HPO4 - 21.75 g/L; Na2HPO4·2H2O - 33.40 g/L; NH4Cl - 0.50 g/L (pH = 7.4)
Solution B: CaCI2 - 27.50 g/L
Solution C: MgSO4.7H2O - 22.50 g/L
Solution D: FeCI3·6H2O - 0.25 g/L
Ion exchange and reverse osmosis treated tap water mixed with 1,000 mL of solution A and 100 mL each of solution B, C and D to give 100 L final volume.
- Test temperature: 21°C
- pH: 7.2 - 7.4 on Day 28
- Agitation: Yes; by magnetic stirrer
- Aeration of dilution water: Using CO2 free air at 40 - 70 mL/min.
- Suspended solids concentration: 30 mg/L
- Continuous darkness: Yes

TEST SYSTEM
- Culturing apparatus: 5 L glass culture vessel
- Number of culture flasks: 2 replicates each for test and reference substance
- Test performed in closed vessels: Yes (foiled)
- Trap for evolved CO2: Absorber vessels (no details reported)

SAMPLING
- Sampling frequency: On Day 0, 1, 2, 3, 6, 8, 10, 14, 16, 20, 22, 24, 27, 28 and 29*
- Sampling method: 2 mL sample taken
- Sample storage before analysis: Samples taken on Days 12 and 22 stored at -20°C for later analysis.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes (in duplicate)
- Abiotic sterile control: Not required
- Toxicity control: Not required

* After addition of 1 mL concentrated HCl on Day 28 to release remaining CO2

Reference substance:

benzoic acid, sodium salt

Remarks:

17.1 mg/L equivalent to 10 mg carbon/L; Batch no. 65H1093

Preliminary study:

Preliminary investigational work was carried out using the Activated Sludge Respiration Inhibition test method (OECD Guideline No. 209), which showed that test material did not inhibit the respiration of sewage sludge micro-organisms at the concentration employed in the test (see Table 3 in attached full study report for details).

Test performance:

None

Key result

Parameter:

% degradation (inorg. C analysis)

Value:

ca. 97

Sampling time:

28 d

Details on results:

Degradation of the test material attained 10 % on Day 2 and 62 % on Day 10 of the study, thereby meeting the 10 d window validation criteria. The percentage degradation value for the test material increased to 100 % on Day 29 due to release of remaining CO2 by addition of HCl (see Table 1 for details).

Results with reference substance:

Sodium benzoate attained 97% degradation after 28 d (also fulfilled 10 d window criteria) thereby confirming the suitability of the inoculum and test conditions. The percentage degradation value for the test material increased to 98% on Day 29 due to release of remaining CO2 by addition of HCl (see Table 1 for details).

Table 1. % Biodegradation values of reference and test material at various time intervals

 

Day	% Degradation (Reference)	% Degradation (Test)
0	0	0
1	9	6
2	22	10
3	37	23
6	54	60
8	58	58
10	64	62
14	79	77
16	92	100
20	91	99
22	101	96
24	94	98
27	96	96
28	97	97
29	98	100

 

DOC analysis: The measured concentrations of DOC were 0 - 23% of nominal on Day 0 and 0 - 34% of nominal on Day 28. A marked decline in carbon concentration was also observed after centrifugation of the 200 mg/L stock dispersion used to prepare the test vessels. This effect was considered to be due to the test material being a fine homogenous dispersion and not a true solution at the concentrations employed in the study.

Validity criteria fulfilled:

not specified

Remarks:

All the criteria met but the total CO2 evolution in blank exceeded normal 40 mg/L value and initial IC content of one of the test vessel was greater than 5% of TC

Interpretation of results:

readily biodegradable

Conclusions:

Under the study conditions, the test substance was considered to be readily biodegradable

Executive summary:

A study was conducted to determine the ready biodegradability of the read across substance, C12 MIPA, according to OECD Guideline 301 B (Modified Sturm test), in compliance with GLP. A dispersion of the test substance in a defined medium, corresponding to 20 mg carbon/L, was inoculated with activated sludge (30 mg suspended solid/L). The test vessels were aerated by the passage of carbon dioxide-free air and incubated under aerobic conditions for 28 days. The reference material used was sodium benzoate at a concentration of 10 mg carbon /L. Degradation was followed by determining the CO2 produced and trapped in CO2 absorber vessel via IC measurement at 1-4 day intervals until Day 28. On Day 28, HCI was added to flasks in order to eject all the remaining CO2 and a last analysis was carried out on Day 29. Sodium benzoate attained 97% degradation after 28 days (98% on Day 29), thereby confirming the suitability of the inoculum and test conditions. The test substance also attained 97% degradation after 28 days (100% on Day 29). Under the study conditions, the test substance was therefore considered to be readily biodegradable (Mead, 1997).