DL-serinohydrazide monohydrochloride

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 Dec 2000 - 11 Jan 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Federal Office of Public Health, Bern, Switzerland

Test material

Test material information

Constituent 1

Reference substance name:

DL-serinohydrazide monohydrochloride

EC Number:

259-839-8

EC Name:

DL-serinohydrazide monohydrochloride

Cas Number:

55819-71-1

Molecular formula:

C3H9N3O2.ClH

IUPAC Name:

2-amino-3-hydroxy-propanehydrazide;hydrochloride

Details on test material:

- Name of test material (as cited in study report): DL-Serine hydrazide HCl
- Substance type: white solid
- Physical state: solid
- Expiration date of the lot/batch: 06 Dec 2001
- Storage condition of test material: in refrigerator at about 4 °C, under N2

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): The study was performed with aerobic activated sludge from a wastewater treatment plant (ARA Ergolz II, Fullinsdorf, Switzerland).
- Preparation of inoculum for exposure: The sludge was washed once with tap water by centrifugation and the supernatant liquid phase was decanted. A homogenized aliquot of the final sludge suspension was weighed, thereafter dried and the ratio of wet to dry weight was calculated. Based on this ratio, calculated amounts of wet sludge were suspended in test water to obtain a concentration equivalent to 4 g (± 10%) dry material per liter. During holding, the sludge was aerated at room temperature until use. Prior to use, the sludge was diluted with test water to a concentration of 1 g per liter (dry weight basis). This diluted activated sludge was used as inoculum to give a final concentration of 30 mg dry material per liter.
- Concentration of sludge: 30 mg dry material/L

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

other: BOD (biochemical oxygen demand)

Details on study design:

TEST CONDITIONS
- Composition of medium: according to testing guideline
- Test temperature: 22 °C
- pH: 7.4
- pH adjusted: yes
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 500 mL Erlenmeyer flasks
- Number of culture flasks/concentration: 2

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2
- Abiotic control: 1
- Toxicity control: 1

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Parameter:

other: BOD

Value:

89

Sampling time:

28 d

Remarks on result:

other: The percent biodegradation of the test item was calculated based on the theoretical oxygen demand (ThOD, not corrected for nitrification) of 0.41 mg O2/mg test item.

Details on results:

The biochemical oxygen demand (BOD) of DL-Serine hydrazide HCI in the test media significantly increased from Day 4 until test-termination after 28 days. At the end of the 28-day exposure period, the mean biodegradation rate of DL-Serine hydrazide HGI amounted to 89%. The pass level for ready biodegradability, i.e. a biodegradation rate of at least 60% of the ThOD in a 10-day window within the 28-day period of the test, was clearly reached. Consequently, DL-Serine hydrazide HCl was found to be readily and completely biodegradable under the test conditions within 28 days.

BOD5 / COD results

Results with reference substance:

The percent biodegradation of the reference item sodium benzoate was calculated based on the theoretical oxygen demand of 1.67 mg O2/mg (ThOD). In the procedure controls, the reference item was degraded by an average of 88% by exposure Day 14, thus confirming suitability of the activated sludge. At the end of the test (Day 28), the reference item was degraded by an average of 92%.

No degradation of the test item occurred in the abiotic control under the test conditions.

The percent biodegradation in the toxicity control containing both the test item and the reference item was calculated based on the ThOD of the test item and the reference item. The biodegradation rate in the toxicity control showed a similar course of biodegradation over the 28-day exposure period as the two procedure controls containing the reference item only. Within 14 days of exposure, a biodegradation rate of 87% was observed. Thus, according to the test guidelines, the test item had no inhibitory effect on activated sludge microorganisms because the biodegradation rate in the toxicity control was >25% within 14 days.

Any other information on results incl. tables

Table 1: Cumulative biochemical oxygen demand (BOD mg O2/L) in the test flasks

	Test item		Inoculum control		Procedure control		Abiotic control	Toxicity control
Time (days)	Flask number		Flask number		Flask number		Flask number	Flask number
	7	8	1	2	11	12	9	10
0	0	0	0	0	0	0	0	0
1	0	0	0	0	0	12	0	0
2	-	-	-	-	-	-	-	-
3	-	-	-	-	-	-	-	-
4	10	9	0	0	121	120	0	135
5	14	14	0	0	133	131	0	147
6	18	19	0	0	137	135	0	154
7	22	23	0	0	141	139	0	161
8	26	26	0	0	143	139	0	165
9	-	-	-	-	-	-	-	-
10	-	-	-	-	-	-	-	-
11	34	32	3	0	149	143	0	177
12	-	-	-	-	-	-	-	-
13	36	34	4	0	152	145	0	181
14	36	35	4	0	154	145	0	183
15	36	35	4	0	154	145	0	183
16	-	-	-	-	-	-	-	-
17	-	-	-	-	-	-	-	-
18	40	37	5	0	159	145	0	188
19	40	37	6	0	160	145	0	190
20	40	37	6	0	161	145	0	191
21	40	37	6	0	162	145	0	192
22	42	37	7	0	163	145	0	194
23	-	-	-	-	-	-	-	-
24	-	-	-	-	-	-	-	-
25	44	38	7	0	165	145	0	200
26	44	38	8	0	166	146	0	201
27	44	38	8	0	167	147	0	204
28	44	38	9	0	168	148	0	206

- = no reading taken

Table 2: Biodegradation of DL-Serine hydrazide HCl and the reference item

Time (days)	Percentage Biodegradation*
	Test item		Procedure control		Toxicity control
	Flask No. 7	Flask No. 8	Flask No. 11	Flask No. 12	Flask No. 10
0	0	0	0	0	0
1	0	0	0	7	0
2	-	-	-	-	-
3	-	-	-	-	-
4	24	22	72	72	65
5	34	34	80	78	71
6	44	46	82	81	74
7	54	56	84	83	77
8	63	63	86	83	79
9	-	-	-	-	-
10	-	-	-	-	-
11	79	74	88	85	84
12	-	-	-	-	-
13	83	78	90	86	86
14	83	80	91	86	87
15	83	80	91	86	87
16	-	-	-	-	-
17	-	-	-	-	-
18	91	84	94	85	89
19	90	83	94	85	90
20	90	83	95	85	90
21	90	83	95	85	91
22	94	82	96	85	92
23	-	-	-	-	-
24	-	-	-	-	-
25	99	84	97	85	94
26	98	83	97	85	95
27	98	83	98	86	96
28	96	82	98	86	97
Mean (Day 28)	89		92

* = Corrected for the inoculum controls

- = not determined

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Under the conditions of the study the test item was readily biodegradable. The biochemical oxygen demand at the end of the 28-day exposure period amounted to 89%. The pass level for ready biodegradability, i.e. a biodegradation rate of at least 60% of the ThOD in a 10-day window within the 28-day period of the test, was clearly reached. All validity criteria were fulfilled.

Executive summary:

The test item DL-Serine hydrazide HCI was investigated for its ready biodegradability in a 28-Day Manometric Respirometry Test based on Directive 92/69 EEC, C.4-D, 1992 and OECD Guideline for Testing of Chemicals No. 301 F, 1992.

The nitrite and nitrate concentrations in the test media and in the inoculum controls were in the same low range at the end of the test. Consequently, no significant nitrification had occurred in the test media with DL-Serine hydrazide HCI during the degradation test period. Therefore, the measured biological oxygen demand is caused only by the biodegradation of the test item. For that reason, the percent biodegradation of the test item was calculated based on the theoretical oxygen demand ThOD NH4 of 0.41 mg O2/mg test item (without taking nitrification into account).

The biochemical oxygen demand (BOD) of DL-Serine hydrazide HCI in the test media significantly increased from Day 4 until test-termination after 28 days. At the end of the 28-day exposure period, the mean biodegradation rate of DL-Serine hydrazide HCI amounted to 89%.

The pass level for ready biodegradability, i.e. a biodegradation rate of at least 60% of the ThOD in a 10-day window within the 28-day period of the test, was clearly reached. Consequently, DL-Serine hydrazide HCI was found to be ready and completely biodegradable under the test conditions within 28 days.

In the toxicity control, containing both DL-Serine hydrazide HCI and the reference item sodium benzoate, no inhibitory effect on the biodegradation of the reference item was determined. Thus, DL-Serine hydrazide HCI had obviously no inhibitory effect on the activity of activated sludge microorganisms.

In the procedure controls, the reference item sodium benzoate was biodegraded by an average of 88% on exposure Day 14, and reached an average biodegradation rate of 92% by the end of the test (Day 28), thus confirming suitability of the activated sludge.