Magnesium glycerophosphate

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:

28 - 08 - 2017 - 27 - 10 - 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Magnesium glycerophosphate

EC Number:

213-149-3

EC Name:

Magnesium glycerophosphate

Cas Number:

927-20-8

Molecular formula:

C3H9O6P.Mg

IUPAC Name:

magnesium glycerophosphate

Test material form:

solid: particulate/powder

Details on test material:

Batch: INVG003917

Specific details on test material used for the study:

Name: Magnesium Glycerophosphate
Synonym: Magna-C
Batch No.: INVG003917
Composition: 96.5 %(w/w) (calculated)
Magnesium 2,3-dihydroxypropyl phosphate:
96.5% (w/w)
Aggregate State at Room Temperature: Solid
Colour: White
Molecular Formula / Molecular Weight C3H7O6P Mg/ 194.36 g/mol
Theoretical Oxygen Demand: ThODNH4: 0.494 mg oxygen per mg test item
Expiration Date: June 10, 2021
Storage Conditions at Test Facility: At 20  5 °C, in the dark

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Aerobic activated sludge, microorganisms from a domestic waste water treatment plant was supplied by the sewage treatment plant Bensheim, Germany.
The aerobic activated sludge used for this study was deposited for 30 min, washed by centrifugation and the supernatant liquid phase was decanted. The solid material was re-suspended in test water and centrifuged again. This procedure was done three times. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 3.5 g dry material per litre were mixed with test water and aerated overnight. This suspension was used for the experiment.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

ca. 100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

The test item Magnesium Glycerophosphate was investigated for its ready biodegradability in a manometric respirometry test over a period of 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.

Test Units:
Manometric Test System with test flasks containing a volume of approximately 500 mL.
BSB/BOD-Sensor-System, Aqualytic Dortmund, Germany
Principle:
The test flasks prepared according paragraph 6.6 were incubated at 22°C * 1°C. The pressure decrease in the reaction vessels was measured over complete experimental phase of 28 days using the BSB/BOD-Sensor-System, Aqualytic Dortmund, Germany. The test flasks were closed gas-tight by a measuring head. Potassium hydroxide solution (45%) was used for trapping the produced carbon dioxide. The amount of O2 consumed by the activated sludge was calculated from the decrease of pressure in the reaction vessel.
Preparation of test flasks:
The amounts of test item and reference item were directly weighed into the test flasks. No emulsifiers and solvents were used.
Incubation:
The cllosed test flasks were incubated in a climatised chamber under continuous stirring. The consumption of oxygen was determined by measuring the change of pressure in tthe flasks. Evolved carbon dioxicd was absorbed in an aqueous solution (45%) of potassium hydroxide.
Test duration:
28days
Measurement of oxygen:
The change of pressure in the test flasks was measured by means of a manometric method (BSB/BOD-Sensor-System, Aqualytic Dortmund, Germany) each day.
Temperature:
The temperature was recorded by means of the automated sooftware AMR Wincontrol ©.
pH-Value:
pH-values were measured in procedure control, a separately prepared test flask with test item (to prevent
loss of test item in the test flasks) and a separately prepared test flask without test item (control) at test start and in all flasks at the end of the test, except in the abiotic and toxicity control, using a pH-electrode
WTW pH 340i.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

Test performance:

The degradation rate of Magnesium Glycerophosphate did not reach 60% within the 10-day window, but after 28 days.

% Degradation

Key result

Parameter:

% degradation (CO2 evolution)

Value:

85

Sampling time:

28 d

Details on results:

The 10-day windows began on day 1 after application, the mean value was calculated to be 15% biodegradation. Therefore, the end of the 10-day window was day 11. After correction for the mean biochemical oxygen demand of the inoculum controls the mean biodegradation percentage based on ThODNH4 at the end of the 10-day window was 50%; the criterion of the 10 day window was not passed. The mean biodegradation percentage at the end of the 28-day exposure period was 85%.

The degradation rate of Magnesium Glycerophosphate did not reach 60% within the 10-day window, but after 28 days.
Therefore, Magnesium Glycerophosphate is considered to be readily biodegradable after 28 days, but failing the 10-day window criterion.

BOD5 / COD results

Results with reference substance:

The reference item sodium benzoate was sufficiently degraded to 80% after 14 days and to 83% after 28 days of incubation.

The percentage biodegradation of the reference item confirms the suitability of the used aerobic activated sludge inoculum.

Any other information on results incl. tables

Table2. Cumulative Biochemical Oxygen Demand (mg O₂/L) in Test Flasks during the Test Period of 28 Days

Time	Flask No.
(days)	1	2	3	4	5	6	7
1	5	15	0	5	50	0	80
2	10	25	5	5	80	0	115
3	15	30	5	10	110	0	125
4	20	35	10	10	120	0	130
5	25	35	10	10	125	0	135
6	30	35	10	10	130	0	150
7	30	35	15	15	135	0	155
8	35	35	15	15	140	0	160
9	40	40	15	15	145	0	170
10	40	40	15	20	150	0	175
11	45	40	15	20	150	0	180
12	45	40	20	20	150	0	180
13	50	40	20	20	155	0	190
14	50	40	20	20	155	0	190
15	50	40	20	20	155	0	190
16	55	45	20	20	155	0	195
17	55	45	20	20	160	0	195
18	55	45	20	25	160	0	195
19	55	45	20	25	160	0	195
20	55	45	20	25	160	0	200
21	60	45	20	25	160	0	205
22	60	45	20	25	160	0	205
23	60	55	20	25	165	0	210
24	60	55	20	25	165	0	215
25	60	55	20	25	165	0	215
26	65	55	20	25	165	0	215
27	65	55	20	30	165	0	215
28	65	70	20	30	165	0	215

            Flasks 1 and 2: Magnesium Glycerophosphate

            Flasks 3 and 4: inoculum control

Flask 5:reference(procedure control)

            Flask 6: abiotic control

            Flask 7: toxicity control

Table3. Percentage Biodegradation of Test Item, of Sodium Benzoate and of the Toxicity Control based on ThOD_NH4

Time	Percentage Biodegradation^1
(Days)	Magnesium Glycerophosphate^1		Sodium Benzoate^2	Toxicity control^1, 2
	Flask 1 [%]	Flask 2 [%]	Flask 5 [%]	Flask 7 [%]
1	5	25	28	35
2	10	40	44	50
3	15	45	61	53
4	20	50	65	54
5	30	50	68	57
6	39	50	71	63
7	30	40	71	63
8	39	40	74	66
9	49	50	77	70
10	44	45	79	71
11	54	45	79	73
12	49	40	77	72
13	59	40	80	77
14	59	40	80	77
15	59	40	80	77
16	69	50	80	79
17	69	50	83	79
18	64	45	82	78
19	64	45	82	78
20	64	45	82	80
21	74	45	82	83
22	74	45	82	83
23	74	65	84	85
24	74	65	84	87
25	74	65	84	87
26	84	65	84	87
27	79	60	83	86
28	79	90	83	86

               ¹ThOD_NH4of Magnesium Glycerophosphate: 0.494 mg O₂/mg test item
               ²ThOD_NH4of sodium benzoate: 1.666 mg O₂/mg reference item

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable, but failing 10-day window

Conclusions:

Biodegradation Test Item:
The degradation rate of Magnesium Glycerophosphate did not reach 60% within the 10-day window, but after 28 days.
Therefore, Magnesium Glycerophosphate is considered to be readily biodegradable after 28 days, but failing the 10-day window criterion.

Biodegradation Reference Item:
The reference item sodium benzoate was sufficiently degraded to 80% after 14 days and to 83% after 28 days of incubation.
The percentage biodegradation of the reference item confirms the suitability of the used aerobic activated sludge inoculum.

Executive summary:

Title:	Magnesium Glycerophosphate: Ready Biodegradability in a Manometric Respirometry Test
Guidelines:	This study was designed to comply with the following methods: -     Commission Regulation 440/2008/EC, Method C.4-D of: Manometric Respirometry Test (EEC Publication No. L 142/496, May 2008) -     OECD Guideline for Testing of Chemicals No. 301 F: "Ready Biodegradability: Manometric Respirometry Test", adopted
Material and Methods:
Test Item:	Magnesium Glycerophosphate; Batch No.:INVG003917
Test Species:	Aerobic activated sludge (microorganisms from a domestic waste­water treatment plant) was supplied by the sewage treatment plant of Bensheim,.
Test Design:	The test item Magnesium Glycerophosphate was investigated for its ready biodegradability in a manometric respirometry test over a period of 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control.
Endpoints:	Degradation rate of test item calculated by the oxygen consumption of the aerobic activated sludge microorganisms after 28 days of incubation.
Test Item Loading Rate (initial concentration in medium C0):	102.0 mg/L corresponding to an oxygen demand of about 50.4 mg/L (ThODNH4)
Reference Item:	Sodium Benzoate
Reference Item Loading Rate:	101.2 mg/L corresponding to an oxygen demand of about 168.6 mg/L (ThODNH4)
Test Conditions:	22°C ± 1°C, darkness
Results:
Biodegradation of Magnesium Glycerophosphate:	The criterion for ready biodegradability under the conditions of a manometric respirometry test is the degradation of the test item of at least 60%, reached within a 10-day window; the 10-day window starts when the degradation of the test item reaches at least 10% degradation. The mean biodegradation of 10% of Magnesium Glycerophosphate was reached at day 1 (ThODNH4). At the end of the 10-day window at day 11, the mean degradation of Magnesium Glycerophosphate was 50% (ThODNH4) and therefore the 10 day window criterion was not passed. The mean biodegradation at test end after 28 days was 85% (ThODNH4). Therefore, Magnesium Glycerophosphate is considered to be readily biodegradable after 28 days, but failing the 10-day window.
Biodegradation of Sodium Benzoate:	The reference item sodium benzoate was sufficiently degraded to 80% after 14 days and to 83% after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used.
Biodegradation of the Toxicity Control:	In the toxicity control containing both, the test item and the reference item sodium benzoate, 77% biodegradation was noted within 14 days and 86% biodegradation after 28 days of incubation. According to the test guidelines, the test item can be assumed to be not inhibitory to the aerobic activated sludge microorganisms because degradation was >25% within 14 days.