Bis(neodecanoyloxy)dioctylstannane

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Study period:

06 December 2002 to 15 January 2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to valid guidelines and the study was conducted under GLP conditions. Since the study was conducted with the read across substance dioctyltin oxide it has been assigned a reliability score of 2.

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

(100 mg (dry weight) of suspended solids, as no biodegradation occurred, this was not considered to affect the results)

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)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: The activated sludge was obtained from an oxidation ditch situated in the municipality of Hazerswoude, the Netherlands (3 Dec 2002).
- Preparation of inoculum for exposure: 8 mL of sludge was added to 300 mL of mineral medium.
- Concentration of sludge: 100 mg of solids per litre.

Duration of test (contact time):

755 h

Initial conc.:

23.7 mg/L

Based on:

test mat.

Initial conc.:

50.5 mg/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

PREPARATION OF THE TEST MATERIAL
The test material was thoroughly mixed (homogenisation was not possible). Portions with an average weight of 0.00712 g of the test material (average of all bottles containing test material, including the toxicity control bottles) were dosed directly on glass fibre filters. The filters were placed into the test flask containing 300 mL of the medium.

TEST CONDITIONS
- Composition of medium: 1 mL of the following nutrient stock solutions were added to ultrapure water with a final volume of 1 liter.
Stock solution a) Dissolved in and made up to 1000 mL ultrapure water: 8.5 g KH2PO4, 21.8 g K2HPO4, 33.4 g Na2HPO4.7H2O, 0.5 g NH4Cl and 100 g NaNO3. (pH 7.4 ± 0.1)
Stock solution b) Dissolved in and made up to 1000 mL ultrapure water: 22.5 g MgSO4.7H20
Stock solution c) Dissolved in and made up to 1000 mL ultrapure water: 36.4 g CaCL2.2H2O
Stock solution d) 0.25 g FeCl3.6H2O
To prevent nitrogen limitation, additional NaNO3 was added to the mineral medium.
- Test temperature: 20 ± 2 °C
- pH: 7.3-7.4
- pH adjusted: no
- Suspended solids concentration: 100 mg/L

TEST SYSTEM
- Number of culture flasks/concentration: 3 flasks containing test material and 3 flasks containing a blank filter.
- Measuring equipment: A Micro-Oxymax respirometer. The respirometer measured the percentage oxygen in the air of the respective flasks and calculated, based on the earlier measurement, the resulting oxygen consumption in a certain time period. Based on these values the oxygen consumption per flask was derived. Oxygen concentration was determined every 5 hours.

CONTROL AND BLANK SYSTEM
- Inoculum activity control: 3 flasks containing mineral medium only and 2 flasks containing 100 mg/L sodium acetate.
- Toxicity control: 2 flasks containing 100 mg/L of sodium acetate and 23.7 mg/L test material.

STATISTICAL METHODS: The oxygen consumption in each flask was calculated based on the respiration rate (mg O2/flask/hour). The oxygen consumption due to the test or control substance at each time was calculated by subtracting the mean cumulative oxygen consumption in the blanks from that in the flask under consideration. These crude values were then converted to values per mg substance (BOD). The percentage biodegradation of the test material was calculated as BOD/ThOD x 100.
Based on the empirical formula, the Theoretical Oxygen Demand (ThOD) without nitrification (ThODNH3) value of the test material was calculated to be 2.13 mg O2/mg. The degree of biodegradation was calculated with this ThODNH3 value, assuming a purity of 100 %.

Reference substance:

acetic acid, sodium salt

Test performance:

The pH of the test medium was fairly constant during the test with the final values in the range of 7.2-7.8 after 39 days incubation. The higher pH values were found in the activity and toxicity control vessels were CO2 production was highest.
The temperature during the test was recorded as between 20.1-22.3 °C.
On day 32, oxygen measurements were stopped for a short period to allow recalibration. In a later stage all data after day 31 were considered unreliable and were not reported. Between 661 and 675 h a data point was missing as it was out of range.
Very low negative values of oxygen consumption and high values that are not part of a peak are attributed to possible leakages of the system. These occurred mainly after 755 h and between 581 and 675 h and are related to a technical failure of the oxygen sensor, these results were therefore disregarded.

Parameter:

% degradation (O2 consumption)

Value:

1.5

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

1.9

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

1.9

Sampling time:

31 d

Details on results:

The average percent degradation of the test material after 28 days was approximately 2 % with a concentration of 23.7 mg/L. In two flasks, negligible biodegradation occurred, in the third approximately 8 % biodegradation was observed.
The oxygen consumption in the blanks (with and without filter) was 1.21 to 2.96 mg per flasks after 28 days incubation, equivalent to 4.0-9.9 mg/L.
- Figure 1 depicts the oxygen consumption in the control and test flasks over time.
- Figure 2 depicts the biological oxygen demand (BOD).
- Figure 3 depicts the percentage biodegradation based on the ThODNH3.

Results with reference substance:

>25 % biodegradation was observed in the toxicity controls, demonstrating the the test material is not toxic to the inoculum.
The reference substance was sufficiently degraded within 14 days of incubation (>60%).

Table 1: Results with test material

Time (days)	BOD mg O2/mg	Biodegradation ThODNH3%
14	1.4	1.7
28	1.8	2.1
31	1.7	2.0

 

Table 2: Results with control vessels

Time (days)	Inoculum blank (mg O2/flask)	Inoculum blank with filter (mg O2/flask)	Inoculum activity control		Toxicity control
			mg O2/flask	Biodegradation ThOD %^1	mg O2/flask	Biodegradation ThOD %^1
14	1.4	1.7	21.6	99	21.5	56.0
28	1.8	2.1	23.1	105	23.2	56.6
31	1.7	2.0	23.0	105	23.1	59.6
All values are expressed as the mean of all the replicates in that test series ^1Corrected for corresponding blank

 

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Under the conditions of the study the average percentage degradation of the test material after 28 days was approximately 2 %. In two of the three flasks containing the test material, no significant biodegradation was observed. In the third flask approximately 8 % biodegradation was observed. Furthermore the test material was not toxic to the inoculum.

Executive summary:

The ready biodegradability of the test material was assessed in a Manometric Respirometry test conducted in accordance with OECD guideline 301F and EU Method C.4 -D and to GLP. Under the conditions of the test, the test material degraded approximately 2 % within 28 days of incubation with activated sludge. Two of the flasks performed with the test material gave negligible oxygen consumption, whilst the third gave 8 % within 28 days. All controls performed as part of the study were demonstrated that the test system was operating correctly and the test material exhibited no toxic effect on the inoculum. All validity criteria of the guideline were met. Therefore, under the conditions of the study, the test material can be categorised as not readily biodegradable.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

other: Risk assessment

Adequacy of study:

supporting study

Study period:

Not reported

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Information is taken from the Human & Environmental Risk Assessment on ingredients of European household cleaning products draft report. The report contains information on the read across substance of a hydrolysis product of the registered substance, sodium laurate. However, the report refers to secondary data only and contains no information on materials and methods.

Principles of method if other than guideline:

No test guidelines or methods are mentioned in the report.

GLP compliance:

not specified

Duration of test (contact time):

5 d

Parameter followed for biodegradation estimation:

O2 consumption

Parameter:

BOD5

Value:

58 other: %

The BOD5 was reported to be 58%.

Validity criteria fulfilled:

not specified

Interpretation of results:

other: not readily biodegradable

Conclusions:

The BOD5 value was reported, from a secondary source, to be 58%.

Executive summary:

The Environmental Risk Assessment report included a BOD5 value for ready biodegradation. The value was reported as 58 %. No information is provided on materials and methods.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

July - September 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material:
16JSVA015
- Expiration date of the lot/batch:
14. September 2018
- Purity test date:
not state

RADIOLABELLING INFORMATION (if applicable)
not applicable

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material:
Room Temperature: (20 ± 5°C), keep container tightly closed, store under inert gas
- Stability under test conditions:
assumed stable


TREATMENT OF TEST MATERIAL PRIOR TO TESTING
none

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Specification
Activated sludge from a biologic sewage treatment plant was used. The chosen plant is
treating mostly domestic sewage.

Source
The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt)
sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf.
Date of collection: 02. Jun. 2017, batch no: 20170602.
Pre-Treatment
The sludge was filtrated, washed with tap water (2x), then washed with and re-suspended
in test medium. It was then aerated until use. The dry matter was determined as 4840 mg
suspended solids/L.

Duration of test (contact time):

ca. 28 d

Initial conc.:

>= 31.7 - <= 32.2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium:
The medium was freshly prepared (volumes were adapted to final volume needed in the
test).
Composition:
Solution a 10 mL
Solution b 1 mL
Solution c 1 mL
Solution d 1 mL
H2O demin. ad 1000 mL
Solution a
Potassium dihydrogen phosphate (KH2PO4) 8.5 g
Dipotassium hydrogen phosphate (K2HPO4) 21.75 g
Disodiumhydrogen phosphate dihydrate (Na2HPO4*2H2O) 33.4 g
Ammonium chloride (NH4Cl) 0.5 g
H2O demin. ad 1000 mL
The pH was 7.4.
Solution b
Calcium chloride (CaCl2) 27.5 g
H2O demin. ad 1000 mL
Solution c
Magnesium sulphate heptahydrate (MgSO4*7H2O) 22.5 g
H2O demin. ad 1000 mL
Solution d
Iron(III) chloride hexahydrate (FeCl3*6H2O) 0.25 g
Di-sodium-ethylene diaminetetraacetate dihydrate (Na2EDTA*2H2O) 0.4 g
H2O demin ad 1000 mL

- Additional substrate: none
- Solubilising agent (type and concentration if used): none
- Test temperature: 20.0 - 21.3 °C
- pH: 7.7 -7.9
- pH adjusted: no
- CEC (meq/100 g): not stated
- Aeration of dilution water: no
- Suspended solids concentration: not stated
- Continuous darkness: not stated
- Other:

TEST SYSTEM
- Culturing apparatus: 2000 mL-SCHOTT-flasks
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: The test vessels were aerated with purified (by activated charcoal), CO2-scrubbed, moistened
air. The scrubbing of carbon dioxide was achieved by bubbling the purified air
through a flask containing 1.5 M NaOH. To control the absence of CO2, the air was then
led through a flask containing a solution of Ba(OH)2 before reaching the test vessels.
- Method used to create anaerobic conditions: not applicable
- Measuring equipment: Data logger for temperature, Carbon analyser TOC multi N/C 2100S, pH-meter 3310 wtw
- Test performed in closed vessels due to significant volatility of test substance: no
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used: The emitted CO2 was trapped in 0.25 M NaOH. Two scrubbers containing 100 mL each
were connected in series to the test vessels. The initial IC value of the 0.25 M NaOH was
separately determined in each flask.
- Other:

SAMPLING
From each front scrubber flask, 9 samples were taken in order to determine the emitted
CO2 (on day 0, 2, 6, 8, 10, 14, 17, 23 and 29). The sample volume was 1 mL. The resulting
change in the volume of the front flask was considered in the calculation of emitted
CO2 (see also chapter 8.3.1).
On day 28, 5 mL HCl 2 M was added to each test flask in order to drive off dissolved CO2.
On day 29, samples from both scrubber flasks were taken.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: yes
- Other:

STATISTICAL METHODS: none applied

Reference substance:

aniline

Test performance:

Validity
Parameter Criterion Found Assessment
IC content of test item solution in medium <= 5% of TC 0 % valid
CO2 emitted by the controls < 70 mg/L 9.4 mg/L valid
Difference within replicates <= 20% 0.1 % valid
Degradation of positive control > 60% ≤ 14 days 8 days valid
Degradation in the toxicity flask on day 14 > 25% 50.8 % valid

Key result

Parameter:

% degradation (CO2 evolution)

Value:

>= 16.7 - <= 16.8

Sampling time:

29 d

Details on results:

- The test item Bis(neodecanoyloxy)dioctylstannane is considered as “not readily biodegradable“.
- The degree of biodegradation reached 17 % after 28 days.
- The 10-day-window was not detected.
- Therefore, regardless of the 10-day-window, the test item Bis(neodecanoyloxy)
dioctylstannane is considered as “not readily biodegradable within 28 days”.
- The abiotic degradation reached 0.3 %.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Bis(neodecanoyloxy)dioctylstannane is not readily biodegradable and not ultimately biodegradable following OECD 301B and EU
C.4-C respectively

Executive summary:

The test item Bis(neodecanoyloxy)dioctylstannane was tested using a concentration of

nominally 20 mg organic carbon/L (corresponding to 31.8 mg Bis(neodecanoyloxy)-

dioctylstannane/L) in test medium following OECD 301B and EU-Method C.4-C.

Aniline was chosen as positive control.

Activated sludge was used as inoculum (concentration in the test 25.0 mg dry matter/L).

The test was left running for 28 days.

All validity criteria were met. Degradation of the positive control was 68 % after 8 days.

The following data were determined for the test item Bis(neodecanoyloxy)dioctylstannane:

10-day-window: not detected

degradation at the end of 10-day-window none

degradation at the end of the test 17 %

pass level following guideline: 60 % at the end of 10-day-window for pure substances

respective 60 % at the end of the test for mixtures

Therefore, regardless of the 10-day-window, Bis(neodecanoyloxy)dioctylstannane is not

readily biodegradable and not ultimately biodegradable following OECD 301B and EU

C.4-C respectively.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Since no data are available on the substance itself information has been addressed on a weight of evidence basis, reading across to a product of its hydrolysis, dioctyltin oxide, and a structural analogue of another hydrolysis product, sodium laurate.

The ready biodegradability of dioctyltin oxide (Hanstveit, 2003) was assessed in a Manometric Respirometry test conducted in accordance with OECD guideline 301F and EU Method C.4 -D and to GLP. Under the conditions of the test, dioctyltin oxide degraded approximately 2 % within 28 days of incubation with activated sludge. Two of the flasks performed with the dioctyltin oxide gave negligible oxygen consumption, whilst the third gave 8 % within 28 days. Furthermore dioctyltin oxide exhibited no toxic effect on the inoculum. Therefore, under the conditions of the study, dioctyltin oxide can be categorised as not readily biodegradable.

The Environmental Risk Assessment report (2003) included a BOD5 value for ready biodegradation of sodium laurate. The value was reported as 58 %. Therefore, under the conditions of the study, sodium laurate can also be categorised as not readily biodegradable. The data was taken from a secondary source, and as such no information on materials and methods are available.