Reaction mass of 3-O-acetyl-1,5-anhydro-4-butyl-2,4-dideoxy-2-methyl-D-xylitol and (2R,3S)-2-methyloctane-1,3-diyl diacetate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: read-across from a guideline study

Justification for type of information:

The read-across justification is presented in the Endpoint summary Biodegradation in water. The accompanying files are also attached there.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

71

Sampling time:

28 d

Remarks on result:

other: read-across from Jasmal

Interpretation of results:

readily biodegradable

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 March 1999 - 12 April 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

This information is used for read-across to Jessemal.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(1992)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of activated sludge: a biological waste water treatment plant treating predominantly domestic sewage (City of Geneva, Aire, Switzerland)
- Preparation of inoculum for exposure: sludge was collected in the morning, washed three times in mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernatant and resuspending in mineral medium); kept aerobic until being used on the same day
- Concentration of sludge (suspended solids): 3.386 g/L

Duration of test (contact time):

32 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: According to Guideline 301 F. Water used to prepare the medium contained less than 10 mg/L of dissolved organic carbon.
- Test temperature: 22°C
- pH: at t=0 d: 7.42, at test end (t=32 d): 7.42-8.08
- pH adjusted: no
- Suspended solids concentration: 30 mg/L (dry weight)
- Continuous darkness: not reported

TEST SYSTEM
- Culturing apparatus: Water bath of the SAPROMAT D 12 respirometer
- Number of culture flasks/concentration: 2
- Measuring equipment: SAPROMAT D 12 (J.M. VOITH GmbH, D-7920, Heidenheim, Germany)
- Test performed in closed vessels: yes
- Details of trap for CO2: Soda lime (approx. 2g) was placed in an attachment of the stopper

SAMPLING
- Sampling frequency: Oxygen consumption of each flask was measured daily
- pH was measured at test initiation (in mineral medium) and at test end (after 32 days, in each flask)

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: no
- Toxicity control: yes

Reference substance:

benzoic acid, sodium salt

Remarks:

purity: min. 99.0%

Parameter:

% degradation (O2 consumption)

Value:

18

Sampling time:

2 d

Parameter:

% degradation (O2 consumption)

Value:

29

Sampling time:

5 d

Parameter:

% degradation (O2 consumption)

Value:

38

Sampling time:

12 d

Parameter:

% degradation (O2 consumption)

Value:

49

Sampling time:

21 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

71

Sampling time:

28 d

Remarks on result:

other: 76% degradation after 32 days (end of test period)

Details on results:

Based on the percent degradation of sodium benzoate when tested in combination with the test substance (toxicity control), it is concluded that the test substance is not toxic to microorganisms at a concentration of 100 mg/L (>25% degradation based on ThOD).

- Validity criteria:
1. Not more than 20% difference between replicates of the flasks containing the test substance was reported.
2. The percentage degradation of the reference substance was 85% after 14 days.
3. In the toxicity control, >25% degradation occurred within 14 days, thus the test substance was not toxic to microorganisms at a test concentration of 100 mg/L.
4. Oxygen consumption of the inoculum blank was not greater than 60 mg/L in 28 days (22.0 mg O2/L).

Results with reference substance:

- Sodium benzoate (ThOD is 1.67 mg O2/mg): 71% degradation after 7 days and 85% after 14 days was achieved. Therefore, validity criteria was met.

Biodegradation of the test substance appears to take place in phases; a first biodegradation steps starts immediately and reaches 43% on day 18. Then, a second step starts and reaches 76% at the end of the test (32 days). Similar behaviour is observed in the toxicity control flasks. See graphs under 'Attached background material'.

In view of the > 70 % biodegradation in a test with strictly controlled conditions it can be assumed that the substance is readily biodegradable despite failing the 10-day window. This conclusion is motivated by using the criterion in CLP (2011, http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2011:083:FULL:EN:PDF), section 4.1.9.2.5 b). Here it is presented that if a substance is a multi-constituent the 10-day window does not need to be considered for ready biodegradability.

Validity criteria fulfilled:

yes

Remarks:

85% biodegradation of reference substance after 14 days; oxygen uptake of incoulum blank is <60 mg/L in 28 days; not more than 20% difference between replicates of the flasks containing the test substance

Interpretation of results:

readily biodegradable

Conclusions:

The substance showed 71% biodegradation after 28-days and 76% biodegradation after 32 days in an OECD TG 301F test.

Executive summary:

The ready biodegradability of the substance was investigated in a study conducted in accordance with OECD TG 301 F (1992, Manometric Respirometry) and GLP. The concentration tested was 100 mg/l test substance, with an activated sludge concentration of 30 mg/L. The test substance biodegraded for 71% after 28 -days and 76% after 32 days and it was not toxic to the inoculum. In view of the pass level of > 70% after 28 -days and the substance is a multi-constituent the substance is considered to be readily biodegradable.

Description of key information

Jessemal is readily biodegradable based on read-across from Jasmal, which is readily biodegradable in a study according to OECD TG 301F.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

Biodegradability in water is assessed based on read-across from Jasmal to Jessemal. The executive summary of the source information is presented below, followed by the read-across rationale.

Jasmal and its ready biodegradability

The ready biodegradability of the substance was investigated in a study conducted in accordance with OECD TG 301 F (1992, Manometric Respirometry) and GLP. The concentration tested was 100 mg/l test substance, with an activated sludge concentration of 30 mg/L. The test substance biodegraded for 71% after 28 -days and 76% after 32 days and it was not toxic to the inoculum. In view of the pass level of > 70% after 28 -days, and the substance is a multi-constituent, the substance is considered to be readily biodegradable.

Biodegradation of Jessemal based on read across from data available for Jasmal (CAS# 18871-14-2).

 

Introduction and hypothesis for the analogue approach

For the multi-constituent substance Jessemal all constituents > 1% are identified. The substance consists mainly of two sub-groups of constituents, Tetrahydropyran acetate -like constituents, and Branched alkyl diacetates-type.For Jessemal no experimentalbiodegradation data are available.In accordance with Article 13 of REACH, lacking information can be generated by means other than experimental testing, i.e. applying alternative methods such as, QSARs, grouping and read-across.For assessing the ready biodegradability of Jessemal, the analogue approach is selected because for one of the constituents, Jasmal, ready biodegradation information is available which can be used for read across.

Hypothesis: Jessemal has the same ready biodegradability potential as Jasmal.

Available information: For Jasmal ready biodegradation study was performed according to OECD TG 301F (Rel. 1, Manometric Respirometry Test under GLP). In this study, Jasmal was biodegraded by 71% at day 28.

Target chemical and source chemical(s)

Chemical structures of the target chemical and the source chemical(s) are shown in the data matrix, including physico-chemical properties.

Purity / Impurities

The major and minor constituents of Jessemal are presented in the Data matrix. The impurities < 10% are grouped based on their resemblance with Tetrahydropyran acetate -like constituents, and Branched alkyl diacetates-type.

Analogue approach justification

According to Annex XI 1.5 read across can be used to replace testing when the similarity can be based on a common backbone and a common functional group. When using read across the result derived should be applicable for C&L and/or risk assessment and it should be presented with adequate and reliable documentation, which is presented below.

Analogue selection:For Jessemal the substance Jasmal was selected as source chemical for read-across becauseJessemal‘sconstituents arethe same and/orvery similar to Jasmal’sand for Jasmal experimental biodegradation information is available.

Structural similarities and differences:Jessemal andJasmal are both reaction masses containing similar Tetrahydropyran acetate-like constituents with molecular weight of 214. Jessemal also contains constituent of Branched alkyl diacetates with molecular weights of 244. These diacetates have one additional acetic ester and have an open ring structure not present in Jasmal. Jessemal hastwo minor impurities just exceeding the 1% level, one being the alcohol derivative of the Tetrahydropyran acetates and the other one of the Branched alkyl diacetates, which will not be addressed further being only very minor constituents.

Bioavailability: The bioavailability of Jessemal and Jasmal is very similar based on similarities in log Kows.

Biodegradability fragments: The Tetrahydropyran acetates have a slightly lower probability of biodegradation due to the ring structure compared to the Branched alkyl diacetates as predicted by BIOWIN 5 and 6. The Tetrahydropyran type has biodegradation probabilities of ca. 0.65 and 0.53, respectively, while the Branched alkyl type has values of ca. 0.82 and 0.9, respectively. Both types exceed the 0.5 probability and present therefore ready biodegradability.

Uncertainty of the prediction: There are no uncertainties other than those addressed above.

Data matrix

The relevant information on physico-chemical properties and environmental fate characteristics are presented in the data matrix below.

Conclusions on biodegradationfor hazard and risk assessment

For Jessemal no experimental biodegradation information is available. Read-across from Jasmal is used to fill this data gap. When using read-across, the result derived should be applicable for C&L and/or risk assessment, and be presented with adequate and reliable documentation. This documentation is presented in the current text. Jasmal is readily biodegradable in a ready biodegradation study (OECD TG 301F, Rel. 1). This information can be used for read across to Jessemal.

Final conclusion: Jessemal is readily biodegradable.

Data matrix to support the read across for Jessemal from Jasmal for biodegradability

Names	Jessemal	Tetrahydro-pyran acetates	Jasmal + 3 other similar const.	Branched alkyl diacetates	Other branched alkyl diacetates (4 impurities)
Read-across	Target	Target Major constituent	Source (and impurity)	Target Minor constituent:	Target Impurities
Chemical structures	Not applicable
Typical conc. (%)	Not applicable	20-40	<23	10-20	<22
CAS #	Not applicable	38285-49-3	18871-14-2	67634-09-7	--
Einecs	945-946-3		242-640-5
MW	Not applicable	214	214	244	244
Phys-chem*
Log Kow	3.5# (exp.)	3.2 (est.)	3.2 - 3.7 (exp.)	3.7 (est.)	3.7 (est.)
Ws (mg/L)	714.1 (exp.)	67.8 (est.)	214.9 (exp.)	17.8 (est.)	17.8 (est.)
Environmental fate
Ready biodegradability	Readily biodegradable (Read across)	Readily biodegradable (Read across)	Readily biodegradable (OECD TG 301F)	Readily biodegradable (Read across)	Readily biodegradable (Read across)

*EpiSuite calculation where needed; # The log Kow relate to the major constituent is presented, the full range is 3.5 to 4.2.