Phosphoric acid, butyl ester, branched, compd. with 2-ethyl-N-(2-ethylhexyl)-1-hexanamine

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

04 Jul - 03 Aug 2012

Reliability:

2 (reliable with restrictions)

Cross-reference

Reason / purpose for cross-reference:

read-across source

Remarks:

link to target

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

weight of evidence

Study period:

04 Jul - 03 Aug 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

read-across

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The present analogue approach contemplates Phosphoric acid, butyl ester, branched, compd. with 2-ethyl-N-(2-ethylhexyl)-1-hexanamine (CAS 98679-19-7) as target substance for read across from the source substance Amines, C12-14-tert-alkyl, mixed sec-Bu and iso-Bu phosphates (CAS 96690-34-5). The read-across approach is used to evaluate the hazardous potential of the target substance with respect to ecotoxicological endpoints and human health for REACH Annex VII.
Based on similar chemical structures, read-across based on different compounds having the same type of effect(s) as described in scenario 2 of the Read-Across Assessment Framework document can be used as a basis for assessment.
The target substance (Phosphoric acid, butyl ester, branched, compd. with 2-ethyl-N-(2-ethylhexyl)-1-hexanamine) and the source substance (Amines, C12-14-tert-alkyl, mixed sec-Bu and iso-Bu phosphates) are both organic UVCB substances.
In consequence, read-across can be justified due to the high structural similarities as well as common properties, which will be outlined in detail below.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

Source: Amines, C12-14-tert-alkyl, mixed sec-Bu and iso-Bu phosphates (EC 306-227-4, CAS 96690-34-5)
The substance is manufactured from the educts phosphorus pentoxide (CAS 1314-56-3, EC 215-236-1), 2-butanol (CAS 78-92-2, EC 201-158-5), iso-butanol (CAS 78-83-1, EC 201-148-0) and Amines, C12-14-tert-alkyl (CAS 68955-53-3, EC 273-279-1).

Target: Phosphoric acid, butyl ester, branched, compd. with 2-ethyl-N-(2-ethylhexyl)-1-hexanamine (EC 308-859-6, CAS 98679-19-7)
The substance is manufactured from the educts phosphor pentoxide (CAS 1314-56-3, EC 215-236-1), 2-butanol (CAS 78-92-2, EC 201-158-5), iso-butanol (CAS 78-83-1, EC 201-148-0) and bis(2-ethylhexyl)amine (CAS 106-20-7, EC 203-372-4)

Both substances do not contain any impurities which may impact the feasibility of read-across.

3. ANALOGUE APPROACH JUSTIFICATION
Both substances are organic UVCBs and are manufactured from the educts phosphorus pentoxide (CAS 1314-56-3, EC 215-236-1), 2-butanol (CAS 78-92-2, EC 201-158-5), iso-butanol (CAS 78-83-1, EC 201-148-0) in similar ratios, the only slight difference is the amine part. In the source chemical, Amines, C12-14-tert-alkyl is used, and in the target bis(2-ethylhexyl)amine.
So, the reaction products have a similar distribution pattern with regard to varied alkyl phosphate species (mainly dialkyl phosphates). Both used amines have similar molecular weights, i.e. 185.35-213.41 g/mol (CAS 68955-53-3) and 241.46 g/mol (CAS 106-20-7), which are hence not expected to alter their toxicokinetic behaviour essentially. The fact that one amine is mono-substituted and the other di-substituted, is also not considered to impact the suitability for read-across, as amines are considered to be rather stable functional groups, e.g. hydrolytically stable, and are not considered to be altered to a relevant extent in the body. Both amines are not covalently bound to the phosphates, so they are expected to dissociate into similar dissociation products, too.
Last but not least, both substances show similar physico-chemical properties. They are both liquid at all relevant handling temperatures, both are characterized by negative glass transition temperatures they do not boil but decompose, have similar densities and low vapour pressures indicating that they are no volatile liquids. They have both logPow values and water solubilities which, despite slight variations, are not expected to alter essentially their uptake and distribution through the body.
As there is not sufficient data on both source and target substance available, and the amine is considered to be the main difference and also not covalently bound to the phosphates, data on human health relevant endpoints is retrieved from publically available data sources, i.e. ACToR (https://actor.epa.gov/actor/searchidentifier.xhtml) and RTECS (http://ccinfoweb.ccohs.ca/rtecs/search.html). Further, ecotoxicological properties were estimated via US EPA EpiSuite ECOSAR Class Program v1.11.
Data indicate that both amines produce severe irritating reactions when applied into the eye or onto the skin. Further, the acute dermal toxicity LD50 values are nearly identical in the rabbit (acute tox. Cat. 4), and when applied orally, the available LD50 values similarly indicate that a classification as acute toxic Cat. 4 is triggered. With regard to ecotoxicological properties, the estimated values slightly differ. However, they consistently trigger the same classification, as both substances are not biodegradable; the source chemical is not, so the same can be applied to the amines.
So in consequence, taking into account the similar manufacturing process, i.e. identical and similar educts, and so similar reaction products, similar physico-chemical properties of the source and target chemical and similar (eco)toxicological properties of the source and target amines, the read-across from Amines, C12-14-tert-alkyl, mixed sec-Bu and iso-Bu phosphates to Phosphoric acid, butyl ester, branched, compd. with 2-ethyl-N-(2-ethylhexyl)-1-hexanamine is scientifically justified.

4. DATA MATRIX

Table: Data Matrix, source and target chemical
Endpoint Source: CAS 96690-34-5 Target: CAS 98679-19-7
Physical state at 20°C, 1013 hPa liquid liquid
Glass transition temperature -44.95 °C -72.1 °C (onset)
Decomposition 243.36 °C 167.1°C (onset)
Density 0.97 g/cm³ 0.968 g/cm³
Vapour pressure ≤ 54 Pa at 20°C < 6.7 Pa at 20°C
logPow ≥ 0.69 - ≤ 5.6 (estimated) - 0.61 at 23°C
Water solubility 1322 mg/L at 25 °C and pH 3.57 17.14 g/l at 20°C
Surface tension 42.9 mN/m at 20°C and 0.66g/l 37.8 mN/m ≤ST ≤ 41.2 mN/m at 20°C and 1g/l
Flash point 1 35°C at 101.325 kPa 107.5°C at 101.3 kPa

Table: Data Matrix, source and target amine
Endpoint Source amine: CAS 68955-53-3 Target: CAS 106-20-7
Acute oral toxicity LD50 = 552 mg/kg (m/f mice, 470 - 719 mg/kg) (ACToR) LD50 = 800µL/kg (mouse, intraperitoneal) (ACToR, RTECS)
LD50 = 320 mg/kg (male rats) (ACToR; RTECS) LD50 = 1640mg/kg (rat) (ACToR, RTECS)
LD50 = 300 mg/kg (rat) (RTECS)
Acute dermal toxicity LD50 = 251 mg/kg (m/f rats, 190 - 322 mg/kg) (ACToR) LD50 = 1190uL/kg (rabbit) (ACToR, RTECS)
LD50 = 1.12 g/kg (rabbits, 0.83 - 1.51) (ACToR, RTECS)
Acute toxicity inhalation LC50 = 157 ppm (female rats, 1.19 mg/L; 90 - 249 ppm) (ACToR, RTECS)
LC50 > 231 ppm (male rats, 1.75 mg/L) (ACToR, RTECS) No data
LC50 > 940 mg/m³/4h (rats) (RTECS)
Skin irritation Severe reaction (rabbit, Draize test) (RTECS) Severe reaction (rabbit, Draize test) (RTECS)
Severe reaction (rabbit, open irritation test) (RTECS)
Mild reaction (rabbit, open irritation test) (RTECS)
Eye irritation Severe reaction (rabbit, Draize test) (RTECS) Severe reaction (rabbit, Draize test) (RTECS)
Genetic Toxicity No data Negative ±S9 (Ames test) (ACToR)
Fish 96-hr LC50 0.644 mg/L* 0.047 mg/L*
0.632 mg/L** 0.016 mg/L**
Daphnid 48-hr LC50 0.104 mg/L* 0.010 mg/L*
0.458 mg/L** 0.014 mg/L**
Green Algae 96-hr EC50 0.047 mg/L* 0.003 mg/L*
0.939 mg/L** 0.059 mg/L**
Fish ChV 0.015 mg/L* 0.000546 mg/L*
0.082 mg/L** 0.003 mg/L**
Daphnid ChV 0.012 mg/L* 0.00131 mg/L*
0.088 mg/L** 0.004 mg/L**
Green Algae ChV 0.019 mg/L* 0.00134 mg/L*
0.424 mg/L** 0.039 mg/L**
* Aliphatic Amines
** Neutral Organic SAR (Baseline Toxicity)

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Energie, Landwirtschaft und Verbraucherschutz, Wiesbaden, Germany

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: activated sludge from the sewage plant at Taunusstein-Bleidenstadt
- Pretreatment: The sludge was washed twice with mineral nutrient solution and aerated for four hours. Sludge was homogenized in a “Warning Blender”, filtered and rinsed with deionized water. Filtrate was used as inoculum.
- Concentration of sludge: 35 mL
- Type and size of filter used, if any: cotton filter

Duration of test (contact time):

28 d

Initial conc.:

66.2 mg/L

Based on:

test mat.

Remarks:

11 mg C/L

Initial conc.:

62.9 mg/L

Based on:

test mat.

Remarks:

10 mg C/L

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Test temperature: 20.6 to 26.3 °C (mean 22.1 °C)
- Aeration of dilution water: The aeration rate of the lest system was controlled at 4 L/h being assured by precise flowmeters

TEST SYSTEM
- Culturing apparatus: 5 litre amber carboys, closed with stoppers with tubing for gas inlet and outlet
- Method used to create aerobic conditions: mineral nutrient solution was aerated for 24 h with CO2 free compressed air
- Measuring equipment: Resting Ba(OH)2 (0.025 N) in the CO2 trap removed from the trap system was titrated with HCI (0.05 N) using phenolphthalein as an indicator. Each millilitre HCI of difference between the blank control and the test series with the test item titrated corresponds to 1.1 mg of CO2 produced (as indicated in the OECD Test Guideline 301 B). For this purpose values of titration for the 'Blank' (mean values of two parallel Blank solutions) were subtracted (CO2 production by the inoculum) from that of the test unit with the test item.
- Details of trap for CO2 and volatile organics if used: CO2 released from the test item was trapped as BaCO3 using a trap system according to the guideline. Gas outlet was connected to three CO2 absorber bottles filled with 100 mL 0.025 N Ba(OH)2 and bubbling of CO2 free compressed air through the solution was continued.

SAMPLING
- Sampling frequency: On the 4th, 7th, 12th, 18th, 25st, 28th and 29th day
- Sampling method: Periodically the CO2 absorber nearest the test vessel was removed for analysis and a new CO2 absorber was connected farest carboy. Precipitation of BaCO3 in the second CO2 trap indicated that the absorber bottle nearest the test vessel had be changed any analyzed for CO2.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (2 replicates)
- Toxicity control: yes (1 replicate)
- Reference control: yes (1 replicate)

STATISTICAL METHODS: no

Reference substance:

benzoic acid, sodium salt

Remarks:

20 mg C/L

Key result

Parameter:

% degradation (CO2 evolution)

Value:

16

Sampling time:

28 d

Remarks on result:

other: 1st Test solution (11 mg TOC/L)

Key result

Parameter:

% degradation (CO2 evolution)

Value:

16

Sampling time:

28 d

Remarks on result:

other: 2nd Test solution (10 mg TOC/L)

Parameter:

% degradation (CO2 evolution)

Value:

83

Sampling time:

28 d

Remarks on result:

other: Functional control (sodium benzoate)

Parameter:

% degradation (CO2 evolution)

Value:

56

Sampling time:

28 d

Remarks on result:

other: Toxicity control (test item + sodium benzoate)

Results with reference substance:

From the results of the toxicity control it is assumed that there is no toxicity towards the microorganisms.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Energie, Landwirtschaft und Verbraucherschutz, Wiesbaden, Germany

Test material

Test material information

Constituent 1

Reference substance name:

Amines, C12-14-tert-alkyl, mixed sec-Bu and iso-Bu phosphates

EC Number:

306-227-4

EC Name:

Amines, C12-14-tert-alkyl, mixed sec-Bu and iso-Bu phosphates

Cas Number:

96690-34-5

Molecular formula:

C4H11O4P to C8H20O7P2 as representative molecular formula of the composition as specified in section 1.2

IUPAC Name:

Amines, C12-14-tert-alkyl, mixed sec-Bu and iso-Bu phosphates

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): EC 306-227-4; CAS 96690-34-5; Amines, C12-14- tert-alkyl, mixed sec-Bu and iso-Bu phosphates
- Physical state: Light yellow liquid with a characteristic odour
- Analytical purity: no applicable (UVCB)
- Lot/batch No.: 0900215946
- Storage condition of test material: At room temperature in a tightly closed vessel 100% (UVCB)

Specific details on test material used for the study:

Physical state at 20°C, 1013 hPa: liquid
Glass transition temperature: -44.95 °C
Decomposition: 243.36 °C
Density: 0.97 g/cm³
Vapour pressure: ≤ 54 Pa at 20°C
log Pow: ≥ 0.69 - ≤ 5.6 (estimated)
Water solubility: 1322 mg/L at 25 °C and pH 3.57
Surface tension: 42.9 mN/m at 20°C and 0.66g/l
Flash point: 135°C

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: activated sludge from the sewage plant at Taunusstein-Bleidenstadt
- Pretreatment: The sludge was washed twice with mineral nutrient solution and aerated for four hours. Sludge was homogenized in a “Warning Blender”, filtered and rinsed with deionized water. Filtrate was used as inoculum.
- Concentration of sludge: 35 mL
- Type and size of filter used, if any: cotton filter

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

66.2 mg/L

Based on:

test mat.

Remarks:

11 mg C/L

Initial test substance concentration 2

Initial conc.:

62.9 mg/L

Based on:

test mat.

Remarks:

10 mg C/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Test temperature: 20.6 to 26.3 °C (mean 22.1 °C)
- Aeration of dilution water: The aeration rate of the lest system was controlled at 4 L/h being assured by precise flowmeters

TEST SYSTEM
- Culturing apparatus: 5 litre amber carboys, closed with stoppers with tubing for gas inlet and outlet
- Method used to create aerobic conditions: mineral nutrient solution was aerated for 24 h with CO2 free compressed air
- Measuring equipment: Resting Ba(OH)2 (0.025 N) in the CO2 trap removed from the trap system was titrated with HCI (0.05 N) using phenolphthalein as an indicator. Each millilitre HCI of difference between the blank control and the test series with the test item titrated corresponds to 1.1 mg of CO2 produced (as indicated in the OECD Test Guideline 301 B). For this purpose values of titration for the 'Blank' (mean values of two parallel Blank solutions) were subtracted (CO2 production by the inoculum) from that of the test unit with the test item.
- Details of trap for CO2 and volatile organics if used:CO2 released from the test item was trapped as BaCO3 using a trap system according to the guideline. Gas outlet was connected to three CO2 absorber bottles filled with 100 mL 0.025 N Ba(OH)2 and bubbling of CO2 free compressed air through the solution was continued.

SAMPLING
- Sampling frequency: On the 4th, 7th, 12th, 18th, 25st, 28th and 29th day
- Sampling method: Periodically the CO2 absorber nearest the test vessel was removed for analysis and a new CO2 absorber was connected farest carboy. Precipitation of BaCO3 in the second CO2 trap indicated that the absorber bottle nearest the test vessel had be changed any analyzed for CO2.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (2 replicates)
- Toxicity control: yes (1 replicate)
- Reference control: yes (1 replicate)

STATISTICAL METHODS: no

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

20 mg C/L

Results and discussion

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (CO2 evolution)

Value:

16

Sampling time:

28 d

Remarks on result:

other: 1st Test solution (11 mg TOC/L)

% Degradation 2

Key result

Parameter:

% degradation (CO2 evolution)

Value:

16

Sampling time:

28 d

Remarks on result:

other: 2nd Test solution (10 mg TOC/L)

% Degradation 3

Parameter:

% degradation (CO2 evolution)

Value:

83

Sampling time:

28 d

Remarks on result:

other: Functional control (sodium benzoate)

% Degradation 4

Parameter:

% degradation (CO2 evolution)

Value:

56

Sampling time:

28 d

Remarks on result:

other: Toxicity control (test item + sodium benzoate)

BOD5 / COD results

Results with reference substance:

From the results of the toxicity control it is assumed that there is no toxicity towards the microorganisms.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable