Reaction mass of 4,4'-Isopropylidenediphenol, oligomeric reaction products with 1-chloro-2,3-epoxypropane and Orthophosphoric acid, oligomeric reaction products with 4,4'-isopropylidenediphenol -1-chloro-2,3-epoxypropane co-oligomer

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

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
[Please provide information for all of the points below. Indicate if further information is included as attachment to the same record, or elsewhere in the dataset (insert links in 'Cross-reference' table)]

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
[Describe why the read-across can be performed (e.g. common functional group(s), common precursor(s)/breakdown product(s) or common mechanism(s) of action]

The read-across target substance EP-49-10P2 is composed of a mixture of phosphate esters with bisphenol A diglycidylether (BADGE, CAS 1675-54-3, EC 216-823-5) that is dissolved in BADGE. The amount of esters in the target substance EP-49-10P2 ranges between 10% and 20%; the large rest is BADGE. Therefore, BADGE can be used as read-across source substance.

Based on the high content of BADGE (80-90%) and on the fact that the phosphate esters have higher molecular weights (MW > 1200 Da – approx. 3500 Da) and accordingly lower bioavailability it is concluded that the toxic and eco-toxic potential of EP-49-10P2 will be the same as that of BADGE. With the phosphate esters no hazardous functional groups are introduced.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
[Provide here, if relevant, additional information to that included in the Test material section of the source and target records]

3. ANALOGUE APPROACH JUSTIFICATION
[Summarise here based on available experimental data how these results verify that the read-across is justified]

No experimental data from toxicological or eco-toxicological studies with the target substance EP-49-10P2 are available for comparison of effects. However, based on the composition of EP-49-10P2 it is considered justified to make read-across from study results obtained with the read-across source substance BADGE in order to fulfil the information requirements for REACH registration of EP-49-10P2.

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

5

Sampling time:

28 d

Parameter:

% degradation (test mat. analysis)

Value:

10

Sampling time:

7 d

Parameter:

% degradation (test mat. analysis)

Value:

37

Sampling time:

14 d

Parameter:

% degradation (test mat. analysis)

Value:

46

Sampling time:

21 d

Parameter:

% degradation (test mat. analysis)

Value:

82

Sampling time:

28 d

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Jan 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Principles of method if other than guideline:

Ready biodegradability was followed based on enhanced O2 consumption due when compared to a control without test material. In order to account for the poor water solubility , the test material was coated onto silica before adding to the reactors. Test material specific was performed at selected time points during the exposure and an attempt was made to identify metabolites.

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

A mixed population of sewage treatment micro-organisms was obtained on
21 January 2010 from the final effluent stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK, which treats predominantly domestic sewage.

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

other: coated to silica gel (50 mg/L)

Initial conc.:

33.2 mg/L

Based on:

COD

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation:

test mat. analysis

Reference substance:

aniline

Parameter:

% degradation (O2 consumption)

Value:

5

Sampling time:

28 d

Parameter:

% degradation (test mat. analysis)

Value:

10

Sampling time:

7 d

Parameter:

% degradation (test mat. analysis)

Value:

37

Sampling time:

14 d

Parameter:

% degradation (test mat. analysis)

Value:

46

Sampling time:

21 d

Parameter:

% degradation (test mat. analysis)

Value:

82

Sampling time:

28 d

Results with reference substance:

Aniline attained 98% degradation after 28 days, calculated from the results of the DOC analyses performed on Days 0 and 28. The degradation rate calculated from the results of the DOC analyses was higher than that calculated from oxygen consumption values. This is considered to be due to incorporation of the test material/aniline into the microbial biomass prior to degradation, and hence oxygen consumption, occurring.

Based on the chemical oxygen demand for the test material, the test material attained 5% degradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301F.

The compound specific analyses conducted on Day 0 using gas chromatography analysis showed the measured concentrations in the test material plus inoculum vessels to range from 87% to 90% of the nominal value.  In the abiotic test material vessels the measured concentrations ranged from 92% to 99% of the nominal value.  Examination of the chromatograms from Day 0 of the test period showed one peak attributable to the test material in all vessels containing the test material.

The compound specific analyses conducted on Day 28 showed measured concentrations in the test material plus inoculum vessels to range from 15% to 16% of nominal values.  Two new peaks in the chromatogram were identified as the mono-diol and di-diol of the test material using liquid chromatography mass spectrometry.  In the abiotic vessels the measured concentration of the test material was 9% of the nominal value with two additional peaks which were identified as the mono-diol and di-diol of the test material using liquid chromatography mass spectrometry.  

Although the results from chemical analysis on Day 28 indicated that there was an approximate 85% loss of test material from the inoculated test material vessels, this loss was considered not to be due to biological degradation as a similar loss was observed in the abiotic vessels. The two additional peaks shown in the chromatograms of the test material and abiotic control vessels analysed using liquid chromatography mass spectrometry on Day 28 confirmed that hydrolysis of the test material occurred over the test period.

The oxygen consumption values from the inoculated test material vessels confirmed no biological degradation of the test material occurred over the test period.

Table 1: BOD and Biodegradation Values

Sample Description		ThOD/COD (mg O2/l)	Day 7		Day 14		Day 28
			BOD (mg O2/l)	Degradation (%)	BOD (mg O2/l)	Degradation (%)	BOD (mg O2/l)	Degradation (%)	Mean Biodegradation (%)
Control	R1	-	7.24	-	12.82	-	27.04	-	-
	R2	-	7.38	-	13.62	-	31.24	-
Aniline		309	96.80	29	211.16	64	248.70	71	-
Test Material	R1	33.2	6.28	-3	12.74	-1	30.36	4	5
	R2	33.2	7.38	0	14.36	3	30.90	5
Toxicity Control		342.2	7.74	0	115.38	30	225.88	57	-
Abiotic Control	R1	33.2	2.34	-	3.88	-	6.82	-	-

R₁– R₂= Replicates 1 and 2

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

No biodegradation observed. However, significant hydrolysis occurred eliminating 82 % over 28 days.

Executive summary:

The material has been tested for biodegradation in an enhanced ready test following the OECD 301F (oxygen depletion) design. Enhancement consisted of coating the material to silica gel to address the low solubility and the high viscosity of the test material. For a series of similar materials (epoxydes), respiration rates in test vessels were significantly lower than in the controls. This is taken as a sign of inhibition of the inoculum that is more relevant than the toxicity control. Based on these findings, test material concentration was reduced to 20 mg/l. After 28 days of exposure, 5% of the test material has mineralised. Test material specific analysis revealed a substantial elimination of the diepoxide with the mono- and di-diol as relevant products formed. At termination of the study (day 28) 18% of the initial measured concentration could be recovered. The same elimination was observed in the inhibited reactions mixtures (sodium azide) indicating that this is not due to a biological process (Harlan, 2010). The pseudo first order rate of elimination in activated sludge at 20 °C is - 0.0565 [1/d].

Description of key information

Biodegradation in water: screening tests: biodegradation 5% (O2 consumption) in 28 days (OECD 301F)

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater