4-(1,1,3,3-tetramethylbutyl)phenol

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

unknown

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study meets generally accepted scientific standards, is well documented and acceptable for assessment. However, information regarding acclimation period and conditions is missing.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 305 (Bioconcentration: Flow-through Fish Test)

Deviations:

yes

Remarks:

tested only one concentration

GLP compliance:

no

Radiolabelling:

no

Details on sampling:

Samples (water and fish) were collected and analyzed at test initiation, 6, 12, 24, 48, 72, 120, and 168 h

Vehicle:

yes

Details on preparation of test solutions, spiked fish food or sediment:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 400 ug/L stock solution prepared by diluting ethanol solutions of 1000 µg/ml OP with dechlorinated tap
- Controls: solvent control
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): ethanol
- Concentration of vehicle in test medium (stock solution and final test solution(s) at different concentrations and in control(s)): not given

Test organisms (species):

Oryzias latipes

Details on test organisms:

TEST ORGANISM
- Common name: killifish
- Source: local pet shop
- Length at study initiation (lenght definition, mean, range and SD): 2.2-2.7 cm
- Weight at study initiation (mean and range, SD): 0.16-0.24 g
- Health status: NP or OP was not detected in fish before test initiation
- Feeding during test: not noted
- Food type: commercial assorted feed, Tetra Min
- Amount: 2.0 mg/fish
- Frequency: daily

ACCLIMATION
- Acclimation period: not provided
Fish did not show any signs of lethargy or agitation during the test

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

168 h

Total depuration duration:

24 h

Hardness:

44-46 mg/L as CaCO3

Test temperature:

19+/- 1 °C

pH:

6.9-7.0 s.u.

Dissolved oxygen:

8.2-8.4 mg/L

TOC:

not provided

Salinity:

NA

Details on test conditions:

TEST SYSTEM
- Test vessel: glass tanks
- Material, size, headspace, fill volume: 10 L for accumulation phase, 5 L for depuration phase
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): not given
- Renewal rate of test solution (frequency/flow rate): 6.0 L/h
- No. of organisms per vessel: 250
- No. of vessels per concentration (replicates): not given
- No. of vessels per control / vehicle control (replicates): not given


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dechlorinated tap
- Intervals of water quality measurement: daily for pH and after 72 h for DO and hardness


RANGE-FINDING / PRELIMINARY STUDY
- Results used to determine the conditions for the definitive study: 48 h LC50 to carp and 96 h LC50 for salmon used to estimate test concentration

Nominal and measured concentrations:

Average measured 4.7+/- 0.8 µg/L

Details on estimation of bioconcentration:

BCF was not estimated prior to testing
BCF was calculated based on actual measurements from test

Lipid content:

2.2 %

Time point:

start of exposure

Remarks on result:

other: sample size n=3

Type:

BCF

Value:

261 dimensionless

Basis:

whole body w.w.

Time of plateau:

48 h

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:4.7 ug/L

Elimination:

yes

Parameter:

other:

Depuration time (DT):

24 h

Details on kinetic parameters:

- Uptake rate constant (k1): not provided
- Depuration (loss) rate constant (k2):0.09, half-life 7.7h

Metabolites:

not provided

Results with reference substance (positive control):

NA

Details on results:

Study does not give control survival but states no lethargy or agitation during accumulation and excretion phases seen during test

Reported statistics:

not reported

Summary of BCF Measurements

4 -OP	6 h	12 h	24 h	48 h	72 h	120 h	168 h	BCF ww	BCF dw
	38	63	128	271	326	158	287	261 +/-62	1184 +/-284

Validity criteria fulfilled:

not specified

Conclusions:

Study authors conclude that estimation of log BCF in field fish by lab log BCF can be performed for organic chemicals with the same range of logPow.

Executive summary:

The 7-day chronic toxicity and bioconcentration of octylphenol to Orysias latipes was studied under flow-through conditions in a laboratory. Juvenile fish were exposed to a control concentration of 0 mg octylphenol/L and chemical test average measured concentration of 4.7 ug octylphenol/L for 7 days.  Fish whole body tissue and water column concentrations were measured at hrs 0, 6, 12, 24, 48, 72, 120, and168 h for mean BCF determination. Steady state was reached at 48 h. Depuration stage was for 24 h.

 

This study is classified as acceptable and satisfies the guideline requirements for a bioconcentration test with Orysias latipes.

 

Results Synopsis

 

Mean BCF based on whole body tissue wet weight = 261 (adjusted for lipid content 2.2% and water content 78%)

 

This study was selected as a key study because it provides bioconcentration information on a common test organism Oryzias latipes to octylphenol.There were no other reliable octylphenol bioconcentration data available for fish. Results of this test are in agreement with experimental bionconcentration results with nonylphenol.

Reference 2

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

In accordance with Regulation (EC) 1907/2006 Annex XI (1.5) and the relevant ECHA guidance documents, the substances detailed in the table below are grouped for the purposes of read across to reduce the need for unnecessary repeat testing on the basis that the substances are similar on the basis of a common functional groups.

Reason / purpose for cross-reference:

read-across source

Type:

BCF

Value:

740 dimensionless

Basis:

whole body w.w.

Time of plateau:

14 d

Calculation basis:

steady state

Remarks on result:

other: steady state reached somewhere between day 14 and day 28

Details on kinetic parameters:

No uptake rate constant or depuration constant determined

Details on results:

Significant mortality seen in highest test concentration

Reported statistics:

none

Day 28 BCF calculation

Concentration (ug/L)	Mean Wet Fish Weight (g)	Mean Tissue Conc. (ug/g)	Mean BCF	Comments
0	0.448	BDL	'-
9.3	0.39	7.16	769	steady state not reached
19.2	0.327	18.9	984	steady state not reached
38.1	0.374	33.4	876	steady state reached
77.5	0.266	46.7	603	steady state reached
193	.206	91	472	mortalities occurred in this concentration

Final BCF = average of 876 and 603 = 740

Paper states average 28 day BCF = 741, but this included averaging results for concentration which had significant mortalities. USEPA Guidance states that concentrations proving lethal should not be used for BCF determination.

Chronic NOEC = 77.5 ug/L LOEC = 193 ug/L

Conclusions:

The read across for 4-tert-octylphenol (CAS: 140-66-9); is based upon the analogous substances to which basic form, degree of substitution of functional groups is not considered to effect the proposed read across for the endpoint of bioaccumulation aquatic/sediment. Based on the information available for the read across substances, the substance is not anticipated to be bioaccumulative.

Reference 3

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

unknown

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study generally meets accepted scientific standards, is well documented and acceptable for assessment. Study does not contain a depuration stage during the chronic test and did not measure lipid %. Although ASTM methods were followed, there is no indication that the study was performed according to GLP.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: ASTM 1993. Standard Practice for Conducting Bioconcentration Tests with fishes and Saltwater Bivalve Mollluscs. E1022-84 (Reapproved 1988)

Qualifier:

according to guideline

Guideline:

other: USEPA (no method number provided)

GLP compliance:

not specified

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms: 8 fish sampled at test initiation, day 14 and day 28 all concentrations

Day 0 fish were weighed and frozen in aluminium foil. All other fish were stored in iso-octane or hexane. On day 14, the Day 0 fish were transferred from aluminium foil and preserved in iso-octane.

- Sampling intervals/frequency for test medium samples: at 4 h from test initiation, three times a week in all treatment levels.

For at least 20% of samples, duplicate samples were collected; at least 10% of samples were spiked. Duplicate agreement was > 87.4% and spike recovery was > 93.0%. Total and dissolved measurements were made at least twice during the test. Measurement of nonylphenol was performed by using HPLC. Disposable glass pipettes were used to collect media samples from center of test chambers. Samples were injected directly into HPLC on day of collection.

Vehicle:

no

Details on preparation of test solutions, spiked fish food or sediment:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: liquid: liquid equilibration system
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): none
- Evidence of undissolved material (e.g. precipitate, surface film, etc): none as total and dissolved NP were "essentially" the same.

Test contained control treatment

Test organisms (species):

Pimephales promelas

Details on test organisms:

TEST ORGANISM
- Common name: fathead minnow
- Source: brood cultures maintained at University of Winsconsin-Superior Lab
- Age at study initiation (mean and range, SD): 4 week old juvenile
- Feeding during test: yes
- Food type: live brine shrimp
- Frequency: twice a day

ACCLIMATION
- Acclimation period: none as fish were cultured
- Acclimation conditions (same as test or not): same
- Type and amount of food: live brine shrimp
- Feeding frequency: twice a day

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

28 d

Total depuration duration:

0 d

Hardness:

average 49.1 mg/L as CaCO3

Test temperature:

average 25.1 deg C

pH:

average 7.6 s.u.

Dissolved oxygen:

average 6.5 mg/L

TOC:

Samples were collected for TOC analysis but results provided elsewhere (information not provided)

Salinity:

NA

Details on test conditions:

TEST SYSTEM
- Test vessel: glass chamber 2.5 L
- Type of flow-through (e.g. peristaltic or proportional diluter): proportional mini diluter
- Renewal rate of test solution (frequency/flow rate): 16 ml/min
-No. of organisms per chamber: 20
- No. of vessels per concentration (replicates): 2
- No. of vessels per control / vehicle control (replicates): 2


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dechlorinated tap
- Alkalinity: 48.6 mg/L
- Conductance: 151 umhos/cm
- Holding medium different from test medium: no
- Intervals of water quality measurement: 3 times a week for pH, temp, D.O. measured daily, hardness, alkalinity, conductivity measured at least once.


OTHER TEST CONDITIONS
- Photoperiod: 16L:8D


RANGE-FINDING / PRELIMINARY STUDY
- Test concentrations: 0, 18.4, 41.9, 83.1, 230, 544 µg/L measured, 96 h NOEC = 83.1, LOEC = 230 µg/L

Nominal and measured concentrations:

Mean measured test concentrations: 0, 9.3, 19.2, 38.1, 77.5, 193 ug/L
0.5 dilution series

Details on estimation of bioconcentration:

Results based on measured concentrations of nonylphenol in water column versus measured concentrations in whole fish tissue. Final BCF is mean of all concentrations that had no mortality and reached steady state.

Type:

BCF

Value:

740 dimensionless

Basis:

whole body w.w.

Time of plateau:

14 d

Calculation basis:

steady state

Remarks on result:

other: steady state reached somewhere between day 14 and day 28

Details on kinetic parameters:

No uptake rate constant or depuration constant determined

Details on results:

Significant mortality seen in highest test concentration

Reported statistics:

none

Day 28 BCF calculation

Concentration (ug/L)	Mean Wet Fish Weight (g)	Mean Tissue Conc. (ug/g)	Mean BCF	Comments
0	0.448	BDL	'-
9.3	0.39	7.16	769	steady state not reached
19.2	0.327	18.9	984	steady state not reached
38.1	0.374	33.4	876	steady state reached
77.5	0.266	46.7	603	steady state reached
193	.206	91	472	mortalities occurred in this concentration

Final BCF = average of 876 and 603 = 740

Paper states average 28 day BCF = 741, but this included averaging results for concentration which had significant mortalities. USEPA Guidance states that concentrations proving lethal should not be used for BCF determination.

Chronic NOEC = 77.5 ug/L LOEC = 193 ug/L

Conclusions:

Study author does not make study conclusions, but simply presents study results.

Executive summary:

The 28-day chronic toxicity and bioconcentration of nonylphenol to Pimephales promelas was studied under flow-through conditions in a laboratory.  Juvenile fish were exposed to a control concentration of 0 mg nonylphenol/L and chemical test nominal concentrations of 9.3, 19.2, 38.1, 77.5, and 193 ug nonylphenol/L for 28 days.  Mortality was recorded and the NOEC was 77.5ug nonylphenol/L. Fish whole body tissue and water column concentrations were measured at day 0, 14 and 28 for mean BCF determination. Steady state was reached for the three highest concentrations between days 14 and 28. No depuration stage was performed.

 

Based on the results of this study, nonylphenol would be classified as bioccumulative in fish.

 

This study is classified as acceptable and satisfies the guideline requirements for a bioconcentration test with Pimephales promelas.

 

Results Synopsis

 

Mean BCF based on whole body tissue wet weight = 740

 

This study was selected as a key study because it provides bioconcentration information on a preferred test organism Pimephales promelas to nonylphenol. Results of this study show the highest BCF of valid fish bioconcentration studies but are lower than the REACH default BCF of > 5,000 based on K_ow.

Description of key information

The bioconcentration factor (BCF) is based on experimental results which are read-across from nonylphenol studies. The key study is Brooke (1993) that provided BCF result of 740 for the fish, Pimephales promelas (Fathead minnow).  This BCF results in a default biomagnification factor (BMF) of 1 for both the freshwater and the marine environment.

Key value for chemical safety assessment

BCF (aquatic species):

740 dimensionless

Additional information

Determination of a bioconcentration factor (BCF) follows Guidance on information requirements and chemical safety assessment Chapter R.16: Environmental Exposure Estimation (ECHA 2008) and Chapter R. 7c Endpoint Specific Guidance (ECHA 2008). Chapter R.16.5.3.5 states that there may be bioaccumulation potential if log Kow is >3. The log K_owof octylphenol as given by Environment Agency in Environmental Risk Evaluation Report: 4-tert-Octylphenol (2005) is 4.12. Therefore, as per REACH Annex IX, bioaccumulation information, preferably for fish, must be presented forsubstances manufactured or imported in quantities of 100 t/y or more.

 

Chapter R.7c states that BCFs can be determined experimentally, by calculation using K_ow, or by estimating using BCF models such as QSARs. Since adequate reliable experimental data is available for the preferred organism, fish, BCFs for octylphenol are based on actual measured values from experimental tests.

 

Only one reliable bioconcentration study was available for octylphenol. Tsuda et al. (2001) presented BCF result of 261, based on whole body wet weight, from a 7-day test with Oryzias latipes where steady-state was reached at 48 hrs. Although the source of the test organisms was a local pet shop, tests were carried out similar to acceptable procedures.

 

Due to the limited amount of reliable bioconcentration data for octylphenol, it is recommended that it would be appropriate to take a read-across approach from nonylphenol. Study results from Tsuda et al. (2001) show that bioconcentration of octylphenol is likely similar to nonylphenol.

BCFs were determined by Brooke (1993) for juvenile Pimephales promelas and Lepomis macrochirus from a 28-day flow-through exposure to five concentrations of nonylphenol. Concentrations were measured and steady state was reached by Day 14 of the test. Measured BCFs are 740 and 231, based on whole body wet weight for Pimephales promelas and Lepomis macrochirus, respectively. This study is considered a valid test and a Key Study, although it was not conducted according to GLP.

According to Annex XIII of Regulation (EC) No 1907/2006 and to the Guidance on information requirements and chemical safety assessment Chapter R.11 (PBT Assessment, ECHA (2008)), a substance does not fulfil the criteria “bioaccumulative (B)” or “very bioaccumulative (vB)” if the bioconcentration factor (BCF) is below 2000 or 5000 respectively or the log Kow is below 4.5. The BCF of octylphenol was determined to be 740 based on a measured concentration in Pimephales promelas by Brooke (1993). It is concluded that octylphenol is not bioaccumulative within the PBT criteria.