6,6'-di-tert-butyl-2,2'-thiodi-p-cresol

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:

key study

Study period:

March 22, 1979 to July 23, 1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted in accordance with acceptable scientific methods.

Qualifier:

according to guideline

Guideline:

other: Based on Bioconcentration test of chemicals in fish and shellfish (Kanpogyo No. 5, Yakuhatsu No. 615, 49 Kikyoku No. 392)

GLP compliance:

not specified

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Radiolabelling:

no

Details on sampling:

Test water:
No 1 concentration area:

Sampling of water 100 mL, addition of chloroform 50 mL (repeated twice)
Shaking
Dehydration filtration
Chloroform phase: drying, Addition of benzene-hexane (1:1 v/v) 5mL, column chromatography (see below for conditions)
Elution fraction: Drying, Quantification, 10mL (acetonitrile)

No 2 concentration area:

Sampling of water 1000 mL, addition of chloroform 100 mL (repeated twice)
Shaking
Dehydration filtration
Chloroform phase: drying, Addition of benzene-hexane (1:1 v/v) 5mL, column chromatography (see below for conditions)
Elution fraction: Drying, Quantification, 10mL (acetonitrile)

Fish:

- Measurement of body weight and length
- Fragmentation
- Addition of the sea sand, 10 g
- Addition of anhydrous sodium sulfate, 100 g
- Dehydration
- Addition of acetonitrile, 150 mL on 1st addition, 100 mL on 2nd addition, 100 mL on 3rd addition (repeated 3 times)
- Shaking (repeated 3 times)
- Vacuum filtration (repeated 3 times)

Filtrate: Addition of hexane, 100 mL and Shaking (repeated twice)
Acetonitrile phase: Drying, Addition of benzene-hexane (3:7 v/v) 5mL, Column chromatography method ( see below)
Elution fraction: Drying, Quantification, 10mL (acetonitrile)

Vehicle:

yes

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

Dissolution method (dispersant and dispersion method)
Dispersant: Hydrogenated castor oil (HCO-20)
Dissolution (dispersion) method:
1 g of the test substance and 10 g of hydrogenated castor oil (HCO-20) were dissolved in 50 mL of acetone. Acetone was evaporated by rotary evaporator. Subsequently, water was added to quantify the constant volume of 1 L to prepare 1000 ppm (w/v) of the stock solution.

Test organisms (species):

Cyprinus carpio

Details on test organisms:

Test fish
Carp: Mean body weight: 27.1 g, Mean body length: 10.3 cm

External disinfection and acclimatization
(1) External disinfection
Medicated bathing for 24 hours was conducted with 10 ppm of aqueous chlortetracycline hydrochloride under static water condition.
(2) Acclimatization
25 degreesC x 21 days

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

not specified

Remarks:

freshwater

Total exposure / uptake duration:

1 008 h

Hardness:

no data

Test temperature:

25 +/ 2 degrees C

pH:

no data

Dissolved oxygen:

no data

TOC:

no data

Salinity:

not applicable

Details on test conditions:

Test conditions:
(a) Aquatic environment control equipment: Flow-through system
Test vessel: Glass vessel, Volume 100 L, Flow rate 576 L/day
(Stock solution: dilution water = 4 mL/minute : 400 mL/minute)

(b) Test fish
Carp Mean body weight: 27.1 g Mean body length: 10.3 cm

(c) External disinfection and acclimatization
(1) External disinfection
Medicated bathing for 24 hours was conducted with 10 ppm of aqueous chlortetracycline hydrochloride under static water condition.

(2) Acclimatization
25 degrees C x 21 days

(d) Dissolution method
1 g of the test substance and 10 g of hydrogenated castor oil (HCO-20) were dissolved in 50 mL of acetone. Acetone was evaporated by rotary evaporator. Subsequently, water was added to quantify the constant volume of 1 L to prepare 1000 ppm (w/v) of the stock solution.

(e) Test temperature
25 ± 2 degrees C

Nominal and measured concentrations:

Concentration for the vessel
Reason for the selection of the concentration
The concentration which provides accurate quantification is approximately 2 ppm (see Figure 4). Recovery rate was 82 % at 100 fold concentration in pre-treatment on analysis of water. Based on the result of preliminary breeding for 10 days, decrease of concentration in the vessel was assumed as 10% and the concentration in the vessel for No.2 Concentration area was set at 0.03 ppm. The concentration of No.1 Concentration area was set at 10 fold of the concentration of No.2 Concentration area.

(Calculation formula)
Concentration in the vessel for No.2 Concentration area was calculated as follows: (2/100 x 82/100 x 90/100)/0.03 ppm)

Nominal value
No.1 Concentration Area: test substance 300 ppb w/v, dispersant 3000 ppb w/v
No.2 Concentration Area: test substance 30 ppb w/v, dispersant 300 ppb w/v

Measured value
Mean concentration for calculation of concentration rate

No.1 Concentration Area: 2W: 290, 3W: 287, 4W: 293, 6W: 298 ppb w/v
No.2 Concentration Area: 2W: 29.0, 3W:28.8, 4W: 26.7, 6W: 27.2 ppb w/v

Reference substance (positive control):

no

Type:

BCF

Value:

0.12 - <= 4.2

Remarks on result:

other: Conc.in environment / dose:300 ppb

Type:

BCF

Value:

1.3 - <= 11

Remarks on result:

other: Conc.in environment / dose:30 ppb

Details on kinetic parameters:

No data available

Metabolites:

No data

Results with reference substance (positive control):

Not applicable

Details on results:

Condition of test fish
Result of external observation: normal
See tables below under any other information on results.

Bioconcentration rate/factor of the test substance:

	2W	3W	4W	6W
No.1 Concentration area	3.2	0.12 or below	(0.68)	(2.0)
	0.12 or below	(0.17)	(1.2)	4.2
No.2 Concentration area	(1.1)	(1.7)	1.3 or below	(5.7)
	1.3 or below	1.3 or below	1.3 or below	(6.7)

Referential values are shown in the parentheses.

The correlation of bioconcentration rate and quantification accuracy is shown below:

	Concentration in fish body  (ppm)	Bioconcentration rate	Calculation method (ppm)
Range of accurate quantification	0.859 and above	No.1 Concentration area: 2.9 and above No.2 Concentration area: 32 and above	A      C  x  D   100   E x F
Range of referential value	0.859-0.034	No.1 Concentration area: 0.12-2.9 No.2 Concentration area: 1.3-32
Range of detection limit	0.034 or below	No.1 Concentration area: 0.12 folds or below No.2 Concentration area: 1.3 folds or below	B       C  x  D   100   E x F

Validity criteria fulfilled:

not specified

Conclusions:

The bioaccumulation study was conducted in 1979 and according to the method used in ‘Bioconcentration test of chemicals in fish and shellfish (Kanpogyo No. 5, Yakuhatsu No. 615, 49 Kikyoku No. 392’. A flow-through system was used and the fish tested were carp (mean body weight: 27.1 g and mean body length: 10.3 cm). Two concentrations of the substance were tested (30 and 300 ppb w/v) and a dispersant was used (hydrogenated castor oil). The condition of the test fish was considered to be normal throughout the study. At 30 ppb w/v, the BCF value ranged from 0.12 or below to 4.2. At 300 ppb w/v, the BCF value ranged from 1.3 to 11 .

Executive summary:

The bioaccumulation study was conducted in 1979 and according to the method used in ‘Bioconcentration test of chemicals in fish and shellfish (Kanpogyo No. 5, Yakuhatsu No. 615, 49 Kikyoku No. 392’. A flow-through system was used and the fish tested were carp (mean body weight: 27.1 g and mean body length: 10.3 cm). Two concentrations of the substance were tested (30 and 300 ppb w/v) and a dispersant was used (hydrogenated castor oil). The condition of the test fish was considered to be normal throughout the study. At 30 ppb w/v, the BCF value ranged from 0.12 or below to 4.2. At 300 ppb w/v, the BCF value ranged from 1.3 to 11 . Based on these results, the test substance is not considered to be bioaccumulative.

Reference 2

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

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

Adequacy of study:

key study

Study period:

April 2018

Justification for type of information:

see justification attached below

Reason / purpose for cross-reference:

read-across source

Key result

Type:

BCF

Value:

>= 0.12 - <= 4.2 dimensionless

Remarks on result:

other: Conc.in environment / dose:300 ppb

Key result

Type:

BCF

Value:

>= 1.3 - <= 11 dimensionless

Remarks on result:

other: Conc.in environment / dose:30 ppb

Validity criteria fulfilled:

not applicable

Remarks:

Read across

Conclusions:

Based upon the data available, the substances are considered to be equivalent, except for the positioning of the functional groups, and are structural isomers of each other. The substances follow a regular pattern with regards to their chemical properties as a result of that structural similarity. Therefore, the definition of a chemical category has been met, and read across is considered appropriate for the category of chemical. The substance, CAS: 90-66-4; EC: 202-009-7, is analogous to the substance to be read across to, in terms of basic form, and the degree of substitution of functional groups is not considered to bias the effects for the endpoint of bioaccumulation. Steric hindrance is not considered a decisive factor in the case of this read across, and as such, it is considered that the substances would show similar bioaccumulation properties in the event of exposure. The substance is therefore considered to be not bioaccumulative for the defined endpoints on the basis of read across.

Executive summary:

Based upon the data available, the substances are considered to be equivalent, except for the positioning of the functional groups, and are structural isomers of each other.  The substances follow a regular pattern with regards to their chemical properties as a result of that structural similarity. Therefore, the definition of a chemical category has been met, and read across is considered appropriate for the category of chemical. The substance, CAS: 90-66-4; EC: 202-009-7, is analogous to the substance to be read across to, in terms of basic form, and the degree of substitution of functional groups is not considered to bias the effects for the endpoint of bioaccumulation. Steric hindrance is not considered a decisive factor in the case of this read across, and as such, it is considered that the substances would show similar bioaccumulation properties in the event of exposure.  The substance is therefore considered to be not bioaccumulative for the defined endpoints on the basis of read across.  

Description of key information

LOWINOX TBP-6 is not bioaccumulative (BCF 1.3 -11).

Based upon the data available, the source and target substances are considered to be equivalent, except for the positioning of the functional groups, and are structural isomers of each other.  The substances follow a regular pattern with regards to their chemical properties as a result of that structural similarity. Therefore, the definition of a chemical category has been met, and read across is considered appropriate for the category of chemical. The substance, CAS: 90-66-4; EC: 202-009-7, is analogous to the substance to be read across to, in terms of basic form, and the degree of substitution of functional groups is not considered to bias the effects for the endpoint of bioaccumulation. Steric hindrance is not considered a decisive factor in the case of this read across, and as such, it is considered that the substances would show similar bioaccumulation properties in the event of exposure.  The substance is therefore considered to be not bioaccumulative for the defined endpoints on the basis of read across.  

Key value for chemical safety assessment

BCF (aquatic species):

11 dimensionless

Additional information

The key value for bioaccumulation has been derived via the use of a read across to 6,6'-di-tert-butyl-4,4'-thiodi-m-cresol; CAS: 96-69-5; EC: 202-525-2 in accordance with ANNEX XI (General rules for adaptation of the standard testing regime set out in annexes VII to X) of the REACH Regulation.