2,5-bis(1,1,3,3-tetramethylbutyl)hydroquinone

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 January 2010 to 25 February 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Klimisch 1 – Reliable experimental study following Standards for test facilities to conduct tests on new chemical substances: Bioconcentration Tests of Chemical Substances in Fish/Shellfish Bodies for Test Methods for New Chemical Substances (Pharmaceutical and Food Safety Bureau Notice No. 1121002 dated November 21, 2003, Manufacturing Industries Bureau Notice No. 2 dated November 13, 2003, Environmental Health Policy Planning Division Notice No. 031121002, Final Amendment: November 20, 2006) and OECD 305I: Aqueous Exposure Bioconcentration Fish Test and GLP standards.

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 (Bioaccumulation in Fish: Aqueous and Dietary Exposure) -I: Aqueous Exposure Bioconcentration Fish Test

Deviations:

no

GLP compliance:

yes

Radiolabelling:

no

Vehicle:

not specified

Test organisms (species):

Cyprinus carpio

Details on test organisms:

The test organism, Carp (Cyprinus carpio, Cyprinidae) were obtained from the Niikura Fish Farm on July 21, 2009. Test organisms were less than 1 year old after hatching and were 8 ± 4 cm in length and weighed about 5 g.

Route of exposure:

aqueous

Justification for method:

aqueous exposure method used for following reason:

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

28 d

Total depuration duration:

32 d

Hardness:

Not reported.

Test temperature:

Water Temperature during the test was 24 ± 2°C.

pH:

pH range during the test was 6.0 to 8.5.

Dissolved oxygen:

The saturated dissolved oxygen concentration throughout the test was 60% or more (5 mg/L or greater at 24°C).

TOC:

Not reported.

Salinity:

Not reported.

Conductivity:

Not reported.

Details on test conditions:

One series each of flow-through type bioconcentration testing apparatus was installed for a first concentration area (high-concentration area) and second concentration area (low-concentration area) and the fish were raised in water containing the test substance. Further, one series of the same was installed for a control area, and fish were raised in water not containing the test substance. During this period, the concentration of the test substance in the test water and that in the fish bodies were regularly measured, and the bioconcentration in fish was assessed by calculating concentration ratios based on a comparison between the measured values.

Nominal and measured concentrations:

The test concentration of the first experiment was 0.05 mg/L TMBH and the test concentration of the second experiment was 0.005 mg/L TMBH. The concentration in the control test was 0 mg/L TMBH.
 

Reference substance (positive control):

no

Details on estimation of bioconcentration:

The fat content of the fish was measured at the start and the end of the uptake period. Upon the start, five fish were sampled from the naturalisation tank and at the end of the uptake, five fish were sampled from the control area. Measurements were conducted on three of the fish in accordance with the test procedure.

Lipid content:

5.5 %

Time point:

start of exposure

Remarks on result:

other: average

Lipid content:

5 %

Time point:

end of exposure

Remarks on result:

other: average

Key result

Conc. / dose:

0.05 mg/L

Temp.:

> 23.8 - <= 24.5 °C

pH:

7.5

Type:

BCF

Value:

234 dimensionless

Basis:

other:

Remarks:

ratio of concentration in the fish

Calculation basis:

steady state

Key result

Conc. / dose:

0.005 mg/L

Temp.:

> 23.8 - <= 24.5 °C

pH:

7.5

Type:

BCF

Value:

271 dimensionless

Basis:

other:

Remarks:

ratio of concentration in the fish

Calculation basis:

steady state

Details on results:

The bioconcentration ratio (BCF; bioconcentration factor) during the uptake period was 78 to 351 times in the first concentration area and 154 to 339 times in the second concentration area. The variation in the bioconcentration factor (average) in the three consecutive measurements made at intervals of 48 hours or longer was within 20%, and a steady state was determined for the 28-day uptake period. The bioconcentration ratios (BCFSS) in the steady states of the first and second concentration areas were 234 times and 271 times, respectively.

Table 1: Bioaccumulation test results

		7 d	13 d	19 d	22 d	28 d
1st concentration area	Test substance concentration (µg/L)	43.6	43.8	44.0	44.0	44.5
	Bioconcentration factor (L/kg)	148	182	186	237	263
		136	78	351	236	167
2nd concentration area	Test substance concentration (µg/L)	3.64	3.41	3.34	3.28	3.31
	Bioconcentration factor (L/kg)	177	208	157	280	223
		<154	181	276	307	339

 

Validity criteria fulfilled:

yes

Remarks:

Temperature, dissolved oxygen, fluctuation of test substane concentration in test water, fish death and disease rates were all within valid limits.

Conclusions:

The test substance variation of the bioconcentration ratio (average) in three consecutive measurements taken at intervals of 48 hours or longer was within 20%, and a steady state was confirmed during the 28 day of uptake period. The bioconcentration ratios (BCFSS; bioconcentration factor at steady state) at the steady states of the first and second concentration experiments were 234 times and 271 times, respectively.

Description of key information

The low BCf value of 271 indicates a low bioaccumulation potential of the substance.

Key value for chemical safety assessment

BCF (aquatic species):

271 dimensionless

Additional information

The key study was a bioconcentration study conducted following the standards set out by the Ministry of International Trade and Industry, Japan Guideline for Bioconcentration Tests of Chemical Substances in Fish/Shellfish Bodies which is equivalent to OECD 305: Bioaccumulation in Fish: Aqueous and Dietary Exposure Guideline.

The test was conducted with common carp (Cyprinus carpio) as test organism in a flow-through test system. The fish were exposed for 28 days to test substance concentrations of 0.05 mg/L and 0.005 mg/L, respectively. The total depuration duration was 32 days. The bioconcentration ratios (BCF_SS; bioconcentration factor at steady state) at the steady states of the first and second concentration experiments were 234 and 271, respectively. The experimentally determined BCF values indicate a low bioaccumulation potential of the substance.