Phenol, styrenated

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: data is from secondary source

Justification for type of information:

Data is from Environmental risk evaluation report

Qualifier:

according to guideline

Guideline:

other: refer principle below

Principles of method if other than guideline:

The bioaccumulation of test chemical was determined by using dietary bioaccumulaton study rainbow trout (Oncorhynchus mykiss) fish for 10-day uptake period and 42-day depuration period.

GLP compliance:

not specified

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms:days 0, 1, 5 and 10 of the uptake phase and days 1, 2, 4, 7, 14, 28 and 42 of the depuration phase (ten fish were analysed at each sampling point).

- Sample storage conditions before analysis:
- Details on sampling and analysis of test organisms and test media samples (e.g. sample preparation, analytical methods):

Vehicle:

yes

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

PREPARATION OF SPIKED FISH FOOD
- Details of spiking : Distyrenated phenol (57.6 mg) and tristyrenated phenol (86.4 mg) were added to 10 ml of solvent (methyl tertiary butyl ether (MTBE)) and 7.2 ml of fish oil, shaken for 10 seconds and then added to 144 g standard fish food (floating and/or sinking pelletised diet) in 750 μl portions.
- Quantity of fish oil vehicle, if used, per unit mass of fish food: 144 g
- Chemical name of vehicle (organic solvent), if used: methyl tertiary butyl ether (MTBE))
- Method of mixing: Bottle roller was used for misxing
- Equilibration time: 1 hour
- Method for removal of solvent, if used: evaporation

The MTBE was allowed to evaporate under a gentle flow of nitrogen for 24 hours and the spiked food was again shaken for a final 30 minutes.

The Control food and positive control food was prepared in the same way without addition of the test substance (control food) or with the addition of hexachlorobenzene in place of the test substance. The prepared food was stored under a nitrogen atmosphere at -18°C until required.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

The fish were three-months old at the start of the test and had a mean initial body weight of 1.57
g.

Route of exposure:

feed

Justification for method:

dietary exposure method used for following reason: The substance tested was a mixture of distyrenated phenol (40 per cent by weight) and tristyrenated phenol (60 per cent by weight)

Test type:

flow-through

Total exposure / uptake duration:

10 d

Total depuration duration:

42 d

Hardness:

55-57 mg/l as CaCO3

Test temperature:

15 oC

pH:

7.06 and 7.70

Dissolved oxygen:

not less that 60 per cent of saturation through the test

Details on test conditions:

no data

Nominal and measured concentrations:

The nominal concentrations prepared were 1,000 mg/kg food for the mixture of distyrenated phenol and tristyrenated phenol and 250 mg/kg food for the
hexachlorobenzene positive control. The lipid content of the food was 18.8 per cent

Reference substance (positive control):

yes

Remarks:

hexachlorobenzene

Key result

Conc. / dose:

1 000 other: mg/kg food

Temp.:

15 °C

pH:

7

Type:

BCF

Value:

10 395 L/kg

Basis:

whole body w.w.

Time of plateau:

10 d

Calculation basis:

kinetic, corrected for growth

Remarks on result:

other: for tristyrenated phenol

Key result

Conc. / dose:

1 000 other: mg/kg food

Temp.:

15 °C

pH:

7

Type:

BCF

Value:

6 695 L/kg

Basis:

whole body w.w.

Time of plateau:

10 d

Calculation basis:

other: non-growth corrected BCF

Remarks on result:

other: For tristyrenated phenol

Elimination:

yes

Parameter:

DT50

Depuration time (DT):

18.4 d

Remarks on result:

other: for tri-styerenated phenol

Details on kinetic parameters:

BCF =k update / k depuration

k uptake= 520 W-032
where BCF = growth corrected fish bioconcentration factor.
k uptake = rate constant for uptake in fish via gills (day-1).
k depuration = growth corrected depuration rate constant = 0.038 day-1 for
tristyrenated phenol.
W = fish weight (g) at end of uptake/start of depuration period.

Validity criteria fulfilled:

yes

Conclusions:

The growth-corrected BCFvalue for test chemical was determined to be 10395 L/kg and non-growth corrected BCF determined 6695 l/kg in a dietary bioaccumulation study with rainbow trout (Oncorhynchus mykiss). By considering the above mentioned BCF value test chemical is considered to be very bioaccumulative in nature.

Executive summary:

A dietary bioaccumulation study was performed with rainbow trout (Oncorhynchus mykiss) was carried out with styrenated phenol. The substance tested was a mixture of distyrenated phenol (40 per cent by weight) and tristyrenated phenol (60 per cent by weight). The study consisted of a 10-day uptake period, during which the fish were fed a diet spiked with the test substance, followed by a 42-day depuration period where the fish were fed uncontaminated diet. Hexachlorobenzene was used as positive control. The spiked food was prepared by using solvent and fish oil. The test system used was a flow-through system.

One replicate was carried out per test group with each replicate consisting of 125 fish in either 140 litres of water (test substance exposure) or 110 litres of water (control and positive control group). The initial loading rates were therefore 0.57 g fish/litre/day for the group exposed to the mixture of di/tristyrenated phenol and 0.059 g fish/litre/day for the control and positive control group. A daily feeding rate of three per cent of the body weight was used during the study.The fish were observed daily for mortality, behaviour and other effects. The levels of distyrenated phenol and tristyrenated phenol in the exposed fish were determined analytically on days 0, 1, 5 and 10 of the uptake phase and days 1, 2, 4, 7, 14, 28 and 42 of the depuration phase (ten fish were analysed at each sampling point).

The uptake and depuration pattern for tristyrenated phenol shows increasing concentrations with time over the entire exposure period followed by decreasing concentrations during the depuration period thw growth-corrected depuration half-life in the fish was around 18.4 days. The growth-corrected BCFvalue for test chemical was determined to be 10395 L/kg and non-growth corrected BCF determined 6695 l/kg in a dietary bioaccumulation study with rainbow trout (Oncorhynchus mykiss). By considering the above mentioned BCF value test chemical is considered to be very bioaccumulative in nature.

Description of key information

The growth-corrected BCFvalue for test chemical was determined to be 10395 L/kg and non-growth corrected BCF determined 6695 l/kg in a dietary bioaccumulation study with rainbow trout (Oncorhynchus mykiss). By considering the above mentioned BCF value test chemical is considered to be very bioaccumulative in nature.

Key value for chemical safety assessment

BCF (aquatic species):

10 395 L/kg ww

Additional information

Experimental study for target chemical and supporting predicted studies have been reviewed for bioaccumulation of test chemical endpoint and their results are summarized below.

To determine BCF value of test chemical a dietary bioaccumulation study was performed with rainbow trout (Oncorhynchus mykiss) was carried out with styrenated phenol. The substance tested was a mixture of distyrenated phenol (40 per cent by weight) and tristyrenated phenol (60 per cent by weight). The study consisted of a 10-day uptake period, during which the fish were fed a diet spiked with the test substance, followed by a 42-day depuration period where the fish were fed uncontaminated diet. Hexachlorobenzene was used as positive control. The spiked food was prepared by using solvent and fish oil. The test system used was a flow-through system.

One replicate was carried out per test group with each replicate consisting of 125 fish in either 140 litres of water (test substance exposure) or 110 litres of water (control and positive control group). The initial loading rates were therefore 0.57 g fish/litre/day for the group exposed to the mixture of di/tristyrenated phenol and 0.059 g fish/litre/day for the control and positive control group. A daily feeding rate of three per cent of the body weight was used during the study.The fish were observed daily for mortality, behaviour and other effects. The levels of distyrenated phenol and tristyrenated phenol in the exposed fish were determined analytically on days 0, 1, 5 and 10 of the uptake phase and days 1, 2, 4, 7, 14, 28 and 42 of the depuration phase (ten fish were analysed at each sampling point).

The uptake and depuration pattern for tristyrenated phenol shows increasing concentrations with time over the entire exposure period followed by decreasing concentrations during the depuration period thw growth-corrected depuration half-life in the fish was around 18.4 days. The growth-corrected BCFvalue for test chemical was determined to be 10395 L/kg and non-growth corrected BCF determined 6695 l/kg in a dietary bioaccumulation study with rainbow trout (Oncorhynchus mykiss). By considering the above mentioned BCF value test chemical is considered to be very bioaccumulative in nature.

Further, to corroborate the above study prediction was done by using BCFBAF Program (v3.00) model of EPI suite (2018) in this prediction the bio concentration factor (BCF) for test chemical distyrenated phenol was estimated to be 11440 L/kg wet-wt at 25 deg. c tristyrenated phenol. Therefore it is concluded that test chemical is very bioaccumulative in food chain.

In addition to it one prediction was done by using BCFBAF Program (v3.00) model of EPI suite (2018) the estimated bio concentration factor (BCF) for test chemical tristyrenated phenol is 3246  L/kg wet-wt at 25 deg. c which  exceeds the bioconcentration threshold of 2000. Therefore it is concluded that test chemical bioaccumulative in food chain.

By considering results of all the studies mentioned above it is concluded that BCF value of test chemical is in range of 3246- 11440 L/kg. This range BCF value exceeds the bioconcentration threshold of 2000 which indicates that test chemical is very bioaccumulative in aquatic organisms.