4-poly(propyl), benzene sulfonic acid

Bioaccumulation: aquatic / sediment

Administrative data

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

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

Adequacy of study:

key study

Study period:

7 October 2008 to 18 September 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test material

Reference

Name:

Unnamed

Type:

Constituent

Details on test material:

- Name of test material (as cited in study report): SP6012 (oil free)
- Physical state: clear, colourless solution (radiolabelled); brown solid (cold)
- Lot/batch No.: TS05021 (cold)
- Specific activity (if radiolabelling): 3.71 Mbq/mg; 100.4 µCi/mg
- Storage condition of test material: approximately -20 ºC in the dark (radiolabelled); room temperature in the dark (cold)

Specific details on test material used for the study:

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

Radiolabelling:

yes

Sampling and analysis

Details on sampling:

Water samples were taken from the solvent control, 0.001 mg/L and 0.1 mg/L test groups on days 0, 7, 14, 21, 25, 28, 32, 25 and 39 of the exposure phase and days 3, 6, 11, 13 and 61 of the depuration phase for quantitative analysis. Water samples were taken once a week during the test for total radioactivity determination. Duplicate samples were taken stored frozen for further analysis if necessary.

Four fish were selected at random for each of the solvent control, 0.001 mg/L and 0.01 mg/L test groups on days 21, 25, 28, 32, 35 and 39 of the exposure phase and days 3, 6, 11, 13 and 61 of the depuration phase for quantitative analysis. Each fish was weighed prior to analysis and analysed for total readioactivity. Three fish were sampled on day 0 of the exposure phase and day 28 of the depuration phase for the determination of lipid content.

Test solutions

Vehicle:

yes

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

For the purpose of the definitive test, the test material was prepared using a preliminary solution in dimethylformamide.

Two solvent stock solutions of 14C labelled test material, in dimethylformamide, were supplied at a concentration of 1.05 mg/mL at 292 MBq with a specific activity of 100.4 µCi/mg.

1 Ci=3.7x10E+10 Bq therefore 1 mCi = 37 MBq

The specific activity of the solvent stock solutions provided was therefore: 100.4 (mCi/g supplied) x 37 (MBq in 1 mCi) = 3715 MBq/g = 3715 Bg/µg.

Therefore the mass of chemical supplied was: 292 x 10E+6 Bq / 3715 Bq/µg = 78600 µg = 78.6 mg.

As the test involved the use of radio labelled test material, two solvent stock solutions were prepared which were sufficient to dose the entire test. This was done to minimise the handling of the radio labelled test material. Once the solvent stock solutions had been prepared they were stored at approximately 4°C in the dark. Gas tight syringes were filled from these solvent stock solutions and used to dose the test system.

Solvent stock solution preparation for the 0.001 mg/L test concentration: 75 mL of one of the 14C labelled solvent stock solutions supplied was diluted in a final volume of 2.6 litres of dimethylformamide to give a 30 mg/L solvent stock solution. The specific activity of the solvent stock solution was 3715 Bq/µg.

Solvent stock solution preparation for the 0.01 mg/L test concentration: 671.4 mg of cold material was dissolved in dimethylformamide and transferred to a 2 litre volumetric flask. 75 mL of the remaining 14C labelled solvent stock solution supplied was dispensed to the same flask and the volume adjusted to 2 litres with dimethylformamide. This solvent stock solution was then transferred to the storage vessel, along with a further 500 mL of dimethylformamide, to give a 300 mg/L solvent stock solution. The specific activity of the solvent stock solution was: 292 x 10E+6 Bq / 750 000 µg = 389.33 Bq/µg

The solvent control group was prepared in an identical manner without the addition of test material. The solvent control group was exposed to 33.3 µL of dimethylformamide.

Test organisms

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: rainbow trout
- Source: Brow Well Fisheries Limited, Hebden, Yorkshire, UK
- Length at study initiation (lenght definition, mean, range and SD): 8.9 cm (sd = 0.2)
- Weight at study initiation (mean and range, SD): 10.25 g (sd = 0.39)
- Feeding: commercail trout pellets at a rate of approximantely 2% bodywright in two equal portions of 1% bodyweight

ACCLIMATION
- Acclimation period: 14 days
- Type and amount of food: commercial trout pellets
- Feeding frequency: 2% bodyweight per day
- Health during acclimation (any mortality observed): <1%

Study design

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

42 d

Total depuration duration:

61 d

Test conditions

Hardness:

106-110 mg/L as CaCO3

Test temperature:

Approximately 14 degrees C

pH:

7.2-7.8

Dissolved oxygen:

7.3-10.5 mg O2/L

TOC:

1.47-18.31 mg C/L during the exposure phase and less than the LOQ - 7.1 mg C/L during the depuration phase.

Salinity:

Not applicable.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 litre glass exposure vessels for each test concentration
- Type (delete if not applicable): covered to reduce evaporation
- No. of organisms per vessel: 52

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: laboratory tap water, dechlorinated by passage through an activated carbon filter (Elga AC 1)
- Parameters: see Appendix 4 (attached).

OTHER TEST CONDITIONS
- Photoperiod: 16 hrs light/8 hrs dark

RANGE-FINDING / PRELIMINARY STUDY
- Test concentrations: 0.0033 mg/L
- Results used to determine the conditions for the definitive study: the results of the pilot study shoswed that a steady state bioconcentration factor would be reached after 35 days exposure. The sampling regime for the definitive test was set at 21, 25, 28, 32 and 35 days.

Nominal and measured concentrations:

0.001 and 0.01 mg/L based on the water solubility of the test material of 0.06 mg/L.

Reference substance (positive control):

not required

Details on estimation of bioconcentration:

The concentration of test material in fish tissues was plotted graphically to show the rate of uptake, the plateau concentration and the rate of depuration. When the uptake curve had reached a plateau (steady-state), the BCFss was calculated as follows:

BCF = Cf at steady-state (mean) / Cw at steady-state (mean)

Where:
BCFss = Bioconcentration factor at steady-state
Cf = Mean concentration in test fish at steady-state
Cw = Mean concentration in water at steady-state

The BCF will be expressed both as a function of the total wet weight of fish, and for high lipophilic materials), as a function of the lipid content.

The BCF values were calculated directly from the kinetic rate constants k1 and k2 and termed the kinetic bioconcentration factor as follows:

BCFk = k1 / k2

Where:
BCFk = Kinetic bioconcentration factor
k1 = Uptake rate constant
k2 = Depuration rate constant

The rate constants k1 and k2 and hence the bioconcentration factor were estimated by the use of non-linear parametric estimation given the sequential time concentration data and the model using the SAS computer software package and the equation as follows:

Cf=CwK1/K2*(1-e^-K2t)

Results and discussion

Lipid content

Lipid content 1

Lipid content:

5 %

Time point:

start of exposure

Lipid content 2

Lipid content:

9 %

Time point:

other: day 69 of the test

Bioaccumulation factor

Bioaccumulation factor 1

Type:

BCF

Value:

45

Basis:

whole body w.w.

Calculation basis:

steady state

Remarks on result:

other: After 39 days exposure

Remarks:

Conc.in environment / dose:0.001 mg/L

Bioaccumulation factor 2

Type:

BCF

Value:

38

Basis:

whole body w.w.

Calculation basis:

kinetic

Remarks on result:

other: Conc.in environment / dose:0.001 mg/L

Bioaccumulation factor 3

Type:

BCF

Value:

58

Basis:

whole body w.w.

Calculation basis:

steady state

Remarks on result:

other: After 39 days exposure

Remarks:

Conc.in environment / dose:0.01 mg/L

Bioaccumulation factor 4

Type:

BCF

Value:

64

Basis:

whole body w.w.

Calculation basis:

kinetic

Remarks on result:

other: Conc.in environment / dose:0.01 mg/L

Depuration

Depuration 1

Elimination:

yes

Parameter:

other: 70% (0.001 mg/l concentration)

Depuration time (DT):

61 d

Depuration 2

Elimination:

yes

Parameter:

other: 97% (0.01 mg/l concentration)

Depuration time (DT):

61 d

Details on kinetic parameters:

- Uptake rate constant (k1): 2.8321 (0.001 mg/L test concentration); 48 (0.01 mg/L test concentration)
- Depuration (loss) rate constant (k2): 0.0742 (0.001 mg/L test concentration); 0.7442 (0.01 mg/L test concentration)

Metabolites:

Not applicable.

Results with reference substance (positive control):

Not applicable.

Details on results:

Further information on BCF values can be found in Tables 5 to 8. The BCF (ss and k) were observed to be greater at the 0.01 mg/L test concentration compared to 0.001 mg/L. This was considered to be due to the increased body burden at the higher test concentration. It was considered that the fish were only able to metabolise/eliminate/excrete a certain amount of test material. Therefore at the higher concentration more SP6012 (Oil free) was accumulated in the fish tissues compared to the lower concentration.

The BCFs in the definitive test were lower than those observed in the pilot test. This was considered to be possibly due differences in fish size and/or the number of fish introduced into the tanks.

The test material was shown not to significantly accumulate in fish tissue and was observed to be eliminated from the fish tissues over a 61 day depuration period. At the end of the depuration period 70% and 97% of the test material was eliminated from the fish tissues for the 0.001 and 0.01 mg/L test concentrations respectively. Based on this information the biological half-life of the test material is considered to be 39 to 54 days.

No sub-lethal effects of exposure were observed.

Reported statistics:

See above.

Any other information on results incl. tables

PILOT TEST

Analysis of the water samples (see Appendix 5) taken throughout the pilot test showed measured concentrations to range from 0.0012 to 0.0040 mg/L with average concentrations of 0.0033 mg/L. It was therefore considered that the systsem was dosing correctly.

Analysis of the test fish (see Appendix 5) showed mean measured values for whole fish of 0.750, 0.890 and 0.897 mg/kg on days 28, 35 and 42 respectively. The corresponding bioconcentration factors (BCF) are given in Table 2 in Appendix 5.

Based on the results of the pilot test it was considered that a steady state bioconcentration factor (BCF) would be reached after 35 days exposure. Therefore the sampling regime for the uptake phase for the definitive test was initially set at 21, 25, 28, 32 and 35 days. Due to a delay in the analytical results being available an additional sample timing was conducted 39 days after exposure.

MEASURED TEST CONCENTRATIONS

Analysis of the test solutions based on total readioactivity showed measured test concentrations to range from 90%-150% and 80%-140% of the nominal concentrations for the 0.001 mg/L and 0.01 mg/L test concentrations respectively. The overall mean measured concentrations were 0.0013 mg/L and 0.01 mg/L for the 0.001 mg/L and 0.01 mg/L test concentrations respectively. Despite some of the results being slightly in excess of the 120% acceptance limit it was considered that the test system was dosing accurately with the slight variations observed being due to the limited water solubility of the test marterial.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

validity criteria as stated above fulfilled.

Conclusions:

The test material was shown not to significantly accumulate in fish tissue (BCF values of 48 and 58 for the 0.001 and 0.01 mg/L test concentrations respectively) and was observed to be eliminated from the fish tissues over a 61 day depuration period. At the end of the depuration period, 70% and 97% of the test material was eliminated from the fish tissues for the 0.001 and 0.01 mg/L test concentrations respectively. The biological half-life is considered to be 39 to 54 days.

Executive summary:

A study was performed to assess the bioconcentration potential of SP6012 in rainbow trout in line with OCED Guideline 305. Rainbow trout were exposed to test concentrations of 0.001 mg/L and 0.01 mg/L for a period of 42 days under dynamic test conditions. Samples of test fish were taken from the control and test groups on days 21, 25, 28, 32, 35 and 39 of the uptake phase and the concentration of test material in the fish tissues determined. After 42 days exposure the remaining fish were subjected to a depuration period of 61 days. Samples of test fish were taken from the control and test groups on days 3, 6, 11, 13 and 61 of the depuration phase and the concentration of test material determined.

The BCF (BCF_ss) values were determined to be 45 and 58 for the test concentrations of 0.001 mg/L and 0.01 mg/L respectively. The BCF (BCF_k) values were calculated to be 38 and 64 for the test concentrations of 0.001 mg/L and 0.01 mg/L respectively. The uptake and depuration rate constants k₁ and k₂ were determined to be 2.8321 and 0.0742 for the 0.001 mg/L test concentration and 48 and 0.7442 for the 0.01 mg/L test concentration.

SP6012 was shown not to significantly accumulate in fish tissue and was observed to be eliminated from the fish tissues over a 61 day depuration period. At the end of the depuration period, 70% and 97% of the test material was eliminated from the fish tissues for the 0.001mg/L and 0.01 mg/L test concentrations respectively. Based on this information, the biological half-life is considered to be 39 to 54 days.