2-Propyl-4-methyl-6-(1-methylbenzimidazol-2-yl)benzimidazole

Bioaccumulation: aquatic / sediment

Administrative data

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009-08-10 to 2009-10-14

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test procedure in accordance to OECD 305 B with acceptable restrictions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 B (Bioaccumulation: Semi-static Fish Test)

Version / remarks:

(1981)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1730 (Fish Bioconcentration Test)

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: SEPA. HJ/t 154-2004: The guidelines for the hazard evaluation of new chemical substances (June 2004)

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: SEPA. HJ/t 153-2004: The guidelines for the testing of chemicals (June 2004)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-Propyl-4-methyl-6-(1-methylbenzimidazole-2-yl)benzimidazole

IUPAC Name:

2-Propyl-4-methyl-6-(1-methylbenzimidazole-2-yl)benzimidazole

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Radiolabelling:

not specified

Sampling and analysis

Details on sampling:

Sampled 50 mL of water per tank from the test tanks for the determination of test substance concentration 2h after fish loaded and 2h before water renewed during every 4-day interval period throughout the test. Remove seven fish per tank per time (day) at 22nd, 23rd, 24th, 25th, 26th, 27th, 28th day after beginning of the test. Rinsed the sampled fish quickly with water, killed instantly, using the most appropriate and humane method, and then weighed.Water sample:Water sample was filtered with a 0.45 µm millipore hydrophilic membrane, after mixed with same volume of methanol, the mixture was analyzed by UPLC-MS/MS without any extraction.Fish sample:To a glass bowl seven weighed fish are put in. The fish was whetted with 5g of anhydrous sodium sulphate to powder. Then the powder is completely transferred into a Teflon centrifugal tube (with capacity of 50 mL). The glass bowl is washed by methanol (5mL x 3). The wash solutions are collected and transferred into the homogenized (800 rpm for 2 min). The rotor of the homogenizer is washed with 5 mL of methanol. Then the tube is centrifuged for 5 min (4000 rpm). The supernatant is separated, and the residue is washed with 5 mL of methanol. The supernatant and the wash solution are collected together and then concentrated decompressed on a rotary evaporator to remove the organic solvent at 45°C water bath. The final residue was re-dissolved with accurate 2 mL of methanol. Prior to analysis, the final solution was filtered through a 0.45 µm organic micro-filter (Millipore, Millex-GP, USA), then undergone for UPLC-MS/MS

Test solutions

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: standard storage solution 1000 mg/L: 0.1 g test substance in 100mL methanol; standard working solution: 0.1-100 mg/L with methanol; the filtered (through 0.45 µm membrane) fish cultivation water was mixed with the volume of the standard solutions to obtain water matrix matched standard working solutions for quantification of the substance in water sample. The spiked ratio of Fish matrix solution and standard working solution was 19:1. Fish matrix solution was prepared using non test fish but the same batch with test fish.

Test organisms

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM- Common name: zebra fish- Length at study initiation (length definition, mean, range and SD): average body length 3.0 +- 0.5 cm (including the length of their tail)ACCLIMATION- Acclimation period: 7-14 days- Acclimation conditions (same as test or not): same

Study design

Route of exposure:

aqueous

Test type:

semi-static

Water / sediment media type:

natural water: freshwater

Test conditions

Hardness:

no data

Test temperature:

21.1°C to 25°C (average 22.7°C)

pH:

no data

Dissolved oxygen:

5.44 mg/L (minimum concentration)

TOC:

no data

Salinity:

not applicable

Details on test conditions:

TEST SYSTEM- Test vessel: square-shaped aquaria with capacity of 25L; column-shaped aquaria with capacity of 20L- Renewal rate of test solution (frequency/flow rate): Semi-static with 96 h renewal- No. of organisms per vessel: 50- Biomass loading rate: fish loading: 0.7-1.0 g/LOTHER TEST CONDITIONS- Photoperiod: 12 hours light/12 hours dark RANGE-FINDING / PRELIMINARY STUDYMaximum non-effect concentration (MNOEC) test was conducted:Test concentration ranged from 1 to 50 mg/L. 10 fish per vessel were loaded. Control group was only without test substance. Following a 96 -h settling-in period, mortalities and poisoning symptom were recorded. During test periods, culture water was not replaced. MNOEC was used for Bioconcentration test.

Nominal and measured concentrations:

0.918 and 0.212 mg/L (nominal; mean concentration)

Reference substance (positive control):

no

Results and discussion

Bioaccumulation factor

Key result

Temp.:

>= 21.1 - <= 25 °C

Type:

BCF

Value:

< 10 dimensionless

Basis:

whole body w.w.

Calculation basis:

steady state

Details on results:

- Mortality of test organisms: in the two exposure groups and control group, the mortality rate was 7% (at 0.212 mg/L), 9% (at 0.918 mg/L) and 6% (control), respectively

Any other information on results incl. tables

Calibration curve:

For water sample, the linear regression equation of the substance was: y=9783.5x+793.36, with good linearity of r^2 =0.9995 for 0.05 ~5.0 mg/L

For Fish sample, the linear regression equation of the substance was: y=2659.6x+37.532, with good linearity of r^2 =1 for 0.05~1.0 mg/L

Recovery and precision:

The recovery in the water sample was between 98.6%~113.5% and RSD was 3.61%~6.03%;

The recovery in the fish sample was between 77.7%~109.7% and RSD was 2.41%~9.22%;

Bioconcentration factor (BCF):

For 0.2 mg/L exposure group, the maximum fluctuating rate of concentration of the test substance in water was 8.5% (absolute value) during 4 -day period and 19.3% between the maximum concentration and the minimum concentration. The average concentration of the test substance in water was 0.212 mg/L;

For 1.0 mg/L exposure group, the maximum fluctuating rate of concentration of the test substance in water was 10.1% (absolute value) during 4 -day period and 11.9% between the maximum concentration and the minimum concentration. The average concentration of the test substance in water was 0.918 mg/L;

The concentration of the test substance in fish archives to "steady-state" at 27th day. The "steady-state" concentration was 0.632 mg/kg and 0.702 mg/kg for 0.2 mg/L exposure group and 1.0 mg/L exposure group, respectively;

Considering that the substance was stable in water (half-life time was upper than 1 year in pH5, pH7 and pH9) and the cultivation media was moderate acidic water, the average concentrations of the test substance in water were regarded as steady-state concentration. BCFss 2.98 at 0.212 mg/L and 0.76 at 0.918 mg/L were estimated.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The BCFss was 2.98 at 0.212 mg/L and 0.76 at 0.918 mg/L. The bioconcentration factors of the substance was in fish were below 10, so has low bioconcentration effect on fish during the exposure of 28 days.