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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Reference
Endpoint:
bioaccumulation in aquatic species: fish
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study.
Principles of method if other than guideline:
according to the test method relating to new chemical substances (1974, amended 1998), which prescribes the procedure for testing new chemical substances as required by the Chemical Substances Control Law of Japan
GLP compliance:
yes
Radiolabelling:
no
Details on sampling:
Sampling of test water on day: 0, 2, 7, 14, 21, 28, 36.
On days 2, 7, 14, 21, 28 and 36 of the exposure period, four fish were taken from each concentration levels and analyzed two by two.
Vehicle:
yes
Details on preparation of test solutions, spiked fish food or sediment:
Preparation of feed solutions:
- test item (10 g) was dissolved in HCO-40 (200 g) and 2-methoxyethanol and diluted with dilution water to 1000 mL (Feed solution 1, high concentration level)
- feed solution for low concentration level: 100 mL of feed solution 1 was diluted with 2-methoxyethanol and dilution water to 1000 mL (feed solution 2)
- to prepare feed solutions for the control group, only 2-methoxyethanol and HCO-40 were diluted with dilution water to the desired volume

Preparation of test water:
- each of the feed solutions was supplied to a mixing glass tube by a metering pump and diluted to their respective nominal concentrations by mixing with dilution water deliverd by another metering pump, then poured into each test chamber
Test organisms (species):
Cyprinus carpio
Details on test organisms:
- Species: Carp (Cyprinus carpio)
- Source: Sankyo Suisan Co., 1-1, Ichigayatamachi, Shinjuku-ku, Tokyo, Japan
- Date of purchase: July 29, 2003
- Lot number: 03-K-0729
- Pre-acclimation: At the lot of fish was received, visual observation was made and abnormal fish were removed. The remaining fish were then reared in an aquarium with water flowing through. During the acclimation period, fish were kept wi thout receiving medicine in the aquarium
- total length: 8 +/- 4 cm 
- body weight: approx. 5 g
- age: about 1 year after hatching 
- lot no.: 03-K-0729
- supplier: Sankyo Suisan Co., 1-1, Ichigayatamachi, Shinjuku-ku, Tokyo,  Japan

ACCLIMATION:
- acclimation period: >= 2 weeks
- temperature: 24 +/- 2 °C
- no medicine throughout the acclimation period
- food was given in an amount of 2 % of the fish weight (Babygold from  Kyorin) 
Mortality during the 1 week before testing: <5%
Route of exposure:
aqueous
Test type:
flow-through
Water / sediment media type:
natural water: freshwater
Total exposure / uptake duration:
36 d
Test temperature:
24 °C
measured when test water was sampled
pH:
6.0 - 8.5
measured at start and end of exposure period
Dissolved oxygen:
>= 60 % of saturation
measured when test water was sampled
Details on test conditions:
The bioconcentration test system was operated with no fish for at least 1 day until LC/MS analysis proved that the test substance concentrations in both test chambers were kept at their respective nominal concentrations. The bioconcentration test was then started by introducing fish into the system.
- Feeding: Babygold® from Kyorin was given in an amount of approximately 2% of the fish weight everyday except weekends.
- photoperiod: 16 hr/day (Hf fluorescent lamp with wavelengths of 400 -  700 nm)
- dissolved oxygen: >= 60 % of the saturation (>= 5 mg/l at 24 °C)
- continuous aeration
- supply of dilution water: 400 L/day (turnover rate 8 times/day)
- supply of feed solution: 40 mL/day
- number of fish per test vessel (50L test water) for:   
- high concentration: 36   
- low concentration: 36   
- control: 28
- test concentration: 1 mg/L, 0.1 mg/L plus 1 control
- exposure period: 36 days
- Conditions of fish: Observations were made on the external appearance of fish and the swimming and feeding behavior.
- Lipid content: At the start and end of the exposure period, five control fish were taken and three of them were measured lipid content (n=3, respectively).
Nominal and measured concentrations:
Nominal: 1 mg/L and 0.1 mg/L
The concentration levels over the exposure period averaged 0.994 mg/L (peak A), 0.988 mg/L (peak B), 0.950 mg/L (peak C) and 0.976 mg/L (peak D) at high concentration level and 0.0947 mg/L (peak A), 0.0936 mg/L (peak B), 0.0912 mg/L (peak C) and 0.0948 mg/L (peak D) mg/L at low concentration level, sufficiently close to the nominal values. The coefficients of variation were 5.3% (peak A), 5.2% (peak B), 5.0% (peak C) and 5.3% (peak D) at high concentration level, and 7.7% (peak A), 11.7% (peak B), 8.8% (peak C) and 7.6% (peak D) at low concentration level, respectively. The concentrations of the test substance in the chamber were maintained within ±20% of the mean of the measured values.
Conc. / dose:
1 mg/L
Type:
BCF
Value:
>= 7 - <= 39 dimensionless
Basis:
whole body w.w.
Calculation basis:
steady state
Conc. / dose:
0.1 mg/L
Type:
BCF
Value:
>= 56 - <= 212 dimensionless
Basis:
whole body w.w.
Calculation basis:
steady state
Details on results:
As Mesamoll is an UVCB substance four peaks were detected in the chromatogram. The BCF values were determined using these peaks as representatives of the mixture yielding a BCF range, whereas the lowest and hightes value is presented.

Steady-state: It is considered that steady-state is reached, when three successive results of BCF at intervals of 48 hours or longer are within 20% of each other.
Although variation of the mean bioconcentration factors determined at 3 consecutive measurements by the end of exposure period at peak A in high concentration level did not fall within ±20%, bioconcentration factors were regarded to have reached the steady state since the bioconcentration factors during exposure period were less than 100. However, bioconcentration factors at steady state (BCFss) were indicated as range of factors.
The bioconcentration factors at peak A in low concentration level were regarded to have reached the steady state since the bioconcentration factors during exposure period were less than 100 and the detection limit. However, bioconcentration factors at steady state (BCFss) were indicated as range of factors.
For levels, steady peak B, peak C and peak D in high and low concentration bioconcentration factors were confirmed to have reached state since variation of mean bioconcenration factors determined at 3 consecuti ve measurements by the end of exposure period fell within ± 20%. Bioconcentration factors at steady state were 7 (peak B), 39 (peak C) and 24 (peak D) at high concentration level and 56 (peak B), 212 (peak C) and 117 (peak D) at low concentration level, respectively.


In the blank test the concentration of Mesamoll in fish was calculated to  be < 5.8 µg/g.

The following quality criteria were met:
During the period of the test, the concentration of dissolved oxygen and the temperature variation fulfilled the test conditions;
the pH values were within the range;
the mortalities in both control and treated fish were less than 10 % at the end of the test;
there was no abnormality in shape of the body or in swimming and feeding behaviour observed
chemical analysis stated that the test substance was sufficiently stable under test conditions and the concentration in the test system was sufficiently close to the nominal values
Validity criteria fulfilled:
yes
Conclusions:
The BCF of Mesamoll ranges from 7 to 39 and 56 to 212 having a concentration in the water phase of 1 mg/L and 0.1 mg/L, respectively. Accordingly, the test item has only a low potential to accumulate in aquatic organisms.
Executive summary:

The study was conducted in accordance with the Test Method Relating to New Chemical Substances (1974, amended 1998), which precribes the procedure for testing new chemical subst:ances as required by the Chemical Substances Control Law of Japan. In addition to the control (28 fish), two groups of 36 carps each were exposed to the test substance at different concentration levels (0.1 mg/L and 1 mg/L) through the medium of dilution water for 36 days. The water was aerated and maintained at 24°C. During the exposure period, the concentrations of the test substance in water and fish were measured periodically. The bioconcentration factors (BCF) calculated from the results were used to evaluate the potential for the test substance to accumulate in the tissues of carp. Before starting the bioconcentration test, an acute toxicity test with Medaka was conducted for 96 hours and a 50% lethal concentration (LC50 ) was determined. As the test substance was a mixture, four peaks were detected in LC/MS chromatograms. Concentration of the test substance was measured at retention time of each peaks.

Although variation of the mean bioconcentration factors determined at 3 consecutive measurements by the end of exposure period at peak A in high concentration level did not fall within ± 20%, bioconcentration factors were regarded to have reached the steady state since the bioconcentration factors during exposure period were less than 100. However, bioconcentration factors at steady state (BCFssl were indicated as rage of factors. The bioconcentration factors at peak A in low concentration level were regarded to have reached the steady state since the bioconcentration factors during exposure period were less than 100 and the detection limit. However, bioconcentration factors at steady state (BCFss) were indicated as range of factors. For peak B, peak C and peak D in high and low concentration levels, bioconcentration factors were confirmed to have reached steady state since variation of mean bioconcenration factors determined at 3 consecutive measurement.s by the end of exposure period fell wi thin ± 20%. Bioconcentration factors at steady state were 7 (peak B), 39 (peak C) and 24 (peak D) at high concentration level and 56 (peak B), 212 (peak C) and 117 (peak D) at low concentration level, respectively.

The bioconcentration factors (BCF) obtained in this study were as follows: 7 to 39 and 56 to 212 having a concentration in the water phase of 1 mg/L and 0.1 mg/L, respectively.

Description of key information

The study was conducted in accordance with the Test Method Relating to New Chemical Substances (1974, amended 1998), which precribes the procedure for testing new chemical subst:ances as required by the Chemical Substances Control Law of Japan. In addition to the control (28 fish), two groups of 36 carps each were exposed to the test substance at different concentration levels (0.1 mg/L and 1 mg/L) through the medium of dilution water for 36 days. The water was aerated and maintained at 24°C. During the exposure period, the concentrations of the test substance in water and fish were measured periodically. The bioconcentration factors (BCF) calculated from the results were used to evaluate the potential for the test substance to accumulate in the tissues of carp. Before starting the bioconcentration test, an acute toxicity test with Medaka was conducted for 96 hours and a 50% lethal concentration (LC50 ) was determined. As the test substance was a mixture, four peaks were detected in LC/MS chromatograms. Concentration of the test substance was measured at retention time of each peaks.

Although variation of the mean bioconcentration factors determined at 3 consecutive measurements by the end of exposure period at peak A in high concentration level did not fall within ± 20%, bioconcentration factors were regarded to have reached the steady state since the bioconcentration factors during exposure period were less than 100. However, bioconcentration factors at steady state (BCFssl were indicated as rage of factors. The bioconcentration factors at peak A in low concentration level were regarded to have reached the steady state since the bioconcentration factors during exposure period were less than 100 and the detection limit. However, bioconcentration factors at steady state (BCFss) were indicated as range of factors. For peak B, peak C and peak D in high and low concentration levels, bioconcentration factors were confirmed to have reached steady state since variation of mean bioconcenration factors determined at 3 consecutive measurement.s by the end of exposure period fell wi thin ± 20%. Bioconcentration factors at steady state were 7 (peak B), 39 (peak C) and 24 (peak D) at high concentration level and 56 (peak B), 212 (peak C) and 117 (peak D) at low concentration level, respectively.

The bioconcentration factors (BCF) obtained in this study were as follows: 7 to 39 and 56 to 212 having a concentration in the water phase of 1 mg/L and 0.1 mg/L, respectively.

Key value for chemical safety assessment

BCF (aquatic species):
212 dimensionless

Additional information

Based on the measured BCF values the test substance is assumed to have a low potential to accumulate in aquatic organisms.