N,N-dicyclohexylbenzothiazole-2-sulphenamide

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:

1996-2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

This study was conducted in accordance with The Test Methods Relating to New Chemical Substances “Bioconcentration test of chemical substances in fish and shellfish” (Kanpogyo No. 5, Yakuhatsu No. 615 and 49 Kikyoku No. 392 dated July 13, 1974, amended on October 8, 1998) and the OECD Guidelines for Testing of Chemicals “Bioaccumulation: Flow-through Fish Test (Guideline 305, June 14, 1996)

Deviations:

not specified

Remarks:

Sixth concentration level, 0.01 µg/l

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish)

Version / remarks:

This study was conducted in accordance with The Test Method Relating to New Chemical Substances “Bioconcentration test of chemical substances in fish and shellfish” (Kanpogyo No.5, Yakuhatsu No.615, 49 Kikyoku No.392, July 13, 1974) and OECD Guidelines for Testing of Chemicals 305C “Bioaccumulation: Test for the degree of Bioconcentration in Fish (May 12, 1981).

Deviations:

not specified

Remarks:

Fifth concentration level, 0.1 µg/l

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish)

Version / remarks:

This study was conducted in accordance with The Test Method Relating to New Chemical Substances “Bioconcentration test of chemical substances in fish and shellfish” (Kanpogyo No.5, Yakuhatsu No.615, 49 Kikyoku No.392, July 13, 1974) and OECD Guidelines for Testing of Chemicals 305C “Bioaccumulation: Test for the degree of Bioconcentration in Fish (May 12, 1981).

Deviations:

not specified

Remarks:

Fourth concentration level, 1 µg/l

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish)

Version / remarks:

This study was conducted in accordance with The Test Method Relating to New Chemical Substances “Bioconcentration test of chemical substances in fish and shellfish” (Kanpogyo No.5, Yakuhatsu No.615, 49 Kikyoku No.392, July 13, 1974) and OECD Guidelines for Testing of Chemicals 305C “Bioaccumulation: Test for the degree of Bioconcentration in Fish (May 12, 1981).

Deviations:

not specified

Remarks:

Third concentration level, 0.01 mg/l

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish)

Version / remarks:

This study was conducted in accordance with The Test Method Relating to New Chemical Substances “Bioconcentration test of chemical substances in vivo in fish and shellfish” (Kanpogyo No.5, Yakuhatsu No.615 and 49 Kikyoku No.392 dated July 13, 1974) and OECD Guidelines for Testing of Chemicals 305C “Bioaccumulation: Test for the Degree of Bioconcentration in Fish” (May 12, 1981).

Deviations:

not specified

Remarks:

Second concentration level, 0.1 mg/l

Qualifier:

according to guideline

Guideline:

OECD Guideline 305 C (Bioaccumulation: Test for the Degree of Bioconcentration in Fish)

Version / remarks:

This study was conducted in accordance with The Test Method Relating to New Chemical Substances “Bioconcentration test of chemical substances in vivo in fish and shellfish” (Kanpogyo No.5, Yakuhatsu No.615 and 49 Kikyoku No.392 dated July 13, 1974) and OECD Guidelines for Testing of Chemicals 305C “Bioaccumulation: Test for the Degree of Bioconcentration in Fish” (May 12, 1981).

Deviations:

not specified

Remarks:

First concentration level, 1 mg/l

GLP compliance:

yes

Radiolabelling:

no

Details on sampling:

A) First and second concentration level (1 mg/l and 0.1 mg/l)
Frequency of analysis
Analyses of the test substance in the test water were carried out in the First concentration level twice a week during the exposure period, a total 20 times; and in the Second concentration level twice a week during the exposure period, a total 16 times; one analysis sample being taken per analysis. Moreover, analyses of the test substance in the test fish were carried out five times in total at 2, 4, 6, 8 and 10 weeks after the start of the exposure in the First concentration level; and four times in total, at 2, 4, 6 and 8 weeks after the start of the exposure in the Second concentration level; the analysis samples comprising two fish each time. For the control levels, analyses were performed before and on completion of the exposure, again the analysis samples comprising two fish each time.

B) Third concentration level (0.01 mg/l)
Frequency of analysis
Analyses of the test substance in the test water were carried out twice a week during the exposure, a total 16 times, using one analysis sample per analysis. Moreover, analyses of the test substance in the test fish were carried out four times in total at 2, 4, 6 and 8 weeks after the start of the exposure, with two fish being used as analytical samples each time. For the control, analyses were performed before and on completion of the exposure, with two fish being used as analytical samples each time.

C) Fourth and fifth concentration level (1 µg/l and 0.1 µg/l)
Frequency of analysis
Analyses of the test substance in the test water were carried out twice a week during the exposure, a total 16 times, using one analysis sample per analysis. Moreover, analyses of the test substance in the test fish were carried out four times in total at 2, 4, 6 and 8 weeks after the start of the exposure, with two fish being used as analytical samples each time. For the control, analyses were performed before and on completion of the exposure, with two fish being used as analytical samples each time.

D) Sixth concentration level (0.01 µg/l)
Test water
Test water analysis was carried out once during the sixth concentration level exposure period up until the first test fish analysis, and then once again at the test fish analysis. One sample was eased used for each analysis.
Test fish
The test fish analysis was carried out five times during the Sixth concentration level exposure period, the number sampled per analysis was set at four fish, divided into two groups (2 fish per group)*3.
Moreover, the bioconcentration factor exceeded 1000 times, and so a depuration study was carried out. The test fish analysis was carried out four times during the depuration phase. The number of fish sampled per analysis was set at four, divided into two groups (two fish per group). On the sixth day, the number of fish sampled was six, divided into three groups (two fish per group).
For the control, analysis was carried out before the start of the experiment and on completion. The number of fish sampled per analysis was set at four, divided into two groups (two fish per group).
*3: As the quantity of analysis sample obtained per individual fish is insufficient for storage for lipid content measurement, two fish per group were used.

Vehicle:

yes

Remarks:

HCO-20, Olive oil

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

Preparation of stock solution

A) First and second concentration level (1 mg/l and 0.1 mg/l)
Dispersants: HCO-20, Olive oil
First concentration level preparation method: The test substance together with a 20 fold amount of HCO-20 and a 20 fold amount of olive oil were dissolved in acetone, and then after distilling off the acetone, a stock solution of the test substance in a concentration of 400 mg/L was prepared by dissolving in ion-exchanged water.
Second concentration level preparation method: The test substance together with a 20 fold amount of HCO-20 and a 20 fold amount of olive oil were dissolved in acetone, and then after distilling off the acetone, a stock solution of the test substance in a concentration of 40 mg/L was prepared by dissolving in ion-exchanged water.

B) Third concentration level (0.01 mg/l)
Dispersants: HCO-20, Olive oil
Preparation method: The test substance together with a 20 fold amount of HCO-20 and a 20 fold amount of olive oil were dissolved in acetone, and then after distilling off the acetone, dissolution in ion-exchanged water was performed and the concentration in the glass stock solution tank adjusted to 4 mg/L.

C) Fourth concentration level (1 µg/l)
Dispersants: HCO-20, Olive oil
Preparation method: The test substance together with a 20 fold amount of HCO-20 and a 20 fold amount of olive oil were dissolved in acetone, and then after distilling off the acetone, a stock solution of the test substance in a concentration of 500 mg/L was prepared by dissolving in ion-exchanged water. Using this stock solution, the concentration in a glass stock solution tank was adjusted to 0.4 mg/L.

D) Fifth concentration level (0.1 µg/l)
Dispersants: HCO-20, Olive oil
Preparation method: The test substance together with a 20 fold amount of HCO-20 and a 20 fold amount of olive oil were dissolved in acetone, and after distilling off the acetone, a stock solution of the test substance in a concentration of 500 mg/L was prepared by dissolving in ion-exchanged water. A 50 mg/L stock solution was prepared by diluting with ion-exchanged water, and using this, the concentration in a glass stock solution tank was adjusted to 0.04 mg/L.

E) Sixth concentration level (0.01 µg/l)
Dispersants: HCO-20, Olive oil
The test substance together with a 20 fold amount of HCO-20 and a 20 fold amount of olive oil were dissolved in acetone, and then after distilling off the acetone a stock solution of the test substance in a concentration of 8 µg/L was prepared by dissolving in ion-exchanged water.

Test organisms (species):

Cyprinus carpio

Details on test organisms:

A) First and second concentration level (1 mg/l and 0.1 mg/l)
Source: Sugishima Fish Farm, Test fish received on June 15, 1995
Body weight, body length etc. before starting exposure:
Body weight Average 20.4 g
Body length Average 9.0 cm
Lipid content Average 3.9%
Feed
Type: Pellet formula feed for carp
Manufacturer: Nippon Formula Feed Manufacturing Co., Ltd.
Feeding method: The fish were fed twice daily at a total rate of approximately 2% of their body weight per day. The feeding was stopped on the day before sampling.

B) Third concentration level (0.01 mg/l)
Source: Sugishima Fish Farm, Date fish received : October 17, 1995
Body weight, body length etc. before the exposure
Body weight Average 23.2 g
Body length Average 9.6 cm
Lipid content Average 4.0%
Feed
Type: Pellet formula feed for carp
Manufacturer: Nippon Formula Feed Manufacturing Co., Ltd.
Feeding regime: The fish were fed twice daily at a total rate of approximately 2% of their body weight per day. The feeding was stopped on the day before sampling.

C) Fourth and fifth concentration level (1 µg/l and 0.1 µg/l)
Supplier: Sugishima Fish Farm, Date fish received : March 29, 1996
Body weight, body length etc. before the exposure
Body weight Average 21.9 g
Body length Average 9.2 cm
Lipid content Average 4.0%
Feed
Type: Pellet formula feed for carp
Manufacturer: Nippon Formula Feed Manufacturing Co., Ltd.
Feeding regime: The fish were fed twice daily at a total rate of approximately 2% of their body weight per day. The feeding was stopped on the day before sampling.

D) Sixth concentration level (0.01 µg/l)
Supply source: Sugishima Fish Farm, Delivery date September 20, 2000
Body length: 7.3-9.1 cm
Age: yearlings
Feed
Type: Composite feed for raising young carp
Composition: Protein content 43.0% or more
Fat content 3.0% or more
Manufacturer: Nippon Formula Feed Manufacturing Co., Ltd.
Feeding regime: The fish were fed twice daily at a total rate of approximately 2% of their body weight per day. The feeding was stopped on the day before sampling

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

other: Ground water (Drinking Water Quality Standards based on the Waterworks Act (MHLW Ordinance No.69, amended on December 21, 1992))

Remarks:

OECD Guideline for Testing of Chemicals 210, Fish, Early-life Stage Toxicity Test

Total exposure / uptake duration:

>= 6 - <= 10 wk

Total depuration duration:

13 d

Test temperature:

25+/-2°C

pH:

7.7 - 8.0

Dissolved oxygen:

6.1-8.2 mg/L

Details on test conditions:

A) First and second concentration level (1 mg/l and 0.1 mg/l)
Method of water supply for the test: A flow-through apparatus assembled at this laboratory was used.
Test vessels: 100 L glass aquaria
Quantity of water for the test: 1155 L/day (in proportions of 2 mL/minute stock solution and 800 mL/minute test water) was supplied to the test vessel.
Stock solution tank: 25 L glass jar
Test temperature: 25±2°C
Dissolved oxygen concentration
First concentration level: 6.1-7.4 mg/L
Second concentration level: 7.2-7.8 mg/L
Control level: 6.4-7.7 mg/L
Number of test fish: First and second concentration level 11 fish
Duration of exposure:
First concentration level and control level: 10 weeks
Second concentration level: 8 weeks
Culturing conditions: On arrival, the fish were visually inspected and those with an abnormality were removed, the fish were placed in a medicated bath tank, and raised for 18 days under flow-through conditions.
Acclimatization conditions: After culturing, and after the fish had been transferred to the acclimatization water tank and treated with a medicated bath, the acclimatization was carried out. During this procedure, the fish were reared for 2 days at 25±2°C under flow-through conditions; fish with abnormalities were removed. Thereafter screening and treatment with a medicated bath were carried out once again, and the fish were reared for 48 days under flow-through conditions.
Completion of acclimatization: August 29, 1995

B) Third concentration level (0.01 mg/l)
Method of water supply for the test: A flow-through apparatus assembled at this laboratory was used.
Test vessels: 70 L glass aquaria
Quantity of water for the test: 1155 L/day (in proportions of 2 mL/minute stock solution and 800 mL/minute test water) was supplied to the test tank.
Stock solution tank: 25 L glass jar
Test temperature: 25±2°C
Dissolved oxygen concentration:
Third concentration level 6.6-7.7 mg/L
Control level 7.6-8.1 mg/L
Number of test fish
Third concentration level: 15 fish (at the start of exposure)
Control level: 5 fish (at the start of exposure)
Duration of exposure: 8 weeks
Culturing conditions: The fish were visually inspected on their arrival, and those with an abnormality were removed, the remaining fish were treated with a medicated bath, and then cultured for five days under flow-through conditions.
Acclimatization conditions: After culturing, the fish were treated with a medicated bath for parasite removal, then transferred to an acclimatization water tank, and following treatment with a medicated bath subjected to acclimatization. During this period, the fish were reared for 39 days under flow-through conditions at 25±2°C; fish with abnormalities were removed. Furthermore, following transfer of the fish into a further test vessel and treatment with a medicated bath, the fish were then reared for 9 days under flow-through conditions at the same temperature.
Completion of acclimatization: December 4, 1995

C) Fourth concentration level (1 µg/l)
Method of water supply for the test: A flow-through apparatus assembled at this laboratory was used.
Test vessels 100 L glass aquaria
Quantity of water for the test: 1155 L/day (in proportions of 2 mL/minute stock solution and 800 mL/minute test water) was supplied to the test vessel.
Stock solution tank: 25 L glass jar
Test temperature: 25±2°C
Dissolved oxygen concentration: Fourth concentration level 7.0-7.7 mg/L (see: Fig.9)
Control level: 7.8-8.2 mg/L (see: Fig.10)
Number of test fish: Fourth concentration level 20 fish (at the start of exposure)
Control level: 5 fish (at the start of exposure)
Duration of exposure: 8 weeks
Culturing conditions: The fish were visually inspected on their arrival, and those with an abnormality were removed, the remaining fish were treated with a medicated bath, and then cultured for two days under flow-through conditions.
Acclimatization conditions After culturing, the fish were treated with a medicated bath for parasite removal, then transferred to an acclimatization water tank, and following treatment with a medicated bath subjected to acclimatization. During this period, the fish were reared for 34 days under flow-through conditions at 25±2°C; fish with abnormalities were removed. Furthermore, following transfer of the fish into a further test vessel and treatment with a medicated bath, the fish were then reared for 13 days under flow-through conditions at the same temperature.
Completion of acclimatization: May 8, 1996

D) Fifth concentration level (0.1 µg/l)
Method of water supply for the test: A flow-through apparatus assembled at this laboratory was used.
Test vessels 70 L glass aquaria
Quantity of water for the test: 1155 L/day (in proportions of 2 mL/minute stock solution and 800 mL/minute test water) was supplied to the test vessel.
Stock solution tank: 25 L glass jar
Test temperature: 25±2°C
Dissolved oxygen concentration: Fifth concentration level 7.2-7.8 mg/L (see: Fig.17)
Control level: 7.7-8.0 mg/L (see: Fig.18)
Number of test fish: Fifth concentration level, 16 fish (at the start of exposure)
Control level 5 fish (at the start of exposure)
Duration of exposure: 8 weeks
Culture conditions: The fish were visually inspected on their arrival, and those with an abnormality were removed, the fish were placed in a medicated bath tank, and raised for two days under flow-through conditions.
Acclimatization conditions: After culturing, the fish were treated with a medicated bath for parasite removal, then transferred to an acclimatization water tank, and following treatment with a medicated bath subjected to acclimatization. During this period, the fish were reared for 49 days under flow-through conditions at 25±2°C; fish with abnormalities were removed. Furthermore, following transfer of the fish into a further test vessel and treatment with a medicated bath, the fish were then reared for 29 days under flow-through conditions at the same temperature.
Completion of acclimatization: August 5, 1996

E) Sixth concentration level (0.01 µg/l)
Method of water supply for the test: Water was supplied using a device assembled at Kurume laboratory.
Test vessel: 100 L glass aquaria
Quantity of water for the test: 2307 L/day (in proportions of 2 mL/minute stock solution and 1600 mL/minute test water) was supplied to the test vessel.
Stock solution tank: 25 L capacity glass jar
Replacement frequency: around 1-2 times/week
Test temperature: Sixth concentration level: 25.0-25.3°C
Control level: 25.0-25.3°C
Dissolved oxygen concentration: Sixth concentration level: 7.7-8.1 mg/L
Control level: 8.0-8.2 mg/L
pH: Sixth concentration level: 7.7-8.0
Control level: 7.7-8.0
Illumination period: Artificial light with white fluorescent lamp (14 hours light / 10 hours dark)
Number of test fish: Sixth concentration level: 60 fish (at start of exposure)
Control level: 8 fish (at start of exposure)
Duration of exposure:42 days
Rationale: From the results of a preliminary study, it was predicted that the steady state would not be reached in 28 days.
Depuration period:13 days
Culturing conditions: The fish were visually inspected on their arrival, and those with an abnormality were removed; the remaining fish were treated with a medicated bath, and then cultured for nineteen days under flow-through conditions.
Acclimatization conditions: After culturing, the fish were treated with a medicated bath for parasite removal; then transferred to an acclimatization water tank, and following treatment with a medicated bath, subjected to acclimatization. During this period, the fish were reared for 27 days under flow-through conditions at 25±2°C; fish with abnormalities being removed. Furthermore, following transfer of the fish into a further test vessel and treatment with a medicated bath, the fish were then reared for 27 days under flow-through conditions at the same temperature.

Nominal and measured concentrations:

Considering of the result of preliminary test for 48-hr LC50 and analytically detecting limit of the test substance, test concentrations were decided.
Nominal: 1000, 100, 10, 1, 0.1 and 0.01 µg/L

Lipid content:

2.58 %

Time point:

start of exposure

Remarks on result:

other: for sixth concentration level BCF = 6000

Lipid content:

2.1 %

Time point:

end of exposure

Remarks on result:

other: for sixth concentration level BCF = 6000

Lipid content:

3.9 %

Time point:

start of exposure

Remarks on result:

other: for first concentration level BCF = 15-80

Lipid content:

3.9 %

Time point:

start of exposure

Remarks on result:

other: for second concentration level BCF = 74-316

Lipid content:

4 %

Time point:

start of exposure

Remarks on result:

other: for third concentration level BCF = 331-916

Lipid content:

4 %

Time point:

start of exposure

Remarks on result:

other: for fourth concentration level BCF = 1150-3950

Lipid content:

3.7 %

Time point:

start of exposure

Remarks on result:

other: for fifth concentration level BCF = 3380-7310

Conc. / dose:

>= 0.947 - <= 0.954 mg/L

Temp.:

25 °C

pH:

7.7

Type:

BCF

Value:

>= 15 - <= 80 dimensionless

Basis:

whole body w.w.

Time of plateau:

10 wk

Calculation basis:

other: no data

Remarks on result:

other: Conc.in environment / dose:1000 µg/L

Conc. / dose:

>= 0.094 - <= 0.095 mg/L

Temp.:

25 °C

pH:

7.7

Type:

BCF

Value:

>= 74 - <= 316 dimensionless

Basis:

whole body w.w.

Time of plateau:

8 wk

Calculation basis:

other: no data

Remarks on result:

other: Conc.in environment / dose:100 µg/L

Conc. / dose:

>= 9.65 - <= 9.71 µg/L

Temp.:

25 °C

Type:

BCF

Value:

>= 331 - <= 916 dimensionless

Basis:

whole body w.w.

Time of plateau:

8 wk

Calculation basis:

other: no data

Remarks on result:

other: Conc.in environment / dose:10 µg/L

Conc. / dose:

>= 0.826 - <= 0.854 µg/L

Temp.:

25 °C

Type:

BCF

Value:

>= 1 150 - <= 3 950 dimensionless

Basis:

whole body w.w.

Time of plateau:

8 wk

Calculation basis:

other: no data

Remarks on result:

other: Conc.in environment / dose:1 µg/L

Key result

Conc. / dose:

>= 0.074 - <= 0.081 µg/L

Temp.:

25 °C

Type:

BCF

Value:

>= 3 380 - <= 7 310 dimensionless

Basis:

whole body w.w.

Time of plateau:

8 wk

Calculation basis:

other: no data

Remarks on result:

other: Conc.in environment / dose:0.1 µg/L

Conc. / dose:

>= 0.009 - <= 0.01 µg/L

Temp.:

24.5 °C

pH:

7.8

Type:

BCF

Value:

6 000 dimensionless

Basis:

whole body w.w.

Time of plateau:

42 d

Calculation basis:

steady state

Remarks on result:

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

Elimination:

yes

Parameter:

DT50

Remarks:

depuration half-life

Depuration time (DT):

6.1 d

Remarks on result:

other: at the sixth concentration level BCF = 6000

Elimination:

yes

Parameter:

DT50

Remarks:

depuration half-life

Depuration time (DT):

9 d

Remarks on result:

other: at the fifth concentration level BCF = 3380-7310

Elimination:

yes

Parameter:

DT50

Remarks:

depuration half-life

Depuration time (DT):

11 d

Remarks on result:

other: at the fourth concentration level BCF = 1150-3950

Details on results:

No information on mortality of fishes given.

48h, LC50 = 130 mg/L or more (Calculation performed by the Doudoroff method)

96h, LC50 = >250 mg/L or more (Calculation performed by the Doudoroff method)

Validity criteria fulfilled:

yes

Remarks:

Blank tests were carried out on the test water, using the same procedures as in the recovery tests (both performed on duplicate samples). In the blank test, no peak was observed at the identical position to the test substance in the chromatogram.

Conclusions:

In a bioaccumulation test corresponding to OECD Guideline 305C, BCF of 15 -7310 for DCBS was determined on Cyprinus carpio as test organism within 6-10 weeks (MITI, 2005). According to this result, DCBS can be taken as highly bioaccumulative. However, the depuration phase of 13 d may be a bit short for a depuration half-life of 11 d for a concentration of 1 µg/L.

Executive summary:

In a bioaccumulation test corresponding to OECD Guideline 305C, BCF of 15 -7310 for DCBS was determined on Cyprinus carpio as test organism within 6-10 weeks (MITI, 2005). According to this result, DCBS can be taken as highly bioaccumulative. However, the depuration phase of 13 d may be a bit short for a depuration half-life of 11 d for a concentration of 1 µg/L.

Description of key information

In a bioaccumulation test corresponding to OECD Guideline 305C, BCF of 15 -7310 for DCBS was determined on Cyprinus carpio as test organism within 10 weeks (MITI, 2005). According to this result, DCBS can be taken as highly bioaccumulative. A hydrolysis half-life of 53 hours at pH 7 and 25°C was observed for DCBS (Bayer AG, 1997) with Dicyclohexylamine and 2-mecarptobenzothiazole (MBT) as the main hydrolysis products (MITI, 2005). Dicyclohexylamine occurs in aquatic environmental mostly in protonated form and has an estimated BCF of 3.2 (SIDS, 2006), which indicates no bioaccumulation potential. A BCF of < 0.8 (0.1 mg/l) - < 8 (0.01 mg/l) for 2-mercaptobenzothiazole (MBT) was determined on Cyprinus carpio within 6 weeks (MITI 1992), according to which MBT is also not bioaccumulative. The described metabolites from MBT are also non-bioaccumulative (BCF<100) according to the Appendix A of EU-Risk Assessment for CBS (CAS: 95-33-0).
In a monitoring study in Japan (MITI 2010) no DCBS (<4.4 µg/kg) was found in biota such as fish and mussels. From this study, no BCF can be derived as both, the concentrations in the water and in animals were below the limit of quantitation (LOQ). The reported extremely low LOQs (0.3 - 1.1 µg/L in water, 4,4 µg/L in animals) represent a high-end analysis. Finally the monitoring results indicate that bioaccumulation in the real environment occurs limited and yields no measureable residues in aquatic organisms. For comparison: MITI 2005 reported concentrations in fish of 50 to 100 µg/kg in a flow-throug system with 0.01 µg/L in water which resulted in the BCF of up to 7310. Therefore, the classification as vB is correct from a formal point of view (BCF >5000) but indeed questionable having the monitoring results in mind.

Key value for chemical safety assessment

BCF (aquatic species):

7 310 dimensionless