N-tert-butylbenzothiazole-2-sulphenamide

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Data from peer-reviewed handbook or collection of data

Justification for type of information:

TBBS has a hydrolysis half- life of 1.8h (MITI1996) to 9.53 h (Monsanto 1984) and therefore hydrolysis is a significant factor in the aquatic environment. According to REACH Guidance Document R.7c (20142017, p. 2629) it can be assumed that the rate of hydrolysis is greater than that for uptake by the exposed organisms, where hydrolysis half-life is below 12 h. In these cases, it may sometimes be appropriate to perform a BCF test on the hydrolysis products, if identified, instead of the parent substance. In case of TBBS, MBT and tert-butylamine are identified hydrolysis products for which bioaccumulation tests are available. The experimentally determined BCF of MBT is lower than 8 and the one of tert-butylamine lower than 9; and hence MBT and tert-butylamine and therefore also TBBS are considered to have very low potential for bioaccumulation (MITI, 2000 and 2003).

Qualifier:

according to guideline

Guideline:

other: "Bioaccumulation test of chemical substance in fish and shellfish", order of the prime minister, the minister of health and welfare, the minister of international trade and industry No 1, Japan, 1974

Deviations:

no

Principles of method if other than guideline:

This guideline corresponds to OECD Guideline 305C (Bioaccumulation: Test for the degree of bioconcentration in Fish), 1981

GLP compliance:

not specified

Radiolabelling:

no

Details on sampling:

- Sampling intervals/frequency for test organisms: every two weeks, n=2, control fish analysis: before the initiation and the termination of exposure, n=2
- Sampling intervals/frequency for test medium samples: twice a week, n=1

Vehicle:

not specified

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

It is necessary to prepare a solution of the test substance 100 times highly concentrated than that in the aquarium. If the test substance is not soluble enough in water, suitable solubilisers were used. More detailled information is not available for the substance tested .

Test organisms (species):

Cyprinus carpio

Details on test organisms:

Supplier: Sugishima fish farm, Japan
Weight: about 30 g, Length: about 10 cm, Lipid content: 2-6 % (at the initiation of exposure)

Route of exposure:

aqueous

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Total exposure / uptake duration:

6 wk

Test temperature:

25 +-2 °C

Dissolved oxygen:

6-8 mg/L

Details on test conditions:

Test tank: 100L glass tank
Number of fish: 15-20 fish/Level
Renewal rate of test solutions: flow rate 200-800 mL/min

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.

Lipid content:

> 2 - < 6 %

Time point:

start of exposure

Key result

Type:

BCF

Value:

< 0.8

Basis:

whole body w.w.

Calculation basis:

steady state

Remarks on result:

other: Conc.in environment / dose:0.1 mg/l

Key result

Type:

BCF

Value:

< 8

Basis:

whole body w.w.

Calculation basis:

steady state

Remarks on result:

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

Calculation of bioconcentration factor

BCF = concentration of test substance in fish/concentration of test substance in water

Conclusions:

In a flow-through system for 2-mercaptobenzothiazole (MBT) a BCF of < 0.8 (0.1 mg/L) - < 8 (0.01 mg/L) was determined on Cyprinus carpio within 6 weeks (MITI 1992), and hence MBT is not bioaccumulative.

Executive summary:

In a flow-through system for 2-mercaptobenzothiazole (MBT) a BCF of < 0.8 (0.1 mg/L) - < 8 (0.01 mg/L) was determined on Cyprinus carpio within 6 weeks (MITI 1992), and hence MBT is not bioaccumulative.

Reference 2

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13.12.1999-16.02.2020

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

TBBS has a hydrolysis half- life of 1.8h (MITI1996) to 9.53 h (Monsanto 1984) and therefore hydrolysis is a significant factor in the aquatic environment. According to REACH Guidance Document R.7c (20142017, p. 2629) it can be assumed that the rate of hydrolysis is greater than that for uptake by the exposed organisms, where hydrolysis half-life is below 12 h. In these cases, it may sometimes be appropriate to perform a BCF test on the hydrolysis products, if identified, instead of the parent substance. In case of TBBS, MBT and tert-butylamine are identified hydrolysis products for which bioaccumulation tests are available. The experimentally determined BCF of MBT is lower than 8 and the one of tert-butylamine lower than 9; and hence MBT and tert-butylamine and therefore also TBBS are considered to have very low potential for bioaccumulation (MITI, 2000 and 2003).

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Version June14, 1996

GLP compliance:

yes

Details on sampling:

Sampling intervals:
(1) Test water
The test water analysis was performed once before the first test fish analysis and at the same time as the test fish analysis during the exposure period in both the first and second concentration groups. The number of analysis samples per analysis was one replicate.
(2) Test fish
The test fish analysis was performed 5 times during the exposure period in both the 1st and 2nd concentration groups, and the number of fish collected per time was 4, and the fish were divided into 2 groups (2 fish per group). The control group was performed before the start of exposure and at the end of exposure.

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

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test substance was dissolved in ion-exchanged water and adjusted to pH 7 with hydrochloric acid to prepare a stock solution with a test substance concentration of 10 g/L (acute toxicity test) or 400 mg/mL (for both 1st and 2nd concentration group of the concentration test).
- Controls: the concentration of the test item in test water was quantified using HPLC

Test organisms (species):

Cyprinus carpio

Details on test organisms:

ACUTE TOXICITY TEST (96 h)

(1) Test fish: Himedaka; common name: Himedaka Oryzias latipes
(2) Source of the test fish: Nakajima fish farm, (Address: 2029 Nagasu, Nagasu-cho, Tamana-gun, Kumamoto 869-0123)
(3) Exposure period: 96 hours
(4) Exposure method: Semi-stop type (water change every 24 hours)
(5) Length: 3.1 cm (mean average)
(6) Body weight: 0.26 g (mean average)
(7) Food type: Formula feed for raising carp fry (Protein content 43.0% or more; Lipid content 3.0% or more; Manufacturer: Nippon Formula Feed Co., Ltd.)
(8) Food amount: Approximately 2% of the body weight of the test fish was fed
(9) Feeding frequency: twice a day, however, feeding was stopped for 24 hours before the test fish were collected.
(10) Test water: Groundwater pumped on the premises of the Kurume Plant; the water quality was verified on August 6, 1999 and October 26, 1999, (measurement frequency 1 time/6 months).
(11) Acclimation:
- When the fish were obtained, they were visually observed to remove any abnormalities, and after taking a cleaning bath in a farming tank, they were bred in freshwater for 19 days.
- The fish were kept in freshwater at 25±2°C for 22 days. The fish were then sorted and bathed again. The animals were then bred in freshwater for 52 days.

CONCENTRATION TEST

(1) Test fish: Koi; common name: Cyprinus carpio
(2) Source of the test fish: Sugishima fish farm (Address 123-2, Gunchiku 1bancho, Yatsushiro City, Kumamoto Prefecture 866-0024) Date of acceptance of test fish November 11, 999
(3) Exposure period: 28 days
(4) Exposure method: Continuous water flow
(5) Length before exposure: 8 +/- 4 cm (mean average)
(6) Food type: Formula feed for raising carp fry (Protein content 43.0% or more; Lipid content 3.0% or more; Manufacturer: Nippon Formula Feed Co., Ltd.)
(7) Food amount: Approximately 2% of the body weight of the test fish was fed
(8) Feeding frequency: twice a day, however, feeding was stopped for 24 hours before the test fish were collected.
(9) Test water: Groundwater pumped on the premises of the Kurume Plant; the water quality was verified on August 6, 1999 and October 26, 1999, (measurement frequency 1 time/6 months).
(10) Acclimation:
- When the fish were obtained, they were visually observed to remove any abnormalities, and after taking a cleaning bath in a farming tank, they were bred in freshwater for 8 days.
- After cultivating, a cleaning procedure to remove parasites was performed, then the aquarium was carried into a junction aquarium, and the cleaning procedure was repeated. Fish with abnormalities were removed and the remainig fish were bred for 27 days in freshwater at a water temperature of 25 ± 2 °C. The fish were transferred to a test water tank, and after cleaning were bred for 17 days in freshwater at the same temperature.
(11) Analysis method: High performance liquid chromatography
(12) Test concentration 1st concentration group 1mg/L
2nd concentration group 0.1 mg/L

Route of exposure:

other: see remark

Remarks:

acute toxicity text: semi-stop type (water change every 24 hours); concentration test: continuous water flow

Test type:

flow-through

Water / sediment media type:

natural water: freshwater

Remarks:

Groundwater pumped on the premises of the Kurume Plant

Total exposure / uptake duration:

28 d

pH:

see table 1

Dissolved oxygen:

see table 1

Details on test conditions:

TEST SYSTEM ACUTE TOXICITY TEST
(1) Test water tank: Shaped glass aquarium
(2) Test water volume: 4 L/concentration group
(3) Number of test fish: 10 fish/concentration group

TEST SYSTEM CONCENTRATION TEST
(1) Test water supply method: Kurume Plant assembly running water type equipment
(2) Test water tank : 100 L glass aquarium
(3) Test water volume: 1155 L/day was applied to the test water tank at a ratio of 2 mL/min of the stock solution and 800 mL/min of the test water.
(4) Stock solution tank: 25 L glass bottle
(5) Illumination: Artificial lighting with white fluorescent light (14 hours light/10 hours dark)
(6) Number of fish: 1st and 2nd concentration Group: 28 fish (at the start of exposure); Control group: 10 fish (at the start of exposure)

Nominal and measured concentrations:

The test substance concentration in the test water was maintained at 85% or more of the set value. In addition, the fluctuation of the test substance concentration was kept within ± 20% of the average of the measured values. Details see below.

Reference substance (positive control):

yes

Remarks:

Sensitivity Test: PCP-Na (Pentachlorophenol sodium reagent) manufactured by Tokyo Chemical

Lipid content:

1.78 %

Time point:

end of exposure

Remarks on result:

other: Lipid content of fish samples was determined by chloroform/methanol extraction and gravimetric analysis, using samples for lipid content determination that were weighed from control fish homogenates. The average value was determined.

Lipid content:

2.03 %

Time point:

start of exposure

Remarks on result:

other:

Remarks:

Lipid content of fish samples was determined by chloroform/methanol extraction and gravimetric analysis, using samples for lipid content determination that were weighed from control fish homogenates. The average value was determined.

Key result

Conc. / dose:

0.1 mg/L

Temp.:

25 °C

Type:

BCF

Value:

9 dimensionless

Basis:

not specified

Time of plateau:

28 d

Calculation basis:

steady state

Key result

Conc. / dose:

1 mg/L

Temp.:

25 °C

Type:

BCF

Value:

0.86 dimensionless

Basis:

not specified

Time of plateau:

28 d

Calculation basis:

steady state

Results with reference substance (positive control):

The 48-hour LC50 value of the reference substance PCP-Na from the test fish of the same lot (TFO-990928) was 0.621 mg/L.

Details on results:

N-tert-butylbenzothiazole-2-sulphenamide (TBBS) hydrolyses in water to produce 2 -mercaptobenzothiazole, and tert-butylamine. These hydrolysis products have been tested and shown to have low potential for bioaccumulation. Based on these findings, TBBS is judged to also have low potential for bioaccumulation.

Bioconcentration factors (BCF) of tert-butylamine (CAS No. 75 -64 -9):
Level 1 (nominal concentration = 1 mg/L) : 0.86
Level 2 (nominal concentration = 0.1 mg/l) : 9.0

Results of the acute toxicity test
96-hour LC50 value >500 mg/L

Validity criteria fulfilled:

yes

Conclusions:

Due to the fast hydrolysis, only the BCF of the degradation products are relevant for risk assessment of TBBS in the environment. The experimentally determined BCF of tert-butylamine is lower than 9; and hence TBBS is considered to have very low potential for bioaccumulation.

Executive summary:

Due to the fast hydrolysis, only the BCF of the degradation products are relevant for risk assessment of TBBS in the environment. The experimentally determined BCF of tert-butylamine is lower than 9; and hence TBBS is considered to have very low potential for bioaccumulation.

Description of key information

TBBS has a hydrolysis half-life of 1.8h (MITI1996) to 9.53 h (Monsanto 1984) and therefore hydrolysis is a significant factor in the aquatic environment. According to REACH Guidance Document R.7c (2017, p. 29) it can be assumed that the rate of hydrolysis is greater than that for uptake by the exposed organisms, where hydrolysis half-life is below 12 h. In these cases, it may sometimes be appropriate to perform a BCF test on the hydrolysis products, if identified, instead of the parent substance. In case of TBBS, MBT and tert-butylamine are identified hydrolysis products for which bioaccumulation tests are available. The experimentally determined BCF of MBT is lower than 8 and the one of tert-butylamine lower than 9; and hence MBT and tert-butylamine and therefore also TBBS are considered to have very low potential for bioaccumulation (MITI, 2000 and 1992).