Benzyltrimethylammonium hydroxide

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 Sep 2018 - 24 Oct 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The substance can be produced through different process routes, yielding solutions in water or organic solvent (e.g. methanol or ethylene glycol).
It was initially unclear how to register the substance (mono-constituent or multi-constituent substance) and which manufactured substance to test to fulfil the REACH data requirements. After consultation with the ECHA helpdesk, the test program was started with the manufactured substance of the Lead registrant (solvent: methanol) in which the highest amount of solvent could be removed without causing degradation of the substance. This resulted in the selection of a solution of 56-57% BTMAOH in methanol as test substance.
During the course of the test program, and in order to aid meaningful risk assessment, after consultation with ECHA and upon ECHA's recommendation, it was considered to be more appropriate to test the water-based manufactured substance. As a consequence, some testing was performed with a BTMAOH solution in methanol, and some testing was performed with a BTMAOH solution in water.

The current entry reflects a test performed with a water-based test solution.

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all test concentrations and Control
- Sampling method: 2.0 mL at t=0 h, t=24 h and t=96 h.
- Sample storage conditions before analysis: Samples were stored in a freezer (≤-15°C) until analysis at the analytical laboratory of the Test Facility.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- The batch of test item tested was a clear and almost colourless liquid and completely soluble in test medium at the concentrations tested. A correction was made for the water content of the test item. All reported concentrations are based on the pure test item.
- Preparation of test solutions started with the highest concentration of 100 mg/L applying a 15-minute period of magnetic stirring to accelerate dissolution of the test item in test medium. After adjusting the pH from 10 to 7.9 in the limit test, the solution was used as the highest test concentration. All test solutions were clear and colorless at the end of the preparation procedure.

- Controls:
Test medium without test item or other additives

Test organisms (species):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM
- Common name: Carp (Cyprinus carpio, Teleostei, Cyprinidae) Linnaeus, 1758
- Source: Zodiac, proefacc. "De Haar Vissen", Wageningen University and Research Centre, The Netherlands
- Mean length at study initiation: 2.8 +/- 0.2 cm (Limit test)
- Mean weight at study initiation: 0.25 +/- 0.07 g (Limit test)
- Method of breeding: F1 from a single parent-pair bred in UV-treated water

- Total fish used: 26 (Range-Finding study and Final Test)

HOLDING
- Quarantine/Acclimatisation: At least 12 days after delivery
- Medium: Adjusted ISO medium, formulated using tap-water purified by reverse osmosis
- Feeding: Daily with pelleted fish food (Essence (300-500 um), Coppens International bv, Helmond, The Netherlands)
- Validity of batch: In the batch of fish used for the test, mortality during the seven days prior to the start of the test was less than 5%.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

180 mg CaCO3 / L

Test temperature:

20 - 21 °C

pH:

Control:
- t=0 h: 7.9
- t=96 h: 7.6

100 mg/L:
- t=0 h: 7.9
- t=96 h: 7.5

Dissolved oxygen:

Control:
- t=0 h: 9.1
- t=96 h: 8.0

100 mg/L:
- t=0 h: 9.1
- t=96 h: 8.1

Nominal and measured concentrations:

Nominal: 100 mg/L
Measured (mg/L): The measured concentrations were at 96-97% of the nominal concentration throughout the test duration. Based on these results, the nominal exposure concentrations were used to express the effect parameters. See Table 1 in 'Any other information on results' for details on measured concentrations.

Details on test conditions:

TEST SYSTEM
- Test vessel: 6.5 litres, all-glass, containing 5 litres of test solution
- Test type: static
- Aeration: no aeration
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.58 g fish/L

TEST MEDIUM / WATER PARAMETERS
- Test medium: Adjusted ISO medium
- Culture medium different from test medium: no
- Intervals of water quality measurement: Dissolved oxygen content, pH and temperature were measured daily in all vessels with surviving fish, beginning at the start of the test (day 0).

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h daily
- Feeding: No feeding from 24 hours prior to the test and during the total test period
- Introduction of fish: Within 13 minutes after preparation of the test media from a holding tank with comparable water quality parameters and pH and temperature differences between test and holding tank media of less than 1.0 unit and 1.0°C, respectively.

TERMINAL PROCEDURES
- Euthanasia: At the end of the test, the surviving fish were rapidly killed by exposing them to ca. 1.2% ethylene glycol monophenylether in water.

EFFECT PARAMETERS MEASURED
- Mortality and other effects: At 3.75, 24, 48, 72 and 96 hours following the start of exposure. In addition, every afternoon from day 0 to observe for any dead or severely distressed fish. Dead fish were removed when observed.

TEST CONCENTRATIONS
- Range finding study test concentrations: 0.1, 1.0, 10 and 100 mg/L (3 fish per concentration).
- Results used to determine the conditions for the definitive study: yes; no mortality or clinical effects were observed at any of the test concentrations during the test period, therefore a limit test was performed.

Reference substance (positive control):

yes

Remarks:

Pentachlorophenol (performed March 2018)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: BTMAOH

Basis for effect:

mortality (fish)

Details on results:

- One fish died in the limit concentration after 24 hours of exposure. No further mortality or clinical effects were recorded during the test period.
- 24h-, 48h-, 72h- and 96h-LC50 were all >100 mg/L
- All environmental parameters remained within the limits as specified in the study plan.

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Mortality: 0% at 0.10 mg/L PCP; 100% at 0.22 mg/L PCP (already observed after 24h); 100% at 0.46 mg/L PCP (already observed after 24h)
- LC50: 0.15 mg/L, 95% confidence interval 0.10-0.22 mg/L
- The range of the 96h-LC50 for carp is generally between 0.10 mg/L and 0.46 mg/L based on historical data of reference tests performed by the Test Facility. Hence, the sensitivity of carp originating from the batch used in the reference test for PCP falls within the range of sensitivities generally observed during the past years.

Reported statistics and error estimates:

No LC50 could be determined because the test item proved to be non-toxic (LC50 > maximum concentration tested).

Sublethal observations / clinical signs:

Table 1: Limit Test: Test Samples

Time of sampling [hours]	Concentration [mg/L]		Relative to nominal [%]	Relative to initial [%]
	Nominal	Analyzed
0	0	n.d.	n.a.
	100	96.8	97
24	0	n.d.	n.a.	n.a.
	100	96.1	96	99
96	0	n.d.	n.a.	n.a.
	100	97.0	97	100

n.d.Not detected.

n.a.Not applicable.

Table 2: Incidence of Mortality and Total Mortality During the Limit Test

Test substance nominal concentration (mg/L)	Initial number of fish	Cumulative mortality					Total mortality (%)
		3.75h	24h	48h	72h	96h
Control	7	0	0	0	0	0	0
100	7	0	1	1	1	1	10

Validity criteria fulfilled:

yes

Remarks:

See 'Overall remarks' for details on validity criteria.

Conclusions:

The 96h-LC50 was beyond the range tested, i.e. exceeded the analytically confirmed nominal concentration of 100 mg/L (corrected for water content).

Executive summary:

In a study performed in accordance with OECD 203 (1992) and according to GLP principles, the acute toxicity of the substance to carp (Cyprinus carpio) was investigated. In a static test, carp were exposed for 96 hours to an untreated control and a nominal concentration of 100 mg/L (corrected for water content, 7 fish per treatment group). A correction was made for the water content of the substance, i.e. all reported concentrations are based on the pure test substance.

Measured concentrations were 96 -97% of the nominal concentration throughout the test duration. Based on these results, the nominal exposure concentrations were used to express the effect parameter.

One fish died in the limit concentration after 24 h of exposure. No further mortality or clinical effects were recorded during the test period.

The 96h-LC₅₀ of the substance to carp is concluded to be beyond the range tested, i.e. exceeded the analytically confirmed nominal concentration of 100 mg/L (based on the pure test item, corrected for water content).

The test met all validity criteria and is considered to be reliable without restriction.

Description of key information

The 96h-LC50 was beyond the range tested, i.e. exceeded the analytically confirmed nominal concentration of 100 mg/L (based on BTMAOH); 96h-LC50: > 100 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

100 mg/L

Additional information

In a study performed in accordance with OECD 203 (1992) and according to GLP principles, the acute toxicity of the substance to carp (Cyprinus carpio) was investigated. In a static test, carp were exposed for 96 hours to an untreated control and a nominal concentration of 100 mg/L (7 fish per treatment group). A correction was made for the water content of the test item, i.e. all reported concentrations are based on BTMAOH.

Measured concentrations were 96 -97% of the nominal concentration throughout the test duration. Based on these results, the nominal exposure concentrations were used to express the effect parameter.

One fish died in the limit concentration after 24 h of exposure. No further mortality or clinical effects were recorded during the test period.

The 96h-LC₅₀ of the substance to carp is concluded to be beyond the range tested, i.e. exceeded the analytically confirmed nominal concentration of 100 mg/L.