potassium titanium oxide (K2Ti6O13)

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:

(Range-finding study) 11 March to 15 March 1999, (Definitive study) 14 June to 18 June 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

92/69/EEC (Annex V of Council Directive 67/548/EEC)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

(Date of inspection: 23 March 1998 Date of Signature: 21 July 1998)

Analytical monitoring:

yes

Details on sampling:

Water samples were taken from the control and each replicate test vessel at 0, 24 and 96 hours for quantitative analysis. Duplicate samples were taken and stored frozen (approximately -20°C) for further analysis, if necessary.

Vehicle:

no

Details on test solutions:

Due to the low aqueous solubility and high purity of the test material the test concentration used in the definitive study was a saturated solution prepared from an initial dispersion at a concentration of 100 mg/l.
Prior to the addition of the test material, the dechlorinated tap water was stirred by magnetic stirrer using a stirring rate such that a vortex depth of approximately 25% of the overall height of the water column was achieved. An amount of test material (2.1 g) was added to the vortex of 21 Iitres of dechlorinated tap water to give an initial test material dispersion at a concentration of 100 mg/l. This was stirred for 47 hours. The stirring was stopped after 47 hours and the dispersion allowed to stand for 1 hour. The dispersion was then filtered through 0.2 pm filters to give a saturated solution.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout.

- Source: Parkwood Trout Farm, Harrietsham, Kent, United Kingdom, maintained in-house since 18 May 1999.

- Feeding during test: No.


ACCLIMATION
- Acclimation period:12 days.

- Acclimation conditions (same as test or not): Same as the test condition.

- Type and amount of food: commercial trout pellets.

- Feeding frequency: (discontinued 24 hours prior to the start of the definitive study)

- Health during acclimation (any mortality observed): There was approximately 1% mortality in the 7 days prior to the start of the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Post exposure observation period:

Not applicable.

Hardness:

100 mg CaCO3/L

Test temperature:

14ºC.

pH:

7.3 - 7.4.

Dissolved oxygen:

9.3 - 9.7 mg O2/l.

Salinity:

No data.

Nominal and measured concentrations:

100 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed

- Material, size, headspace, fill volume: 20 litre glass

- Aeration: aerated via narrow bore glass tubes.

- Renewal rate of test solution (frequency/flow rate): daily.

- No. of organisms per vessel: 10.

- Biomass loading rate: 0.57 g bodyweight/litre.

TEST MEDIUM / WATER PARAMETERS
- Source: tap water.

- Total organic carbon: 1 mg/l.

- Particulate matter (mean):
- Metals:
Al < 20 µg/l
Pb 4 µg/l
Fe < 36 µg/l
Cd < 0.5 µg/l
Cr < 5.0 µg/l
Cu < 10 µg/l
Ni < 5.0 µg/l
Hg < 0.2 µg/l
Mn < 5.0 µg/l
Zn 40 µg/l

- Pesticides: < 0.02 μg/l.

- Chlorine: 34 mg/l.

- Alkalinity: 134 mg/l.

- Ca/mg ratio: 67 mg/l / 10 mg/l

- Conductivity: 434 μS/cm

OTHER TEST CONDITIONS
- Adjustment of pH: No

- Photoperiod: 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods.

EFFECT PARAMETERS MEASURED
Any mortalities and sub-lethal effects of exposure were recorded at 3, 6, 24, 48, 72 and 96 hours after the start of exposure. The criteria of death were taken to be the absence of both respiratory movement and response to physical stimulation.

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 10 and 100 mg/l

- Results used to determine the conditions for the definitive study: The results showed no mortalities at the saturated solutions prepared from initial
test material dispersions at concentrations. Based on this information 100 mg/l was selected for the (limit test).

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

> 0.22 mg/L

Nominal / measured:

estimated

Conc. based on:

dissolved

Basis for effect:

mortality (fish)

Remarks on result:

other: -

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

> 0.22 mg/L

Nominal / measured:

estimated

Conc. based on:

dissolved

Basis for effect:

mortality (fish)

Remarks on result:

other: -

Duration:

72 h

Dose descriptor:

LC50

Effect conc.:

> 0.22 mg/L

Nominal / measured:

estimated

Conc. based on:

dissolved

Basis for effect:

mortality (fish)

Remarks on result:

other: -

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.22 mg/L

Nominal / measured:

estimated

Conc. based on:

dissolved

Basis for effect:

mortality (fish)

Remarks on result:

other: -

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 0.22 mg/L

Nominal / measured:

estimated

Conc. based on:

dissolved

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.22 mg/L

Nominal / measured:

estimated

Conc. based on:

dissolved

Basis for effect:

other: mortality, sub-lethal effects

Details on results:

No effects were observed in the study.

Results with reference substance (positive control):

Not applicable.

Reported statistics and error estimates:

Not reported.

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test material to the freshwater fish rainbow trout (Oncorhynchus mykiss) has been investigated and based on an estimate of the dissolved concentration of the test material (limit of quantitation) gave a 96-Hour LC50 of greater than 0.22 mg/l. Correspondingly the No Observed Effect was 0.22 mg/l.

Executive summary:

Methods

A study was performed to assess the acute toxicity of the test material to rainbow trout. The method followed that described in the OECD Guidelines for Testing of Chemicals (1992) No 203, "Fish, Acute Toxicity Test" referenced as Method C.1 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

 

Procedures

Following a preliminary range-finding study fish were exposed, in two groups of ten, to a saturated solution prepared from an initial test material dispersion at a concentration of 100 mg/I for a period of 96 hours under semi-static test conditions. The number of mortalities and any sub-lethal effects of exposure in each test and control vessel were determined 3 and 6 hours after the start of exposure and then daily throughout the study

until termination after 96 hours.

 

Results

Analysis of the saturated solution (prepared from an initial test material dispersion at a concentration of 100 mg/I) at 0, 24 and 96 hours showed the measured test concentrations to be below the limit of quantitation of the analytical method employed. This does not infer that no test material was in solution but that the dissolved concentration of test material (ie bioavailable to the test fish) was below the limit of quantitation which was

assessed down to 0.22 mg/l. It was considered unnecessary and unrealistic to test saturated solutions from initial test material dispersions at concentrations in excess of 100 mg/1. Therefore the 96-Hour LC50 based on the limit of quantitation was greater than 0.22 mg/I and correspondingly the No Observed Effect Concentration was 0.22 mg/l.

Description of key information

A study was performed to assess the acute toxicity of the test material to rainbow trout (Oncorhynchus mykiss). Under the test condition, the dissolved concentration of test material (ie bioavailable to the test fish) was below the limit of quantitation which was assessed down to 0.22 mg/L. It was considered unnecessary and unrealistic to test saturated solutions from initial test material dispersions at concentrations in excess of 100 mg/L. Therefore the 96-Hour LC50 based on the limit of quantitation was greater than 0.22 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

> 0.22 mg/L

Additional information

Only one study is available for this endpoint and this will be submitted as a key study for the substance. The 96-Hour LC50 based on the limit of quantitation was greater than 0.22 mg/L.

The method followed that described in the OECD TG 203, and conducted at a GLP-facility with a reliability of the study 1, according to the scoring system of Klimisch et al., 1997).