Barium titanium trioxide

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Results are based on nominal values, and test did not exacty follow existing guidance (1972-study), but followed test method well described and test conditions (eg.g. test medium composition) were properly identified, and meets generally accepted scientific standards. NOEC is estimated value based on ECHA methodology (i.e., EC16/2).

Qualifier:

no guideline followed

Principles of method if other than guideline:

General test methods of this study are in line with existing guidelines (e.g., OECD 211 D magna reproduction) with regard to age and number of test organisms, exposure period, test conditions, volume of test beakers, renewal and endpoints (survival and reproduction)

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: laboratory clone
- Source: University of Michigan
- Age at study initiation (mean and range, SD): 12h +/- 12h
- Feeding during test: yes
- Type of food: 0.5 g of powdered dried grass and 10g of enriched trout-fry granules to 250 mL of Lake Superior water and mixed vigorously in a blender for 5 minutes. This suspension was strained through 20 bolting cloth. The blender was then rinsed with an additional 50 mL of lake water, and the rinse water was added to the suspension. This suspension was stored in a refrigerator and mixed thoroughly each time an aliquot was withdrawn.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 wk

Hardness:

45.3 mg/L as CaCO3

Test temperature:

18 +/- 1 °C

pH:

7.74

Dissolved oxygen:

+/- 9 mg/L

Salinity:

not reported

Nominal and measured concentrations:

5-12 concentrations (not specified); a geometric series af concentrations was used for obtaining an approximation of toxicity; a linear series of concentrations was used for delineating reproductive impairment levels

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open 250 mL beaker, but covered with a pane glass to minimize evaporation
- Fill volume: 200 mL
- Renewal rate of test solution (frequency/flow rate): weekly renewal of test medium
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Lake Superior water; unfiltered water strained through a 20 bolting cloth
- Metals: 14 µg Ba/L ; 16 µg Sr/L ; 0.78 µg Zn/L ; <0.5 µg Ni/L ; 1.51 µg Cu/L ; <0.5 µg Co/L ; < 0.01 g Hg/L ; < 0.1 µg Cd/L
- Chloride: 1.22 mg/L
- Alkalinity: 42.3 mg/L as CaCO3
- Ca: 13.7 mg /L
- Mg: 3.12 mg/L
- K: 0.53 mg/L
- Na: 1.13 mg/L



OTHER TEST CONDITIONS
- Photoperiod: 16h light
- Light intensity: +/- 115 ft-c at the air-water interface


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
1) survival after 1, 2 3 weeks
2) reproduction (counting of the young produced each week)

Duration:

3 wk

Dose descriptor:

other: EC16

Effect conc.:

5 800 µg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

metal ion

Basis for effect:

reproduction

Details on results:

According to ECHA methodology, the EC16 (i.e., effects situated between 10 and 20%) can be used to estimate a NOEC-value; ECx (10% < x < 20%) /2 = NOEC. In this case, a NOEC of 2900 µg/L cas be derived.

Other 21d-effect levels that were reported, are the 21d-EC50 (reproduction) of 8900 µg/L and the 21d-LC50 of 13500 µg/L (12200-15000 µg/L). Endpoints are nor relevant for PNEC derivation, hence not included as K2-data points

Reported statistics and error estimates:

Results were statistically evaluated with the method of Litchfield and Wilcoxon (1949) for establishing approximations of the 95% confidence limits for survival. The terminology recommended by Sprague (1969) (i.e., LC), was used for survival and represents an interpolation from three or more partial-effect concentrations. reproductive effects were analyzed in a similar manner excluding confidence limits, but are given in terms of reproductive impairments by percentage.

Chemical characteristics of Lake Superior water were monitored during the testing period according to procedures outlined by the American Public Health Association and procedures employing atomic absorption spectroscopy.

Conclusions:

Results are based on nominal values, and test did not exacty follow existing guidance (1972-study), but followed test method well described and test conditions (e.g. test medium composition) were properly identified, and meets generally accepted scientific standards. NOEC is estimated value based on ECHA methodology (i.e., EC16 / 2).
The EC16 for reproduction was estimated to be 5800 µg/L based on metal ion. According to ECHA methodology, the EC16 (i.e., effects situated between 10 and 20%) can be used to estimate a NOEC-value; ECx (10% < x < 20%) /2 = NOEC. In this case, a NOEC of 2.9 mg/L for Ba2+ has been derived. This would mean a NOEC of 4.9 mg/L for Barium titanium trioxide (calculated from its molecular weight).

Description of key information

Read-across; test item: barium dichloride; Daphnia magna: NOECC = 2900 µg/L Ba2+ and 4.3 mg/L for BaCl2 (non-guideline study, Biesinger & Christensen, 1972). This would mean a NOEC of 4.9 mg/L for Barium titanium trioxide (calculated from its molecular weight).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

4.9 mg/L

Additional information

In order to assess the long-term toxicity to aquatic invertebrates of the analogous test substance barium dichloride, the test in Daphnia magna was performed according to generally accepted scientific standards and methodology (Biesinger & Christensen, 1972). General test methods of this study are in line with existing guidelines (e.g., OECD 211) with regard to age and number of test organisms, exposure period, test conditions, volume of test beakers, renewal and endpoints (survival and reproduction).

Five animals per concentration were exposed for 21 days in semi-static freshwater which means the test medium weekly renewed. The nominal/measured test concentrations were not reported. Five to 12 concentrations (not specified); a geometric series of concentrations was used for obtaining an approximation of toxicity; a linear series of concentrations was used for delineating reproductive impairment levels.

 

The EC16 for reproduction was estimated to be 5800 µg/L based on metal ion. According to ECHA methodology, the EC16 (i.e., effects situated between 10 and 20%) can be used to estimate a NOEC-value; ECx (10% < x < 20%) /2 = NOEC. In this case, a NOEC of 2.9 mg/L for Ba2+ has been derived. This would mean a NOEC of 4.9 mg/L for Barium titanium trioxide (calculated from its molecular weight).

Therefore, the test substance barium titanium trioxide does not show a long-term toxicity to aquatic invertebrates as the NOEC is > 1 mg/L under the conditions chosen.