Barium nitrate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

The justification for read across is attached in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 6.65 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Remarks:

dissolved Ba(NO3)2

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 3.5 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

element (dissolved fraction)

Remarks:

dissolved Ba

Basis for effect:

mortality (fish)

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29.03.2010 - 02.04.2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

2009-03-04

Analytical monitoring:

yes

Details on sampling:

Samples from test solutions were taken for analysis of actual test item concentrations in comparison to the nominal concentrations. The test solutions were vigorously stirred by use of a steel blade in order to homogenise the suspension. Samples were taken immediately after stirring.
A sample of the stock solution was taken, and samples of the test concentrations (incl. control) were taken at the start and end of the test period.
Immediately after sampling and before shipment, the samples were stored in polyethylene bottles in the refrigerator.

Vehicle:

no

Details on test solutions:

Reconstituted water according to OECD guideline No. 203 was used to dilute the test item and to keep the fish before and during the period of the test. Local tapwater was treated by reverse osmosis and ion-exchanger to prepare deionised water. Therefore a contamination with heavy metals, pesticides and TOC is excluded.
The reconstituted water consists of deionised water and salts in the following final concentrations:
A) CaCl2 * 2 H2O: 294.0 mg/L
B) MgSO4 * 7 H2O: 123.0 mg/L
C) NaHCO3: 64.8 mg/L
D) KCl: 5.75 mg/L

Prior to use, the reconstituted water was diluted with deionised water (1:1; v/v), and supplemented with 1% of artificial seawater.
Reconstituted water was used for the control. The test item was weighed in a plastic weighing boat. The test concentrations were prepared by dissolving 1289.4 mg of the test item in 10.998 L of reconstituted water (100 mg/L nominal) and 1957.7 mg in 11.011 L of reconstituted water (152 mg/L nominal) directly in the respective test vessel. The test solutions were stirred for approx. one minute before use. The test solutions appeared as milky suspension.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

Organisms coming from ECT Oekotoxikologie GmbH, Germany (own breed; since November 2009)
- Average body weight of fish: 0.10 - 0.17 (mean: 0.12 g/fish; assessed from the total weight of a sample consisting of 10 fish)
- Average standard length of fish: 2.18 - 2.96 cm (mean: 2.69 cm; assessed in a sample consisting of 10 fish)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

171-179 mg/L as CaCO3

Test temperature:

21.3 - 22.4 degrees Celcius

pH:

7.1 - 7.5

Dissolved oxygen:

94 - 105 %

Nominal and measured concentrations:

nominal: 66 and 100 mg Ba/L - 100 and 152 mg BaCl2/L - 117 and 178 mg/L test item
measured dissolved at t=0: below detection limit, 1.44, 3.35 mg Ba/L
measured dissolved at t=4d: below detection limit, 1.42, 3.68 mg Ba/L
measured total Ba at t=0: below detection limit, 62, 100 mg Ba/L
measured total Ba at t=4d: below detection limit, 64, 95 mg Ba/L
total expressed as test item (t=0): below detection limit, 111, 178 mg/L test item
total expressed as test item (t=4): below detection limit, 113, 170 mg/L test item

Details on test conditions:

- Amount of test solution per test vessel: 10 L
- Depth of test solution in the test vessels: approx. 12.5 cm
- Number of fish per test vessel: 7
- Average length of fish: 2.69 cm (n = 10)
- Average weight of fish: 0.12 g (n = 10)
- Fish loading: 0.08 g per L
- Renewal of test solution and control water during the test period: none
- Feeding: none
- Photoperiod: light/dark - 16 h/8 h
- Light intensity: 100 - 1000 lx; measured: 312 - 321 lx
- Temperature (min / max): 21.3 / 22.2°C (daily measurements); 22.2 / 22.4°C (online measurements in one test vessel)
- Aeration: permanent

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 3.5 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 97.5 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

element (total fraction)

Remarks:

total Ba

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 174 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

There were no behavioural differences to be seen in fish in the treatments compared with the control fish. The fish were barely visible due to the milky appearance of the test suspensions.
The recovery of the test item in the 0.45 µm-filtered test solutions was between 2 and 4% of the nominal concentrations. The characteristics of the test item may have led to a precipitation in the test medium, probably as bariumsulfate.
The recovery of the test item in the non-filtered test solutions was between 95 and 100% of the nominal concentrations.

Reported statistics and error estimates:

No statistical method was used to evaluate the fish mortalities because no mortality was observed during the test period in the control or the test item treatments.

Sublethal observations / clinical signs:

Mortality in the control: none (required: ≤ 10%, or one out of seven fish)

Dissolved oxygen concentration in control and test vessels: ≥ 105% (required: ≥ 60% of air saturation value (ASV))

Validity criteria fulfilled:

yes

Conclusions:

The LC50 (96 h) based on measured concentrations in 0.45 µm-filtered test solutions was higher than 3.5 mg Ba/L.
The LC50 (96 h) based on measured concentrations in 0.45 µm-filtered test solutions was higher than 5.4 mg BaCl2/L.

The LC50 (96 h) based on measured concentrations in non-filtered test solutions was higher than 97.5 mg Ba/L
The LC50 (96 h) based on measured concentrations in non-filtered test solutions was higher than 149 mg BaCl2/L.

The LC50 (96 h) based on nominal concentrations was higher than 152 mg BaCl2/L.

These data can be used for hazard assessment purposes.

Description of key information

No key study is available on the acute toxicity of barium dinitrate to fish. A read across approach was followed to cover this endpoint. The key study is a study from Egeler and Kiefer (2010) for barium chloride, performed using Danio rerio as test organism. The LC50 (96 h) based on mean measured dissolved Ba concentrations was > 3.5 mg Ba/L (equivalent to > 5.4 BaCl2/L). This result was recalculated to barium dinitrate based on the barium content of both substances (i.e. 6.65 mg barium trinitrate/L).

Additional information

A single relevant and reliable study was available for the read across substance BaCl2 (Egeler and Kiefer, 2010). In this study, no mortality in Danio rerio was observed up to and including the highest test concentration (i.e., 152 mg BaCl/L, nominally). When based on mean measured concentrations (geometric mean), the 96-h LC50 for Danio rerio was > 3.5 mg dissolved Ba/L and > 97.5 mg Ba total/L. These values are equivalent to > 5.4 and > 149 mg BaCl2/L, respectively.