Sodium bromide

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
no further details

Analytical monitoring:

no

Details on sampling:

None stated

Vehicle:

no

Details on preparation and application of test substrate:

Type and source of dilution water - Deionised reverse osmosis water prepared in house.
Vehicle control performed - Yes, Water only added to artificial soil and maintained under the same conditions as the test vessels

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

Criteria Details
Species/strain Eisenia foetida
Source of the initial stock Blades Biological, Cowden, Edenbridge, Kent, UK
Culturing techniques Maintained in 20 L plastic trays at 22°C on a substrate consisting of 50% by volume peat and 50% by volume animal manure.
Age/weight At least 2 months old with clitellum
Mean weight: 0.4 g
Pre-treatment Transferred to artificial soil without test material 24°h before start of test.

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Test temperature:

21C to 23ºC

pH:

6.0 ± 0.5

Moisture:

Experience has shown that a moisture content of 35% of dry weight, as stated in the Test Guideline, may be too high for the preparation of the artificial soil, causing sludge formation. Therefore, a moisture content of 30% of dry weight was considered appropriate for use during the study, as this level of moisture has been shown to ensure that a good crumb structure is formed within the soil.
The moisture content of the soil used in the definitive test was 28% to 29% of dry weight of basic substrate on Day 0 and 26% to 27% on Day 14.

Details on test conditions:

Criteria Details
Artificial soil test substrate Industrial quartz sand: 70% w/w
Kaolinite clay: 20% w/w
Sphagnum moss peat:10% w/w
Test mixture 50 mL stock solution :05 kg dry weight soil + 90 mL water
Size, volume and material of test container 1L glass beaker
Amount of artificial soil (kg)/ container 0.5 kg dry weight
Nominal levels of test concentrations Range-finding study: 10, 100 and 1000 mg bromide/kg
Initial study: 1000 mg bromide/kg
Definitive study: 10, 32, 100, 320 and 1000 mg bromide/kg
Number of replicates/concentration 1 per concentration
Number of earthworms/test concentration 10 per concentration
Number of earthworms/container 10
Light source Not specified
Test performed in closed vessels due to significant volatility of test substrate No

Nominal and measured concentrations:

0, 10, 32, 100, 320, 1000 mg/kg

Reference substance (positive control):

yes

Remarks:

chloroacetamide

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Basis for effect:

mortality

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

10 mg/kg soil dw

Nominal / measured:

nominal

Basis for effect:

other: bodyweight

Results with reference substance (positive control):

. A positive control using chloroacetamide, conducted approximately every 6 months, was reported for reference purposes

Reported statistics and error estimates:

The LC50 values and associated confidence limits were calculated by the probit method (Finney 1971) on Day 7 and by the trimmed Spearman-Karber method (Hamilton et al 1977) on Day 14 using the ToxCalc computer software package (ToxCalc 1999).
Probit analysis is used where two or more partial responses to exposure are shown.
When only one partial response is shown the trimmed Spearman-Karber method is appropriate
Statistical analysis of the earthworm weight data was performed using Bartlett's test for homogeneity of variance (Sokal and Rohlf 1981) and Dunnett's multiple comparison procedure for comparing several treatments with a control (Dunnet 1995). All statistical analyses were performed using the SAS computer software package (SAS 1999 - 2001)

Validity criteria fulfilled:

yes

Conclusions:

A study to OECD 207 was performed to assess the acute toxicity of sodium bromide to the earthworm (Eisenia foetida) in an artificial soil.
Following a preliminary range-finding test and an initial experiment, earthworms were exposed in groups of 40 (four replicates of 10 worms per concentration) to a range of concentrations of 10, 32, 100, 320 and 1000 mg bromide/kg of soil for a period of 14 days at a temperature of 21ºC to 24°C. The number of mortalities were determined after 7 and 14 days exposure. A positive control using chloroacetamide, conducted approximately every 6 months, was reported for reference purposes
The No Observed Effect Concentration (NOEC) was 10 mg bromide/kg on the basis that no mortalities were observed after 14 days exposure and additionally no sub-lethal effects on weight or behaviour were observed at 10 mg bromide/kg.
The result of the positive control gave a 14-Day LC50 for chloroacetamide of 24 mg/kg with 95% confidence limits of 23 – 25 mg/kg. The No Observed Effect Concentration was 18 mg/kg.

Description of key information

Sodium bromide: Acute toxicity to earthworm (Eisenia foetida)

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

1 000 mg/kg soil dw

Long-term EC10, LC10 or NOEC for soil macroorganisms:

10 mg/kg soil dw

Additional information

A study to OECD 207 was performed to assess the acute toxicity of sodium bromide to the earthworm (Eisenia foetida) in an artificial soil. Earthworms were exposed to a range of concentrations of 10, 32, 100, 320 and 1000 mg bromide/kg of soil for a period of 14 days. The number of mortalities were determined after 7 and 14 days exposure. The No Observed Effect Concentration (NOEC) was 10 mg bromide/kg on the basis that no mortalities were observed after 14 days exposure and additionally no sub-lethal effects on weight or behaviour were observed at 10 mg bromide/kg.