Ammonium bromide

Toxicity to soil microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil microorganisms

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study to current guideline with no major deviations or deficiencies.

Qualifier:

according to guideline

Guideline:

OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test)

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):
Ammonium bromide is an inorganic salt that dissociates to its composite ions in aqueous solutions at environmental pH and temperature. Comparison of the available data on the various bromide salts have shown that the bromide ion is the relevant ion for determination of the toxicological profile with simple cations such as potassium, sodium or ammonium, that are ubiquitous in nature, having little or no influence on the bromide ion properties. It is therefore justified to read-across data from other inorganic bromide salts to ammonium bromide.

Analytical monitoring:

yes

Details on sampling:

Day 0, 7 and 28

Vehicle:

no

Test organisms (inoculum):

soil

Total exposure duration:

28 d

Test temperature:

21 degree C

Moisture:

6.14 g/100 g i.e. 40% of the Water Holding Capacity as recommended by the guideline
Deionised reverse osmosis water added on a weight basis on days 7, 14, 21 and 28 where necessary to maintain the moisture content within ± 5% of the initial moisture content.

Details on test conditions:

Criteria Details
Culturing apparatus Glass beakers
Number of vessels / concentration Nine control and eighteen test material replicates
Aeration device Not specified
Measuring equipment UV spectrophotometer
Test performed in closed vessels Covered in plastic film to retain moisture
Criteria Details
Organic substrate Powdered Lucerne-green-grass-meal (7.5 g) added to surface of soil
Incubation temperature 21°C
Soil moisture 6.14 g/100 g i.e. 40% of the Water Holding Capacity as recommended by the guideline
Deionised reverse osmosis water added on a weight basis on days 7, 14, 21 and 28 where necessary to maintain the moisture content within ± 5% of the initial moisture content.
Method of soil incubation Samples maintained in a temperature controlled room at approximately 21°C in the dark.
Aeration No

Nominal and measured concentrations:

10, 100 and 1000 mg bromide/kg

Reference substance (positive control):

no

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

bromide

Basis for effect:

nitrate formation rate

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

bromide

Basis for effect:

nitrate formation rate

Details on results:

no further details

Results with reference substance (positive control):

no further details

Reported statistics and error estimates:

A Students t-test was carried out on the nitrate concentration on day 28 for the control and the 1000 mg/kg test concentration to determine any statistically significant differences between the test and control groups. All statistical analysis were performed using the SAS computer software package (SAS 1999- 2001).

Validity criteria fulfilled:

yes

Conclusions:

A study to assess the long-term effects of the test material (expressed in terms of bromide ion) after a single exposure on nitrogen transformation activity of soil microorganisms was performed in accordance with OECD No 2.16
The study was performed on one soil with a limit test concentration of 1000 mg bromide/kg soil with a 28 day incubation period.
Activity was measured by UV absorbance.
The test material showed no significant effect on the nitrogen transformation activity of soil microorganisms at a test concentration of 1000 mg bromide / kg over a 28-day period.
The test material can be considered to have no long-term effect on nitrogen transformation in soil.
The variation between replicate control notification rates was less than 15% and therefore satisfied the validation criterion given in the Test Guidelines.

Description of key information

A study to assess the long-term effects of sodium bromide after a single exposure on nitrogen transformation activity of soil microorganisms was performed in accordance with OECD No 216. The test material showed no significant effect on the nitrogen transformation activity of soil microorganisms at a test concentration of 1000 mg bromide / kg over a 28-day period.

Key value for chemical safety assessment

Long-term EC10 or NOEC for soil microorganisms:

1 000 mg/kg soil dw

Additional information

Ammonium bromide is an inorganic salt that dissociates to its composite ions in aqueous solutions at environmental pH and temperature. Comparison of the available data on the various bromide salts have shown that the bromide ion is the relevant ion for determination of the toxicological profile with simple cations such as potassium, sodium or ammonium, that are ubiquitous in nature, having little or no influence on the bromide ion properties. It is therefore justified to read-across data from other inorganic bromide salts to ammonium bromide.

A study to assess the long-term effects of sodium bromide after a single exposure on nitrogen transformation activity of soil microorganisms was performed in accordance with OECD No 216

The study was performed on one soil with a limit test concentration of 1000 mg bromide/kg soil with a 28 day incubation period.

The test material showed no significant effect on the nitrogen transformation activity of soil microorganisms at a test concentration of 1000 mg bromide / kg over a 28-day period.

The test material can be considered to have no long-term effect on nitrogen transformation in soil.