Ammonium bromide

Endpoint summary

Additional information

Background concentration

Bromide ions are known to be naturally present in soils in varying background concentrations. Published data have been summarised (Flury M., et al., 1993) indicating an average concentration of ca. 1 mg(Br-)/kg for typical soils throughout Europe. These observations are supported by soil bromide concentrations determined in a number of soils in the UK ranging from 0.3 to 1.6 mg(Br-)/kg (Maw G.A., et al., 1982). Further data have been published detailing soil water bromide levels of 0.5 mg(Br-)/L (Hill A.R., et al., 1998) for soils in Canada, and soil bromide levels of 0.5 to 1.6 mg(Br-)/kg (Hatton T.J., et al., 2002) for soils in Australia.

Consequently an approximate background level of 1 mg(Br-)/kg in soil, as presented by Flury, et al., is considered justified, and such levels can be considered to result in minimal adverse effects on the flora and fauna present in such soils through chronic exposure.

Earthworm

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 was 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.

The toxic effects of Sodium Bromide (NaBr) on survival, growth, and reproduction of the earthworm Eisenia fetida were assessed during a test period of eight weeks based on the OECD Guideline 222.

Sodium Bromide (NaBr) was homogeneously mixed into an artificial soil at the following test concentrations: 1.0, 3.2, 10, 32 and 100 mg per kg dry soil.Adult earthworms were exposed in treated soils for a period of four weeks. After this period, the adults were removed from the test vessels and the survival and growth rate were determined. The cocoons and juvenile earthworms remained in the vessels for additional four weeks. The reproduction rate was determined by counting the number of offspring hatched from the cocoons after this additional test period of four weeks.

Taking into account the survival, growth and reproduction rates of the exposed adult test organisms, the highest concentration of Sodium Bromide (NaBr) without toxic effects was determined to be 32 mg/kg dry soil. The lowest concentration with toxic effects (LOEC) was 100 mg/kg dry soil due to a high mortality, statistically significant change in mean body weight, reduced food consumption and reduced reproduction rate of the worms at this test concentration.

Plants

A study to OECD No 208 was performed to assess the effects of sodium bromide on the emergence and growth of three plant species. Three plant species were exposed to concentrations of 100, 180, 320, 560 and 1000 mg bromide/kg. The number of seedlings emerged and any mortalities and/or morphological abnormalities were determined daily for 21 days after 50% emergence in the control for each species.

The EC50 (emergence) and EC50 (growth) for the test material to the plants tested based on nominal test concentrations were greater than 1000 mg bromide/kg. The No Observed Effect Concentration for both emergence and growth was 1000 mg bromide/kg however, morphological effects were observed therefore the overall No Observed Effect Concentration was considered to be 180 mg bromide/kg to oat (Avena sativa).

 

Microorganisms

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.

 

Birds

An acute toxicity test was conducted according to FIFRA guideline 71-1andASTM Standard E857-81. Bobwhite quail (Colinus virginianus) and mallard duck (Anas platyrhynchos) were given single oral doses of sodium bromide by gavage and monitored for 14 days afterwards – 10 birds per dose group were tested.

No mortalities occurred in any dose groups of bobwhite quail. When compared to controls, there was no effect on body weight or feed consumption at any dosage level. Various signs of toxicity were observed in each dose groups at some point during the first week except the lowest dose and control groups. No signs persisted into the second week of observation. No mortalities occurred during the course of the study for mallard duck. Signs of toxicity typical of intoxication with sodium bromide included slight to severe ataxia (increasing with external stimuli), wing droop, lethargy, ventral head curl, and loss of righting reflex. When compared with the controls there was no effect on body weight or consumption at any of the concentrations tested. The 5-d LC50 > 5633 mg/kg for both species.