Bromide in the Natural Environment: Occurrence and Toxicity

Abstract

Abstract Bromide ion is widely used as a tracer to study water and solute transport because it does not adsorb to negatively charged soil minerals. Therefore is moves approximately as fast as water in soil. This property and the small natural background concentration make Br − an ideal tracer. It is much better than Cl − , which behaves similarly, but which is ubiquitous in the environment. Since Cl − is a component of several fertilizers, it usually is found in agricultural soils in concentrations too high to allow its use. When using chemicals in the environment, one must consider their fate and toxicity. This review summarizes data on the occurrence of Br − in the environment and its toxicology. Since Br − has low toxicity in mammals, most freshwater organisms, and most plants, its use in small‐scale field studies should not endanger the biota. However, its application on a larger scale requires a careful evaluation of the concentration to be expected in ground and surface water. Based on the toxicity data, a quality criterion for groundwater of 1 mg Br − L −1 was established in the literature. To avoid the risk of chronic toxicity, the concentration of Br − water should not exceed the proposed criterion.