Bromate Environmental Contamination: Review of Impact and Possible Treatment

Abstract

Contamination of drinking water with bromate (BrO₃ ⁻) at levels ranging from 0.4 to 60 μ g L⁻¹ may be found following ozonation of water containing background bromide (Br⁻). Based on rodent studies, bromate is classified as a “possible human” carcinogen, and drinking water standards of 10–25 μ g L⁻¹ are now implemented in many countries. Bromate is highly soluble, stable in water, and difficult to remove using conventional treatment technologies. This has led to investigations into novel removal techniques, but many have not developed beyond laboratory trials. Analytical advances have recently led to detection of bromate contamination within both rivers and groundwater, which has provided an additional requirement for bromate remediation. This review summarizes bromate environmental characteristics and the regulatory situation, and outlines bromate remediation processes, including filtration, ultraviolet irradiation, catalysis, chemical reduction, activated carbon, and biodegradation. These techniques are evaluated for developmental progress in a potable water system and also for potential application within the natural water environment.

Keywords:

• bioremediation
• bromate
• groundwater
• oxyanion
• remediation
• toxicology

Notes

#—Little residual other than bromide (and low-level microbial biomass) produced by treatment;

##—Treated water includes chemical or carbon residues;

###—Concentrated ionic waste stream produced which requires treatment prior to disposal.

^a ‘Real’ describes a natural water matrix, ‘Artificial’ describes a distilled water sample spiked with bromate.

^b Empty bed contact time.

^c Trial tested an RSSCT (Rapid Small-Scale Column Test) configuration; data given for theoretical scale-up to pilot scale.