Co-Occurrence of Bromine and Iodine Species in US Drinking Water Sources That Can Impact Disinfection Byproduct Formation

Abstract

Bromine and iodine species are precursors for forming disinfection byproducts in finished drinking waters. Our study incorporates spatial and temporal data to quantify concentrations of inorganic (bromide (Br − ), iodide (I − ), and iodate (IO 3 − )), organic, and total bromine (Br T ) and iodine (I T ) species from 286 drinking water sources and 7 wastewater effluents across the United States. Br − ranged from <5−7800 μg/L (median of 62 μg/L in surface water (SW) and 95 μg/L in groundwater (GW)). I − was detected in 41% of SW (1−72 μg/L, median = <1 μg/L) and 62% of GW (<1−250 μg/L, median = 3 μg/L) samples. The median Br − /I − ratio in SW and GW was 22 μg/μg and 16 μg/μg, respectively, in paired samples with detect Br − and I − . Br T existed primarily as Br − , while I T was present as I − , IO 3 − , and/or total organic iodine (TOI). Inorganic iodine species (I − and IO 3 − ) were predominant in GW samples, accounting for 60−100% of I T ; however, they contributed to only 20−50% of I T in SW samples. The unknown fraction of I T was attributed to TOI. In lakes, seasonal cycling of I-species was observed and was presumably due to algal productivity. Finally, Spearman Rank Correlation tests revealed a strong correlation between Br − and I T in SW (R Br − ,IT = 0.83) following the log 10 (Br − , μg/L) = 0.65 × log 10 (I T , μg/L) − 0.17 relationship. Br − and I − in treated wastewater effluents (median Br − = 234 μg/L, median I − = 5 μg/L) were higher than drinking water sources.

Phototransformation of Brominated Disinfection Byproducts and Toxicity Elimination in Sunlit-Ozonated Reclaimed Water

“…Bromide ions have been found in the sewage of coastal cities as well as the groundwater supplied to cities. The levels of bromide ions range from hundreds of μg/L to tens of mg/L in wastewater. , Ozonation is widely applied for the treatment of sewage because it is rapid, efficient, and does not cause secondary pollution; however, it produces toxic brominated disinfection byproducts (Br-DBPs) when applied to bromide-containing water.…”