Disinfection By-Products: Formation in Pool Water and the Role of Iodinated Medical Imaging Compounds as a Potential Precursor in the Formation of Iodo-DBPs

摘要

Disinfection by-products (DBPs) are the unintended consequence of using chemical disinfectants to kill pathogens in water. They are formed from the reaction between disinfectants and natural organic matter (NOM), anthropogenic contaminants, and bromide/iodide present in the raw source water. DBPs are cause for concern because studies have found them to be toxic. This research focuses on identifying and studying the formation of DBPs. Specifically, the presence of DBPs in chlorinated pool water and tap water from Barcelona, Spain was studied to better understand which DBPs are formed in the pool as compared to those that enter the pool from the tap water source used to fill the pool. Samples from the pool and tap were analyzed using gas chromatography-mass spectrometry (GC-MS) and approximately 100 DBPs were comprehensively identified. It was found that more nitrogen-containing DBPs (N-DBPs) were identified in the pool water than in the tap water, likely due to the increased nitrogenous input from swimmers in the pool (urine, sweat, skin cells, hair,cosmetics). Additionally, this research evaluated the role of X-ray contrast media (ICM) as a precursor for iodo-DBPs, by studying source waters from several locations that had been reacted with ICM and chlorine disinfectant. Several iodo-DBPs were found in the iopamidol-chlorinated waters, including five new iodo-DBPs not previously known: iodoacetonitrile, chloroiodoacetonitrile, dichloroiodoacetic acid, bromochloroiodoacetic acid, and chlorodiiodoacetic acid. Gas chromatography (GC)- high resolution mass spectrometry (HRMS) (with electron ionization [EI]) was used to identify the new iodo-nitriles, and a new, sensitive GC-EI-MS/MS method was used to identify the new iodo-acids.