Formation of DBPs and halogen-specific TOX in the presence of iopamidol and chlorinated oxidants

Chlorination of Source Water Containing Iodinated X-ray Contrast Media: Mutagenicity and Identification of New Iodinated Disinfection Byproducts

“…DCAA and trichloroacetic acid (TCAA) were the most abundant HAAs in the chlorinated source water, followed by either bromodichloroacetic acid (BDCAA) or BAA. These results are consistent with those of a recent study 51 , which also found chloroform and TCAA to be the predominant THM and HAA species formed in chlorinated IPAM-containing source water.…”

“…Formation of iodate, a non-toxic sink of iodide, was not monitored in the solutions. Previous studies have shown the absence of detectable levels of this inorganic iodine species in chlorinated ICM-containing source waters 45,51 .…”

“…However, this contribution pattern of DBP classes was altered considerably after chlorination of source water containing IPAM, resulting in the initial total HAN concentration of 7.8 µg/L increasing to 83.7 µg/L. Although ICM reactivity to form HANs has not been studied previously, IPAM is the ICM that is generally most reactive with chlorine 45,51 . This is borne out in the lower amounts of residual free chlorine remaining after the 72-h reaction for IPAM than for the other three ICM evaluated (Table S3).…”

“…For example, diatrizoate (DTZ) has been quantified at levels between 20 and 100 µg/L 47 , and ICM have also been detected in finished drinking waters 46,[49][50] . Among the ICM, iopamidol (IPAM) 40,[45][46][51][52][53][54][55] , iohexol (IHX) [45][46] , iopromide (IPR) [45][46]54 , DTZ [45][46]54 , iomeprol 46 , iodixanol 54 , and histodenz 54 have been investigated as potential precursors of I-DBPs during chlorination or chloramination of water. According to these studies, IPAM is the ICEM that is most reactive with chlorine.…”

Iodinated disinfection byproducts: Formation and concerns

“…Besides natural iodide salts, iodinated X-ray contrast media (ICM) used for medical imaging of soft tissues have been discovered as a relevant source of iodine that leads to the formation of iodo-DBPs during chlorination and chloramination of drinking water sources. Since the first work carried out on this topic by Duirk et al [31], several studies have confirmed this [22,[32][33][34][35][36]. Of all ICM tested (i.e., diatrizoate, iodixanol, iohexol, iomeprol, iopamidol, and iopromide), iopamidol seems to be the most reactive compound.…”