Occurrence of Regulated and Emerging Iodinated DBPs in the Shanghai Drinking Water

Xiao Wei,Dong Zhang,Xin Chen,Gengsheng He,Songhui Jiang,Xia Wang,Choon Nam Ong,Weidong Qu,Weiwei Zheng,Dajun Tian,Zhi Zhou

doi:10.1371/journal.pone.0059677

Abstract

Drinking water chlorination plays a pivotal role in preventing pathogen contamination against water-borne disease. However, chemical disinfection leads to the formation of halogenated disinfection by products (DBPs). Many DBPs are highly toxic and are of health concern. In this study, we conducted a comprehensive measurements of DBPs, including iodoacetic acid (IAA), iodoform (IF), nine haloacetic acids and four trihalomethanes in drinking waters from 13 water plants in Shanghai, China. The results suggested that IAA and IF were found in all the water treatment plants, with maximum levels of 1.66 µg/L and 1.25 µg/L for IAA and IF, respectively. Owing to deterioration of water quality, the Huangpu River has higher IAA and IF than the Yangtze River. Our results also demonstrated that low pH, high natural organic matter, ammonia nitrogen, and iodide in source waters increased IAA and IF formation. Compared to chlorine, chloramines resulted in higher concentration of iodinated DBP, but reduced the levels of trihalomethanes. This is the first study to reveal the widespread occurrence of IAA and IF in drinking water in China. The data provide a better understanding on the formation of iodinated disinfection byproducts and the findings should be useful for treatment process improvement and disinfection byproducts controls.

Highlights

Drinking water chlorination plays an important role in preventing pathogen contamination against water-borne disease
Our results demonstrated that the levels of I-disinfection by products (DBPs) were significantly higher in finished water of the Huangpu River than those of the Yangtze River (Table 3)
River were generally higher than those from the Yangtze River as the water quality in the Huangpu River has been noted to be deteriorated over the past years

Summary

Introduction

Drinking water chlorination plays an important role in preventing pathogen contamination against water-borne disease. Chemical disinfection leads to the formation of halogenated disinfection by products (DBPs) due to reaction with natural organic matter (NOM), and result in potential health concerns [1]. Epidemiologic investigations have demonstrated the associations between exposure to DBPs in drinking water with cancers (bladder [2], colon [3] and rectum [4]), adverse birth outcomes [5,6,7,8,9,10,11] and birth defects [12,13]. Toxicological assessments have revealed that several DBPs (e.g.,3-chloro-4-(dichloromethyl)-5-hydroxyl-2(5H) -furanone (MX) and formaldehyde) are potential carcinogens [1]. About 600–700 DBPs have been identified in drinking water [1,14], and only a few of DBPs have been evaluated for adverse effects. Some DBPs, especially newly emerging DBPs do not have maximum acceptable values and are not required for routine surveillance

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