Occurrence, influencing factors, toxicity, regulations, and abatement approaches for disinfection by-products in chlorinated drinking water: A comprehensive review. (15th July 2021)

• Record Type: Journal Article
• Authors: Kali, Sundas; Khan, Marina; Ghaffar, Muhammad Sheraz; Rasheed, Sajida; Waseem, Amir; Iqbal, Muhammad Mazhar; Bilal khan Niazi, Muhammad; Zafar, Mazhar Iqbal
• Is Part Of: Environmental pollution. Volume 281(2021)
• Publication Date: 2021-07-15
• Subjects: Chlorination -- Drinking water -- Disinfection by-products -- Occurrence -- Influencing factors -- Toxicity -- Abatement approaches; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2021.116950
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Disinfection is considered as a vital step to ensure the supply of clean and safe drinking water. Various approaches are adopted for this purpose; however, chlorination is highly preferred all over the world. This method is opted owing to its several advantages. However, it leads to the formation of certain by-products. These chlorination disinfection by-products (DBPs) are genotoxic, carcinogenic and mutagenic. Still chlorination is being practiced worldwide. Present review gives insights into the occurrence, toxicity and factors affecting the formation of regulated (THMs, HAAs) and emerging DBPs (N-DBPs, HKs, HAs and aromatic DBPs) found in drinking water. Furthermore, remediation techniques used to control DBPs have also been summarized here. Key findings are: (i) concentration of regulated DBPs surpassed the permissible limit in most of the regions, (ii) high chlorine dose, high NOM, more reaction time (up to 3 h) and high temperature (up to 30 °C) enhance the formation of THMs and HAAs, (iii) high pH favors the formation of THMs while low pH is suitable of the formation of HAAs, (iv) high NOM, low temperature, low chlorine dose and moderate pH favors the formation of unstable DBPs (N-DBPs, HKs and HAs), (v) DBPs are toxic not only for humans but for aquatic fauna as well, (vi) membrane technologies, enhanced coagulation and AOPs remove NOM, (vii) adsorption, air stripping and other physical and chemical methods are post-formation approaches (viii) step-wise chlorination is assumed to be an efficient method to reduce DBPs formation without any treatment. Toxicity data revealed that N-DBPs are found to be more toxic than C-DBPs and aromatic DBPs than aliphatic DBPs. In majority of the studies, merely THMs and HAAs have been studied and USEPA has regulated just these two groups. Future studies should focus on emerging DBPs and provide information regarding their regulation. Graphical abstract: Image 1 Highlights: Levels of regulated DBPs surpassed the permissible limit in most of the regions. High chlorine dose, NOM, time and temperature enhance the formation of THMs and HAAs. Effect of metal ions on DBPs formation depends upon the properties of NOM. More DBPs are formed in PE pipes. Aromatic DBPs are more toxic than aliphatic but data is scarce for their regulation. Abstract : Levels of DBPs have been reported higher than the permissible limits by USEPA. Emerging DBPs are more toxic yet unregulated. Adsorption is one of the efficient techniques for the removal of DBPs from drinking water.