Innovative drinking water treatment techniques reduce the disinfection-induced oxidative stress and genotoxic activity

• Disinfection of drinking water using chlorine can lead to the formation of genotoxic by-products whenchlorine reacts with natural organic matter (NOM). A vast number of such disinfection by-products(DBPs) have been identified, making it almost impossible to routinely monitor all DBPs with chemicalanalysis. In this study, a bioanalytical approach was used, measuring oxidative stress (Nrf2 activity),genotoxicity (micronucleus test), and aryl hydrocarbon receptor (AhR) activation to evaluate an innovativewater treatment process, including suspended ion exchange, ozonation, in-line coagulation,ceramic microfiltration, and granular activated carbon. Chlorination was performed in laboratory scaleafter each step in the treatment process in order to investigate the effect of each treatment process to theformation of DBPs. Suspended ion exchange had a high capacity to remove dissolved organic carbon(DOC) and to decrease UV absorbance and Nrf2 activity in non-chlorinated water. High-dose chlorination(10 mg Cl2 L-1) of raw water caused a drastic induction of Nrf2 activity, which was decreased by 70% inwater chlorinated after suspended ion exchange. Further reduction of Nrf2 activity following chlorinationwas achieved by ozonation and the concomitant treatment steps. The ozonation treatment resulted indecreased Nrf2 activity in spite of unchanged DOC levels. However, a strong correlation was found betweenUV absorbing compounds and Nrf2 activity, demonstrating that Nrf2 inducing DBPs were formedfrom pre-cursors of a specific NOM fraction, constituted of mainly aromatic compounds. Moreover, highdosechlorination of raw water induced genotoxicity. In similarity to the DOC levels, UV absorbance andNrf2 activity, the disinfection-induced genotoxicity was also reduced by each treatment step of theinnovative water treatment technique. AhR activity was observed in the water produced by the conventionalprocess and in the raw water, but the activity was clearly decreased by the ozonation step inthe innovative water treatment process.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Environmental Sciences (hsv//eng)

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Oceanografi, hydrologi och vattenresurser (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Oceanography, Hydrology and Water Resources (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Hälsovetenskap -- Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Health Sciences -- Public Health, Global Health, Social Medicine and Epidemiology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Hälsovetenskap -- Arbetsmedicin och miljömedicin (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Health Sciences -- Occupational Health and Environmental Health (hsv//eng)

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Livsmedelsvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Food Science (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Miljöbioteknik -- Vattenbehandling (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Environmental Biotechnology -- Water Treatment (hsv//eng)

Nyckelord

Drinking water

disinfection byproducts

oxidative stress

Nrf2

genotoxicity

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