Algae impacted drinking water: Does switching to chloramination produce safer drinking water?

Md Tareq Aziz; Caroline O Granger; John L Ferry; Susan D Richardson

doi:10.1016/j.scitotenv.2023.162815

Algae impacted drinking water: Does switching to chloramination produce safer drinking water?

Sci Total Environ. 2023 Jun 15:877:162815. doi: 10.1016/j.scitotenv.2023.162815. Epub 2023 Mar 13.

Authors

Md Tareq Aziz¹, Caroline O Granger¹, John L Ferry¹, Susan D Richardson²

Affiliations

¹ Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
² Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA. Electronic address: richardson.susan@sc.edu.

PMID: 36921861
DOI: 10.1016/j.scitotenv.2023.162815

Abstract

Harmful algal (cyanobacterial) blooms (HABs) are increasing throughout the world. HABs can be a direct source of toxins in freshwater sources, and associated algal organic matter (AOM) can act as precursors for the formation of disinfection by-products (DBPs) in drinking water. This study investigated the impacts of algae on DBP formation using treatment with chloramine, which has become a popular disinfectant in the U.S. and in several other countries because it can significantly lower the levels of regulated DBPs formed. Controlled laboratory chloraminations were conducted using live field-collected algal biomass dominated by either Phormidium sp. or Microseira wollei (formerly known as Lyngbya wollei) collected from Lake Wateree and Lake Marion, SC. Sixty-six priority, unregulated or regulated DBPs were quantified using gas chromatography (GC)-mass spectrometry (MS). The presence of HAB-dominated microbial communities in source waters led to significant increases in more toxic nitrogen-containing DBPs (1.5-5 fold) relative to lake waters collected in HAB-free waters. Compared to chlorinated Phormidium-impacted waters, chloraminated waters yielded lower total DBP levels (up to 123 μg/L vs. 586 μg/L for low Br^-/I^- waters), but produced a greater number of brominated, iodinated, and mixed halogenated DBPs in high Br^-/I^- waters. Among the DBPs formed in Phormidium-impacted chloraminated waters, dichloroacetic acid, trichloromethane, chloroacetic acid, chloropropanone, and dichloroacetamide were dominant. For Microseira wollei-impacted chloraminated waters, total DBP concentrations ranged from 33 to 145 μg/L (approximately 3-5 times lower than chlorination), with dichloroacetic acid, dichloroacetamide, and trichloromethane dominant. Overall, chloramination significantly reduced calculated cytotoxicity and genotoxicity in low Br^- and I^- waters, but produced 1.3 fold higher calculated cytotoxicity (compared to chlorine) with high Br^-/I^- waters due to increased formation of more toxic iodo- and mixed halogenated DBPs.

Keywords: Algae; Chloramination; DBPs; Disinfection by-products; Lyngbya; Microseira wollei; N-DBPs; Phormidium.

MeSH terms

Chloroform / analysis
Dichloroacetic Acid / analysis
Disinfectants* / analysis
Disinfection / methods
Drinking Water* / chemistry
Halogenation
Water Pollutants, Chemical* / analysis
Water Purification* / methods

Substances

Drinking Water
2,2-dichloroacetamide
Chloroform
Dichloroacetic Acid
Disinfectants
Water Pollutants, Chemical

Supplementary concepts

Microseira wollei