Making Swimming Pools Safer: Does Copper–Silver Ionization with Chlorine Lower the Toxicity and Disinfection Byproduct Formation?

Abstract

Swimming pools are commonly treated with chlorine, which reacts with the natural organic matter and organic matter introduced by swimmers and form disinfection byproducts (DBPs) that are associated with respiratory-related issues, including asthma, in avid swimmers. We investigated a complementary disinfectant to chlorine, copper–silver ionization (CSI), with the aim of lowering the amount of chlorine used in pools and limiting health risks from DBPs. We sampled an indoor and outdoor pool treated with CSI-chlorine during the swimming season in 2017–2018 and measured 71 DBPs, speciated total organic halogen, in vitro mammalian cell cytotoxicity, and N-acetyl-l-cysteine (NAC) thiol reactivity as a cytotoxicity predictor. Controlled, simulated swimming pools were also investigated. Emerging DBP concentrations decreased by as much as 80% and cytotoxicity decreased as much as 70% in the indoor pool when a lower chlorine residual (1.0 mg/L) and CSI was used. Some DBPs were quantified for the first time in pools, including chloroacetaldehyde (up to 10.6 μg/L), the most cytotoxic haloacetaldehyde studied to date and a major driver of the measured cytotoxicity in this study. Three highly toxic iodinated haloacetic acids (iodoacetic acid, bromoiodoacetic acid, and chloroiodoacetic acid) were also quantified in pools for the first time. We also found that the NAC thiol reactivity was significantly correlated to cytotoxicity, which could be useful for predicting the cytotoxicity of swimming pool waters in future studies.

Are Disinfection Byproducts (DBPs) Formed in My Cup of Tea? Regulated, Priority, and Unknown DBPs

“…Sixty DBPs were measured, including 4 HALs, 7 HANs, 9 HKs, 4 HNMs, 4 THMs, 6 I-THMs, 9 HAAs, 4 IAAs, and 13 HAMs (Table S1). Extraction and derivatization methods were adapted from previously published methods from our laboratory. − In brief, 100 mL of water or brewed tea was pH adjusted to a pH < 1 using concentrated H 2 SO 4 . Then, 30 g of sodium sulfate and 10 mL of MTBE (for the first extraction) were added to 125 mL amber bottle and the samples were shaken for 15 min.…”

“…Diazomethane derivatization was used for the analysis of HAAs and IAAs. Diazomethane was freshly generated according to a US EPA Standard Operating Procedure. − An Aldrich diazomethane generator apparatus (St. Louis, MO) was used. In brief, approximately 0.367 g of Diazald and 1.0 mL of CARBITOL (Sigma-Aldrich, St. Louis, MO) were added to the inner piece of the generator, and 3.0 mL of MTBE were added to the outer piece.…”

“…Total organic chlorine (TOCl), bromine (TOBr), and iodine (TOI) were analyzed using a Mitsubishi TOX analyzer (Mitsubishi Chemical Analytech, Chigasaki, Japan; Cosa Xentaur, Yaphank). Procedures were based on published papers, with a few modifications described in Text S1. ,, Briefly, acidified samples (pH < 2) were adsorbed onto activated carbon, washed with sodium nitrate, and combusted at 1000 °C in the presence of oxygen and argon as the carrier gas. Combusted gases were collected in an aqueous solution containing 0.03% hydrogen peroxide, which was analyzed for chloride, bromide, and iodide using a Dionex 1600 ion chromatograph (Dionex, Sunnyvale, CA).…”

Comparison of Estrogenic, Spectroscopic, and Toxicological Analyses of Pilot-Scale Water, Wastewaters, and Processed Wastewaters at Select Military Installations

“…Apart from genotoxicity, when comparing wastewaters before and after AnMBR treatment (centralized supply and decentralized low energy wastewater treatment), other toxicity endpoints, in general, followed the trend (not statistically significant) of the spectroscopic indicator SFI values but not the SUVA 254 values likely because of the production of high UV-absorbing SMPs during the treatment that passed through the membrane module . Among all processed wastewaters, there was a high correlation between CTI and TRI ( r = 0.99; P ≤ 0.001), indicating that TRI may be a useful high-throughput metric to predict mammalian cell cytotoxicity. , …”

“…56 Among all processed wastewaters, there was a high correlation between CTI and TRI (r = 0.99; P ≤ 0.001), indicating that TRI may be a useful high-throughput metric to predict mammalian cell cytotoxicity. 52,60 Process Design. To investigate conventional versus advanced water reuse treatments regarding the toxicological and estrogenic endpoints, we classified and compared all design scenarios: (1) centralized supply and decentralized wastewater treatment; (2) 4).…”