Jiafu Li

2,4,6-Trichlorophenol is a well-known carcinogen, aromatic disinfection byproduct (DBP), and anthropogenic contaminant in drinking water, with a high detection frequency and concentration. Natural organic matter (NOM) is considered as its key precursor; however, the formation potential of NOM to 2,4,6-trichlorophenol during chlorination does not explain the μg/L levels observed in disinfected drinking water. In this study, concentrations of 2,4,6-trichlorophenol in drinking water from South Carolina were determined, and important new tert-butylphenol precursors were identified using nontarget and suspect screening analysis with gas chromatography (GC)-mass spectrometry (MS). Concentrations of 2,4,6-trichlorophenol in 12 chlorinated and chloraminated drinking water samples ranged from 9 to 14,966 ng/L (mean: 4805 ng/L), higher than 11 other classes of aromatic DBPs and 4 classes of aliphatic DBPs. During chlorination, yields of 2,4,6-trichlorophenol from Suwannee River NOM were 22 ng/mg-total organic carbon (TOC). In contrast, 2-tert-butylphenol, 4-tert-butylphenol, 2,4-di-tert-butylphenol, and 2,6-di-tert-butylphenol, found up to 41,037 ng/L in river water as industrial contaminants, showed yields of 737, 711, 1261, and 2939 ng/mg-TOC, respectively. tert-Butylphenols in source water contributed ∼3% of 2,4,6-trichlorophenol in the studied chlorinated river waters. Formation mechanisms were proposed. This study provides insight into uncovering additional unknown precursors of chlorophenols.

Haloacetonitriles (HANs), toxic disinfection by-products, are unregulated in China, with no standardized analytical methods. This study established a simultaneous quantitative method for six typical HANs in drinking water using an optimized purge-and-trap gas chromatography–mass spectrometry (P&T-GC/MS) system. Key parameters, including sorbent trap selection, purge time, and moisture control settings, were systematically optimized. The OI No. 7 trap and a 13 min purge time were selected to maximize sensitivity while minimizing moisture interference. Under optimal conditions, all target analytes showed good linearity (R² > 0.999). The method detection limits (LODs) ranged from 0.007 to 0.202 μg/L, and the limits of quantitation (LOQs) ranged from 0.2 to 2.0 μg/L. Average spiked recoveries in tap water were 89.5–111.0%, with relative standard deviations (RSDs) below 5% (n = 7). A core optimization was omitting pH adjustment and ascorbic acid quenching to avoid non-target degradation of brominated HANs and ensure accurate in situ concentration determination. Application to 16 Kunshan tap water samples showed total HAN concentrations of 0.59–3.03 μg/L (average: 1.62 μg/L), dominated by bromochloroacetonitrile (BCAN) and dibromoacetonitrile (DBAN). Process analysis indicated significant synergistic HAN removal by sand filtration and activated carbon, while chloramination significantly increased brominated HANs via enhanced bromination. This efficient, sensitive P&T-GC/MS method is suitable for trace HAN monitoring and provides technical support for HAN control in water treatment.

Cyanuric acid, as a by-product of chloroisocyanuric acids, is frequently detected in swimming pool water. However, its cytotoxicity, persistence, mobility, and bioaccumulation potential remain poorly understood. This study evaluates the cytotoxicity of cyanuric acid and investigates its occurrence and toxicological impact in water samples. Additionally, data on its biodegradation half-life, octanol-water partition coefficient (Kow), and bioconcentration factor (BCF) were collected. The average concentrations of cyanuric acid in 20 swimming pools were 26,600 µg/L, which were 3–5 orders of magnitude higher than other known organic disinfection byproducts (DBPs). The median lethal concentration (LC50) of cyanuric acid for Chinese hamster ovary (CHO) cells was 13.7 mM. Given its widespread occurrence and high concentration, cyanuric acid is likely a significant contributor to swimming pool cytotoxicity. The calculated cytotoxicity of cyanuric acid (15,054) exceeded that of all reported cyclic DBPs in swimming pools, including halonitrobenzoic acids (0.04), halonitrophenols (0.1), and halobenzoquinones (4.4). Furthermore, its calculated cytotoxicity was also much higher than most aliphatic DBPs. Overall, cyanuric acid contributed approximately 21.4% of pool water cytotoxicity, identifying it as an overlooked cyclic DBP. In terms of environmental persistence, cyanuric acid had a biodegradation half-life of 6.17 days, which is approximately comparable to the median level of aliphatic DBPs. The LogKow and BCF of cyanuric acid was −0.72 and 0.501 L/kg, suggesting a high mobility and minor bioaccumulation potential. Moreover, due to its extremely high concentration in swimming pool water (up to 79,000 µg/L), these values do not eliminate concerns about its environmental risks. Given that chloroisocyanuric acids have been identified as ideal oxidants in advanced oxidation processes (AOPs) for micropollutant degradation in water in recent years, this study may reveal the potential risk of cyanuric acid in swimming pool water and UV/chloroisocyanuric acid-treated water.

Phthalates are a widely used class of plasticizers known to cause various health issues. Although numerous review articles have addressed the multi-organ toxicities of Phthalates and their metabolites, a specialized review focusing on their nephrotoxicity remains scarce. In this study, the nephrotoxicity of Phthalates and their metabolites is summarized from the views of epidemiological and toxicological evidence. Epidemiological studies have demonstrated a correlation between Phthalate exposure and abnormal urinary albumin-to-creatinine ratio (ACR) as well as glomerular filtration rate (eGFR) in children. In contrast, for adults, the epidemiological evidence for the association between Phthalates and ACR/eGFR remains controversial, necessitating further investigation. In this review, we explore the potential mechanisms by which Phthalates and their metabolites may induce nephrotoxicity. These mechanisms include the following: (1) induction of oxidative stress in renal cells; (2) reduction in aldosterone levels; (3) dysregulation of the renin-angiotensin system; (4) activation of endoplasmic reticulum (ER) stress; (5) renal fibrosis; (6) disruption of sodium and water homeostasis; and (7) activation of the heat shock response defense system. Finally, based on the current understanding, we propose future research directions and necessary efforts to advance knowledge in this field.

As a major component of natural organic matter (NOM), lignin represents a significant source of potential disinfection byproducts (DBPs) in drinking water. However, lignin-derived DBPs have remained largely uncharacterized until now. Our study identified a class of aromatic DBPs - chloroguaiacols - in chlor(am)inated drinking water using non-target analytical approaches, with concentrations of 17.4-153 ng/L in 11 tap water samples. Controlled chlorination experiments demonstrated that lignin-derived phenols serve as important precursors, with vanillin showing particularly high reactivity (yield: 7705 ng/mg-C), followed by guaiacol (378 ng/mg-C) and vanillic acid (168 ng/mg-C). These yields were 27- to 272-fold higher than that observed for Suwannee River NOM, clearly establishing the significance of these specific phenolic precursors for chloroguaiacol formations. Through combined experimental and computational approaches, we elucidated potential formation pathways that provide a foundation for future mechanistic studies. While chloroguaiacols exhibit substantial cytotoxicity (28× greater than trihalomethanes and comparable to other aromatic DBPs), their low concentrations in drinking water suggest minimal contribution to overall toxicity compared to priority aliphatic DBPs. By elucidating both the precursor structures and their transformation pathways, this study provides important mechanistic insights into the transformation of lignin-derived phenols during chlorination.