Degradation of benzophenone-4 in a UV/chlorine disinfection process: Mechanism and toxicity evaluation

Yang

2022

JoX

Since 1974, more than 800 disinfection byproducts (DBPs) have been identified from disinfected drinking water, swimming pool water, wastewaters, etc. Some DBPs are recognized as contaminants of high environmental concern because they may induce many detrimental health (e.g., cancer, cytotoxicity, and genotoxicity) and/or ecological (e.g., acute toxicity and development toxicity on alga, crustacean, and fish) effects. However, the information on whether DBPs may elicit potential endocrine-disrupting effects in human and wildlife is scarce. It is the major objective of this paper to summarize the reported potential endocrine-disrupting effects of the identified DBPs in the view of adverse outcome pathways (AOPs). In this regard, we introduce the potential molecular initiating events (MIEs), key events (KEs), and adverse outcomes (AOs) associated with exposure to specific DBPs. The present evidence indicates that the endocrine system of organism can be perturbed by certain DBPs through some MIEs, including hormone receptor-mediated mechanisms and non-receptor-mediated mechanisms (e.g., hormone transport protein). Lastly, the gaps in our knowledge of the endocrine-disrupting effects of DBPs are highlighted, and critical directions for future studies are proposed.

Section: Introductionmentioning

confidence: 99%

Research Progress of the Endocrine-Disrupting Effects of Disinfection Byproducts

Sui

Yang

2022

JoX

“…In terms of toxicity measurements, a previous study has used Vidua fischeri to assess toxicity changes in the degradation of BTZ by UV/chlorine, providing limited information on the effects on human and ecological health at the cellular level. Instead, as an indicator of water quality assessment, cytotoxicity provides a convenient and ideal way for risk evaluation against mammalian cells. , Prior studies have measured the cytotoxicity of the chlorinated TPs, disinfection byproducts (DBPs), and inorganic arsenic, and the results showed a certain level of cytotoxicity. − Hence, the cytotoxicity assay using Chinese hamster ovary (CHO) cells arouse our interest to investigate the cytotoxicity changes during the degradation of organic contaminant before and after Fe(II) adsorption during UV/chlorine treatment.…”

Section: Introductionmentioning

confidence: 99%

Efficient Degradation of Organoarsenic by UV/Chlorine Treatment: Kinetics, Mechanism, Enhanced Arsenic Removal, and Cytotoxicity

Yang

et al. 2021

Environ. Sci. Technol.

Roxarsone (ROX) has been widely used as an organoarsenic additive in animal feeding operations and poses a risk to the environment. Here, we first report the efficient degradation of ROX by UV/chlorine, where the kinetics, removal of total arsenic (As), and cytotoxicity were investigated. The kinetics study presented that reactive chlorine species (RCS) and HO• were the dominant species to react with ROX. Furthermore, the degradation rate of ROX can reach the maximum value at pH 7.5 due to the formation of more RCS. The degradation of ROX was affected by the amount of chlorine, pH, and water matrix. Through product analysis and Gauss theoretical calculation, two possible ROX degradation pathways were proposed. The free radicals attacked the As–C bond of ROX and resulted in releasing arsenate (As(V)). It was the reason that for an enhancement of the removal of total As by ferrous appeared after UV/chlorine, and over 98% of the total As was removed. In addition, cytotoxicity studies indicated that the cytotoxicity significantly enhanced during the degradation of ROX by UV/chlorine. However, by combination of UV/chlorine and adsorption, cytotoxicity can be greatly eliminated, probably due to the removal of As(V) and chlorinated products. These results further demonstrated that UV/chlorine treatment could be an effective method for the control of the potential environmental risks posed by organoarsenic.

“…The chlorination of chemicals has frequently been observed during the disinfection process. , Previous studies have shown that free chlorine at dosages up to 200 μM can transform benzophenones into various chlorinated products, , which was associated with increased acute toxicity to luminescent bacteria, − and higher genotoxicity. − The recommended residual chlorine level for swimming pools is 0.2–1.0 mg/L for safe use; however, whether this low level of residual chlorine could trigger the natural occurrence of BP-1 chlorination remains unknown. Additionally, little is known concerning the joint toxicity of a potentially large number of chlorinated byproducts with varying toxicities .…”

Section: Introductionmentioning

confidence: 99%

Enhanced Disrupting Effect of Benzophenone-1 Chlorination Byproducts to the Androgen Receptor: Cell-Based Assays and Gaussian Accelerated Molecular Dynamics Simulations

Zhan

Cui

et al. 2021

Chem. Res. Toxicol.

Benzophenone-1 (BP-1), one of the commonly used ultraviolet filters, has caused increasing public concern due to frequently detected residues in environmental and recreational waters. Its susceptibility to residual chlorine and the potential to subsequently trigger endocrine disruption remain unknown. We herein investigated the chlorination of BP-1 in swimming pool water and evaluated the endocrine disruption toward the human androgen receptor (AR). The structures of monochlorinated (P1) and dichlorinated (P2) products were separated and characterized by mass spectrometry and 1H–1H NMR correlation spectroscopy. P1 and P2 exhibited significantly higher antiandrogenic activity in yeast two-hybrid assays (EC50, 6.13 μM and 9.30 μM) than did BP-1 (12.89 μM). Our 350 ns Gaussian accelerated molecular dynamics simulations showed the protein dynamics in a long-time scale equilibrium, and further energy calculations revealed that although increased hydrophobic interactions are primarily responsible for enhanced binding affinities between chlorinated products and the AR ligand binding domain, the second chloride in P2 still hinders the complex motion because of the solvation penalty. The mixture of BP-1–P1–P2 elicited additive antiandrogenic activity, well fitted by the concentration addition model. P1 and P2 at 1 μM consequently downregulated the mRNA expression of AR-regulated genes, NKX3.1 and KLK3, by 1.7–9.1-fold in androgen-activated LNCaP cells. Because chlorination of BP-1 occurs naturally by residual chlorine in aquatic environments, our results regarding enhanced antiandrogenic activity and disturbed AR signaling provided evidence linking the use of personal care products with potential health risks.