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Using current water treatment systems, significant amounts of microplastics (MPs) are passing through and being released into the aquatic environment. However, we do not clearly know what effects disinfection processes have had on these particles. In this study, we applied inductively coupled plasma-mass spectrometry (ICP-MS) operating in time-resolved analysis (TRA) mode for quantifying changes in the chlorine (Cl) content of MPs under a variety of water treatment scenarios. Our results illustrated that time-resolved ICP-MS offers a potential method for sensitive and direct analysis of Cl content, including Cl mass and chlorine association (%Cl/C), of discrete particles in the MP suspension by the fast sequential measurements of signals from 35 Cl 1 H 2 and 12 C 1 H. Our research, across various water treatment scenarios, also showed that polystyrene (PS) MPs exhibited greater reactivity to Cl disinfectant after being pre-disinfected with UV light and in mildly acidic to neutral pH environments. It is noteworthy that about half of the particles in MP suspension exposed to 10 mg Cl 2 /L, a typical Cl dose applied in water treatment, were chlorinated, and had a Cl content comparable to that of particles subjected to extreme conditions. Of even greater concern is the fact that our cell viability tests revealed that chlorinated MPs induced considerably higher rates of cell death in both human A549 and Caco-2 cells, and that the effects were Cl dose- and polymer type-dependent. Overall, this study demonstrates the potential of time-resolved ICP-MS as a valuable technique for quantifying the Cl content of MP particles, which is crucial to assessing the fate and transformation of MPs in our water supply and treatment systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Nanoplastics (NPs) have raised concerns about the combined toxicity to living organisms due to their ability to adsorb heavy metals. There is still uncertainty, however, whether NPs combined with heavy metals exert adverse effects on intestinal microenvironment, especially the intestinal cells and microbiota. Herein, the combined effects of 500 nm spherical-shaped polystyrene nanoplastics (PSNPs) and copper ions (Cu 2+ ) on intestinal cells and gut microbiota were assessed using HCT-116 cells and zebrafish models. The combined exposure of PSNPs (10 mg/L) and Cu 2+ (0.5 mg/L) induced more severer hatching interference of zebrafish embryos, deformation, and mortality. In larval stage, PSNPs (10 mg/L) accumulated and carried more Cu 2+ in the gastrointestinal tract (GIT) of zebrafish after co-exposure for 5 days. Excessive neutrophil recruitment and oxidative stress in GIT of zebrafish larvae were observed. The mechanism of the combined toxicity was revealed by transmission electron microscopy (TEM) showing the injuries of GIT, transcriptome and 16S rDNA gene sequencing showing the toxicity pathways, including oxidative phosphorylation and respiratory electron transport chain, as well as microbial community analysis showing the induced microbiota dysbiosis. In vitro tests using HCT-116 cells showed that PSNPs (10 mg/L) and Cu 2+ (0.5 mg/L) increased cell death while decreasing ATP concentration and mitochondrial membrane potential after 48 h exposure. These findings may provide new insights into the combined toxicity of nanoplastics and heavy metals in the intestinal microenvironment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Manganese oxide (MnO 2 ) is one of the most abundant metal oxides, and it is renowned for its ability to degrade various phenolic micropollutants. However, under MnO 2 -mediated transformation, BP-3 transforms into 12 different radical-coupled transformation products (TPs) out of 15 identified TPs. These radical-coupled TPs are reported with adverse environmental impacts. This study explored the effects of MnO 2 on organic UV filter mixtures and different water constituents (i.e., bicarbonate ion (HCO 3 - ), humic acid (HA) and halide ions) in terms of degradation efficiency and transformation chemistry. When a mixture of benzophenone-3 (BP-3) and avobenzone (AVO) underwent transformation by MnO 2 , hybrid radical-coupled TPs derived from both organic UV filters were generated. These hybrid radical-coupled TPs were evaluated by an in silico prediction tool and Vibrio fischeri bioluminescence inhibition assay (VFBIA). Results showed that these TPs were potentially toxic to aquatic organisms, even more so than their parent compounds. The higher the concentration of HCO 3 - , HA, chloride ion (Cl - ) and bromide ion (Br - ), the greater the reduction in the efficiencies of degrading BP-3 and AVO. Contrastingly, in the presence of iodide ion (I - ), degradation efficiencies of BP-3 and AVO were enhanced; however, iodinated TPs and iodinated radical-coupled TPs were formed, with questionable toxicity. This study has revealed the environmental risks of hybrid radical-coupled TPs, iodinated TPs and iodinated radical-coupled TPs when the organic UV filters BP-3 and AVO are transformed by MnO 2 ., Competing Interests: Declaration of competing interest The authors report no declarations of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Children are highly vulnerable to environmental pollutants, especially endocrine-disrupting chemicals (EDCs). Previous research has linked both organic UV filters and phthalates exposure to adiposity and pubertal development in children. Nevertheless, the individual and collective effects of these chemicals on this population remain poorly understood. In this study, twelve organic UV filters and metabolites, six phthalate metabolites and two oxidative stress biomarkers were analyzed in a prospective follow-up study in Shanghai, China after a baseline study conducted 1.5 years earlier. Results revealed a positive association between exposure to individual organic UV filters or their mixture and levels of 8-OHdG (β ranging from 0.242 to 0.588, P < 0.05), a marker of oxidative DNA damage. BP-3 and OD-PABA made a greater contribution to oxidative DNA damage than other UV filters. Levels of 8-OHdG were also positively correlated with single phthalate metabolites and their mixture, with MnBP and MMP contributing the most. Stratified analysis found that these associations were mainly observed in girls. Our mixture analysis revealed cumulative risks of oxidative DNA damage when there was co-exposure to these two kinds of EDCs. These results underscore the importance of considering the risks associated with organic UV filters and the necessity of evaluating the effects of all these pollutants, both individually and in mixtures., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Radical-coupled transformation products (TPs) have been identified as the byproducts of various transformation processes, including both natural attenuation and artificial treatments, of phenolic micropollutants. Benzophenone-3 (BP-3), an organic UV filter of emerging concern, has been previously reported with ubiquitous occurrence in the natural environment and water bodies. Current research has demonstrated how TPs are formed from BP-3 when it is treated with manganese oxide (MnO 2 ). The ecological and toxicological risks of these TPs have also been assessed. Polymerization of BP-3 through radical coupling was observed as the major pathway by which BP-3 is transformed when treated with MnO 2 . These radical-coupled TPs haven't shown further degradation after formation, suggesting their potential persistence once occurred in the environment. In silico experiments predict the radical-coupled TPs will increase in mobility, persistence and ecotoxicity. If true, they also represent an ever-increasing threat to the environment, ecosystems and, most immediately, aquatic living organisms. In addition, radical-coupled TPs produced by MnO 2 transformation of BP-3 have shown escalated estrogenic activity compared to the parent compound. This suggests that radical coupling amplifies the toxicological impacts of parent compound. These results provide strong evidence that radical-coupled TPs with larger molecular sizes are having potential adverse impacts on the ecosystem and biota., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Numerous agrochemicals, including pesticides and herbicides, are applied in modern agriculture, resulting in concerns for the ecosystem and human safety as humans are easily exposed to these compounds. Many agrochemicals, and their transformation products or metabolites, have shown toxicity in in vitro and in vivo studies. However, given the rapid development of novel agrochemicals, for many there is no information about their effects nor about metabolic transformations when ingested by humans. Tracing biomarkers may be the best method for assessing the impacts of agrochemicals. A combination of in vitro metabolism study and suspect screening of human samples (e.g., urine, blood) can be utilized to efficiently find biomarkers for agrochemical exposure. In the work reported here, we determined the in vitro metabolic profiling of six prioritized pesticides and synergists, namely boscalid, carbendazim, piperonyl butoxide, spiroxamine, dimethomorph and fludioxonil, in human liver microsomes. 17 major metabolites were structurally elucidated by high resolution mass spectrometry (HRMS). Major metabolic transformation processes (e.g., hydroxylation, demethylation and oxidation) were proposed for each pesticide. Individual in silico toxicity assessments showed that some metabolites had the same or even enhanced toxicity compared to parent compounds. Information about these metabolites obtained from HRMS was used for suspect screening in human activities related samples. Carbendazim and a metabolite of fludioxonil were identified in wastewater and laboratory urine samples, respectively. Our findings provide concrete evidence for the use of in vitro metabolites as biomarkers in biomonitoring studies of potential exposure to toxic chemicals., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Symbiotic corals receive energy not only by ingesting food (e.g. plankton, inorganic/organic matter, i.e. heterotrophy), but also by endosymbiosis, which supplies photosynthates (dissolved inorganic carbon, i.e. autotrophy). These two sources of energy have distinct fatty acid (FA) profiles, which can be used to differentiate corals by their primary feeding mode. FA profiles have been applied as biomarkers to evaluate the quality of nutrition in the midst of environmental change. However, species-specific responses of coral FA profiles and biosynthetic pathway under cultural eutrophication are still unknown. We collected two coral species (Acropora samoensis, Platygyra carnosa) from sites with different levels of eutrophication to test for variations in FA profiles. Gas Chromatography-Mass Spectrometry (GC-MS) was performed to identify FA profiles and quantify their concentration. Our main findings are threefold: 1) chronic eutrophication inhibits corals' ability to synthesize essential FA; 2) PUFA:SFA ratio and certain FA biomarkers or their pathway can be successfully utilized to determine the relative degree of autotrophy and heterotrophy in corals; 3) under eutrophication, different FA profiles of coral host tissue are attributed to different feeding strategies. Thus, our research provides significant new insights into the roles of FA as a risk assessment tool in coral reef ecosystems under the pressure of eutrophication., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Organic UV filters are compounds that absorb UV irradiation by their highly conjugated structure. With the developing consciousness over the last century of the skin damage UV radiation can cause, the demand for organic UV filters has risen, for use not only in sunscreens, but also in other personal care products. The massive production and usage of these organic UV filters has resulted in extensive release into the aquatic environment, and thereby making an important group of emerging contaminants. Considering the widespread occurrence of organic UV filters in not only ambient water, but also sediment, soil and even indoor dust, their threats towards the health of living organisms have been a subject of active investigation. In this review article, we present an overall review of existing knowledge on the risks of organic UV filters from the aspects of both environmental and human health impacts. As for the environment, some organic UV filters are proven to bioaccumulate in various kinds of aquatic organisms, and further to have adverse effects on different kinds of animal models. Toxicological studies including in vivo and in vitro studies are important and effective means to ascertain the effects and mechanisms of organic UV filters on both the ecosystem and humans. Subsequent concerns arise that these compounds will affect human health in the long term. This review concludes by suggesting future lines of research based on the remaining knowledge gaps., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Ethylhexyl methoxycinnamate (EHMC) is one of the most frequently used UV filters in sunscreens and other cosmetic products. Its ubiquitous presence in various environmental matrices and its endocrine disrupting properties have been widely reported. However, we know little about the effect of EHMC exposure on humans, mainly due to its fast metabolism. In this study, urine and plasma of EHMC-dosed rats were analysed to identify its major metabolites. Five metabolites were found, with four firstly reported. Two metabolites were putatively identified as 4-methoxycinnamic acid (4-MCA) and 4'-methoxyacetophenone (4'-MAP). Quantitative results revealed that their excretion concentrations were much higher than the parent compound. Because of these high concentrations, for the human biomonitoring study, EHMC and these two metabolites were detected simultaneously in urine samples from Chinese children and adolescents. The results indicated wide exposure to EHMC, 4-MCA and 4'-MAP. The correlation between urinary concentration of EHMC and 4-MCA as well as 4-MCA and 4'-MAP provided important clues as to the sources and metabolic pathways among these three compounds. Several demographic factors were also assessed with the exposure level. As the first human exposure study of EHMC in a Chinese population, this report would help to establish an exposure database facilitating health risk assessment of EHMC., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Organic UV filters, now considered to be emerging contaminants in aquatic ecosystems, are being intensively tracked in environmental waters worldwide. However, their environmental fate and impact of these contaminants on marine organisms remains largely unknown, especially in Asia. This work elucidates the occurrence and the ecological risks of seven UV filters detected in farmed fish, wild mussels and some other wild organisms collected from local mariculture farms in Hong Kong. For all of the organisms, ethylhexyl methoxycinnamate (EHMC) and octyl dimethyl p-aminobenzoic acid (OD-PABA) were the predominant contaminants with the highest concentrations up to 51.3 and 24.1ng/g (dw), respectively; lower levels were found for benzophenone-8 (BP-8), octocrylene (OC) and benzophenone-3 (BP-3) from