Source tracing and health risk assessment of phthalate esters in household tap-water: A case study of the urban area of Quanzhou, Southeast China

Multi-omics analysis of the toxic effects on gill tissues of crucian carp (Carassius auratus) from chronic exposure to environmentally relevant concentrations of Di(2-ethylhexyl) phthalate (DEHP)

The pervasive use of the plasticizer di(2-ethylhexyl) phthalate (DEHP) poses potential risks to global aquatic ecosystems. This study systematically evaluated the adverse effects of chronic exposure to environmentally relevant concentrations of DEHP on gill tissues of crucian carp, utilizing histological examination, metabolomic, and transcriptomic analysis. The results demonstrated that DEHP induced significant histopathological alterations in gill tissues, with significant enrichment observed in multiple pathways associated with amino acid, hormone, lipid, and xenobiotic metabolism. Metabonomics-transcriptomics analyses indicated that DEHP-induced significantly over-activation of cytochrome P450 1B1-like (p < 0.001) and cytochrome P450 3A30-like (p < 0.05) via the nuclear xenobiotic receptors pathway was a key factor contributing to the disruption of tryptophan metabolism and steroid hormone biosynthesis, as well as inducing circadian rhythm disruption. Moreover, circadian rhythm disruption further exacerbated the imbalance of cytochrome P450 (CYP450) enzyme system as well as linoleic acid, arachidonic acid, sphingolipid, and glycerophospholipid metabolism. Overall, the feedback regulation between the CYP450 enzyme system and circadian rhythms emerged as the primary mechanism underlying DEHP-induced metabolic and transcriptional disruptions, ultimately resulting in gill toxicity. This study not only enriched the toxic effects on aquatic organisms of chronic exposure to DEHP, but provided potential biomarkers for the environmental risk assessment of DEHP.

Annual and Seasonal Variability of Trichloromethane in Drinking Water of Kunshan City 2016-2022 and Associated Health Risks

This study aimed to evaluate the annual pollution characteristics of trichloromethane (TCM) in Kunshan City's tap water from 2016 to 2022. This research analyzed 566 tap water samples from centralized water supply units, utilizing the GB 5749-2006 Sanitary Standard for Drinking Water as the evaluation benchmark. Data analysis employed non-parametric tests and Spearman's correlation analysis using Excel 2017 and SPSS 26.0. The results indicated a 100% compliance rate with the TCM limit (0.06 mg/L), with median annual concentrations ranging from 0.1 to 6.4 μg/L. Significant inter-annual variations were observed (H = 222.5, p < 0.01), with the lowest levels in 2019 and the highest in 2020. Quarterly analysis revealed significant seasonal differences (H = 94.0, p < 0.01), peaking in the third quarter (8.0 μg/L) and bottoming in the first quarter (3.5 μg/L). TCM concentrations showed significant correlations with annual and quarterly trends, turbidity, and chlorides (|rs| > 0.3, p < 0.01) but not with pH (rs = -0.0025, p = 0.55). While Kunshan City's drinking water demonstrates satisfactory TCM levels, an increasing annual trend and higher concentrations in the latter half of the year warrant continued monitoring and investigation. In this study, we assessed the health risks for households in Kunshan, China, due to trichloromethane (TCM) in drinking water. The overall carcinogenic risk from multiple exposure pathways was slightly above the ideal level, while the non-carcinogenic risk was within an acceptable range.

Role of formyl peptide receptor 2 in steatosis of L02 cells exposed to Mono-(2-ethylhexyl) phthalate

Mono-(2-ethylhexyl) phthalate (MEHP) can accumulate in the liver and then lead to hepatic steatosis, while the underlying mechanism remains unclear. Inflammation plays an important role in the disorder of hepatic lipid metabolism. This study aims to clarify the role of the inflammatory response mediated by formyl peptide receptor 2 (FPR2) in steatosis of L02 cells exposed to MEHP. L02 cells were exposed to MEHP of different concentrations and different time. A steatosis model of L02 cells was induced with oleic acid and the cells were exposed to MEHP simultaneously. In addition, L02 cells were incubated with FPR2 antagonist and then exposed to MEHP. Lipid accumulation was determined by oil red O staining and extraction assay. The indicators related to lipid metabolism and inflammatory response were measured with appropriate kits. The relative expression levels of FPR2 and its ligand were determined by Western blot, and the interaction of them was detected by co-immunoprecipitation. As a result, MEHP exposure could promote the occurrence and progression of steatosis and the secretion of chemokines and inflammatory factors in L02 cells. MEHP could also affect the expression and activation of FPR2 and the secretion of FPR2 ligands. In addition, the promotion effect of MEHP on the secretion of total cholesterol and interleukin 1β in L02 cells could be significantly inhibited by the FPR2 antagonist. We concluded that FPR2 might affect the promotion effect of MEHP on steatosis of L02 cells by mediating inflammatory response.

Identify organic contaminants of high-concern based on non-targeted toxicity testing and non-targeted LC-HRMS analysis in tap water and source water along the Yangtze River

Many organic pollutants were detected in tap water (TW) and source water (SW) along the Yangtze River. However, the potential toxic effects and the high-concern organics (HCOs) which drive the effect are still unknown. Here, a non-targeted toxicity testing method based on the concentration-dependent transcriptome and non-targeted LC-HRMS analysis combining tiered filtering were used to reveal the overall biological effects and chemical information. Subsequently, we developed a qualitative pathway-structure relationship (QPSR) model to effectively match the biological and chemical information and successfully identified HCOs in TW and SW along the Yangtze River by potential substructures of HCOs. Non-targeted toxicity testing found that the biological potency of both TW and SW was stronger in the downstream of the Yangtze River, and disruption of the endocrine system and cancer were the main drivers of the effect. In addition, non-targeted LC-HRMS analysis combined with retention time prediction results identified 3220 and 631 high-confidence compound structures in positive and negative ion modes, respectively. Then, QPSR model was further implied and identified a total of 103 HCOs, containing 35 industrial chemicals, 30 PPCPs, 26 pesticides, and 12 hormones in TW and SW, respectively. Among them, the neuroactive and hormonal compounds oxoamide, 8-iso-16-cyclohexyl-tetranor prostaglandin E2, E Keppra, and Tocris-0788 showed the highest frequency of detection, which were identified in more than 1/3 of the samples. The strategy of combining non-targeted toxicity testing and non-targeted LC-HRMS analysis will support comprehensive biological effect assessment, identification of HCOs, and risk control of mixtures.

Occurrence and Health Risk Assessment of Phthalates in Municipal Drinking Water Supply of a Central Indian City

In this study, the occurrence of phthalates in the municipal water supply of Nagpur City, India, was studied for the first time. The study aimed to provide insights into the extent of phthalate contamination and identify potential sources of contamination in the city's tap water. We analyzed fifteen phthalates and the total concentration (∑15phthalates) ranged from 0.27 to 76.36 µg L-1. Prominent phthalates identified were di-n-butyl phthalate (DBP), di-isobutyl phthalate (DIBP), benzyl butyl phthalate (BBP), di (2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DNOP), and di-nonyl phthalate (DNP). Out of the fifteen phthalates analyzed, DEHP showed the highest concentration in all the samples with the median concentration of 2.27 µg L-1, 1.39 µg L-1, 1.83 µg L-1, 2.02 µg L-1, respectively in Butibori, Gandhibaag, Civil Lines, and Kalmeshwar areas of the city. In 30% of the tap water samples, DEHP was found higher than the EPA maximum contaminant level of 6 µg L-1. The average daily intake (ADI) of phthalates via consumption of tap water was higher for adults (median: 0.25 µg kg-1 day-1) compared to children (median: 0.07 µg kg-1 day-1). The hazard index (HI) calculated for both adults and children was below the threshold level, indicating no significant health risks from chronic toxic risk. However, the maximum carcinogenic risk (CR) for adults (8.44 × 10-3) and children (7.73 × 10-3) was higher than the threshold level. Knowledge of the sources and distribution of phthalate contamination in municipal drinking water is crucial for effective contamination control and management strategies.

Pollution characteristics and health risk of sixty-five organics in one drinking water system: PAEs should be prioritized for control

Currently, a large number of emerging organic contaminants have been detected in domestic and international drinking water systems. However, there are differences among the research methods, which lead to system errors in directly comparing the hazards of different contaminants, so it is difficult to analyze the priority control pollutants and the risk control target in drinking water from previous studies. Therefore, we selected a drinking water treatment plant (DWTP) in the east of China, and detected trihalomethanes (THMs), antibiotics, phthalate esters (PAEs), organophosphate esters (OPEs), per and polyfluoroalkyl substances (PFASs), a total of sixty-five organic contaminants in one batch water sample of four seasons, and carried out the whole process monitoring of "Source water-DWTP-Network-Users", and calculated the health risks of contaminants in tap water. The results showed that DWTP could effectively remove antibiotics and PAEs; the removal rate of coagulation for antibiotics can be up to 47%; the release of PAEs in the plastic water supply pipe leads to a significant increase of the concentrations in the water transportation system, which can reach 2.92 times of that in finished water; compared with other contaminants, THMs and PAEs in tap water have higher health risks. This study reveals that THMs and PAEs are priority control organic pollutants, and the water supply network is the key risk control target in the drinking water system, providing a theoretical basis for how to ensure the safety of drinking water.