Many countries have integrated wastewater monitoring systems with their infectious disease surveillance systems to enhance public health response capabilities. An Information System for the Chinese Urban Wastewater Surveillance System (CWSS-IS) was developed based on the unified digital infrastructure of the China CDC. The primary functional modules of the CWSS-IS include information on monitoring sites, wastewater sample collection, relevant physicochemical indicators, qualitative and quantitative laboratory results, and sequencing data. The system implements unified data collection indicators and formats and standardizes data processing procedures and quality control (QC) rules. Launched nationally in February 2024, the CWSS-IS covers 169 cities with >3,000 registered users from CDCs, tracking multiple biomarkers in wastewater treatment plants, hospitals, communities, markets, and inbound flights. By January 2026, data had been collected from 118,729 samples. Compared to previous email-based reporting methods, the CWSS-IS demonstrated significant advantages in terms of efficiency, convenience, security, and scalability. This system offers valuable insights into the prevalence of infectious diseases and can effectively inform public health initiatives. Additionally, it serves as a standard paradigm for developing regional wastewater monitoring information systems. Future efforts should focus on exploring multisource data fusion standards, artificial intelligence frameworks, and large-scale data computational platforms to enhance early warning capabilities.

Wastewater-based epidemiology (WBE) has rapidly emerged as an indispensable and scalable approach for monitoring SARS-CoV-2 circulation within communities worldwide. To systematically assess and further strengthen the reliability, robustness, and comparability of national surveillance data, a nationwide and large-scale interlaboratory proficiency testing (PT) initiative was organized in December 2023 by the Chinese Center for Disease Control and Prevention. A total of 162 laboratories, spanning four hierarchical administrative tiers (provincial, capital city, prefectural, and county levels), were systematically evaluated using standardized SARS-CoV-2 RNA reference materials. Among them, 93.8% of participating laboratories achieved satisfactory analytical performance, 3.7% yielded questionable outcomes, and 2.5% were classified as unsatisfactory. Substantial methodological heterogeneity, especially in virus concentration protocols, nucleic acid extraction reagents, and PCR assay selection, was found to significantly affect detection accuracy and sensitivity. Laboratories using optimized polyethylene glycol (PEG) or automated high-affinity precipitation (AHAP) methods consistently showed superior detection sensitivity and analytical reliability. In contrast, increasing sample volumes did not yield significant improvement in performance, possibly due to the concurrent enrichment of PCR inhibitors. This comprehensive study provides an in-depth and systematic evaluation of the current WBE analytical landscape in China, identifies critical technical challenges, and proposes actionable, evidence-based recommendations to standardize, harmonize, and improve the national SARS-CoV-2 wastewater surveillance infrastructure.

Abstract Wastewater-based surveillance of respiratory viruses increasingly requires multiplex assays capable of detecting low-abundance targets in complex environmental matrices without standard curves. In this study, a highly sensitive and specific one-step quadruplex reverse transcription droplet digital PCR assay was developed for the simultaneous quantification of SARS-CoV-2, respiratory syncytial virus, influenza A virus, and influenza B virus in wastewater. The assay achieved equivalent limits of detection of 0.32–0.44 copies/μL, excellent linearity (R2 > 0.999), and satisfactory precision, with all intra- and interassay coefficients of variation below 25%. No significant quantitative differences were observed between the quadruplex assay and the corresponding singleplex assays (Wilcoxon signed-rank test, P > 0.05). When applied to 38 wastewater samples collected across multiple settings, the assay detected all four viruses at rates of 65.79%–81.58%, with 89.47% of samples positive for two or more viruses, underscoring the value of multiplex monitoring for cocirculating respiratory viruses. Compared with reverse transcription quantitative PCR, the assay showed good qualitative agreement with the evaluated commercial quadruplex RT-qPCR kit (κ = 0.625–0.855, P < 0.001), although discordant results were target-dependent. These findings support the feasibility of the developed assay for multiplex detection of respiratory viruses in wastewater under the conditions tested.

To eliminate language barriers to international water cooperation, the official English language version of China's Standards for Drinking Water Quality (GB 5749-2022) was released in December 2025. Compiled under national translation specifications, this authoritative edition ensures accurate communication of content. A comparative analysis with international standards demonstrates that GB 5749-2022 balances global harmonization and localized adaptation in accordance with China's hydrogeological and public health conditions. The English version effectively eliminates technical ambiguities in transnational water projects and strengthens China's voice in global water governance. Nonetheless, challenges remain, including cross-lingual interpretations issues and gaps in the coverage of emerging contaminants such as per- and polyfluoroalkyl substances (PFAS). This article proposes optimizing interpretative documents, establishing dynamic updating mechanisms, constructing equitable cooperation platforms, and improving multi-dimensional evaluation systems. It aims to facilitate the global application of China's drinking water criteria, provide references for developing countries, and contribute to equitable global public health governance.

Perfluoroalkyl acids (PFAAs) with carboxylic or sulfonic acid groups remain major pollutants in drinking water, posing a significant health risk. To explore the spatial and seasonal trends in PFAA exposure risks, considering different industrial layouts and water consumption habits, this study quantified 11 typical PFAAs in source and drinking water samples collected during winter and summer across nine major water basins in China. PFAA exposure and associated risk were evaluated based on age-and region-specific water consumption habits, and trends in source water contamination were analyzed in relation to varying production activity profiles. Drinking water has become the dominant source of PFAA exposure, mainly due to source water pollution from PFAA-related manufacturing and consumption. Exposure to PFAAs via drinking water varied among different water basins and seasons with total PFAA concentrations ranging from 0.0175 to 22.2 ng/kg/day. A greater risk of exposure to PFAAs was observed in populations from industrialized or highly urbanised areas in eastern and southern China, with a maximum health risk index of 5.53. C8 PFAAs, although regulated, remain the main risk component in drinking water, indicating these contaminants need to be revisited to enhance health-based drinking water safety management. Further studies on the establishment of health-based drinking water standards, water treatment technology updates, and source pollution reduction are required to control the risks of PFAA exposure in drinking water. This study provides important support for the global management of PFAA safety in drinking water.

Introduction:A quadruplex digital polymerase chain reaction (dPCR) method was developed for the simultaneous detection of Salmonella spp., Shigella spp., Vibrio cholerae, and V. parahaemolyticus in wastewater to enhance pathogen identification velocity and efficiency. This study established detection limits for these bacterial pathogens and validated the method using environmental wastewater samples. Methods:Specific primers and probes were designed targeting the invA gene of Salmonella, ipaH gene of Shigella, tlh gene of V. parahaemolyticus, and cholera toxin gene ctxA of V. cholerae. The quadruplex dPCR assay underwent rigorous evaluation for analytical sensitivity and specificity. Detection limits were determined using spiked wastewater samples, and the method's effectiveness was assessed through preliminary testing of 60 environmental wastewater samples. Results:The quadruplex dPCR assay was optimized at an annealing temperature of 58°C. In spiked wastewater samples, the detection limits were 390 CFU/100 mL for Salmonella, 11 CFU/100 mL for Shigella, 660 CFU/100 mL for V. cholerae, and 640 CFU/100 mL for V. parahaemolyticus. Analysis of 60 municipal wastewater samples revealed pathogen concentrations ranging from 100.9-14,560 copies/100 mL for Shigella, 86.5-7,329 copies/100 mL for Salmonella, and 84.5-865.7 copies/100 mL for V. parahaemolyticus. Conclusions:The developed quadruplex dPCR assay demonstrates robust capability for comprehensive surveillance of intestinal bacterial pathogens in wastewater, offering reliable detection even at low concentrations.

Application of wheat straw could contribute to a sulfur-driven reduction in cadmium (Cd) bioavailability under reducing conditions induced by organic matter degradation. A pot experiment was conducted in organic matter deficient paddy soil under waterlogged conditions to assess the effects of sulfur (S, 30 mg kg−1), wheat straw (W, 1.0%), and their combination (WS) on Cd availability and accumulation in rice (Oryza sativa L.). Sulfur application alone increased Cd uptake in rice, whereas straw addition significantly reduced Cd accumulation, with WS achieving the greatest reduction. The mitigating effect was attributed to CdS precipitation and co-precipitation with FeS/FeS2 under straw amendment, as well as enhanced iron plaque formation on roots, which restricted Cd uptake. In contrast, in OM-deficient soil, sulfate promoted Cd mobilization in pore water due to limited electron supply for sulfate reduction. Compared with other sulfur forms, sulfate is more readily absorbed by rice, thereby synergistically enhancing Cd uptake by rice and promoting Cd translocation in different rice tissues. However, straw amendment supported reduction in sulfate, reducing Cd uptake by rice compared with S supplement alone. Overall, wheat straw amendment enhanced sulfur-mediated immobilization of Cd and effectively decreased Cd accumulation in rice.

Wastewater surveillance has emerged as a powerful tool for public health monitoring, particularly during disease outbreaks. This report documents China's pioneering establishment of the first nationwide comprehensive wastewater surveillance system with multi-scenario applications during the coronavirus disease 2019 (COVID-19) pandemic (January 2023-June 2025). The system integrated three components: national urban wastewater surveillance, inbound international aircraft wastewater surveillance, and pilot public health risk surveillance. This integrated framework demonstrated significant effectiveness in providing early warnings for COVID-19, polio, monkeypox, and other infectious disease outbreaks, while advancing variant tracking capabilities. These findings underscore the critical role of wastewater surveillance in augmenting existing public health infrastructure and improving outbreak detection capabilities. Implementing standardized protocols and developing collaborative networks will strengthen pandemic preparedness and enhance global public health resilience.

Perchlorate is widely used in various industrial fields and has been widely detected in aquatic environments because of its high solubility and stability. Considering the endocrine-disrupting properties of perchlorate, the possibility of perchlorate exposure to humans through drinking water has become a public health concern. To examine whether perchlorate pollution in source water causes a risk to populations of different age groups exposed to residues in drinking water, the spatial distribution of perchlorate levels in source water and drinking water from eight major water basins in China in 2019 was quantified with ion chromatography. The average daily potential dose (ADD) of perchlorate from drinking water intake was estimated for different age groups in the Chinese population. The health risks were quantified by dividing the ADD by the reference dose corresponding to 50% inhibition of iodide uptake. The results revealed that source water contamination was the main factor in population exposure to perchlorate via drinking water. A significant difference in perchlorate contamination was observed, ranging from 5.03 µg/L to 1.80 mg/L, and high perchlorate contamination levels were detected in industrial areas with a high concentration of firework production. In contrast to previously inferred possible sources of perchlorate, i.e., emissions from the production of rockets and missiles, firework production was identified as the dominant source of perchlorate exposure via drinking water in this study. This investigation was conducted five years ago; however, the identification of sampling locations with a health risk quotient above 1 provides quantitative evidence that exposure to perchlorate in drinking water poses a risk to residents in areas affected by source pollution, and the results are helpful for identifying priority risk control areas.

This study aims to elucidate the impact of population immunity on the regional evolution of SARS-CoV-2. A total of 3701 wastewater SARS-CoV-2 concentration values and 168 wastewater whole genomes of SARS-CoV-2 were obtained in Beijing over 11 months following the implementation of the "dynamic zero-COVID" policy adjustments in December 2022. The findings indicate that the number of variant strains identified through wastewater surveillance was 2.46 times greater than that detected by clinical monitoring, with single nucleotide polymorphisms showing an increase of up to 7.14 times. This enhanced surveillance facilitates a more comprehensive analysis of regional virus evolution patterns. Following the adjustment of epidemic measure, Beijing experienced three distinct waves of epidemics, and the dominant variant transitioned directly from BA.5 in the first wave to XBB after six months in the second one. During this period, strong population immunity formed by centralized infection in over 90 % of the population blocked the outbreak of internationally prevalent and concerning variants BQ.1 and CH.1.1, resulting in a 12.5 % faster regional evolution of SARS-CoV-2 strains in Beijing compared to the international context. Subsequently, in August 2023, EG.5 became the dominant variant in the third wave, aligning with international trends. The epidemics in Beijing have caused significant positive selection pressure on SARS-CoV-2 strains, favoring those with enhanced antigenic escape mutations in spike gene. These results underscore that the extensive infection after the adjustment of epidemic prevention policies has accelerated the evolution of SARS-CoV-2 in Beijing and been conducive to antigenic escape evolution, which can effectively inform decision making for epidemic control and preemptive vaccine design.

During the COVID-19 pandemic, healthcare systems worldwide faced severe strain. This study, utilizing wastewater virus surveillance, identified that periodic spontaneous avoidance behaviours significantly impacted infectious disease transmission during rapid and intense outbreaks. To incorporate these behaviours into disease transmission analysis, we introduced the Su-SEIQR model and validated it using COVID-19 wastewater data from Beijing and Hong Kong. The results demonstrated that the Su-SEIQR model accurately reflected trends in susceptible populations and confirmed cases during the COVID-19 pandemic, highlighting the role of spontaneous collective avoidance behaviours in generating periodic fluctuations. These fluctuations helped reduce infection peaks, thereby alleviating pressure on healthcare systems. However, the effect of these spontaneous behaviours on mitigating healthcare overload was limited. Consequently, we incorporated healthcare capacity constraints into the model, adjusting parameters to further guide population behaviours during the pandemic, aiming to keep the outbreak within manageable limits and reduce strain on healthcare resources. This study provides robust support for the development of environmental and public health policies during pandemics by constructing an innovative transmission model, which effectively prevents healthcare overload. Additionally, this approach can be applied to managing future outbreaks of unknown viruses or "Disease X".

Aquaculture systems face escalating ecological risks due to the widespread use and persistence of antibiotics, which disrupt microbial-mediated nitrogen cycling and exacerbate greenhouse gas (GHG) emissions. This review synthesizes the recent research on how common antibiotics, such as sulfonamides, quinolones, tetracyclines, and macrolides, with the concentration ranging from μg/L to mg/L, alter microbial community structure, functional gene expression (e.g., amoA, nirK, and nosZ), and key nitrogen transformation processes. These disruptions inhibit nitrogen-removal efficiency by 25–55%, promote the accumulation of toxic intermediates (e.g., NH4+ and NO2−), and enhance emissions of potent GHGs of nitrous oxide (N2O) and methane (CH4). The effects are influenced by antibiotic type; concentration; environmental conditions; and interactions with co-contaminants such as heavy metals (Cu2+ and Pb2+ at 50–200 μg/L) and microplastics (0.1–10 mg/L), which can synergistically amplify ecological risks by 20–40%. The research in this field has largely focused on the toxicity of individual antibiotics, so significant gaps remain regarding combined pollution effects, long-term microbial adaptation, and molecular-scale mechanisms. This review synthesizes research on the impacts of aquaculture antibiotics on microbial nitrogen cycling and GHG emissions, identifying key mechanisms and research gaps. Its significance lies in laying a scientific foundation for integrated antibiotics pollution control strategies and bridging basic research with practical aquaculture management to advance the sustainability of aquaculture ecosystems.

In this study， an online solid-phase extraction-ultra performance liquid chromatography-tandem mass spectrometry （online SPE-UPLC-MS/MS） method was established to rapidly screen and determine 51 per- and polyfluoroalkyl substances （PFASs） in raw and drinking water. Ammonium formate and 24 PFAS internal standards were added to each sample. The ammonium formate concentration in the sample was 2 mmol/L after mixing， and the contents of the PFAS internal standards ranged between 2.5 and 50 ng/L. Each sample was filtered through a 0.22-μm cellulose acetate filter， and a 5-mL aliquot was injected and adsorbed using an HLB online solid-phase extraction column and rinsed with 2 mmol/L ammonium formate. Acetonitrile and 2 mmol/L aqueous ammonium formate were used as mobile phases. Separation was performed on a BEH C18 chromatographic column with gradient elution. Electrospray ionization source negative ion mode and multiple reaction monitoring mode were used for detection， with quantification performed using the internal standard method. The method was validated by determining accuracies and precisions for the 51 PFASs using raw water and drinking water as matrices. Excellent linear relationships within their respective ranges were observed， with correlation coefficients （r2）>0.995. The method exhibited limits of detection （LODs， S/N=3） and quantification （LOQs， S/N=10） of 0.03-1.5 and 0.1-5.0 ng/L， respectively. The PFASs were spiked at levels of 1， 10 and 50 ng/L， with spiked recoveries of 60.2%-126.9% and 60.4%-122.6% obtained for raw- and drinking-water samples， respectively， along with corresponding relative standard deviations （RSDs， n=6） of 0.3%-17.9% and 0.4%-17.7%， respectively. The developed method was used to determine PFAS residues in raw and drinking water， with perfluoroalkyl carboxylic acids， perfluoroalkyl sulfonic acids， and perfluoroalkyl ether acids detected at relatively high rates with contents of 0.1-209.7 and 0.1-63.6 ng/L in raw water and drinking water， respectively. Compared to offline solid-phase extraction methods， the developed method requires fewer samples， is more convenient from a sample-collection perspective， and uses lower quantities of internal standards. It also analyzes rapidly and is highly sensitive and reproducible. Only 20 min was required to determine the 51 PFASs at the ng/L level， from online enrichment to detection. The developed method is suitable for the trace determination of various types of PFAS， such as perfluoroalkyl carboxylic acids， perfluoroalkyl sulfonic acids， perfluoroalkyl ether acids， fluorotelomers， and fluoroalkyl sulfonamides， in raw and drinking water， thereby effectively boosting the detection efficiency for perfluoroalkyl substances in water in a manner that has substantial practical applications value.

This study tried to reveal how the implementation and cancellation of the dynamic zero-COVID policy could affect the development of the epidemic through wastewater surveillance of SARS-CoV-2 in Beijing during its first COVID-19 surge. A total of 443 24 h composite wastewater samples were taken from seven manholes and 10 wastewater treatment plants immediately on December 7, 2022, when the new COVID-19 policy was implemented, for the detection of SARS-CoV-2. The results showed that the first COVID-19 surge in Beijing was characterized by a rapid outbreak, short duration (one month), and extremely high infection rate (92.8%). Wastewater tiling amplicon sequencing showed that the main subvariant for this surge was BF.7.14 (65%), which has never caused an outbreak in other countries in the world. The variant BF.7.14 appeared in Beijing on August 15, 2022, as an imported case and then managed to retain and become a dominant variant as the strict dynamic zero policy had blocked the entry of other more infectious SARS-CoV-2 variants. This is the first study to capture the unique picture of the epidemic development in Beijing during its first COVID-19 surge, demonstrating that the strict dynamic zero-COVID strategy could shape the infection patterns greatly.

Halobenzoquinones (HBQs), an emerging unregulated category of disinfection byproduct (DBP) in drinking water, have aroused an increasing concern over their potential health risks. However, the chronic toxicity of HBQs at environmentally relevant concentrations remains largely unknown. Here, the occurrence and concentrations of 13 HBQs in drinking water from a northern megacity in China were examined using ultrahigh performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UHPLC-MS/MS). Four HBQs, including 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ), 2,6-dibromo-1,4-benzoquinone (2,6-DBBQ), 2,3,6-trichloro-1,4-benzoquinone (TriCBQ), and 2,5-dibromo-1,4-benzoquinone (2,5-DBBQ), were detected beyond 50% occurrence frequency and at median concentrations from 4 to 50 ng/L. The chronic toxicity of these four HBQs to normal human colon and liver cells (FHC and THLE-2) was investigated at these concentrations. After 90 days of exposure, 2,5-DBBQ and 2,6-DCBQ induced the highest levels of oxidative stress and deoxyribonucleic acid (DNA) damage in colon and liver cells, respectively. Moreover, 2,5-DBBQ and 2,6-DCBQ were also found to induce epithelial-mesenchymal transition (EMT) in normal human liver cells via the extracellular signal regulated kinase (ERK) signaling pathway. Importantly, heating to 100 degrees C (boiling) was found to efficiently reduce the levels of these four HBQs in drinking water. These results suggested that environmentally relevant concentrations of HBQs could induce cytotoxicity and genotoxicity in normal human cells, and boiling is a highly efficient way of detoxification for HBQs.

ABSTRACT Water is indispensable to human life. Data on water consumption are essential for many health-related analyses. However, water consumption patterns vary significantly due to many factors, such as region, culture, and season. A survey was conducted on the drinking water intake of adults in typical cities in the major river basins of China. The intake rates of direct plain water, indirect plain water, commercial beverages, total plain water, and total water were assessed. The total plain water intake and total water intake were 1,777 and 1,942 ml/day for males, and 1,564 and 1,678 ml/day for females, respectively. Water intake varies depending on gender, age, body mass index, and seasonal and regional fluctuations. Region is the most important factor influencing the intake of total plain water, direct plain water, and total water, followed by season and gender. The intake of indirect plain water is mainly related to the region. Age is the most important factor affecting commercial beverage intake. A value of 1,666 ml/day is proposed as the recommended daily total plain water intake rate for use in exposure assessments in the Chinese context.

In this study, the raw water, finished water, and tap water of various waterworks in major river basins of China were collected for the determination of the neonicotinoid insecticides (NNIs). The results showed that one or more NNIs were detected in 81.2% of the water samples, and the total concentration of NNIs (& sum;NNIs, sum of eight NNIs) ranged from 0.10 to 210.33 ng/L, with a median of 7.08 ng/L. Thiamethoxam, imidacloprid, and clothianidin had the highest contribution rate among the major & sum;NNIs detected. The concentration of & sum;NNIs detected in the Pearl River was higher than that in other river basins, with a median of 51.11 ng/L. During the dry season, the detection rate of & sum;NNIs was 77.4%, with concentrations ranging from 0.10 to 210.33 ng/L. During the wet season, the detection rate of & sum;NNIs was 85%, and the concentration of & sum;NNIs ranged from 0.10 to 117.03 ng/L. The estimated daily intake (EDI) of NNIs in the raw water and drinking water of each river basin is less than the reference dose (RfD) of imidacloprid. The potential risk of NNIs can be reduced by further optimizing the water treatment processes.

Wastewater-based epidemiology (WBE) is a tool for monitoring the trend and spread of infectious diseases in populations. The COVID-19 pandemic has led to a surge in interest in studying WBE since it can offer a non-invasive and cost-effective way for monitoring the virus at population level. This paper discusses the principles and practices of WBE in the context of COVID-19, with a focus on its applications in Hong Kong. WBE relies on the detection of viral RNA in sewage samples, which can indicate the presence and amount of the virus in a surveyed population. The detection process involves three key steps, including sewage concentration, nucleic acid extraction, and quantitative polymerase chain reaction (qPCR) amplification of target virus sequences. Quality control measures such as positive and negative controls are crucial for generating accurate and reliable testing results. In Hong Kong, a comprehensive WBE system has been established from the ground up in 2020, which now covers 10 large sewage treatment plants, 154 community surveillance sites, and multiple ad hoc sites across residential areas. The adopted sampling frequency and methods could vary according to the type of sampling site and the stage of an outbreak. Composite sewage samples are collected using automatic samplers and analyzed using standardized methods. The data generated from the WBE system is used for providing early warning and epidemiological assessment, as well as guiding public health interventions. However, the interpretation of WBE results requires careful consideration of various factors that can affect the accuracy and sensitivity of the method. These factors include the amount, frequency, and probability of viral shedding in infected individuals, variations in viral shedding over time and across different virus variants, the decay of viral particles in sewage along the sewer system and testing procedure, and the detection limit of the adopted testing method. In addition, the presence of false negative results due to randomness in sampling and fecal shedding is a significant challenge in interpretating WBE results. Therefore, it is essential to include appropriate quality control measures, use optimized sampling strategies, and validate the sewage testing data with clinical and epidemiological evidence. Despite these challenges, the experience of Hong Kong shows that WBE could provide valuable information for monitoring and responding to COVID-19 outbreaks. The WBE system in Hong Kong has been shown to be able to provide early signals of viral transmission, track the development trend of the epidemic, and locate high-risk areas for targeted public health interventions. The success of the Hong Kong WBE system highlights the importance of a comprehensive surveillance system and adaptive methods used in WBE, which requires ongoing evaluation and data analysis. WBE is a promising tool for surveying infectious diseases in populations, and its application in COVID-19 surveillance worldwide has demonstrated its great potential. However, the interpretation of WBE results requires careful considerations of various factors, such as the method’s sensitivity and specificity may vary across populations and stages of an outbreak. Therefore, the establishment of a comprehensive and adaptive WBE system that integrates epidemiological, clinical, and environmental data is important for achieving the full potential of this tool in infectious disease surveillance and control.