Competitive adsorption of heavy metals onto xanthate-modified sludge hydrochar and its solidification as secondary minerals.

In this study, a sulfur-modified magnetic hydrochar was synthesized by grafting thiol-containing groups onto the sludge-derived hydrochar. The modified hydrochar exhibited effective adsorption of Cu2+, Pb2+, Zn2+, and Cd2+ over a wide pH range and in the presence of coexisting ions, and showed almost no secondary leaching in three acidic solutions. In the mult-metal ion system, the modified hydrochar exhibited maximum adsorption capacities were 39.38, 105.74, 26.53, and 38.11 mg g-1 for Cu2+, Pb2+, Zn2+, and Cd2+, respectively. However, the binding capacity and adsorption amount of modified hydrochar for metal ions were lower in the mult-metal ion system compared to the unit-metal ion system. Notably, Pb2+ showed a strong inhibitory effect on the adsorption of other heavy metal ions by modified hydrochar due to strong competition for xanthate functional groups. The Pb2+ occupied the xanthate and native functional groups (-OH, -NH2, and Fe-O etc.), leaving only a small amount of adsorption sites for Cu2+, Zn2+ and Cd2+. Simulation results further supported these findings, indicating that Pb2+ had the highest density profiles near the four functional groups, and the density profiles of the four heavy metals near the xanthate functional groups were greater compared to the other three functional groups. Furthermore, the SEM-EDS, TOF-SIMI, and XPS results indicated that modified hydrochar achieved excellent mineral binding mainly through electrostatic interaction, ion exchange, and chelation. Overall, these results highlight the sulfur-modified magnetic hydrochar as a highly efficient adsorbent for heavy metals in environmental applications.

Occurrence, fate, and ecological risk of antibiotics in wastewater treatment plants in China: A review.

This review offers a comprehensive overview of the occurrence, fate, and ecological risk associated with six major categories of antibiotics found in influent, effluent, and sludge from urban wastewater treatment plants (WWTPs) in China. Further exploration includes examining the correlation between antibiotic residual rates in the effluents and process parameters of urban WWTPs across the country. Lastly, a nationwide and urban cluster-specific evaluation of the ecological risk posed by antibiotics in WWTPs is conducted. The findings reveal that the average concentrations of antibiotics in influent, effluent, and sludge from urban WWTPs in China are 786.2 ng/L, 311.2 ng/L, and 186.8 µg/kg, respectively. Among the detected antibiotics, 42% exhibit moderate to high ecological risk in the effluent, with ciprofloxacin, sulfamethoxazole, erythromycin, azithromycin, and tetracycline posing moderate to high ecological risks in sludge. The current biological treatment processes in WWTPs demonstrate inefficacy in removing antibiotics. Hence, there is a pressing need to develop and integrate innovative technologies, such as advanced oxidation processes. This review aims to offer a more comprehensive understanding and identify priority antibiotics for control to effectively manage antibiotic pollution within WWTPs at both national and regional levels.

Cd immobilization efficacy of biogenic Mn oxide formed by Cladosporium sp. XM01 and its biological response in sediment.

Biogenic Mn oxides (BMOs), the main component of natural Mn oxides, closely relate to Cd in sediment. However, the immobilization behavior of Cd in sediments by BMOs is currently unclear. This study explores the role of BMO produced by the Mn-oxidizing fungus Cladosporium sp. XM01 in mediating the Cd immobilization and its biological response in sediment. A comparison is made with those of a chemical Mn oxide (CMO, triclinic birnessite). After 45 d of remediation, the results showed that the application of BMO reduced the extractable Cd by 32.20-64.40% based on the TCLP (toxicity characteristic leaching procedure) and by 26.16-51.43% based on the PBET (physiologically based extraction test). Additionally, BMO was more effective at immobilizing Cd than CMO in sediments. The BCR (Community Bureau of Reference) extraction results suggested that BMO converted some acid-soluble components (20.63-33.23%) of Cd into residual components (9.40-20.68%). Moreover, the urease and catalase activity gradually increased within the first 25 days and then stabilized after applying BMO. Microbial community analysis revealed that the addition of a high-dose BMO was more conducive to increasing microbial abundance and biodiversity. This study verifies that BMO is a low-cost, high-efficiency, and eco-friendly material for immobilizing Cd in sediment.

Effects of production temperature on the molecular composition and seed-germination-promoting properties of sludge-based hydrochar-derived dissolved organic matter.

Sludge hydrothermal carbonization demonstrates potential for converting sludge into multifunctional carbon materials for soil remediation. However, the influence of dissolved organic matter (DOM) with unclear molecular characteristics in sludge-based hydrothermal carbon on plant growth has not been sufficiently investigated. Herein, the effects of hydrothermal temperature on the molecular transformation pathways and plant-growth-promoting properties of DOM were investigated via FT-ICR MS-based molecular network analyses and seed germination experiments. Results indicated that the highest DOM yield was achieved at 220 °C. During low-temperature (180 °C) hydrothermal treatment, the hydrolysis of biopolymers, as well as the partial condensation and cyclization of small-molecule intermediates, occurred in the sludge. This process produced unsaturated CHNO compounds containing one or two N atoms, which promoted seed germination. Further, the toxicity of DOM to plants increased with rising hydrothermal temperature. This was accompanied by S doping and aromatization reactions, which mitigated the effects of plant growth hormones. This study provides theoretical support for the optimization of sludge hydrothermal treatment and production of plant growth hormones, enhancing the ecological value of sludge-based hydrochar.

A 20-year shift in China's sewage sludge heavy metals and its feasibility of nutrient recovery in land use.

Recycling resources from wastewater is even more important for developing a more sustainable society. Disposing sewage sludge, which accumulates most pollutants and resources in sewage, is the main challenge in wastewater pollution control and resource utilization. Heavy metals (HMs) are the greatest constraint limiting the application of sewage sludge to land as a sustainable use of this material. We conducted a meta-analysis of the concentrations of HMs in Chinese sewage sludge by combining data from studies published from 2000 to 2019 (N = 8477). Over this period, the reported concentrations of HMs in sewage sludge declined in three stages (a fluctuating stage, a slight decrease stage, and a rapid and stable decrease stage). The results revealed that economic development and environmental policy implementation were the main factors mitigating HM pollution in sewage sludge in China. Moreover, if environmental regulations were strengthened and HM pollution-mitigation strategies were made consistent, such that the proportion of sewage sludge applied to land in China could be increased from 18.6% to 48.0% (the proportion applied to land in the United States), the ecosystem services analysis showed that huge ecological-economic benefits could be realized (3.1 billion Chinese Yuan) and the use of fertilizers could be substantially reduced (the use of nitrogen fertilizers by 8.5% and the use of phosphate fertilizers by 18.1%). This review shows that China should formulate a unified policy and interdepartmental committee for sustainable application of sewage sludge to land and wastewater resource recycling management.

Tracking the source of antibiotic resistome in the stormwater network drainage in the presence of sewage illicit connections.

Stormwater pipes are illicitly connected with sewage in many countries, which means that sewage enters stormwater pipes and the drainage is discharged to surface water without any treatment. Sewage contains more pathogens and highly risky antibiotic resistance genes (ARGs) than surface runoff. Therefore, sewage may alter the microbial and ARG compositions in stormwater pipe drainage, which in turn leads to an increased risk of resistance in surface water. However, the effects of sewage on ARGs in the drainage of stormwater networks have not been systematically studied. This study characterized the microbial and ARG composition of several environmental compartments of a typical stormwater network and quantified their contributions to those in the drainage. This network transported ARGs and microorganisms from sewage, sediments in stormwater pipes, and surface runoff into the drainage and thus into the river. According to metagenomic analysis, multidrug resistance genes were most abundant in all samples and the numbers and relative abundance of ARGs in the drainage collected during wet weather were comparable to that of sewage. The results of SourceTracker showed that the relative contribution of sewage was double that of rainwater and surface runoff in the drainage during wet weather for both microorganisms and ARGs. Desulfovibrio, Azoarcus, and Sulfuritalea were connected with the greatest number of ARGs and were most abundant in the sediments of stormwater pipes. Furthermore, stochastic processes were found to dominate ARG and microbial assembly, as the effects of high hydrodynamic intensity outweighed the effects of environmental filtration and species interactions. The findings of this study can increase our understanding of ARGs in stormwater pipe drainage, a crucial medium linking ARGs in sewage to environmental ARGs.

Identification of high oxygen-consuming substances in stormwater drainage systems illicitly connected with sewage system.

The dissolved oxygen content in water is an important indicator for assessing the quality of the water environment, and maintaining a certain amount of dissolved oxygen is essential for the healthy development of the ecological environment. When a water body is anoxic, the activity of anaerobic microorganisms increases and organic matter is decomposed to produce a large number of blackening and odorizing substances, resulting in black and odorous water bodies, which is a very common and typical phenomenon in China. Presently, there is still a relatively universal occurrence of illicitly connected stormwater and sewage pipes in the urban drainage pipe network in China, which makes oxygen-consuming substances be directly discharged into rivers through stormwater pipes and consume the dissolved oxygen in the water bodies, resulting in an oxygen deficiency of the water. This induces seasonal or year-round black and stink phenomena in urban rivers. Hence, identifying high oxygen-consuming substances, which lays the foundation for the subsequent removal of oxygen-consuming substances, is essential. Through a series of comparisons of water quality indicators and analysis of organic characteristics, it was found that the oxygen consumption capacity of domestic sewage was higher than that of industrial wastewater in the selected area of this study, and the oxygen-consuming substances of domestic sewage were small molecular amino acids. By comparing 20 conventional free amino acids, it was found that seven of them consumed oxygen easily, and compared with chemical oxygen consumption, biological oxygen consumption was in a leading position.

Abatement of antibiotics and resistance genes during catalytic ozonation enhanced sludge dewatering process: Synchronized in volume and hazardousness reduction.

Based on the efficiency of the catalytic ozonation techniques (HDWS+O3 and MnFe2O4 @SBC+O3) in enhancing the sludge dewaterability, the effectiveness in synchronized abatement antibiotics and antibiotic resistance genes (ARGs) was conducted to determine. The results revealed that catalytic ozonation conditioning altered the distribution of target antibiotics (tetracycline (TC), oxytetracycline (OTC), norfloxacin (NOR), ofloxacin (OFL)) in the dewatered filtrate, the dewatered sludge cake and the extra-microcolony/cellular polymers (EMPS/ECPS) layers, achieving the redistribution from solid-phase adsorption to liquid-phase dissolution. The total degradation rate was over 90% for TC and OTC, 72-78% for NOR and OFL; the abatement efficiency of eleven ARGs reached 1.47-3.01 log and 1.64-3.59 log, respectively, and more than four eARGs were eliminated. The effective abatement of the absolute abundance of Mobile genetic elements (MGEs) (0.91-1.89 log) demonstrated that catalytic ozonation conditioning could also significantly inhibit horizontal gene transfer (HGT). The abundance of resistant bacteria was greatly reduced and the signal transduction of the typical ARGs host bacteria was inhibited. The highly reactive oxidation species (ROS) generated were responsible for the abatement of antibiotics and ARGs. These findings provided new insights into the sludge conditioning for ideal and synchronized reduction in volume and hazardousness by catalytic ozonation processes in sludge treatment.

Effect of dissolved ozone flotation thickening process on coliform bacteria and antibiotics simultaneous abatement: A pilot-scale study.

This study focused on the removal of the total coliforms, fecal coliforms and four target antibiotics in the dissolved ozone flotation (DOF) thickening sludge process. Additionally, the thickened effluent chromaticity and its effect on thickened sludge hydrolysis process were investigated. Ozonation in the DOF process could inactivate coliforms by oxidizing cellular components and destroying genetic material, as well as altering the chemical structure of antibiotics, leading to the degradation of antibiotics. At an O3 dosage of 16 mg/g TS, the concentration of total coliforms and fecal coliforms decreased by 2.2 log and 2.4 log, corresponding to an overall removal rate of 99.4 % and 99.7 %, respectively. The total degradation rate of four target antibiotics (tetracycline (TC), oxytetracycline (OTC), norfloxacin (NOR), ofloxacin (OFL)) were 66.5 %, 68.8 %, 53.3 % and 57.5 %, respectively. The chromaticity removal rate of the thickened effluent reached 95 %. Analysis of fluorescence spectra indicated alterations in the fluorescence properties of dissolved organic matter, resulting in a decrease in fluorescence intensity by ozonation. The thickened sludge had higher hydrolysis rates, resulting in a greater production of volatile fatty acids (VFAs). This was mainly attributed to the increased amount of soluble protein and carbohydrate in the substrate after DOF treatment, which was more conducive for the rapid conversion of hydrolysis into VFAs during the initial stage. These results provided new ideas for upgrading and transforming the thickening process of wastewater treatment plants (WWTPs).

The occurrence characteristics, removal efficiency, and risk assessment of polycyclic aromatic hydrocarbons in sewage sludges from across China.

Sewage sludge is considered to be an important sink for polycyclic aromatic hydrocarbons (PAHs) in wastewater treatment plants and the potential risks from sludge contaminated with PAHs during land application has attracted attention. To identify the priority PAHs for control and enhance their removal from sludge, the occurrence characteristics, removal efficiency, and risk assessment of PAHs in sewage sludges from across China were analyzed. Data collection was from 2001 to 2023. Results showed that 16 PAHs were widely detected in Chinese sewage sludge with total amounts (∑16PAHs) between 0.06 and 34.93 mg kg dw-1. Fossil fuel, coal, and biomass combustion are main anthropogenic sources of PAHs in China. In general, phenanthrene (PHE), anthracene (ANT), fluorescein (FL), chrysene (CHR), pyrene (PYR), and benzo[b]fluoranthene (BbF) are regarded as the main components and PAHs with 3-5 rings dominate (84.01%-91.53%) sewage sludge in China. Although aerobic composting and anaerobic treatment significantly improve ∑16PAHs removal, sludge stabilization treatment only reduced the risk by a small amount, especially for high-molecular-weight (HMW) PAHs. The benzo[a]anthracene (BaA), benzo[a]pyrene (BaP), and dibenzo[a,h]anthracene (DahA) are proposed as the priority control contaminants for sewage sludge in China because they have consistently high-risk quotient (RQ) values of 2.42-7.47, 1.28-3.16, 1.06-1.83 before and after sludge stabilization, respectively. More attention should be paid to BaA, BbF, benzo[k]fluoranthene (BkF), BaP, DahA, and indeno[1,2,3-cd]pyrene (IcdP) in Beijing; ANT, BaA, and BaP in Shanghai; and BaA and BaP in Guanghzou. Although the toxic equivalent quotient (TEQ) for PAHs met the limit concentration requirements of the national standard, the potential health risks due to long-term exposure to HMW PAHs cannot be ignored because the incremental lifetime cancer risk (ILCR) was consistently in the risk threshold range (>1 × 10-6). Some suggestions on enhanced treatment approaches and land use standards are proposed to further alleviate the risk from HMW PAHs.

Analysis of clinicopathological features and prognostic factors of breast cancer brain metastasis.

BACKGROUND: Breast cancer (BC) has become the most common malignancy in women. The incidence and detection rates of BC brain metastasis (BCBM) have increased with the progress of imaging, multidisciplinary treatment techniques and the extension of survival time of BC patients. BM seriously affects the quality of life and sur-vival prognosis of BC patients. Therefore, clinical research on the clinicopathological features and prognostic factors of BCBM is valuable. By analyzing the clinicopathological parameters of BCBM patients, and assessing the risk factors and prognostic indicators, we can perform hierarchical diagnosis and treatment on the high-risk population of BCBM, and achieve clinical benefits of early diagnosis and treatment. AIM: To explore the clinicopathological features and prognostic factors of BCBM, and provide references for diagnosis, treatment and management of BCBM. METHODS: The clinicopathological data of 68 BCBM patients admitted to the Air Force Medical Center, Chinese People's Liberation Army (formerly Air Force General Hospital) from 2000 to 2022 were collected. Another 136 BC patients without BM were matched at a ratio of 1:2 based on the age and site of onset for retrospective analysis. Categorical data were subjected to χ2 test or Fisher's exact probability test, and the variables with P < 0.05 in the univariate Cox proportional hazards model were incorporated into the multivariate model to identify high-risk factors and independent prognostic factors of BCBM, with a hazard ratio (HR) > 1 suggesting poor prognostic factors. The survival time of patients was estimated by the Kaplan-Meier method, and overall survival was compared between groups by log-rank test. RESULTS: Multivariate Cox regression analysis showed that patients with stage III/IV tumor at initial diagnosis [HR: 5.58, 95% confidence interval (CI): 1.99-15.68], lung metastasis (HR: 24.18, 95%CI: 6.40-91.43), human epidermal growth factor receptor 2 (HER2)-overexpressing BC and triple-negative BC were more prone to BM. As can be seen from the prognostic data, 52 of the 68 BCBM patients had died by the end of follow-up, and the median time from diagnosis of BC to the occurrence of BM and from the occurrence of BM to death or last follow-up was 33.5 and 14 mo, respectively. It was confirmed by multivariate Cox regression analysis that patients with neurological symptoms (HR: 1.923, 95%CI: 1.005-3.680), with bone metastasis (HR: 2.011, 95%CI: 1.056-3.831), and BM of HER2-overexpressing and triple-negative BC had shorter survival time. CONCLUSION: HER2-overexpressing, triple-negative BC, late tumor stage and lung metastasis are risk factors of BM. The presence of neurological symptoms, bone metastasis, and molecular type are influencing prognosis factors of BCBM.

Novelty three stages for humification of sewage sludge during hyperthermophilic aerobic fermentation.

Compared with conventional aerobic fermentation (CAF), there is limited knowledge of how hyperthermophilic aerobic fermentation (HAF) enhances the humification of sewage sludge. This study compared three novel stages of organic degradation, precursors, functional groups, bacterial community, and humus synthesis mechanism in HAF with CAF. The results showed that organic matter (OM) degraded rapidly, and 68% of the degradation could be completed of stage I in HAF. Compared with the initial stage, ammonium nitrogen (NH4+-N), water-soluble organic carbon, and water-soluble total nitrogen increased by 2.83 times, 40.5 times, and 33.5 times, respectively. Cellulose and hemicellulose decreased by 29.22% and 21.85%, respectively. These results suggested that temperature (>80 °C) and Bacillus dominated accelerate the humification process by rapidly improving OM degradation. Compared with the initial value of HAF, the maximum increment of reducing sugar at stage II was 297%, and the degradation rate of cellulose was effectively increased by 21.03% compared with that of CAF. The precursors such as reducing sugars and amino acids formed humus at stage II. The content of Aryl C increased significantly during the HAF process, the degree of polymerization of humus and the aromatization degree of HA and FA increased significantly, and complex organic macromolecular material polymers were formed at stage III. The sugar-amine condensation was the mechanism of humification in the sludge HAF process. This investigation provided three new stages of insights into the synthesis of humification during the HAF process and extended the current mechanism of humification in the HAF process.

Cancer Risk of Peutz-Jeghers Syndrome and Treatment Experience: A Chinese Medical Center.

Peutz-Jeghers syndrome (PJS), also known as hereditary mucocutaneous pigmented gastrointestinal polyposis, is a clinically rare autosomal dominant genetic disease, which falls into the category of hereditary colorectal cancer. There are ∼7,000 new cases of PJS in China every year, and 170,000 PJS patients may survive for a long time in society. PJS polyps are characterized by an early age of onset, difficult diagnosis and treatment, and easy recurrence. With repeated growth, polyps can lead to serious complications such as intestinal obstruction, intussusception, gastrointestinal bleeding, and cancerization, which cause serious clinical problems. Due to repeated hospitalization and endoscopic follow-up, PJS patients and their families suffer from great physical and mental pain and economic burden. With the in-depth understanding of PJS and the development and popularization of endoscopic techniques in the past decade, an integrated treatment modality based on endoscopy plus surgery has gradually become the preferred treatment in most hospitals, which greatly improves the quality of life of PJS patients. However, there is still a lack of effective drug prevention and cure means. In this paper, the current clinical treatment means for PJS polyps were summarized by literature review combined with the treatment experience of our medical center, with a focus on their clinical diagnosis, treatment, and cancer risk.

Residual chlorine persistently changes antibiotic resistance gene composition and increases the risk of antibiotic resistance in sewer systems.

During the COVID-19 pandemic, excessive amounts of disinfectants and their transformation products entered sewer systems worldwide, which was an extremely rare occurrence before. The stress of residual chlorine and disinfection by-products is not only likely to promote the spread of antibiotic resistance genes (ARGs), but also leads to the enrichment of chlorine-resistant bacteria that may also be resistant to antibiotics. Therefore, the potential impact of such discharge on ARG composition should be studied and the health risks should be assessed. Thus, this study combined high-throughput 16S rRNA gene amplicon sequencing and metagenomic analysis with long-term batch tests that involved two stages of stress and recovery to comprehensively evaluate the impact of residual chlorine on the microbial community and ARG compositions in sewer systems. The tests demonstrated that the disturbance of the microbial community structure by residual chlorine was reversible, but the change in ARG composition was persistent. This study found that vertical propagation and horizontal gene transfer jointly drove ARG composition succession in the biofilm, while the driving force was mainly horizontal gene transfer in the sediment. In this process, the biocide resistance gene (BRG) subtype chtR played an important role in promoting co-selection with ARGs through plasmids and integrative and conjugative elements. Moreover, it was further shown that the addition of sodium hypochlorite increased the risk of ARGs to human health, even after discontinuation of dosing, signifying that the impact was persistent. In general, this study strengthens the co-selection theory of ARGs and BRGs, and calls for improved disinfection strategies and more environmentally friendly disinfectants.

Footprints of total coliforms, faecal coliforms and E. coli in a wastewater treatment plant and the probabilistic assessment and reduction of E. coli infection risks.

Wastewater contains various pathogenic microorganisms, and the disease of workers caused by exposure to wastewater at the wastewater treatment plants (WWTPs) is a growing concern. The footprints of total coliforms (TC), faecal coliforms (FC) and Escherichia coli (E. coli) in a conventional activated sludge WWTP during 12 consecutive months were clarified. It was found that TC, FC and E.coli in influent were significantly removed (log 4.71, log 4.43 and log 4.62, respectively) by WWTP with sand filtration playing a key role, and excess sludge was a major potential pathway for them flowing to the environment. Through quantitative microbial risk assessment (QMRA), hand-to-mouth ingestion of untreated wastewater and wastewater in secondary/efficient sedimentation tanks, as well as accidental ingestion of sludge in dewatering workshop presented the highest infection risks of pathogenic E.coli in the WWTP, considerably exceeded the U.S. EPA benchmark (≤1 × 10-4 pppy). PPE application and E.coli concentration reduction in wastewater or sludge were recommended to reduce the infection risks at these stages. Further, partial ozonation and dissolved ozone flotation thickening were investigated able to reduce the infection risks at the stages of secondary and tertiary treatment of wastewater or sludge treatment by 90- 98 %. The findings of this study would assist in selecting appropriate processes for the further sanitation of WWTPs.

Organic amendments for in situ immobilization of heavy metals in soil: A review.

There is a growing need for soil remediation due to the increase in heavy metals (HMs) migrating into the soil environment, especially those from man-made sources dominated by industry and agriculture. In situ immobilization technology, because of its lower life cycle environmental footprint, can achieve "green and sustainable remediation" of soil heavy-metal pollution. Among the various in situ immobilization remediation agents, organic amendments (OAs) stand out as they can act as soil conditioners while acting as HMs immobilization agents, and therefore have excellent application prospects. In this paper, the types and remediation effects of OAs for HMs in situ immobilization in soil are summarized. OAs have an important effect on the soil environment and other active substances in soil while interacting with HMs in soil. Based on these factors, the principle and mechanism of HMs in situ immobilization in soil using OAs are summarized. Given the complex differential characteristics of soil itself, it is impossible to determine whether it can remain stable after heavy-metal remediation; therefore, there is still a gap in knowledge regarding the compatibility and long-term effectiveness of OAs with soil. In the future, it is necessary to develop a reasonable HMs contamination remediation program for in situ immobilization and long-term monitoring through interdisciplinary integration techniques. These findings are expected to provide a reference for the development of advanced OAs and their applications in engineering.

Peutz-Jeghers syndrome without STK11 mutation may correlate with less severe clinical manifestations in Chinese patients.

BACKGROUND: Peutz-Jeghers syndrome (PJS) is an autosomal dominant genetic disease with skin mucosal pigment spots and gastrointestinal (GI) multiple hamartoma polyps as clinical characteristics. At present, it is considered that the germline mutation of STK11 gene is the genetic cause of PJS. However, not all PJS patients can be detected STK11 germline mutations. The specific clinical characteristics of these PJS patients without STK11 mutation is an interesting clinical question. Or, like wild type GI stromal tumor, whether these PJS without STK11 mutation are also called PJS is worth discussing. Therefore, we designed the study to understand the clinical characteristics of these PJS patients without STK11 mutation. AIM: To investigates whether PJS patients with known STK11 mutations have a more severe spectrum of clinical phenotypes compared to those without. METHODS: A total of 92 patients with PJS admitted to the Air Force Medical Center from 2010 to 2022 were randomly selected for study. Genomic DNA samples were extracted from peripheral blood samples, and pathogenic germline mutations of STK11 were detected by high-throughput next-generation gene sequencing. Clinical-pathologic manifestations of patients with and without STK11/LKB1 mutations were compared. RESULTS: STK11 germline mutations were observed in 73 patients with PJS. Among 19 patients with no detectable STK11 mutations, six had no pathogenic germline mutations of other genes, while 13 had other genetic mutations. Compared with PJS patients with STK11 mutations, those without tended to be older at the age of initial treatment, age of first intussusception and age of initial surgery. They also had a lower number of total hospitalizations relating to intussusception or intestinal obstruction, and a lower load of small intestine polyps. CONCLUSION: PJS patients without STK11 mutations might have less severe clinical-pathologic manifestations than those with.

Reactivity of dissolved effluent organic matter (EfOM) with hydroxyl radical as a function of its isolated fractions during ozonation of municipal secondary effluent.

Dissolved effluent organic matter (EfOM) plays an important role in ozonation decomposition and hydroxyl radical (·OH) scavenging in ozonation for the degradation of trace organic contaminants (TrOCs) in municipal secondary effluents. The properties of EfOM have been considered a major concern in this process because EfOM fractions act differently as initiator, promoter or inhibitor of ozone decomposition and ·OH scavenging, which further impacts the degradation effectiveness of TrOCs. This study isolated EfOM from three wastewater treatment plants into six fractions (HoA, HoB, HoN, HiA, HiB and HiN) to understand the reaction kinetics as a function of EfOM and its isolated fractions. Their reaction rate constants with ·OH (kEfOM-·OH), and their roles as the initiator, promoter and inhibitor in the ·OH chain reactions in ozone decomposition were further quantified. The results showed that kEfOM-·OH of hydrophilic fractions (HiF) (accounting for 17%) reached up to 10 times as high as that for hydrophobic fractions (HoF) (accounting for 83%) (7.92 × 108 M-1 s-1 versus 0.78 × 108 M-1 s-1), suggesting the dominating role of HiF in ·OH scavenging. Hydrophilic base (HiB) was the most important fraction dominating the ozone decomposition and reaction with ·OH due to its highest rate constants of initiation and promotion. This study quantifies the kinetics and contribution of EfOM fractions in ·OH scavenging, which will guide the optimization implementation of ozonation and other ·OH-mediated AOPs toward wastewater effluents.

Direct discharge of sewage to natural water through illicitly connected urban stormwater systems: An overlooked source of dissolved organic matter.

The illicit connection of sewage pipes to stormwater pipes commonly occurs in urban stormwater systems. This brings problems that sewage might be directly discharges into natural water and even drinking water sources without treatment, posing risks to ecological safety. Sewage contains various unknown dissolved organic matter (DOM), which could react with disinfectants and lead to the formation of carcinogenic disinfection byproducts (DBPs). Thus, understanding the impacts of illicit connections on downstream water quality is of significance. This study firstly investigated the characteristics of DOM using fluorescence spectroscopy and the formation of DBPs after chlorination in an urban stormwater drainage system in the case of illicit connections. The results found that the concentrations of dissolved organic carbon and dissolved organic nitrogen ranged from 2.6 to 14.9 mg/L and from 1.8 to 12.6 mg/L, respectively, with the highest levels occurring at the illicit connection points. Concerning DBP precursors, pipe illicit connections introduced considerable precursors of highly toxic haloacetaldehydes and haloacetonitriles into the stormwater pipes. Furthermore, illicit connections introduced more contents of tyrosine-like and tryptophan-like aromatic proteins, which may be related to foods, nutrients, personal care products, etc. in the untreated sewage. This indicated that the urban stormwater drainage system was a significant input source of DOM and DBP precursors to natural water. The results of this study are of great significance for protecting the security of water sources and promoting the sustainability of urban water environment.

Degradation kinetics and formation of regulated and emerging disinfection by-products during chlorination of two expectorants ambroxol and bromhexine.

Ambroxol hydrochloride (AMB) and bromhexine hydrochloride (BRO) are classic expectorants and bronchosecretolytic pharmaceuticals. In 2022, both AMB and BRO were recommended by medical emergency department of China to alleviate cough and expectoration for symptoms caused by COVID-19. The reaction characteristics and mechanism of AMB/BRO with chlorine disinfectant in the disinfection process were investigated in this study. The reaction of chlorine with AMB/BRO were well described by a second-order kinetics model, first-order in both AMB/BRO and chlorine. The second order rate reaction constant of AMB and BRO with chlorine at pH 7.0 were 1.15 × 102 M-1s-1 and 2.03 × 102 M-1s-1, respectively. During chlorination, a new class of aromatic nitrogenous disinfection by-products (DBPs) including 2-chloro-4, 6-dibromoaniline and 2, 4, 6-tribromoaniline were identified as the intermediate aromatic DBPs by gas chromatography-mass spectrometry. The effect of chlorine dosage, pH, and contact time on the formation of 2-chloro-4, 6-dibromoaniline and 2, 4, 6-tribromoaniline were evaluated. In addition, it was found that bromine in AMB/BRO were vital bromine source to greatly promote the formation of classic brominated DBPs, with the highest Br-THMs yields of 23.8% and 37.8%, respectively. This study inspired that bromine in brominated organic compounds may be an important bromine source of brominated DBPs.