Emerging Contaminants最新文献

Sulfapyridine (SPY) is a ubiquitous environmental contaminant belonging to the sulfonamide antibiotics. Previous studies showed that hydroxylamine (HA) can improve the performance of advanced oxidation processes (AOPs) by promoting Fe(II) regeneration, yet the reaction mechanisms were not elucidated. Therefore, the role of HA and the degradation mechanisms of SPY were systematically studied therein. The SPY degradation efficiency increased from 77.5 % to 91.6 % after HA was added. With radical scavenger experiment, a function of HA to promote ^•OH production for SPY degradation was clarified. The major radical from SO₄^•- and ^•OH to ^•OH with addition of HA in Fe(II)/potassium peroxydisulfate (PDS). Results showed that alkali, acid condition and high PDS concentration all contributed to SPY degradation. According to experimental results, density functional theory (DFT) was used to calculate the degradation pathway of SPY. Rate-limiting path was obtained by comparing the rate constants calculated from the transition-state theory. The cleavage of C–C bond in benzene ring with the slowest rate was essential to degrade SPY, which not only promotes the mineralization of SPY, but also prevent the production of toxic TPs effectively. This study provides valuable insight into the SPY degradation in HA/Fe(II)/PDS.

The application of plant extracts in the green synthesis of silver nanoparticles (AgNPs) has attracted significant attention owing to their eco-friendliness and cost-effective features. However, nanoparticles synthesized from plant materials may also display unique physicochemical properties. This study described an improved synthesis process for silver nanoparticles (AgNPs) from the peel of the Citrus unshiu fruit, an agricultural waste product. In addition to evaluating the produced AgNPs' physico-chemical characteristics, the research also examines their antibacterial and cytotoxic/anticancer capabilities. The color change from yellow to dark brown was observed immediately when 20 ml of Citrus unshiu fruit peel extract was added to 0.5 g of silver nitrate. A surface plasmon resonance band at 424 nm revealed by ultra-violet spectroscopy was used as additional confirmation that AgNP had formed. The scanning electron microscope (SEM), and the transmission electron microscope (TEM), revealed spherical-shaped NPs with a mean size of 23 nm. Furthermore, X-ray diffraction (XRD) confirmed the high crystallinity of the obtained NPs while Fourier transform infrared spectroscopy (FTIR) confirmed the bioreducing capacity of the Citrus unshiu fruit peel extract. The minimum inhibitory concentration (MIC) (31.25 μg/mL) of AgNPs significantly revealed a strong dose-dependent antibacterial effect on Staphylococcus aureus and Bacillus cereus. In contrast, their impact on gram-negative bacteria, such as Escherichia coli and Salmonella typhimurium, displayed an MIC of 250 μg/mL. The assessment of cytotoxicity on human embryonic kidney cells (HEK293) and lung cancer cells (A549) through a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay revealed no detectable cytotoxic effects. The IC₅₀ values were determined as 37.73 ± 0.34 μg/mL for HEK293 and 56.37 ± 0.73 μg/mL for A549, indicating the absence of significant adverse impacts on these cell lines. The anticancer drug doxorubicin was used as a reference standard, and had an IC₅₀ value of 1.22 ± 0.09 and 0.76 ± 0.12 μg/mL against HEK293 and A549 cells, respectively. The results show that AgNPs synthesized from Citrus unshiu fruit peel could serve as antibacterial agents that may in the future be optimized for us in for example nanofiltration systems.

Emerging synthetic or derivative chemicals have drawn global concern due to their potential endocrine-disrupting effects, either as agonists or antagonists or through indirect effects on enzymes of signal transduction pathways. Currently, in vitro screening models are limited to poor tolerance, robustness, high cost and need for sphisticated equipment or complex procedures that require high levels of expertise. Herein, a multiplex analysis platform based on autobioluminescent yeast strains, including BLYhERαS, BLYhERβS, BLYhPRS, BLYhARS, BLYhMRS, and BLYhGRS, was developed for use in easy, rapid, robust, and sensitive screening for potential modulation of endocrine systems. Methods were applied to assess endocrine-disrupting effects of Bisphenol A (BPA) and its alternatives. Disrupting activities of bisphenols (BPs) varied greatly, and some BPA substitutes exerted more potent activities than those of BPA. Most BPs were primarily agonists of ERα and ERβ, while others were antagonists to AR, PR, GR, and MR. BPP and BPM exhibited non-monotonic dose-response relationships toward ERα and ERβ, and BHPF and BPG displayed converse disrupting activities to ERα and ERβ. Overall, the bioassay system provides an efficient tool for comprehensive evaluation of endocrine-disrupting activities of emerging contaminants.

In the present study, a method was described for the extraction of Sunset Yellow (SY) and Tartrazine (TZ) as anionic food dyes in actual samples by using magnetic calcined layered double hydroxide onto graphene oxide (MgFe CLDH)/GO (called MgO/MgFe₂O₄/GO) sorbent. The analytes were accumulated on MgO/MgFe₂O₄/GO-NCs with more detail recognized by XRD, FESEM, EDS element mapping, VSM and FTIR methods. The prepared nanocomposite (NC) was employed as an extractive phase for dispersive micro-solid phase extraction (D-μ-SPE) of SY and TA from actual samples. Then, the extracted SY and TZ dyes were analyzed by UV–vis spectrophotometer. Main variables related to the extraction process including pH, nano composite mass, sonication and vortex time and eluent volume were optimized by central composite design (CCD). The optimum conditions obtained for pH, nano composite mass, sonication and vortex time and eluent volume were 6.0, 0.02 g, 16 s and 6.40 min, and 500 μL, respectively. The extraction recovery equal to 96.31 % and 97.66 % for SY and TZ, respectively obtained from the predicted model, was in agreement with the experimental data (95.32 ± 2.33 % and 96.89 ± 1.84 %). In addition, under the optimal conditions, the calibration curve was found out to be linear over the concentration range of 0.5–2.50 mg L⁻¹ with R² > 0.98. The LODs ranged from 0.14 to 0.16 mgL⁻¹. Furthermore, the enrichment factors (EF) were achieved in the range of 20.65–36.66 with pre-concentration factor (PF) of 20. In the meantime, the obtained assay accuracy in the analysis of medical extract of Miranda Drink, Saffron and water samples fell within the range of 93.00%–107.00 %, whilst the precision expressed RSD lower than 3.50 %.

Emerging environmental persistent free radicals (EPFRs), can generate reactive oxygen species (ROS), posing potential exposure risks to human health. Incomplete coal combustion is a major source of EPFRs. Organic carbonaceous fractions are essential and important players in the formation of EPFRs during coal combustion. However, relationship between individual organic carbonaceous and non-carbon fractions with EPFRs in such emissions are not well known. This paper investigated the characteristics of EPFRs discharged from simulated coal combustion. Our results showed that the concentration of EPFRs was major concentrated on PM_1.1 (51.66–81.85 %), and more easily oxidized by oxygen resulting in producing more oxygen-centered radicals (semiquinone-type) in PM_1.1. The mean of line width (ΔHp-p) was 5.87 ± 0.41G higher than that of biomass combustion, indicating more free radical species were emitted from coal combustion. Humic-like substances-carbon (HULIS-C) was the major contributor of the formation of EPFRs and facilitate the generated of EPFRs. Secondary processes have also contributed to the formation of EPFRs during the coal combustion. Our result also noted that there was no relationship between transition metals and EPFRs, may be due to the variability and complexity of the chemical properties and composition of PM. This is critical for the prediction of geochemical behavior and risk assessment of EPFRs, which can provide basic data to support policy development to address rural air pollutant emissions.

Distribution and removal of chemicals in wastewater treatment plants (WWTPs) have mainly relied on mathematical models. Existing exposure assessment models such as SimpleTreat, STPWIN are based on conventional activated sludge processes. There is an urgent need to develop an A²/O-based WWTPs exposure assessment model. Organophosphates (OPEs) have different physical and chemical properties and potential environmental risks. The fate and biodegradation kinetics of three types of OPEs, including alkyl OPEs, chlorinated OPEs and triphenyl ester OPEs, were studied in a laboratory-scale anaerobic/anoxic/aerobic (A²/O) sewage treatment system and batch reactors. The three types of OPEs had different anaerobic, anoxic, and aerobic removal characteristics. A compensation mechanism was found between anaerobic and anoxic/aerobic removal. When the hydraulic retention time decreased from 82 to 20.5 h, the removal efficiencies in the anaerobic unit decreased, while those in the anoxic unit increased; as a result, the total removal efficiencies remained high (>80 %) for all OPEs except triphenyl phosphate (65.5%–75.1 %). The concept of effective sludge concentration (MLSS_eff) was proposed to illustrate the compensation mechanism and calibrate the second-order kinetic equation for predicting pollutant removal in the A²/O system: MLSS_eff = k_en × MLSS, where k_en is a constant related to the influent total organic carbon content (TOC). The influent TOC contents of the anoxic and aerobic units affected the value of MLSS_eff and OPEs removal. The results are of great significance for assessing OPEs exposure and predicting exposure to emerging micropollutants in sewage treatment systems.

Polychlorinated biphenyls (PCBs) were continuously receiving attention after their ban for use and production, owing to significant persistence, transport, and toxicity at trace level. Due to the field data gap of all 209 PCB congeners in previous studies, the source and environmental migration of lacustrine PCBs were not comprehensively understood. In this study, 209 PCB congeners in 277 water and 155 sediment samples collected from China's 23 large lakes across a longitudinal transect (18–45 °N) were analyzed. Results showed that the concentrations of Σ₂₀₉PCBs were 0.03–41.04 ng/L and 0.26–163.82 ng/g dry weight in lake water and sediment, respectively. In lake water, the dominant PCB congeners, detected in over 50 % of all samples, were PCB 11, PCB 28+31, PCB 41+64+68, PCB 47+48+75, and PCB 51, with contributions to Σ₂₀₉PCBs as 39.8 %, 6.6 %, 3.5 %, 18.4 %, and 6.4 %, respectively. Source apportionment revealed that major contributions of PCB 11, 41+64+68, 47+48+75, 51, and 209, were mainly from unintentionally produced PCBs (UP-PCBs) while PCB 28+31 and the other congeners from historical PCB commercials. Therefore, the selective congener analysis (excluding UP-PCBs) common in previous lake studies was an omission. Simultaneously, the longitudinal fractionation of PCBs was also found in lake waters, likely caused by the East Asian monsoon. Moreover, fugacity fractions of PCBs between water and sediment indicated their overall equilibrium or net sorption. Overall, PCB 28+31 can be well indicative of PCB migration. This study provides basic information for the migration and transformation of trace toxic persistent organic pollutants.

The present study is the first assessment of inorganic arsenic exposure from various fishery products to the Indonesian population based on a national total diet study (TDS). Based on the TDS report on food chemical contaminants, fish and processed fishery products are among the foodstuffs significantly contributing to total arsenic (t-As) exposure in Indonesia. However, there is no assessment yet for the Indonesian population to inorganic arsenic (i-As), which is known as the most harmful of arsenic compounds as it potentially promotes acute and chronic poisoning. The present assessment is aimed to estimate the exposure to i-As from fish and processed fishery products as well as the level of health risks in different age groups in Indonesia, based on the available t-As concentration data. The results showed that the mean exposure to t-As and i-As from fish and processed fishery products in various age groups were 1.19–2.67 μg/kg bw/day and 0.04–0.08 μg/kg bw/day, respectively. Exposure in various age groups revealed that the highest arsenic exposure was in toddlers (0–4 years) and the lowest in the age group of 19–55 years. Wet seasonings and marine fish consumption led to the most contributors to i-As exposure. The carcinogenic risk of i-As exposure based on the margin of exposure (MOE) demonstrated a low to moderate risk. However, a particular concern to the toddler group is required as the cancer risk (CR) value is higher than the acceptable threshold (>10⁻⁴). Additionally, the hazard quotient (HQ) of i-As exposure was determined as a low possibility of chronic risk.

East Java's mangrove ecosystems are exceptionally susceptible to contamination by anthropogenic activities and degradable marine debris, including plastic. This study aimed to investigate the shapes and distribution of microplastics (MPs) in sediment, water, and wild crabs, as well as the correlation. Wild crabs, sediment, and water originated from ten distinct mangrove ecosystems dispersed throughout northern and southern East Java. The MPs were extracted using digestion and density separation methods. The research identified six discrete shapes of MPs in sediment and water: fiber, fragment, foam, film, pellet, and microbead. The identified MPs were distributed in varying concentrations across various sites. Fibers were prevalent in the majority of water, ranging from 2.5 to 24.90 particles. L⁻¹, with the exception of Gedangan (GD) and Dubibir (DB), whose proportion was relatively low. For the sediments, the seven sites contained a greater proportion of fragments ranging from 1.53 to 1.69 particles. g⁻¹ dw as compared to surface waters. Additionally, each wild crab contained 48 particles identified in the gills and digestive tracts (GIT). Fiber constituted more than 60 % of the total MPs, making it the most prevalent shape in the wild crabs. However, this variety was not preferred. Correlation analysis revealed connections between MPs found in sediment and their presence in crab gills and GIT (p < 0.01). This highlights the potential hazards of biomagnification in East Java's mangrove ecosystems. Factor analysis revealed the influential factors that contribute to pollution in the marine protected areas, emphasizing the intricate nature of coastal contamination. This work enhances comprehension of the distribution and consequences of MPs in mangrove ecosystems, underscoring the necessity for comprehensive efforts to mitigate their effects.

Bisphenol A (BPA) is an endocrine disruptor present in polycarbonate plastics used in food containers and water bottles that resists insulin action and leads to type 2 diabetes mellitus (T2DM). However, there is scant research on the impact of BPA on T2DM-related vascular complications. Fetuin-A (FTA) and osteoprotegerin (OPG) are crucial markers for vascular calcification, which is the primary risk factor for developing vascular complications. This study aims to link external factor BPA levels with the vascular calcification markers FTA and OPG in diabetic subjects with and without vascular complications. Therefore, 120 study subjects were included and divided as control (n = 30), T2DM with cardiovascular diseases (CVD) (n = 30), T2DM with diabetic nephropathy (DN) (n = 30), and T2DM without vascular complications (n = 30). Serum and urinary FTA, OPG, and BPA levels were measured using an ELISA. FTA (AHSG) and OPG (TNFRSF11B) gene expression were analyzed using qPCR. Both serum (p < 0.001) and urinary BPA (p < 0.001) were found higher in T2DM with CVD and DN than T2DM without vascular complications and control. Also, T2DM with CVD and DN patients had lower serum and urinary FTA protein levels and increased serum and urinary OPG (p < 0.001) levels than T2DM without vascular complications and control. Moreover, FTA (AHSG) gene expression was negatively associated with serum BPA (p < 0.001) and urinary BPA (p < 0.01). Likewise, OPG (TNFRSF11B) gene expression was positively significant with serum BPA (p < 0.001) and urinary BPA (p < 0.01) in the study groups. These findings suggest that elevated blood and urinary BPA levels contribute to the severity of vascular complications in T2DM patients through vascular calcification.