Acceleration of Fe³⁺/Fe²⁺ cycle and simultaneous reduction of particle size with enhanced stability is extremely important for iron-based heterogeneous Fenton catalysts. In this work, Fe⁰-Fe₂O₃ composite nanoparticles embedded ordered mesoporous carbon hybrid materials (Fe⁰-Fe₂O₃/OMC) were rationally designed as efficient heterogeneous Fenton catalysts. Because of the confinement and reduction of OMC, highly dispersed Fe⁰-Fe₂O₃ active species with diameter of ∼8 nm were generated by an optimized carbothermic reduction process. In addition, Fe⁰-Fe₂O₃/OMC possesses ordered mesoporous structure with uniform mesopore, high surface area and pore volume. For comparison, two other catalysts, including solely Fe⁰ nanoparticles supported on ordered mesoporous carbon (Fe⁰/OMC) and solely Fe₂O₃ nanoparticles supported on ordered mesoporous carbon (Fe₂O₃/OMC) were also prepared. The Fenton catalytic performance of synthesized catalysts was evaluated by using H₂O₂ as oxidizing agent to degrade Acid Orange II (AOII). The results show that almost 98.1% of 100 mg L⁻¹ AOII was removed by Fe⁰-Fe₂O₃/OMC in condition of neutral pH and nearly room temperature, which is much higher than those of compared catalysts. The enhanced catalytic activity of Fe⁰-Fe₂O₃/OMC for AOII removal is due to the efficient electron transfer between the Fe⁰ and iron oxide and the accelerated Fe³⁺/Fe²⁺ cycle. The stability and reusability of the catalyst was also investigated, which showed a good performance even after five consecutive runs. The as-synthesized catalyst is proved to be an attractive candidate in heterogeneous Fenton chemistry and practical application.

Potentially toxic elements are widespread soil contaminants, whose occurrence could entail a concern for human health upon ingestion of fruit and vegetables harvested in a polluted area. This work set out to evaluate the concentrations of lead and cadmium as well as the levels of thirteen heavy metals for which a limit value is yet to be established by the food safety authorities, in order to perform a risk characterization related to the dietary intake of these metals and to provide a scientific opinion with wider relevance in the light of current worldwide regulatory issues. The sampling consisted of fruit and vegetables grown in a potentially contaminated area of southern Italy due to the illegal dump of hazardous wastes. An evaluation of the dietary exposure through the calculation of the Hazard Index (HI), the Maximum Cumulative Ratio (MCR) and the Target Cancer Risk (TCR) was adopted to this end. The results revealed that about the 30% of samples showed quantifiable levels of chemicals and no significant difference emerged between the potentially polluted area and the nearby cities that were selected as a control landfill site. The overall risk characterization for non-carcinogenic endpoints showed that the HI did not reach unsafe values, except for a small number of samples mainly because of aberrant occurrences and, in any case, the cumulative toxicity was mainly driven by thallium and vanadium. As far as the carcinogenic effects of arsenic are concerned, the distribution of TCR values broadly lay below the safety threshold; a certain percentage of data, however, exceeded this limit and should be taken into account for the enforcement of future regulatory thresholds.

Colloids are ubiquitous in soils, and it has been reported that colloids can act as carriers to increase the mobility of poorly soluble contaminants in subsurface environments. Addition of sulfur (S) fertilizer greatly influences on heavy metal behavior in paddy soil, while the influence of S fertilizer on Cu migration and transformation in colloids of soil pore water has not yet been studied. The influence of S fertilizer (S⁰ and Na₂SO₄) applied in paddy soils on Cu migration and transformation in colloids of soil pore water from the rice rhizosphere region was explored in this study. The speciation of Cu in colloids of soil pore water from the rice rhizosphere region was explored by advanced synchrotron-based X-ray absorption near-edge spectroscopy (XANES) techniques. The morphology of colloids was characterized by field emission scanning electron microscopy coupled to energy dispersive X-ray spectroscopy (SEM-EDX). At a depth of 20 cm, the concentration of Cu in colloids of the rhizosphere soil pore water in the control was 2.4- and 6.5- fold higher than that in treatments of S⁰ and Na₂SO₄, respectively. The colloids in soil pore water were all positively charged, ranging from 2.4 to 7.8 mV, and the size of colloids was 440–740 nm. The proportion of Fe in colloids in the rhizosphere region decreased with S fertilizer application, while the proportions of C and O increased. Sulfur fertilizer application, increased the proportion of Cu-Cysteine, while the proportion of Cu₂S decreased in soil colloids. In conclusion, application of sulfur fertilizer in paddy soil decreased the Cu concentration in soil pore water and colloids of the rhizosphere region, thereby decreasing the vertical migration of Cu in soil pore water.

Process-based models have been widely used for predicting environmental fate of contaminants. Nevertheless, accurate modeling of pentachlorophenol (PCP) dissipation in soils at the millimeter-scale remains a challenge due to the scarcity of observation data and uncertainty associated with model assumptions and estimation of the model parameters. To provide quantitative analysis of PCP-dissipation at the anaerobic/aerobic interface of a rhizobox experiment, this study implemented Bayesian parameter estimation for a process-based reactive chemical transport model. The model considered the main transport and transformation processes of chemicals including diffusion, sorption and degradation. The contributions of the processes to PCP dissipation were apportioned both in space and time. Using the maximum-a-posteriori (MAP) estimation of parameters, our model fitted the experimental data better compared with the previous work. Our results indicated that the most reactive zone for PCP dissipation occurred in the layer of 0–2.4 mm where degradation in solid phase dominated the PCP dissipation, while upward diffusion was the main mechanism for the reduction of PCP concentration in deeper layer (2.4–4.8 mm). By considering the coupled reactive transport of PCP and Cl⁻, the average degrees of PCP dechlorination in each layer were estimated from corresponding total concentrations of PCP and Cl⁻. The degrees of PCP dechlorination in the ponding water and the top layer of soil profile were highest, while 2,3,4,5- TeCP and 3,4,5- TCP were identified as the main dechlorination products in the soil. This study demonstrated that combining Bayesian estimation with process-based reactive chemical transport model can provide more insights of PCP dissipation at the millimeter-scale. This approach can help to understand complex dissipation mechanisms for other contaminants.

Toxicoproteomic analysis of steel industry ambient particulate matter (PM) that contain high concentrations of PAHs and metals was done by treating human lung cancer cell-line, A549 and the cell lysates were analysed using quantitative label-free nano LC-MS/MS. A total of 18,562 peptides representing 1576 proteins were identified and quantified, with 196 proteins had significantly altered expression in the treated cells. Enrichment analyses revealed that proteins associated to redox homeostsis, metabolism, and cellular energy generation were inhibited while, proteins related to DNA damage and repair and other stresses were over expressed. Altered activities of several tumor associated proteins were observed. Protein-protein interaction network and biological pathway analysis of these differentially expressed proteins were carried out to obtain a systems level view of proteome changes. Together it could be inferred that PM exposure induced oxidative stress which could have lead into DNA damage and tumor related changes. However, lowering of cellular metabolism, and energy production could reduce its ability to overcome these stress. This kind of disequilibrium between the DNA damage and ability of the cells to repair the DNA damage may lead into genomic instability that is capable of acting as the driving force during PM induced carcinogenesis.

RT-qPCR allows sensitive detection of viral particles of both infectious and noninfectious viruses in water environments, but cannot discriminate non-infectious from infectious viruses. In this study, we aimed to optimize RT-qPCR-based detection of chlorine-inactivated human norovirus (NoV) and pepper mild mottle virus (PMMoV) in suspension by pretreatment with an optimal combination of a monoazide and a detergent that can efficiently penetrate damaged viral capsids. Four methods were compared to determine the efficacy of chlorine disinfection (at 1, 3, and 5 min mg/L): (A) RT-qPCR alone, (B) RT-qPCR assay preceded by magnetic bead separation for enrichment of viral particles (MBS-RT-qPCR), (C) MBS-RT-qPCR assay with pretreatment with propidium monoazide (PMA-MBS-RT-qPCR), and (D) PMA-MBS-RT-qPCR assay with pretreatment with sodium lauroyl sarcosinate (INCI-PMA-MBS-RT-qPCR). On the basis of a PMA optimization assay, 200 and 300 μM PMA were used in subsequent experiments for NoV GII.4 and PMMoV, respectively. Optimal INCI concentrations, having minimal influence on NoV GII.4 and PMMoV, were found to be 0.5% and 0.2% INCI, respectively. For NoV GII.4, there were significant differences (P < 0.05) in log₁₀ genome copies between the PMA-treated and the INCI + PMA-treated samples (log₁₀ genome copies differed by 1.11 and 0.59 log₁₀ for 3 and 5 min mg/L of chlorine, respectively). For PMMoV, INCI induced differences in log₁₀ genome copies of 0.92, 1.18, and 1.86, for 1, 3, and 5 min mg/L of chlorine, respectively. Overall, the results of this study indicate that an optimal combination of PMA and INCI could be very useful for evaluating disinfection methods in water treatment strategies.

Particulate organic matter (POM) acts as a metals sink in soil, but only a few studies focused on the interaction of POM and heavy metals in paddy soil. The aim of this study is to investigate the interaction between POM and Copper (Cu)/Zinc (Zn). Two levels of Cu (100, 400 mg kg⁻¹) and Zn (250, 500 mg kg⁻¹) were used in a soil culture experiment. Our results showed that POM was porous structure and varied in size. Hydroxyl and carboxyl involved in POM adsorption of Cu and Zn. Rhizosphere effects roughen the surface of POM and enhanced the capacity of POM on heavy metals absorption. Cu-humic (26.2–33.9%) and Cu-citrate (38.5–42.4%) were dominated in POM, and Cu-goethite (41.7–57.7%), Cu-sulphide (6.6–27.6%) was dominated in soil. Rhizosphere effects decreased the proportion of organic-bond Cu along with the increasing the proportion of Cu-sulphide in POM. Addition of Cu and Zn inhibited the degradation of POM but rhizosphere effects promoted. Carbon content was increased in POM by heavy metal and rhizosphere effects. Our findings indicated that POM tended to retain the heavy metals in soil and heavy metals inhibited the degradation of POM, however, rhizosphere effects decreased the stability of POM-metals interactions.

Microplastics and fibres occur in high concentrations along urban coastlines, but the occurrence of microplastic ingestion by fishes in these areas requires further investigation. Herein, the ingestion of debris (i.e., synthetic and natural fibres and synthetic fragments of various polymer types) by three benthic-foraging fish species Acanthopagrus australis (yellowfin bream), Mugil cephalus (sea mullet) and Gerres subfasciatus (silverbiddy) in Sydney Harbour, Australia has been quantified and chemically speciated by vibrational spectroscopy to identify the polymer type. Ingested debris were quantified using gut content analysis, and identified using attenuated total reflectance Fourier transform infrared (ATR-FTIR) and Raman microspectroscopies in combination with principal component analysis (PCA). The occurrence of debris ingestion at the time of sampling ranged from 21 to 64% for the three species, and the debris number ranged from 0.2 to 4.6 items per fish for the different species, with ∼53% of debris being microplastic. There was a significant difference in the amount of debris ingested among species; however, there was no difference among species when debris counts were standardised to fish weight or gut content weight, indicating that these species ingest a similar concentration of debris relative to their ingestion rate of other material. ATR-FTIR microspectroscopy successfully identified 72% of debris. Raman spectroscopy contributed an additional 1% of successful identification. In addition, PCA was used to non-subjectively classify the ATR-FTIR spectra resulting in the identification of an additional 9% of the debris. The most common microplastics found were polyester (PET), acrylic-polyester blend, and rayon (semi-synthetic) fibres. The potential of using Raman microspectroscopy for debris identification was investigated and provided additional information about the nature of the debris as well as the presence of specific dyes (and hence potential toxicity).

This study uses spatiotemporal patterns in ambient concentrations to infer the contribution of regional versus local sources. We collected 12 months of monitoring data for outdoor fine particulate matter (PM₂.₅) in rural southern India. Rural India includes more than one-tenth of the global population and annually accounts for around half a million air pollution deaths, yet little is known about the relative contribution of local sources to outdoor air pollution. We measured 1-min averaged outdoor PM₂.₅ concentrations during June 2015–May 2016 in three villages, which varied in population size, socioeconomic status, and type and usage of domestic fuel. The daily geometric-mean PM₂.₅ concentration was ∼30 μg m⁻³ (geometric standard deviation: ∼1.5). Concentrations exceeded the Indian National Ambient Air Quality standards (60 μg m⁻³) during 2–5% of observation days. Average concentrations were ∼25 μg m⁻³ higher during winter than during monsoon and ∼8 μg m⁻³ higher during morning hours than the diurnal average. A moving average subtraction method based on 1-min average PM₂.₅ concentrations indicated that local contributions (e.g., nearby biomass combustion, brick kilns) were greater in the most populated village, and that overall the majority of ambient PM₂.₅ in our study was regional, implying that local air pollution control strategies alone may have limited influence on local ambient concentrations. We compared the relatively new moving average subtraction method against a more established approach. Both methods broadly agree on the relative contribution of local sources across the three sites. The moving average subtraction method has broad applicability across locations.

Despite not being used for decades in most countries, DDT remains ubiquitous in soils due to its persistence and intense past usage. Because of this it is still a pollutant of high global concern. Assessing long term dissipation of DDT from this reservoir is fundamental to understand future environmental and human exposure. Despite a large research effort, key properties controlling fate in soil (in particular, the degradation half-life (τₛₒᵢₗ)) are far from being fully quantified. This paper describes a case study in a large central European catchment where hundreds of measurements of p,p’-DDT concentrations in air, soil, river water and sediment are available for the last two decades. The goal was to deliver an integrated estimation of τₛₒᵢₗ by constraining a state-of-the-art hydrobiogeochemical-multimedia fate model of the catchment against the full body of empirical data available for this area. The INCA-Contaminants model was used for this scope. Good predictive performance against an (external) dataset of water and sediment concentrations was achieved with partitioning properties taken from the literature and τₛₒᵢₗ estimates obtained from forcing the model against empirical historical data of p,p’-DDT in the catchment multicompartments. This approach allowed estimation of p,p’-DDT degradation in soil after taking adequate consideration of losses due to runoff and volatilization. Estimated τₛₒᵢₗ ranged over 3000–3800 days. Degradation was the most important loss process, accounting on a yearly basis for more than 90% of the total dissipation. The total dissipation flux from the catchment soils was one order of magnitude higher than the total current atmospheric input estimated from atmospheric concentrations, suggesting that the bulk of p,p’-DDT currently being remobilized or lost is essentially that accumulated over two decades ago.