Membrane concentrated landfill leachate (MCLL) contains large amounts of recalcitrant organic matter that cause potential hazards to the environment. Knowledge on the compositional variation of MCLL during treatment is important for a better understanding on the degradation pathway of organic pollutants. In this work, the structural change of MCLL during Fenton oxidation process was examined using spectroscopic techniques. The removal rates of COD, TOC and UV254 reached 78.9 ± 1.3%, 70.2 ± 1.4% and 90.64 ± 1.6%, respectively, under the optimal condition (i.e., dosage of H2O2 = 9.0 mL/200 mL, H2O2/Fe(II) molar ratio = 3.0, pH = 3.0, time = 40 min). Spectral analyses suggested that aromatic/CC structure and CO bonds in MCLL can be successfully destroyed by Fenton oxidation, resulting in a decrease in molecular weight. One fulvic-like and one humic-like components were identified in MCLL, both of which can be removed by Fenton treatment. In addition, two-dimensional correlation spectroscopic analyses suggested the oxidative changes of MCLL structure in the order of fulvic-like component/unsaturated conjugated bond > aromatic structure > humic-like component. The results may provide a new insight to the understanding on the structure variation of MCLL during treatment, which is beneficial for the design of cost-effective treatment strategies.

We investigated the effect of hypoxic-anoxic range of dissolved oxygen (DO) on metal release/bioavailability at sediment-water interface (SWI) in the Ganga River. Here, we consider eight sites in the main river stem along 518 km; sixty sites downstream two point sources and two tributary confluences covering 630 km; and an incubation experiment to verify these results. We found higher concentrations of metals and bioavailable fractions at SWI at two locations of main stem and up to 700 m, 1000 m, 400 m and 500 m downstream Assi drain, Wazidpur drain, Ramganga confluence and Varuna confluence respectively where DO at SWI (DOₛw) was <2.0 mgL⁻¹. The incubation experiment did show higher levels of metal- and P-release and bioavailability under anoxic-hypoxic range of DO. The risk assessment code and eutrophication index indicated high to very high risks of contaminated river sediment and water to aquatic environment at sites with hypoxic-anoxic range of DOₛw. Further, the principal component analyses separated metals and bioavailable fractions opposite to FDAase indicating greater risk at these locations. The study, which forms the first report on benthic hypoxia/anoxia-driven metal release, potential bioavailability and risk to the Ganga River ecosystem will help understanding how human-driven perturbations influence geochemical cycling of metals and ecosystem responses in large rivers.

Environmentally persistent free radicals (EPFRs) are receiving increasing concern due to their toxicity and ubiquity in the environment. To avoid restrictions imposed when using a high-volume active sampler, this study uses tree leaves to act as passive samplers to investigate the spatial distribution characteristics and sources of airborne EPFRs. Tree leaf samples were collected from 120 sites in five areas around China (each approximately 4 km × 4 km). EPFR concentrations in particles (<2 μm) on the surface of 110 leaf samples were detected, ranging from 7.5 × 10¹⁶ to 4.5 × 10¹⁹ spins/g. For the 10 N.D. samples, they were all collected from areas inaccessible by vehicles. The g-values of EPFRs on 68% leaf samples were larger than 2.004, suggesting the electron localized on the oxygen atom, and they were consistent with the road dust sample (g-value: 2.0042). Significant positive correlation was found between concentrations of elemental carbon (tracer of vehicle emissions) and EPFRs. Spatial distribution mapping showed that EPFR levels in various land uses differed noticeably. Although previous work has linked atmospheric EPFRs to waste incineration, the evidence in this study suggests that vehicle emissions, especially from heavy-duty vehicles, are the main sources. While waste incinerators with low emissions or effective dust-control devices might not be an important EPFR contributor. According to our estimation, over 90% of the EPFRs deposited on tree leaves might be attributed to automotive exhaust emissions, as a synergistic effect of primary exhausts and degradation of aromatic compounds in road dust. With adding the trapping agent into the particle samples (<2 μm), signals of hydroxyl radicals were observed. This indicates that EPFRs collected from this phytosampling method can lead to the release of reactive oxygen species (ROS) once they are inhaled by human beings. Thus, this study helps highlight EPFR “hotspots” for potential health risk identification.

In one of our previous studies, the mechanisms of radical-initiated methylmercury (MeHg) degradation in soil with coexisting Fe and Cu have been reported. In this work, various environmental factors, including water table fluctuation, pH and major ions, are discussed to clarify the behavior of MeHg in subsurface environments. Soil column experiments were set up to simulate the degradation of MeHg in the soil with an iron-bearing mineral (annite), which has often undergone repeating wetting-drying cycles, resulting from the local climate. The results indicate that wetting-drying alternation can initiate MeHg degradation in the soil with the annite mineral. Additionally, the majority of the major ions (K⁺, Na⁺, Mg²⁺, Fe³⁺, Cl⁻, SO₄²⁻, NO₃⁻) in the interstitial soil had little effect in the degradation of MeHg with the exception of Cu, which improved the degradation depending on the pH. At acidic pHs Cu increased the production of hydroxyl radical while at more alkaline pHs there was oxidation to Cu(III). The products including Hg(II) and Hg(0) of MeHg degradation were also identified in this work. This study reveals that the geochemical cycle of MeHg is closely linked to local climate and pedosphere processes.

Atmospheric halogenated polycyclic aromatic hydrocarbons (Halo-PAHs) and parent PAHs were monitored in Ulsan, South Korea for one year (January‒December 2015) to investigate their seasonal patterns, gas/particle partitioning behavior, and the impact of meteorological conditions. The mean concentrations of 24 chlorinated PAHs, 11 brominated PAHs, and 13 parent PAHs in the gaseous and particulate phases were 8.64 and 9.64 pg/m³, 11.6 and 1.62 pg/m³, and 2.17 and 2.40 ng/m³, respectively. Winter had the highest ClPAH and PAH levels, with significant contributions from poly-chlorine groups and high-molecular-weight compounds. However, BrPAHs showed reverse patterns with the highest concentration in summer and the dominant gaseous fraction throughout the year. This finding could be explained by the strong local sources of BrPAHs, related to automobile and petrochemical industries. In contrast, the effects of the temperature inversion layer and atmospheric transport from the outside of Ulsan were more apparent for ClPAHs and PAHs, particularly in winter and spring. Regarding gas/particle partitioning, Halo-PAHs exhibited different seasonal behaviors from those of parent PAHs. The sorption pathway of Halo-PAHs seemed to shift from absorption as the sole dominant mechanism in winter and spring to both adsorption and absorption in summer and fall, while both partitioning mechanisms contributed equally for parent PAHs during the entire year. This study implies that Halo-PAHs and parent PAHs might not share the same atmospheric behavior, possibly due to different characteristics in atmospheric reactions with other chemicals and particle-size distribution. However, there have been limited studies about the formation of Halo-PAHs and their physicochemical properties; hence, further in-depth investigations are of vital importance.

Dangerous goods are particularly hazardous, as they can be flammable, explosive, and toxic. These characteristics make them vulnerable to accidents, and such mishaps during port operations can lead to massive economic losses and even deaths. It is, therefore, necessary and important to analyze and study the dangerous goods accidents at ports, so as to identify major factors and prevent them. Formal concept analysis (FCA) is a powerful tool for rule extraction. This paper introduces FCA along with relevant documents and case studies to analyze the dangerous goods accidents at China’s ports, building a concept lattice model of dangerous goods accidents at China’s ports, and reduces the condition attributes to come up with three key attributes of dangerous goods accidents at China’s ports: warehousing management, facilities and equipment, goods registration and extract four effective diagnostic rules for dangerous goods accidents at ports. This paper proposes corresponding governance strategies to the rules of dangerous goods accidents, which can significantly prevent and manage dangerous goods accidents at China’s ports in the future. In the future, the concept scale can be introduced to study the problem that the influencing factor is multi-valued attribute so as to expand the scope of research.

The hexafluoropropylene-oxide-dimer-acid (GenX) is a short-chain perfluoroalkyl substance that was recently introduced following the phase out of PFOA, as an alternative for the process of polymerization. GenX was detected at high concentrations in rivers, drinking water and in sera of exposed workers and recent findings suggested its potential dangerousness for human health.Aim of the study was to assess the consequences of GenX exposure on in vitro thyroid cells with particular attention to the effects on cell-viability, proliferation, DNA-damage and in the thyroid-related genes expression.FRTL-5 rat-thyroid cell line were incubated with increasing concentrations of GenX for 24 h, 48 h and 72 h to assess cell viability by WST-1. DNA-damage was assessed by comet assay and further confirmed by micronucleus assay. The proliferation of survived cells was measured by staining with crystal violet and evaluation of its optical density after incubation with SDS. Changes in TTF-1, Pax8, Tg, TSH-R, NIS and TPO genes expression were evaluated by RT-PCR.GenX exposure reduced FRTL-5 viability in a time and dose-dependent manner (24 h: ANOVA F = 22.286; p < 0.001; 48 h: F = 43.253, p < 0.001; 72 h: F = 49.708, p < 0.001). Moreover, GenX exerted a genotoxic effect, as assessed by comet assay (significant increase in tail-length, olive-tail-moment and percentage of tail-DNA) and micronucleus assay, both at cytotoxic and non-cytotoxic concentrations. Exposure to GenX at concentrations non-cytotoxic exerted a significant lowering of the expression of the regulatory gene TTF-1 (p < 0.05 versus untreated) and higher expression of Pax-8 (p < 0.05 versus untreated) and a down-regulation of NIS (p < 0.05 versus untreated). In addition, cells survived to GenX exposure showed a reduced re-proliferation ability (24 h: ANOVA F = 11,941; p < 0,001; 48 h: F = 93.11; p < 0.001; 72 h F = 21.65; p < 0.001).The exposure to GenX produces several toxic effects on thyroid cells in vitro. GenX is able to promote DNA-damage and to affect the expression of thyroid transcription-factor genes.

Di-(2-ethylhexyl) phthalate (DEHP), a plasticizer that is mainly used in the production of polyvinyl alcohol-containing chloride products, has attracted attention due to potential threats to human health and the environment. Nevertheless, knowledge of DEHP-induced nephrotoxicity is still limited. To explore the mechanism of DEHP-induced nephrotoxicity, quail were treated with 0, 250, 500 and 1000 mg/kg DEHP by oral gavage for 45 days. Based on the results of histopathological analysis, DEHP exposure induced a disorganized renal structure, a partially dilated glomerulus and an atrophied Bowman’s space. Renal tubular epithelial cells were unclear, and swelling of columnar epithelial cells was observed, suggesting that DEHP exposure caused renal disease and renal injury. Notably, DEHP interfered with the homeostasis of cytochrome P450 systems (CYP450s) by increasing the activities or contents of CYP450s (total CYP450, Cyt b5, ERND, APND, AH and NCR). The expression levels of certain CYP450 isoforms (CYP1A, CYP1B, CYP2C, CYP2D, CYP2J and CYP3A) were significantly downregulated in the kidney in DEHP-treated quail. Furthermore, DEHP induced the expression of nuclear receptors (AHR, CAR and PXR) in a dose-dependent manner. The results of this study suggested that DEHP-induced nephrotoxicity in quail was associated with the induction of nuclear xenobiotic receptor (NXR) responses and interference with CYP450 homeostasis. In conclusion, all data indicated that DEHP induced nephrotoxicity by triggering NXRs and modulating the cytochrome P450 system. The results of this study provide a new basis for understanding the nephrotoxicity of DEHP.

The purpose of this long-term experiment was on gaining more insights into the environmental behaviour of veterinary antibiotics in the subsurface after application with manure. Therefore, manure spiked with a bromide tracer and eight antibiotics (enrofloxacin, lincomycin, sulfadiazine, sulfamethazine, tetracycline, tiamulin, tilmicosin and tylosin) in concentrations of milligrams per litre were applied at an experimental field site. Their pathway was tracked by continuous extraction of soil pore water at different depths and systematic sampling of groundwater for a period of two years. Seven target compounds were detected in soil pore water of which four leached into groundwater. Concentrations of the detected target compounds were, with few exceptions, in the range of nanograms per litre. It was concluded that a large fraction of the investigated antibiotics sorbed or degraded already within the first meter of the soil. Further, it was inferred from the data that long and warm dry periods cause attenuation of the target compounds through increased degradation or sorption occurring in the soil. In addition, the comprehensive data-set allowed to estimate a retardation factor between 1.1 and 2.0 for sulfamethazine in a Plaggic Anthrosol soil, and to classify the individual compounds by environmental relevance based on transport behaviour and persistence. According to the distribution of resistant genes in the environment, sulfamethazine was found to be the most mobile and persistent substance.

Glyphosate-based herbicides, the most extensively used herbicides in the world, are available in an enormous number of commercial formulations with varying additives and adjuvants. Here, we study the effects of one such formulation, Credit41, in two genetically diverse yeast strains. A quantitative trait loci (QTL) analysis between a sensitive laboratory strain and a resistant strain linked mitochondrial function to Credit41 resistance. Two genes encoding mitochondrial proteins identified through the QTL analysis were HFA1, a gene that encodes a mitochondrial acetyl CoA carboxylase, and AAC3, which encodes a mitochondrial inner membrane ATP/ADP translocator. Further analysis of previously studied whole-genome sequencing data showed that, although each strain uses varying routes to attain glyphosate resistance, most strains have duplications of mitochondrial genes. One of the most well-studied functions of the mitochondria is the assembly of Fe–S clusters. In the current study, the expression of iron transporters in the transcriptome increased in cells resistant to Credit41. The levels of iron within the cell also increased in cells exposed to Credit41 but not pure glyphosate. Hence, the additives in glyphosate-based herbicides have a significant contribution to the negative effects of these commercial formulations on biological systems.