Dibutyl phthalate (DBP), an important plastic contaminant in the environment, is known to cause organ toxicity. Although current research has shown that DBP-induced organ toxicity is associated with oxidative stress, the toxic effect of DBP on the lungs have not been fully elucidated. Therefore, we investigated the potential mechanism by which DBP induces pulmonary toxicity using a model of DBP-induced allergic airway inflammation in rats. The results showed that chronic exposure to DBP induced histopathological damage, inflammation, oxidative stress, apoptosis, and increased the protein levels of thymic stromal lymphopoietin (TSLP) and its downstream protein Janus kinase 1 (JAK1) and signal transducer and activator of transcription 6 (STAT6). Moreover, DBP exposure inhibited nuclear factor-erythroid-2-related factor 2 (Nrf2) and levels of its target genes NAD(P)H quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1). Additionally, using in vitro experiments, we found that DBP induced oxidative stress, reduced cell viability, and inhibited the Nrf2/HO-1/NQO1 pathway in mouse alveolar type II epithelial cell line. Overall, these data demonstrate that DBP induces allergic airway inflammation in rats via inhibition of the Nrf2/TSLP/JAK1 pathway.

The impact of agricultural pesticides on sensitive aquatic ecosystems is a matter of global concern. Although South Africa is the largest user of pesticides in sub-Saharan Africa, few studies have examined the toxicological threats posed by agricultural runoff, particularly to conservation areas of international importance. This study investigated the occurrence of 11 priority listed herbicides in sediments from Lake St Lucia, located on the east coast of South Africa. While characterised by exceptionally high levels of biodiversity, Lake St Lucia is affected by agricultural runoff primarily via inflow from two major rivers; the Mkhuze and Mfolozi. Sediment samples collected from Lake St Lucia and its two major fluvial inputs reveal widespread herbicide contamination of the aquatic environment. Residues were detected in the vast majority of samples analysed, with Mkhuze (27.3 ± 17 ng g⁻¹) and Mfolozi (25.6 ± 20 ng g⁻¹) sediments characterised by similar total herbicide levels, while lower concentrations were typically detected in Lake St Lucia (12.9 ± 12 ng g⁻¹). Overall, the most prominent residues detected included acetochlor (3.77 ± 1.3 ng g⁻¹), hexazinone (2.86 ± 1.4 ng g⁻¹) and metolachlor (10.1 ± 8.7 ng g⁻¹). Ecological assessment using Risk Quotients (RQs) showed that cumulative values for triazines and anilides/aniline herbicide classes presented low to medium risk for algae and aquatic invertebrate communities. Considering the biological importance of Lake St Lucia as a nursery for aquatic organisms, it is recommended that further research on the aquatic health of the system be undertaken. Additional monitoring and investigation into mitigation strategies is suggested, particularly as agricultural activities surrounding Lake St Lucia are likely to expand in the future.

We investigated the profiles and levels of perfluoroalkyl carboxylic acids in edible clams from five fishing sites in Japan (Hokkaido, Himakajima-Aichi, Atsumi-Aichi, Kyoto, and Kumamoto) and one site in Vancouver, Canada in 2017. The mean concentrations of perfluoroalkyl carboxylic acids with 6–15 carbon atoms (C6–C15) in edible clams from Japanese coastal waters ranged from 197 to 1757 pg/g wet weight, but were only 48 pg/g wet weight in clams from the site in Canada. Total perfluoroalkyl carboxylic acid concentrations in clams collected in Japanese waters were 4–40 times higher than concentrations in clams from Canada. Perfluorooctanoic acid (C8) contributed 53% of total perfluoroalkyl carboxylic acid concentrations in the clams from Japanese waters, which may be contaminated from terrestrial sources though river effluents, but was not detected in the clam samples from Canada. Principal component analysis separated shorter- and longer-chain perfluoroalkyl carboxylic acids, suggesting differing emission sources or environmental fate. Consumption of clams may be an exposure pathway of perfluorooctanoic acid in the Japanese population.

Efficient elimination of As(V) and Sb(V) from wastewater streams has long been a major challenge. Herein, sulfide-modified α-FeOOH adsorbent was fabricated via a simple sulfidation reaction for removing As(V) and Sb(V) from aqueous media. Compared with the pristine α-FeOOH, sulfide-modified α-FeOOH increased the adsorption of As(V) from 153.8 to 384.6 mg/g, and Sb(V) adsorption from 277.8 to 1111.1 mg/g. The enhanced adsorption of both As(V) and Sb(V) was maintained at the pH range from 2 to 11, and was not interfered by various coexisting anions such as Cl⁻, SO₄²⁻, NO₃⁻, SiO₃²⁻ and PO₄³⁻. The adsorption affinity increased from 0.0047 to 0.0915 and 0.0053 to 0.4091 for As(V) and Sb(V), respectively. X-ray photoelectron spectroscopic investigation demonstrated a reductive conversion of As(V) to As(III) during the adsorption process with sulfide-modified α-FeOOH, but with no obvious variation of Sb(V) speciation. While the removal mechanism for As(V) was reduction followed by adsorption via hydroxyl groups, mainly surface complexation was involved in the removal of Sb(V). This study presented a simple strategy to enhance the adsorption capacity and adsorption affinity of α-FeOOH toward As(V)/Sb(V) via sulfide-modification.

The hourly concentration of six criteria air pollutants in the Harbin-Changchun region were used to investigate the status and spatiotemporal variation of target air pollutants and their relationships with meteorological factors. The annual concentrations of particulate matters during 2013–2017 were two times higher than the Chinese Ambient Air Quality Standards (CAAQS) Grade Ⅱ. The annual O₃ concentration increased by two times during 2013–2018 in Harbin. The concentration of PM, SO₂, NO₂, and CO depicted a similar seasonal trend with an order of winter > autumn > spring > summer. The consistent interannual variation trends of PM₂.₅/CO, NO₂ and SO₂ indicated that the formation of secondary inorganic aerosols in the annual scale was dominated by the concentrations of NO₂ and SO₂. The interannual variations of the individual meteorological factors causing on PM₂.₅ and O₃ during 2013–2018 varied significantly in seasonal scale. The interannual variations were stable in annual scale indicating that the continuous decline of PM₂.₅ during 2014–2018 can be attributed to the comprehensive and strict prohibition of small coal-fired boilers and straw burning in the study area. Meanwhile, the increase in O₃ during 2013–2018 in the study area were mainly attributed to the rapid growth of the emission of its precursor (VOCs and NOx). The influence of meteorology on PM₂.₅ and ozone were the most stable and strongest in winter than that in the other three seasons.

Globally, wildfires are increasing in frequency and severity, exposing populations to toxic trace elements stored within forests. Trace element and Pb isotope compositions in aerosols (n = 87) from four major wildfires near Sydney, Australia (1994-2004) were evaluated (Mood’s median test) to determine any significant differences in concentration before, during or after wildfires. The US EPA’s positive matrix factorization (PMF) model was used to distinguish a wildfire-related particulate source factor. Atmospheric concentrations of Cd and Mn were approximately 2.5 times higher during fire periods. PMF modelling distinguished a soil factor (Ca, Si, Ti and Zn) and an anthropogenically-sourced factor (Cd, Pb). The Cd, Pb anthropogenic factor was present at twice the concentration during wildfire periods (compared to before or after). Lead isotopic analyses of aerosols revealed that former leaded gasoline depositions were subject to remobilization during post-2000 wildfire periods. Trace element increases during wildfires are unlikely to exceed health-based criteria.

The main purpose of current study is accurate prediction of NOx emissions from diesel engines considering in-cylinder ion current. To reach this goal, a validated thermodynamic multi-zone model was used. A modified chemical kinetics mechanism of diesel fuel oxidation was used too. A chemical kinetics mechanism of NOX formation including 103 reactions was added to the main mechanism. A set of ions and ionic reactions was added to the developed chemical kinetics mechanism and finally a modified chemical kinetics mechanism with 445 reactions and 100 species was formed. The developed mechanism was coupled to the multi-zone model and a diesel engine was simulated. The importance of Zeldovich mechanism, prompt mechanism, N₂O mechanism and NNH mechanism were investigated. The progress rates of reactions were calculated and important reactions were identified. The results show that the oxygenated ions, NO⁺, O⁺ and O₂⁺, has more effects on NO production than other ions. The prompt mechanism plays an important role in predicting the ion current inside the chamber. Because this mechanism has reactions that can lead to CH production. The CH radicals produced by this mechanism can be employed by basic ionic reactions and lead to ion production. The results show that using NOx related ionic reactions results in accurate prediction of engine exhaust NOx.

The performance of the cathode significantly affects the ability of the electro-Fenton (EF) process to degrade chemicals. In this study, a simple method to modify the graphite felt (GF) cathode was proposed, i.e. oxidizing GF by hydrothermal treatment in nitric acid. The surface physical and electrochemical properties of modified graphite felt were characterized by several techniques: scanning electron microscope (SEM), water contact angle, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and linear scanning voltammetry (LSV). Compared with an unmodified GF (GF-0), the oxygen reduction reaction (ORR) activity of a modified GF was significantly improved due to the introduction of more oxygen-containing functional groups (OGs). Furthermore, the results showed that GF was optimally modified after 9 h (GF-9) of treatment. As an example, the H₂O₂ generation by GF-9 was 2.26 times higher than that of GF-0. After optimizing the process parameters, which include the initial Fe²⁺ concentration and current density, the apparent degradation rate constant of levofloxacin (LEV) could reach as high as 0.40 min⁻¹. Moreover, the total organic carbon (TOC) removal rate and mineralization current efficiency (MCE) of the modified cathode were much higher than that of the GF-0. Conclusively, GF-9 is a promising cathode for the future development in organic pollutant removal via EF.

Both surface and satellite observations have shown a decrease in NOₓ emissions in East Asian countries in recent years. In order to reflect the recent NOx emission reduction and to investigate its impact on surface O₃ concentrations in Asian megacities, we adjusted two bottom-up regional emission inventories of which base years are 2006 (E2006) and 2010 (E2010), respectively. We applied direct and relative emission adjustments to both E2006 and E2010 to constrain NOx emissions using OMI NO₂ vertical column densities. Except for the relative emission adjustment with E2006, modeling results with adjusted emissions exhibit that NOx emissions over East Asian megacities (Beijing, Shanghai, Seoul, and Tokyo) in the bottom-up inventories are generally overestimated. When the direct emission adjustment is applied to E2006, model biases in the Seoul Metropolitan Area (SMA), South Korea are reduced from 24 ppb to 2 ppb for NOx (=NO+NO₂) and from −9 ppb to 0 ppb for O₃. In addition, NO₂ model biases in Beijing and Shanghai in China are reduced from 8 ppb to 18 ppb–0 ppb and 1 ppb, respectively. Daily maximum 8-h average O₃ model biases over the same places are decreased by 8 ppb and 14 ppb. Further analyses suggest that the reduction in domestic South Korean NOₓ emissions plays a significant role in increasing O₃ concentrations in SMA. We conclude that the current strong drive to reduce NOₓ emissions as part of the strategy to lower particulate matter concentrations in South Korea can account for increased O₃ concentrations in recent years and suggest that more aggressive NOₓ emissions will be necessary soon.

Nonylphenol (NP) is a chemical raw material and intermediate which is mainly used in the production of surfactants, lubricating oil additives and pesticide emulsifiers. NP is reported to be toxic on the immune system, nervous system and reproductive system due to its binding to estrogen receptors. However, the toxicity of NP on mammalian oocyte quality remains unclear. In present study, we explored the effects of NP exposure on mouse oocyte maturation. Our results showed that 4 weeks of NP exposure increased the number of atresia follicles and decreased oocyte developmental competence. Transcriptomic analysis indicated that NP exposure altered the expression of more than 800 genes in oocytes, including multiple biological pathways. Subcellular structure examination indicated that NP exposure disrupted meiotic spindle organization and caused chromosome misalignment. Moreover, aberrant mitochondrial distribution and decreased membrane potential were also observed, indicating that NP exposure caused mitochondria dysfunction. Further analysis showed that NP exposure resulted in the accumulation of reactive oxygen species (ROS), which causes oxidative stress; and the NP-exposed oocytes showed positive Annexin-V signal, indicating the occurrence of early apoptosis. In summary, our results indicated that NP exposure reduced oocyte quality by affecting cytoskeletal dynamics and mitochondrial function, which further induced oxidative stress and apoptosis in mice.