The effects of increased mining of seafloor massive sulfide deposits on marine ecosystems have not been characterized. In this study, the impact of leaching metals from a hydrothermal sulfide on photosynthetic protist and cyanobacterial communities in marine environments was investigated by amplicon analyses of small subunit rDNA (SSU rDNA) and rRNA (SSU rRNA). Seawater samples collected from the Iheya North region and Suruga Bay, Japan, were incubated with or without a leachate containing zinc, copper, cadmium, and manganese, of the actual seafloor hydrothermal sulfide from the Hakurei site in the Izena Hole region. The relative abundances of prasinophytes, diatom protists, and the cyanobacteria Synechococcus decreased substantially during incubation with leachate, indicating the vulnerability of these lineages to the leachate. Phylogenetic analysis based on the cyanobacterial phycocyanin cpcBA/rpcBA operon obtained from samples incubated with or without leachate indicated that the individual lineages of Synechococcus can determine sensitivity to heavy metals in different marine regions as well as particular clades and ecotypes.

Experiments were conducted under lead (Pb), cadmium (Cd), and copper (Cu) exposure to observe germination and seedling growth of wheat (Triticum aestivum L), pea (Pisum sativum), and tomato (Solanum lycopersicum L.). Metals were applied in five concentrations (20, 65, 110, 175, and 220 ppm) and Hoagland solution was used to feed the seedlings. Irrespective of the tested crop seeds, copper revealed maximum effect (51.2%) on germination followed by lead (47.5%) and cadmium (35.3%). Tomato seeds were most sensitive in germination stage followed by pea and wheat. In seedling stage, tomato also showed highest sensitivity to both Cd and Cu. However, pea seedlings showed higher tolerance to Pb and wheat seedlings had the highest tolerance to both Cu and Cd. Toxicity and tolerance of metals was found to vary with crops and growth stages. Higher transfer of metals (Pb, Cd, and Cu) in wheat seedling indicates higher risk of food chain contamination when grown in polluted soil. Higher mobility and uptake of Cd in tomato and wheat seedlings even under lower concentration of exposure needs further study.

Green sorption media, which includes the utilization of renewable and recycled materials, can be used as a means for nutrient and copper removal in various low-impact development facilities. In this study, a green sorption media mixture consisting of recycled tire chip, expanded clay, and coconut coir was physiochemically evaluated for copper removal potential in stormwater runoff to deepen the understanding of its application potential. Isotherm, reaction kinetics, and life expectancy tests were conducted using both the media mixture and the individual components of the green sorption media. In addition, the media mixture was analyzed to determine its life expectancy. Isotherm test results revealed that the media mixture follows the Freundlich model and that the coconut coir had the highest affinity for copper. Distinct dynamic adsorption models were explored to determine the most suitable model for implementation based on a column test data set. Five dynamic adsorption models, including the Thomas, Clark, Bohart-Adams, Wolborska, and modified dose-response models, were investigated and the media mixture data collected in the column test were fitted into these five models, leading to the selection of the best model with the highest correlation. The modified dose-response model outperformed others in terms of the overall media mixture and the coconut coir. Life expectancy estimation showed that the media mixture has a life span of 2.13 years with the chosen influent conditions and can be applicable for improving the performance of water quality management in stormwater detention and retention ponds, bioswale, and other stormwater best management practices.

The ozonation process is efficient in degrading aromatic substances and substances with unsaturated bonds, but cannot effectively destroy small-molecule organic compounds, which accumulate. Likewise, the Fenton process is a classic wastewater treatment method, but requires strict pH control and produces secondary pollution when the concentration of organic substances is high. In this study, we applied a 1stO₃-2ndFenton sequential process to treat diazodinitrophenol (DDNP) industrial wastewater and provide suitable reaction conditions for Fenton process. For the 1stOzone process, organics removal increased as O₃ dosage increased. At optimized operation, the 1stO₃ process provided an acidic effluent (pH = 3) and reduced the organics concentration to a level suitable for the 2ndFenton process. Benzene ring substances as well as nitro group and diazo group compounds were greatly degraded in the 1stO₃ process and were further mineralized in the 2ndFenton process. Additionally, the biodegradability of DDNP industrial wastewater was greatly improved. This is the first reported time that ozonation and the Fenton process have been integrated sequentially to treat an explosive production wastewater. The study provides a feasible chemical oxidation method for treating DDNP industrial wastewater by simply combining two classic treatment processes.

A fast sol-dipping-gel method was applied to load Ag and TiO₂ nanoparticles on the surface of crayfish shell biochar to make an inexpensive and novel nanocomposite. Tetra-n-butyl titanate (Ti(OC₄H₉)₄) and silver nitrate (AgNO₃) were used as the nanoparticle precursors. Crayfish shell was pyrolyzed to produce the biochar host. Paper-disk diffusion method was applied to measure antibacterial activities of the nanocomposites to E. coli. The maximum loading rate of TiO₂ and Ag nanoparticles on the biochar reached 7.54% and 3.20%, respectively. Results of long-term antibacterial effect experiment showed that the Ag-TiO₂-biochar had robust antibacterial activity and could be reused for multiple times. The inactivation of E. coli of initial concentration of 10⁵ CFU/mL by Ag-TiO₂-biochar under solar light reached around 99% of sterilization ratio in 5 min. In addition, the antibacterial ability of the nanocomposite was better in light than that in dark due to the presence of TiO₂. Findings of this study suggest that the novel nanocomposite is a promising material for water treatment units and household water purifiers.

In this paper, a conceptual model was developed to predict the seepage of oil sands process-affected water with capabilities of evaluating the transport and attenuation of naphthenic acids through the dykes and the foundations of oil sands tailings pond. The model incorporates naphthenic acid diffusion, adsorption, dispersion, advection, and biodegradation, and was modeled through the commercial software tools to predict naphthenic acid fate in both spatial and time scales. The tailing pond of the Muskeg River Mine in the Athabasca oil sands deposit was investigated in the case study. The comparison between the onsite monitoring data and the simulation results was in good agreement. In addition, limiting factors for migration of naphthenic acid were also discussed based on a parametric sensitivity study.

This study proposed the optimization of a laccase-mediator system to reduce pesticide levels (bentazone, carbofuran, diuron, clomazone, tebuconazole, and pyraclostrobin) on aqueous medium. Firstly, the mediator concentration of 1 mM was established (average removal of 36%). After that, seven redox-mediating compounds, namely, 2,20-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, caffeic acid, chlorogenic acid, p-coumaric acid, ferulic acid, gallic acid, protocatechuic acid, and vanillin, were compared regarding their removal efficiency. The highest removal (77%) was achieved with the laccase-vanillin system. After this screening, the optimization was carried out by a 2² full factorial design. Variables under study were the enzyme (laccase) activity and vanillin concentration. Maximum removal (53–85%) was achieved with 0.95 U/mL laccase and 1.8 mM vanillin. Pesticide removal in reaction media was fitted to the first-order kinetics equation with an average half-time life of 2.2 h. This is the first study of the use of this natural compound as a mediator in the degradation of the pesticides under investigation. The results of this study contribute, with alternative methods, to decrease pesticide levels since they are highly persistent in aqueous samples and, as a result, mitigate the environmental impact.

Ambient particulate matter (PM) pollution has been linked to elevated mortality, especially from cardiovascular diseases. However, evidence on the effects of particulate matter pollution on cardiovascular mortality is still limited in Lanzhou, China. This research aimed to examine the associations of daily mean concentrations of ambient air pollutants (PM₂.₅, PMC, and PM₁₀) and cardiovascular mortality due to overall and cause-specific diseases in Lanzhou. Data representing daily cardiovascular mortality rates, meteorological factors (daily average temperature, daily average humidity, and atmospheric pressure), and air pollutants (PM₂.₅, PM₁₀, SO₂, NO₂) were collected from January 1, 2014, to December 31, 2017, in Lanzhou. A quasi-Poisson regression model combined with a distributed lag non-linear model (DLNM) was used to estimate the associations. Stratified analyses were also performed by different cause-specific diseases, including cerebrovascular disease (CD), ischemic heart disease (IHD), heart rhythm disturbances (HRD), and heart failure (HF). The results showed that elevated concentration of PM₂.₅, PMC, and PM₁₀ had different effects on mortality of different cardiovascular diseases. Only cerebrovascular disease showed a significant positive association with elevated PM₂.₅. Positive associations were identified between PMC and daily mortality rates from total cardiovascular diseases, cerebrovascular diseases, and ischemic heart diseases. Besides, increased concentration of PM₁₀ was correlated with increased death of cerebrovascular diseases and ischemic heart diseases. For cerebrovascular disease, each 10 μg/m³ increase in PM₂.₅ at lag4 was associated with increments of 1.22% (95% CI 0.11–2.35%). The largest significant effects for PMC on cardiovascular diseases and ischemic heart diseases were both observed at lag0, and a 10 μg/m³ increment in concentration of PMC was associated with 0.47% (95% CI 0.06–0.88%) and 0.85% (95% CI 0.18–1.52%) increases in cardiovascular mortality and ischemic heart diseases. In addition, it exhibited a lag effect on cerebrovascular mortality as well, which was most significant at lag6d, and an increase of 10 μg/m³ in PMC was associated with a 0.76% (95% CI 0.16–1.37%) increase in cerebrovascular mortality. The estimates of percentage change in daily mortality rates per 10 μg/m³ increase in PM₁₀ were 0.52% (95% CI 0.05–1.02%) for cerebrovascular disease at lag6 and 0.53% (95% CI 0.01–1.05%) for ischemic heart disease at lag0, respectively. Our study suggests that elevated concentration of atmospheric PM (PM₂.₅, PMC, and PM₁₀) in Lanzhou is associated with increased mortality of cardiovascular diseases and that the health effect of elevated concentration of PM₂.₅ is more significant than that of PMC and PM₁₀.

The increasing trend of nanoparticle usage in science and technology has led to significant human exposure. Occupational exposure to iron oxides and silica dust has been reported in mining, manufacturing, construction, and pharmaceutical operations. The combined toxicological effects of nanoparticles and simultaneous exposure to other compounds have given rise to a new concern. Hence, the objective of this study was to investigate the toxicological effects of magnetite and polymorphous silicon dioxide nanoparticles in single and combined exposures. The polymorphous silicon dioxide nanoparticles were obtained from the milled quartz particles under 100 nm in diameter. The milled particles were purified through chloric and nitric acid wash processes. The toxic effects of the magnetite nanoparticles were investigated independently and in combination with quartz using the A₅₄₉ cell line for durations of 24 and 72 h, and using diverse concentrations of 10, 50, 100, and 250 μg/mL. MTT, ROS, mitochondrial membrane potential, and cell glutathione content assays were used to evaluate the amount of cell damage in this study. The statistical significance level in one-way ANOVA and independent t test was considered to be at the 5% confidence level. The size and purity of polymorphous silicon dioxide nanoparticles were measured by TEM and ICP-OES analysis, respectively. The particles’ diameters were under 100 nm and demonstrated a purity of higher than 99%. The toxicity results of this study showed a dependency on concentration and exposure duration in reducing the cell viability, cellular glutathione content, and mitochondrial membrane potential, as well as increasing the ROS generation in single and combined exposures with magnetite and polymorphous silicon dioxide nanoparticles. The toxic effects of combined exposure to these nanoparticles were less than the single exposures, and statistically significant antagonistic interactions were detected. Combined exposure to polymorphous silicon dioxide and magnetite nanoparticles, in comparison with their single exposures, could affect health in an antagonistic manner. Since this study has been the first of its kind, further studies investigating the health effects of single and combined exposures to these compounds are needed to verify our findings. Generally, studies such as this one could contribute to the field of combined toxicity effects.

Human health and well-being are strongly linked to the state of the environment. The high industrial pressure present in the Province of Brescia, located in Northern Italy, produced strong environmental and health concerns. This narrative review of the literature aims at identifying the studies focused on the association between exposure to environmental pollutants and health effects in the population living in this area. Thirteen papers fitted the inclusion criteria: five were focused on the connection among pollutants present in air matrix and health effects, seven on both air and soil, and one on soil. No study investigated the relationship with water pollution. The great variability in the analyzed end-points made it difficult to draw precise conclusions, but the fact that, in almost all the studies, the investigated health effects have a positive association with the exposure to different kinds of pollutants, allows us to hypothesize that the considered population is living in an area where the “environmental pressure” could produce significant health effects in the future.