In the context of Coronavirus Disease (2019) (COVID-19) cases globally, there is a lack of consensus across cultures on whether wearing face masks is an effective physical intervention against disease transmission. This study 1) illustrates transmission routes of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2); 2) addresses controversies surrounding the mask from perspectives of attitude, effectiveness, and necessity of wearing the mask with evidence that the use of mask would effectively interrupt the transmission of infectious diseases in both hospital settings and community settings; and 3) provides suggestion that the public should wear the mask during COVID-19 pandemic according to local context. To achieve this goal, government should establish a risk adjusted strategy of mask use to scientifically publicize the use of masks, guarantee sufficient supply of masks, and cooperate for reducing health resources inequities.

Due to the abusive usage of antibiotics in animal husbandry, a large amount of residual antibiotics has been released into the environment, therein posing great threat against both environment security and public health. Therefore, it is of great significance to investigate the toxicity of antibiotics on the widely-applied bioindicator-earthworm. In this work, the physiological parameters and the intestinal bacteria community of Metaphire guillelmi were monitored simultaneously to evaluate their sensitivity to the tetracycline (TC) exposure. As expected, the antioxidant enzyme activity and coelomocyte apoptosis acted fairly well as biomarkers for the TC toxicity. In contrast, the intestinal bacteria of Metaphire guillelmi responded varyingly to different TC doses. When TC concentration increased from 0 to 35.7 μg cm⁻², the percentage of the Proteobacteria phylum declined significantly from 85.5% to 34.4%, while the proportions of the Firmicutes, Planctomycetes and Atinomycete phyla clearly increased (p < 0.05). Meanwhile, the levels of TC resistance genes tetA, tetC, and tetW increased with the increasing TC concentration, in contrast to the declined abundance in denitrifying genes nirS and nosZ (p < 0.05). By analyzing the correlation between the antioxidant enzyme activity and the dominant intestinal bacteria in the worm gut, it is interesting to found that the four dominant bacteria genera Mesorhizobium, Aliihoeflea, Romboutsia, and Nitrospira are the promising bioindicator of TC stress due to their sensitive response. This work shed novel light on evaluating the ecotoxicological risks posed by residual TC in environment by using a combination of physiological parameters and intestinal bacterial activity in earthworms.

The ecotoxicology of surfactants is attracting wide attention due to the rapidly expanding global application. As interspecific relationships play one of the central roles in structuring biological communities, it is necessary to take it into risk assessments on surfactants. With this aim, our study investigated the interference of three common surfactants on the inducible defense of a freshwater phytoplankton Scenedesmus obliquus. Nonlethal environmentally relevant concentrations (10 and 100 μg L⁻¹) of several surfactants were set up. Results showed that growth and photosynthetic efficiency of Scenedesmus were inhibited during first 96 h, but recovered in the later stage. Surfactants interfered inducible defense of Scenedesmus against Daphnia grazing, and the interference was related to chemical characteristics of surfactants. The anionic surfactant sodium dodecyl sulfate (SDS) enhanced the colony formation even without grazing cues, whereas fewer defensive colonies were formed under the effects of cationic surfactant benzalkonium bromide (BZK) and nonionic surfactant polyoxyethylene (40) nonylphenol ether (NPE). These findings highlighted the sensitivity of grazer-induced morphological defense of Scenedesmus to surfactants even at nonlethal concentrations, which potentially affects the energy and information flow between trophic levels. This study appeals for more attention to take interspecific relationships into consideration in assessing the potential ecological risk of pollutants.

Our knowledge of the processes leading to the bioaccumulation of rare earth elements (REE) in aquatic biota is limited. As the contamination of freshwater ecosystems by anthropogenic REE have recently been reported, it becomes increasingly urgent to understand how these metals are transferred to freshwater organisms in order to develop appropriate guidelines. We exposed rainbow trout (Oncorhynchus mykiss) to an REE, yttrium (Y), to either a range of Y-contaminated prey (Daphnia magna) or a range of Y-contaminated water. For the feeding experiment, the relationship between the Y assimilation by O. mykiss and the Y subcellular fractionation in D. magna was evaluated. Assimilation efficiency of Y by O. mykiss was low, ranging from 0.8 to 3%. These values were close to the proportion of Y accumulated in D. magna cytosol, 0.6–2%, a theoretical trophically available fraction. Moreover, under our laboratory conditions, water appeared as a poor source of Y transfer to O. mykiss. Regardless of the source of contamination, a similar pattern of Y bioaccumulation among O. mykiss tissues was revealed: muscles < liver < gills < intestine. We conclude that the trophic transfer potential of Y is low and the evaluation of Y burden in prey cytosol appears to be a relevant predictor of Y assimilation by their consumers.

The Changjiang (Yangtze River) River estuary (CRE) and its adjacent coastal waters is a notable region for nutrient pollution, which results in severe problems of coastal eutrophication and harmful algal blooms (HABs). The occurrence of HABs, particularly those of dinoflagellate Alexandrium spp. capable of producing paralytic shellfish toxins (PSTs), has an increasing risk of contaminating seafood and poisoning human-beings. The investigation of PSTs, however, is often hampered by the relatively low abundance of Alexandrium spp. present in seawater. In this study, a monitoring strategy of PSTs using net-concentrated phytoplankton from a large volume of seawater was employed to examine spatiotemporal variations of PSTs in the CRE and its adjacent waters every month from February to September in 2015. Toxins in concentrated phytoplankton samples were analyzed using high-performance liquid chromatography coupled with a fluorescence detector (HPLC-FLD). The results showed that PSTs could be detected in phytoplankton samples during the sampling stage in the CRE and its adjacent waters. Toxin content increased gradually from February to May, reached the peak in June, and then decreased rapidly from July to September. The maximum value of PST content was 215 nmol m⁻³ in June. Low-potency toxins N-sulfocarbamoyl toxins 1/2 (C1/2) were the most dominant components of PST in phytoplankton samples from February to June in 2015, while high-potency gonyautoxin 4 (GTX4) became the dominant component from July to September. Toxins were mainly detected from three regions, the sea area north to the CRE, the sea area east to the CRE, and sea area near Zhoushan Island south to the CRE. Based on the results of this study, it can be inferred that the three regions around the CRE in May and June is of high risk for PST contamination and seafood poisoning.

Particulate air pollution in cities comprises a variety of harmful compounds, including fine iron rich particles, which can persist in the air for long time, increasing the adverse exposure of humans and living things to them. We studied street tree (among other species, Cordyline australis, Fraxinus excelsior and F. pensylvanica) barks as biological collectors of these ubiquitous airborne particles in cities. Properties were determined by the environmental magnetism method, inductively coupled plasma optical emission spectrometry and scanning electron microscopy, and analyzed by geostatistical methods. Trapped particles are characterized as low-coercivity (mean ± s.d. value of remanent coercivity Hcᵣ = 37.0 ± 2.4 mT) magnetite-like minerals produced by a common pollution source identified as traffic derived emissions. Most of these Fe rich particles are inhalable (PM₂.₅), as determined by the anhysteretic ratio χARM/χ (0.1–1 μm) and scanning electron microscopy (<1 μm), and host a variety of potentially toxic elements (Cr, Mo, Ni, and V). Contents of magnetic particles vary in the study area as observed by magnetic proxies for pollution, such as mass specific magnetic susceptibility χ (18.4–218 × 10⁻⁸ m³ kg⁻¹) and in situ magnetic susceptibility κᵢₛ (0.2–20.2 × 10⁻⁵ SI). The last parameter allows us doing in situ magnetic biomonitoring, being convenient because of species preservation, measurement time, and fast data processing for producing prediction maps of magnetic particle pollution.

Cyanobacterial blooms are an increasing problem in a more eutrophic world. It is still a challenge to fully understand the influence of cyanobacteria on the interactions between predator and prey at higher trophic levels. The present study was mainly undertaken to understand the inducible anti-predator responses of cladocerans while using cyanobacteria as part of food. Specifically speaking, we focused on the anti-predator strategies of Ceriodaphnia cornuta in response to different predators (fish and Chaoborus larvae) under food with different proportions of Microcystis aeruginosa. The morphological (i.e., body size and the induction of horns) and life history traits (e.g., time to first reproduction, offspring number, and survival time) responses were measured under different proportions of M. aeruginosa (i.e., 0%, 20%, 40%, 60%, 80%, and 100%). Our results showed that both the life history and the inducible anti-predator responses of C. cornuta were significantly affected by different concentrations of M. aeruginosa. Specifically, lower concentrations of Microcystis (20%–60%) can significantly promote the horns induction under Chaoborus predation risks, and higher Microcystis concentrations (60%–100%) tend to enhance reproduction in response to fish predation risks, such as larger body size, decreased time to first reproduction, and increased total offspring number. Additionally, an increasing concentration of M. aeruginosa decreased the ability of C. cornuta to reverse horns when predation risks removed. Our findings indicated that cyanobacteria affecting life history traits and the subsequent indirect effects on anti-predator responses in cladocerans could impact the interactions between predator and prey at higher trophic levels and may consequently contribute to shaping the structure of the community in a cyanobacteria bloom area.

The influenza is a common viral infection that can be fatal, especially in high-risk groups such as children, pregnant women, elderly, and immune-deficient individuals. Vaccination is the most efficient approach to prevent the spreading of viral infection and promote individual and public health. In contrast, exposure to environmental pollutants such as cigarette smoke reduces the efficacy of vaccination. We investigated whether chronic exposure to hydroquinone (HQ), the most abundant compound of the tobacco particulate phase, could impair the adaptive immune responses elicited by influenza vaccination. For this, adult male C57BL/6 mice were daily exposed to either nebulized HQ or PBS for 1 h for a total of eight weeks. At weeks 6 and 8, the mice were primed and boosted with the trivalent influenza vaccine via IM respectively. Although the HQ exposure did not alter the body weight of the mice and the biochemical and hematological parameters, the pollutant increased the oxidative stress in splenocytes of immunized animals, modified the morphology of spleen follicles, and augmented the size of their lymph nodes. The lymphoid organs of HQ-exposed mice presented a similar number of vaccine-specific IgG-secreting cells, titers of vaccine-specific total IgG, and respective subclasses. Transcriptome studies with HQ, benzene, or cigarette smoke exposure were also analyzed. The genes up-regulated upon pollutant exposure were associated with neutrophil migration and were shown to be co-expressed with antibody-secreting cell genes. Therefore, these findings suggest that HQ exposure may trigger an immune-compensatory mechanism that enhances the humoral responses induced by influenza vaccination.

Atmospheric nitrogen (N) deposition is believed to accelerate dissolved organic carbon (DOC) production and could lead to increased heavy metal mobility into water resources. We sampled intact soil cores from the Isle of Skye with low background N deposition history and having Serpentine rock known for its higher heavy metal concentrations including zinc (Zn), copper (Cu), nickel (Ni) and lead (Pb). The effects of 16 (16kgN) and 32 kg N ha⁻¹ year⁻¹ (32kgN), and liming with 32kgN (32kgN+Lime) on soil solution chemistry and heavy metal mobilization were investigated over the 15-month study. Nitrogen in deposition load was added at five ammonium (NH₄⁺) to nitrate (NO₃⁻) ratios of 9:1, 5:1, 1:1, 1:5 and 1:9 along NO₃⁻dominance. We found significant effects of load on Cu and NH₄⁺/NO₃⁻ ratio on pH, DOC and Zn in soil solution. However, under lime and ratio experimental factors, liming significantly influenced pH, DOC, Cu and Pb, and NH₄⁺/NO₃⁻ ratio pH, DOC, Ni and Zn whereas interactions between lime and ratio was significant for Ni and Cu. pH and DOC increased with N load, liming and NO₃⁻ dominance, and both correlated significantly positively. Liming under NH₄⁺ dominance enhanced DOC production due to supply of base cations in lime. Mobilization of Cu, Ni and Pb was driven by DOC concentrations and, therefore, increased with load, liming and NO₃⁻ dominance in deposition. However, in contrast, low pH and high NH₄⁺ dominance was associated with Zn mobilization in soil solution. On the contrary, despite of some patterns, heavy metals in soil HNO₃ extracts were devoid of any load, lime and NH₄⁺/NO₃⁻ ratio effects. Our study suggests that the effects of N load and forms in deposition on sites with high accumulated loads of metals need to be better quantified through soil solution partitioning models.

Solutions of technical polychlorinated naphthalene (PCN) Halowax formulations (Halowax 1014 and Halowax 1051) diluted with Milli-Q water and sealed in the Pyrex glass tubes and quartz tubes were subjected to artificial solar and natural solar irradiation under different time intervals and field conditions. In particular, the results of several field irradiation experiments have shown increased PCN photodegradation as altitude increases above sea level. Irradiation in artificial solar conditions caused a substantial change in the PCN congener profiles of Halowax 1014 and Halowax 1051 test solutions. Interestingly, in long-term experiments, the relative abundance of congeners that contribute to dioxin-like activity, i.e. the compounds such as 1,2,3,5,7- and 1,2,4,6,7-PentaCN (PeCNs #52/60), 1,2,3,4,6,7- and 1,2,3,5,6,7-HexaCN (HxCNs #66/67), and 1,2,3,4,5,6,7-HeptaCN (HpCN #73), temporally increased substantially. In the field photodegradation experiments, the PCNs #52/60 and #66/67 were formed, while a relative persistence of PCN #73 was evident. Highest chlorinated octachloronaphthalene (OcCN #75), exposed to strong UV radiation at high altitude, was much less stable than lower molecular mass PCNs. Photodegradation of the technical PCN formulations produced also an unidentified aromatic compound. We conclude, that photodegradation of PCNs, which are considered as a widespread anthropogenic pollutants, is not restricted to any specific environmental condition. It can also be observed at low altitudes.