In recent years, many studies are focusing on the negative effects of plastic pollution, and in particular on the nanosized plastic fragments and their implications on the environment and human health. Nanoplastics in the environment interact with a great number of substances, many of which are dangerous to humans, but the interaction mechanisms, the complexes formation processes, and their biological impact are still poorly understood. Here we report a study on the interactions of polyethylene terephthalate nanoplastics, produced by laser ablation, with three different types of contaminants: glyphosate, levofloxacin and Hg²⁺ ions, and we demonstrate that the nanoplastics form complexes with all three contaminants through their favorable binding. Most importantly, this study highlights that to demonstrate the overall effect of the nanoplastics internalized by cells in vitro, it is important to combine alternative methodologies, such as metabolomics, with standard biological assays (i.e., cell viability and ROS production). In this way it becomes possible to better understand the body’s response to this new class of pollutants and their possible chronic toxicity.Summary: PET nanoplastics, fabricated by laser ablation, interact with aqueous pollutants forming nanoclusters. The nanoclusters affect the cells metabolism, suggesting long-term risks.

This experiment was conducted to evaluate the ecotoxicity of typical explosives and their mechanisms in the soil microenvironment. Here, TNT (trinitrotoluene), RDX (cyclotrimethylene trinitramine), and HMX (cyclotetramethylene tetranitramine) were used to simulate the soil pollution of single explosives and their combination. The changes in soil enzyme activity and microbial community structure and function were analyzed in soil, and the effects of explosives exposure on the soil metabolic spectrum were revealed by non-targeted metabonomics. TNT, RDX, and HMX exposure significantly inhibited soil microbial respiration and urease and dehydrogenase activities. Explosives treatment reduced the diversity and richness of the soil microbial community structure, and the microorganisms able to degrade explosives began to occupy the soil niche, with the Sphingomonadaceae, Actinobacteria, and Gammaproteobacteria showing significantly increased relative abundances. Non-targeted metabonomics analysis showed that the main soil differential metabolites under explosives stress were lipids and lipid-like molecules, organic acids and derivatives, with the phosphotransferase system (PTS) pathway the most enriched pathway. The metabolic pathways for carbohydrates, lipids, and amino acids in soil were specifically inhibited. Therefore, residues of TNT, RDX, and HMX in the soil could inhibit soil metabolic processes and change the structure of the soil microbial community.

Microplastic contamination in ecosystems has emerged as an environmental issue of global significance. This research quantified microplastics in oysters from 22 sites along Taiwan coastlines. In total, 6630 microplastic items were found in 660 oysters of two genera (Crassostrea and Saccostrea). The average content of microplastics was 3.24 ± 1.02 items/g (wet weight), ranging from 0.63 ± 0.52 items/g to 37.94 ± 19.22 items/g. Over half of the microplastics were smaller than 100 μm, and the most common shape was fragments (67%), followed by fibers (29%). The dominant color was transparent (49.76%), followed by black (25.66%). Polymer types were identified using a μRaman microscope, and the major component was polyethylene terephthalate (PET) (69.54%). Microplastic contamination was higher overall in wild than in farmed oysters. In addition, the microplastic content of oysters from northeastern waters was significantly greater than that of other oysters; this result is similar to the findings of previous research on floating marine litter and beach cleaning data. The results indicated that the average content of microplastic in oysters along the Taiwan coastline was similar to that in oysters in adjacent regions. This study suggests that innovative technologies should be implemented for monitoring and removing pollution, tracking marine pollution origins, and improving accountability and that plastic limitation strategies should be strengthened.

Natural photic regime has been drastically altered by the artificial night sky luminance. Despite evidence of sufficient light brightness inducing plant physiology and affecting phenology, generalization regarding effects of light pollution on plant phenology across species and locations is less clear. Meanwhile, the relative contributions and joint effects of artificial light pollution and climate change or other anthropic stressors still remain unknown. To fill this knowledge gap, we utilized in situ plant phenological observations of seven tree species during 1991–2015 in Europe, night-time light dataset and gridded temperature dataset to investigate the impacts of the artificial light pollution on spatial-temporal shifts of plant phenological phases under climatic warming. We found 70% of the observation sites were exposed to increased light pollution during 1992–2015. Among them, plant phenological phases substantially delayed at 12–39% observation sites of leaf-out, and 6–53% of flowering. We also found plant species appeared to be more sensitive to artificial light pollution, and phenology advancement was hindered more prominently and even delay phenomenon exhibited when the color level showed stronger sky brightness. Linear mixed models indicate that although temperature plays a dominant role in shifts of plant phenological phases at the spatial scale, the inhibitory effect of artificial light pollution is evident considering the interactions. To our knowledge, this study is the first to quantitatively establish the relationship between artificial light pollution and plant phenology across species and locations. Meanwhile, these findings provide a new insight into the ecological responses of plant phenology to the potential but poorly understood environmental stressors under this warmer world and call for light pollution to be accorded the equal status as other global change phenomena.

Atrazine is an herbicide commonly used in several countries. Due to its long half-life, associated with its use in large scales, atrazine residues remain as environmental pollutants in water bodies. Phytoremediation is often pointed out as an interesting approach to remove atrazine from the aquatic environment, but its practical application is limited by the high toxicity of this herbicide. Here, we characterize the damages triggered by atrazine in Pistia stratiotes, evaluating the role of nitric oxide (NO), a cell-signaling molecule, in increasing the tolerance to the pollutant and the phytoremediation potential of this species. Pistia stratiotes plants were exposed to four treatments: Control; Sodium nitroprusside (SNP) (0.05 mg L⁻¹); Atrazine (ATZ) (150 μg L⁻¹) and ATZ + SNP. The plants remained under those conditions for 24 h for biochemical and physiological analysis and 3 days for the evaluation of relative growth rate. The presence of atrazine in plant cells triggered a series of biochemical and physiological damages, such as the increase in the generation of reactive oxygen species, damages to cell membranes, photosynthesis impairment, and negative carbon balance. Despite this, the plants maintained greater growth rates than other aquatic macrophytes exposed to atrazine and showed high bioconcentration and translocation factors. The addition of SNP, a NO donor, decreased the herbicide toxicity, with an increase of over 60% in the IC₅₀ value (Inhibitor Concentration). Indeed, the NO signaling action was able to increase the tolerance of plants to atrazine, which resulted in increments in pollutant uptake and translocation, with the maintenance of overall cell (e.g. membranes) and organs (root system) structure, and the functioning of central physiological processes (e.g. photosynthesis). These factors allowed for more quickly and efficient removal of the pollutant from the environment, reducing costs, and increasing the viability of the phytoremediation process.

During March 2020, most European countries implemented lockdowns to restrict the transmission of SARS-CoV-2, the virus which causes COVID-19 through their populations. These restrictions had positive impacts for air quality due to a dramatic reduction of economic activity and atmospheric emissions. In this work, a machine learning approach was designed and implemented to analyze local air quality improvements during the COVID-19 lockdown in Graz, Austria. The machine learning approach was used as a robust alternative to simple, historical measurement comparisons for various individual pollutants. Concentrations of NO₂ (nitrogen dioxide), PM₁₀ (particulate matter), O₃ (ozone) and Oₓ (total oxidant) were selected from five measurement sites in Graz and were set as target variables for random forest regression models to predict their expected values during the city’s lockdown period. The true vs. expected difference is presented here as an indicator of true pollution during the lockdown. The machine learning models showed a high level of generalization for predicting the concentrations. Therefore, the approach was suitable for analyzing reductions in pollution concentrations. The analysis indicated that the city’s average concentration reductions for the lockdown period were: -36.9 to −41.6%, and −6.6 to −14.2% for NO₂ and PM₁₀, respectively. However, an increase of 11.6–33.8% for O₃ was estimated. The reduction in pollutant concentration, especially NO₂ can be explained by significant drops in traffic-flows during the lockdown period (−51.6 to −43.9%). The results presented give a real-world example of what pollutant concentration reductions can be achieved by reducing traffic-flows and other economic activities.

Historical mining activities cause widespread, long-term trace metal contamination of freshwater ecosystems. However, measuring trace metal bioavailability has proven difficult, because it depends on many factors, not least concentrations in water, sediment and habitat. Simple tools are needed to assess bioavailabilities. The use of biomonitors has been widely advocated to provide a realistic measure. To date there have been few attempts to identify ubiquitous patterns of trace metal accumulation within and between freshwater biomonitors at geographical scales relevant to trace metal contamination. Here we address this through a nationwide collection of freshwater biomonitors (species of Gammarus, Leuctra, Baetis, Rhyacophila, Hydropsyche) from 99 English and Welsh stream sites spanning a gradient of high to low trace metal loading. The study tested for inter-biomonitor variation in trace metal body burden, and for congruence amongst accumulations of trace metals within taxa and between taxa across the gradient. In general, significant differences in trace metal body burden occurred between taxa: Gammarus sp. was the most different compared with insect biomonitors. Bivariate relationships between trace metals within biomonitors reflected trace metal profiles in the environment. Strong correlations between some trace metals suggested accumulation was also influenced by physiological pathways. Bivariate relationships between insect biomonitors for body burdens of As, Cu, Mn and Pb were highly consistent. Our data show that irrespective of taxonomic or ecological differences, there is a commonality of response amongst insect taxa, indicating one or more could provide consistent measures of trace metal bioavailability.

Increasing heavy metal pollution in wetland ecosystems around the world pose significant health risks to waterbirds, especially the endangered species. We analyzed heavy metal pollution in bird foraging area of Caohai wetland in Guizhou Plateau (China), and used an integrated exposure risk model for assessing heavy metal (Cd, Pb, Cr, Ni, Zn, Sb) exposure risk in birds from the soil, water, plants and benthic invertebrates. There is considerable variation in the extent of heavy metal contamination across the different sampling sites, and Cd and Sb are the main contaminants. The mussel Anodonta showed greater heavy metal accumulation (except for Zn) compared to the snail species C. cathayensis. The different plant species also varied in terms of amount for accumulated heavy metals. The phytophagous together with omnivorous birds were exposed to Cd, Pb, Zn and Ni through plants rather than the soil, whereas the maximum Zn exposure in the omnivorous and carnivorous birds was through consumption of benthic invertebrates. Furthermore, the phytophagous black-necked cranes (Grus nigricollis) were less risk to heavy metal exposure compared to the omnivorous bar-headed goose (Anser indicus) and carnivorous ruddy shelducks (Tadorna ferruginea). The exposure risk of Cr (8.1) was highest, followed by Pb (5.1), Zn (3.8), Sb (1.0), Cd (0.33) and Ni (0.28). The heavy metal assessment heavy metal exposure risk for migratory birds should take into account the exposure from food and soil. Our findings provide new insights into developing measures to minimize heavy metal contamination in migratory birds.

The contamination of the aquatic environment by plastic nanoparticles is becoming a major concern due to their potential adverse effects in aquatic biota. Therefore, in-depth knowledge of their uptake, trafficking and effects at cellular and systemic levels is essential to understand their potential impacts for aquatic species. In this work, zebrafish (Danio rerio) was used as a model and our aims were: i) to determine the distribution, uptake, trafficking, degradation and genotoxicity of polystyrene (PS) NPs of different sizes in a zebrafish cell line; ii) to study PS NPs accumulation, migration of immune cells and genotoxicity in larvae exposed to PS NPs; and iii) to assess how PS NPs condition the survival of zebrafish larvae exposed to a pathogen and/or how they impact the resistance of an immunodeficient zebrafish. Our results revealed that the cellular distribution differed depending on the particle size: the 50 nm PS NPs were more homogeneously distributed in the cytoplasm and the 1 μM PS NPs more agglomerated. The main endocytic mechanisms for the uptake of NPs were dynamin-dependent internalization for the 50 nm NPs and phagocytosis for the 1 μm nanoparticles. In both cases, degradation in lysosomes was the main fate of the PS NPs, which generated alkalinisation and modified cathepsin genes expression. These effects at cellular level agree with the results in vivo, since lysosomal alkalization increases oxidative stress and vice versa. Nanoparticles mainly accumulated in the gut, where they triggered reactive oxygen species, decreased expression of the antioxidant gene catalase and induced migration of immune cells. Finally, although PS NPs did not induce mortality in wild-type larvae, immunodeficient and infected larvae had decreased survival upon exposure to PS NPs. This fact could be explained by the mechanical disruption and/or the oxidative damage caused by these NPs that increase their susceptibility to pathogens.