Tetrabromobisphenol-A (TBBPA) is an emerging organic pollutant and a commonly used brominated flame retardant that has received much attention owing to its toxicity. Although TBBPA is ubiquitously detected in atmospheric particulate matter and dust, few studies have investigated the sub-chronic inhalation exposure to TBBPA. To further understand the excretion characteristics and tissue accumulation of TBBPA after inhalation exposure, we used the rat model to conduct a sub-chronic inhalation exposure study. Male rats were administered with different doses of aerosol TBBPA (12.9, 54.6, 121.6, and 455.0 mg/m³). TBBPA was found in the excretion (feces and urine) and all the target tissues (lung, liver, heart, thymus gland, spleen, testicles, muscles, kidneys, brain and serum). Feces were the main route of excretion, which contributed 19.18% to 72.54% (urine <0.10%). TBBPA excretion through feces following inhalation administration was much higher than that following oral and dermal exposure, thereby indicating lower bioavailability of TBBPA under inhalation exposure. Liver and serum showed higher levels of TBBPA compared with those of other tissues, thereby suggesting tissue-specific accumulation of TBBPA in rats. Owing to the relative non-invasiveness of serum sampling and greatest TBBPA concentration among the tissues, serum is a suitable matrix for estimation of TBBPA bioaccumulation after inhalation exposure.

Volatile organic compounds (VOCs) are important precursors of ozone (O₃) and secondary organic aerosols (SOAs). Tracing VOC pollution sources is important for controlling VOC emissions and reducing O₃ and SOAs. We built a novel mobile proton transfer reaction mass spectrometry (M-PTR-MS) instrument to image the distribution of VOCs and trace their emission sources in cities and industrial parks. The M-PTR-MS is composed of a vibration-resistant proton transfer reaction mass spectrometry (PTR-MS) with a global positioning system receiver, modified box vehicle, and geographic information system (GIS) software. The PTR-MS, mounted on a vehicle, sends VOC data and vehicle position information to the GIS software. These data are used to image the space distribution of VOCs in real time while the vehicle platform is in motion and the VOC sources are precisely traced using the GIS. The spatial data resolution of the M-PTR-MS is typically 0.8 m. The limits of detection, sensitivity, and repeatability of the M-PTR-MS are 43.5 ppt, 347 counts ppb⁻¹, and 2.4% (RSD, n = 5), respectively. The intensity of reagent ions is stable over 8 h (RSD = 0.45%). Compared with commercial PTR-MS equipment, the M-PTR-MS demonstrated high consistency, with a correlation coefficient of 92.665%. Several field experiments were conducted in China using the M-PTR-MS. In one field experiment, the VOC distribution along three different routes was surveyed; the navigation monitoring lasted 1.8 h over a distance of 26.7 km at an average speed of 15 km h⁻¹. The VOC sources in an industrial park were identified by analyzing the components near different factories. The main species from a VOC source in an underground garage was related to paint. The M-PTR-MS instrument can be used by environmental protection agencies to trace VOC pollution sources in real time, and by researchers to survey VOC emissions in regions of concern.

Polystyrene nanoplastics (PS NPs), which are newly emerging as particulate pollutants, are one of the most abundant plastic types in marine debris. Although there has been extensive research on microplastics, the sorption behavior of PS NPs in surface waters remains unknown. In addition, in the previous joint toxicity studies, the concentration of organic pollutant in the joint system was based on the EC₅₀ of this pollutant, rather than the actually amount of this pollutant adsorbed on nanoplastics (NPs). In this study, the sorption behavior of PS NPs with different surface charges in the surface water of estuaries and joint toxicity of that absorbed tetracycline antibiotic in equilibrium were investigated for the first time. Because of the electrostatic repulsion, salting-out effect, and partition function, the sorption capacity of tetracycline antibiotic by differently charged PS NPs was enhanced with increasing salinity. The biological effects of exposure to tetracycline-saturated PS NPs were complicated, which can be attributed to the surface characteristics of mixtures such as hydrophobicity and charges. Thus, the role of NPs in the natural environment as a carrier of antibiotics may provide an alternative for antibiotic inputs from inland water to coastal marine water, which would not only change the environmental fate and ecotoxicology of antibiotics and NPs, but also pose challenges to the safety of coastal aquaculture and marine ecosystem.

Cyanobacterial blooms and their secondary metabolites, microcystins (MCs), are not only toxic to aquatic organisms, but also to humans. MCs exert reproductive toxicity in female fish by affecting the oocyte development. However, the mechanism behind MC-LR interference in oocyte development remains largely unknown. In our study, adult female zebrafish were exposed to MC-LR (0, 1, 5, 20 μg/L) for 30 d. After exposure to MC-LR for 30 d, fertilized eggs from the treated females and healthy males were collected and cultured in water without MC-LR. Histomorphological observations showed pathological damage in the ovary after MC-LR exposure, which was mainly characterized by enlarged intercellular spaces, detachment of follicular cells from oocytes, and vacuolation of parenchymal tissues. The 20 μg/L MC-LR treatment caused a remarkable increase in the rate of the zebrafish oocytes germinal vesicle breakdown (GVBD) and a significant decrease in the levels of cyclic adenosine monophosphate (cAMP) and vitellogenin (VTG). In addition, the phosphorylation levels of the extracellular signal-regulated kinases (ERK) were elevated in ovaries from zebrafish exposed to 5 and 20 μg/L MC-LR, and cyclinB phosphorylation levels were also upregulated notably in the 20 μg/L MC-LR group. However, MC-LR exposure did not cause any change in the levels of cAMP-dependent protein kinase (PKA) protein and cdc2 phosphorylation in all the treatments. All the doses of MC-LR reduced the number of eggs, prematurely hatched the fertilized eggs and increased the abnormal rate of offspring generation. In summary, the present study demonstrates that MC-LR promotes oocyte maturation by activating the ERK1/2 and MPF signaling pathways, and cAMP is involved in this process.

Addressing the presence of rutile nanoparticles (NPs) in the air is a work in progress, and the development of methodologies for the identification of NPs in atmospheric dust is essential for the assessment of its toxicological effects. To address this issue, we selected the fast growing desertic city of Hermosillo in northern Mexico. Road dust (n = 266) and soils (n = 10) were sampled and bulk Ti-contents were tested by portable X-ray fluorescence. NPs were extracted from atmospheric dust by PM₁.₀-PTFE filters and further characterized by Confocal Raman Microscopy, Energy-dispersive X-ray spectroscopy (EDS) coupled to Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). Results showed (i) the average concentration of Ti in road dust (3447 mg kg⁻¹) was similar to natural values and worldwide urban dusts; (ii) the bulk geochemistry was not satisfactory for Ti-NPs identification; (iii) 76% of the total extracted PM₁.₀ sample corresponded to NPs; (iv) mono-microaggregates of rutile NPs were identified; (v) ubiquitous polycyclic aromatic hydrocarbons (PAHs) were linked to NPs. The genotoxicity of rutile and PAHs, in connection with NPs content, make us aware of a crucial emerging environmental issue of significant health concern, justifying further research in this field.

To characterise the mass concentration, size-distribution, and respiratory deposition of selected trace metals (Cr, Mn, Fe, Ni, Cu, Zn, Ba, and Pb) in size-segregated PM₂.₅, a long-term monitoring campaign was undertaken at an urban background site in Como (Northern Italy). 96-h aerosol samples were collected weekly, from May 2015 to March 2016, using a 13-stage low pressure impactor and analysed via laser ablation-inductively coupled plasma-mass spectrometry. Significantly higher levels of trace metals were generally found during the heating season (two to more than four times) compared to the non-heating period at all size ranges, especially for concentrations in PM₀.₁–₁. Distinct distribution profiles characterised the different elements, even though the corresponding heating and non-heating shapes always exhibited similar features, with negligible seasonal shifts in the average mass median aerodynamic diameters. Fe, Ba, and Cu had >70% of their mass in PM₁–₂.₅, whereas Pb, Zn, and Ni showed higher contributions in the accumulation mode (>60%). Finally, broad size-distributions were found for Cr and Mn. The multiple-path particle dosimetry model estimated the overall deposition fractions in human airways varying between 27% (Pb) and 48% (Ba). The greatest deposition variability was always registered in the head region of the respiratory system, with the highest contributions for those metals predominantly accumulated in the PM₂.₅ coarse modes. In contrast, the deposition in the deepest respiratory tract maintained nearly constant proportions over time, becoming notably important for Pb, Ni, and Zn (∼13%) with respect to their total deposition. The comparison with national limits established for Pb and Ni suggested the absence of significant risks for the local population, as expected, with average concentrations two orders of magnitude lower than the corresponding annual limit and objective value. Similar findings were reported for all the other metals, for which the estimated hazard quotients were always well <1.

Hydrophobic pollutants are still present in agricultural soil. The Cucurbitaceae family accumulates hydrophobic pollutants through roots, resulting in the contamination of aerial parts. Major latex-like proteins (MLPs), found in the Cucurbitaceae family, play an important role in the contamination by binding to these hydrophobic pollutants. Thus far, efficient cultivation methods for the production of safe crops with lower concentrations of hydrophobic pollutants have not been developed. Herein, we competitively inhibited the binding of MLPs to hydrophobic pollutants, pyrene and dieldrin, in roots by using MLP binding pesticides. By conducting a chemical array screening, we found that MLPs bound compounds with indole- and quinazoline-like structures. Commercially available pesticides amisulbrom and pyrifluquinazon, which possess such structures, successfully inhibited the binding of MLPs to pyrene and dieldrin in vitro. When zucchini plants were cultivated in the contaminated soil with 1.25 mmol/kg pyrene and 12.5 μmol/kg dieldrin, the concentration of pyrene and dieldrin in xylem sap was significantly decreased by 30% and 15%, respectively. Our results demonstrate that the pesticides binding to MLPs competitively inhibited the binding of MLPs to pyrene and dieldrin in roots, resulting in the reduction of overall contamination. This study proposes a novel approach to cultivate safer crops and advances the utilization of unknown functions of pesticides.

Many reliable studies have provided evidence of microplastic ingestion by soil organisms. However, further research is required to determine the edible size of microplastics, especially given the ubiquity of microplastics and their adverse effects on the soil environment. Determining the size range of microplastics that can be ingested by soil organisms is crucial for the prediction of the exposure route and toxicity mechanisms of microplastics in soil. Springtails, organisms prevalent in a wide variety of soil ecosystems, can ingest or transport microplastics; however, direct evidence for this has not been reported. To address this knowledge gap, we designed dietary exposure experiments under laboratory conditions, using the springtail species Folsomia candida. The springtails were administered polyethylene microplastics in three different sizes (2, 34, and 66 μm) via their food for a short period of time; we further observed the intestinal presence of microplastics via fluorescence microscopy to determine the maximum edible size. We evaluated the effects of ingested microplastics on springtails by quantifying their moving behavior. The results show that the edible size of microplastics is < 66.0 ± 10.9 μm, and microplastics smaller than this can significantly reduce the velocity and distance of springtail movement by 74% ± 38% compared with the control group. Based on this finding, the broader fate and toxicity of microplastics in soil environments can be estimated. Furthermore, the average velocity and distance of springtail movement decreases in response to microplastic ingestion, highlighting the negative effects of microplastics on soil organisms.