Environmental Science & Technology Letters Environ.最新文献

Plastic particles (PPs; ≤5 mm diameter) are ubiquitous environmental contaminants, and concerns exist about their potential to impact human health negatively. Public perceptions about seafood contamination by PPs have been shaped by media communications rather than scientific evidence, and these perceptions can inform behavior and public policy inappropriately. Our objective is to challenge perceptions with evidence and to discuss the extent to which concerns of PP contamination of seafoods are justified. Evidence indicates that levels of PPs in seafoods are consistent with those of other foods and beverages and that human exposure to PPs is higher via indoor air and dust than by ingestion of foods and beverages. While uncertainties remain, there is currently minimal evidence of dietary toxicity of PPs and no consumption advisories for PPs. The levels of substances (e.g., toxic contaminants) associated with PPs that may be released upon PP ingestion are often orders of magnitude below levels of toxicological concern. Overattention on PP contamination of seafoods (>70% compared to all other foods combined) in scientific media communications is unjustified and must be rebalanced to avoid misconceptions and loss of beneficial health effects of seafood consumption.

Microplastics (MPs) are widespread emerging environmental pollutants that present significant health risks to humans. While the presence of MPs has been documented in various human tissues, the detection of MP residues in the human retina remains uncertain. Herein, we characterized the types and concentrations of MPs in 12 post-mortem human retinal samples via pyrolysis gas chromatography–mass spectrometry. The size, shape, and morphologies of MP particles in another two post-mortem human retinal samples were further characterized using laser direct infrared spectroscopy and scanning electron microscopy. MPs were detected in all 12 human retinal samples at concentrations ranging from 8.93 to 91.05 μg/g with an average concentration of 49.21 μg/g. Various MPs such as polystyrene (PS), polyethylene (PE), polypropylene (PP), poly(methyl methacrylate), and polyvinyl chloride (PVC) were identified, with PS, PE, PP, and PVC detected in all analyzed samples. The diameters of the MPs detected in the human retinal samples predominantly ranged from 20 to 50 μm, with most particles exhibiting fragmented or fibrous morphologies. This study presents the first detailed qualitative and quantitative analyses of MPs in the human retina, which provides a crucial foundation for future research assessing their potential risks and detrimental impacts on retinal health.

Incomplete burning of solid fuels in residential stoves emits various hazardous air pollutants, including some volatile toxic organic compounds, to ambient and indoor air. Due to high spatiotemporal variations in combustion emissions and household characteristics, indoor pollution of volatile organic compounds (VOCs) is poorly characterized, especially due to a lack of a nationwide assessment. Here, a field campaign was conducted to evaluate indoor emissions of 37 VOCs, including chlorinated hydrocarbons, aromatics, and chlorinated aromatics, for representative fuel-stove combinations in use for China, and real-world emission rates were used to assess indoor VOC pollution using a single-zone model. VOCs from the solid fuel burning in vented stoves leaked into indoor space substantially, with more leakages for high-molecular-weight VOCs (p < 0.01). In rural China, on the national scale, the simulated 24 h average indoor concentration attributed to residential solid fuel burning was 11.6, 1.76, and 0.28 μg/m³ for benzene, naphthalene, and trichloroethylene, respectively. Approximately 85% of households had indoor benzene concentrations exceeding the WHO guideline of 1.7 μg/m³, while the exceedance of naphthalene and trichloroethylene attributed to indoor fuel combustion emissions was much more limited. Higher indoor VOC contamination was in northern and northeastern China, where large amounts of coal were burned inefficiently for daily energy demands.

Transport of fragmentary nano- and microplastics in environmental porous media is an emerging research concern driven by their prevalence in environmental porous media. This brief critical review highlights opportunities for researchers to explore the relevance of accumulated knowledge from transport experiments and simulations involving commercial spherical nano- and microplastics and other colloids. Several recent publications concerning nano- and microplastic transport in porous media are examined to highlight how interpretations and conclusions could potentially change with incorporation of accumulated knowledge from their commercial spherical counterparts.

Candida is the largest genus of medically significant yeasts, causing diseases ranging from mucosal to life-threatening invasive infections. Airborne transmission of Candida has gained attention following its genotypic detection in ambient air and isolation in occupational air. However, more comprehensive phenotypic evidence, including viability, antifungal resistance, and phylogenetic relatedness to clinical strains, is needed in ambient air, with implications for community-level exposure, colonization, and infection. To address this gap, we sampled air at an urban and a coastal site using six-stage Andersen impactors. Viable isolates of C. parapsilosis, C. albicans, and C. tropicalis─all World Health Organization priority fungal pathogens─were recovered from ambient urban air, primarily associated with respirable particle sizes (2.1–7 μm) across seasons. Antifungal susceptibility testing identified C. parapsilosis as the predominant multidrug-resistant species. Whole-genome sequencing revealed airborne C. parapsilosis shared 99.53% genetic similarity with nearby clinical strains, differing by only 94 out of 20,206 single-nucleotide polymorphisms. This suggests the plausibility of community-acquired infection via airborne routes. These findings highlight the need to investigate airborne transmission from environmental reservoirs to human colonization and infection. This is particularly critical under urban megatrends and climate change, emphasizing an emerging microbial hazard beyond antibiotic-resistant bacteria within the One Health framework.

Formic acid (HCOOH), a key driver of secondary organic aerosol and cloud condensation nuclei formation, is systematically underestimated in atmospheric models due to inadequate source characterization. To address this gap, an integrated field campaign was conducted at a South China Sea (SCS) coastal site during the summer, focusing on gaseous HCOOH (HCOOH_g). Measurements revealed that the average concentrations of HCOOH_g reached as high as 6.7 μg/m³ and 4.0 μg/m³ under land and marine breeze, respectively. On marine breeze days, HCOOH_g exhibited significant correlations with chlorophyll-a (Chl-a) and particulate organic carbon (POC) in seawater, implicating dual production pathways from both biogenic activities of phytoplankton and abiotic processes of dissolved organic matter degradation. Quantification of marine-sourced HCOOH_g revealed that these processes collectively accounted for around 16% of HCOOH_g, with abiotic contributions double the biogenic contributions. Based on the established parametrization linking HCOOH_g to marine tracers (POC and Chl-a), the spatial distribution of marine-sourced HCOOH_g was extrapolated over the SCS, identifying pronounced hotspots in eutrophic coastal regions. This work reveals the coastal eutrophic ecosystem as a pivotal yet unaccounted HCOOH_g source, emphasizing the necessity of coupling the interactions between marine biogeochemical processes and atmospheric chemical components into air quality and climate modeling.

Water-soluble humic-like substances (HULIS) are ubiquitous in the atmosphere affecting air quality and Earth’s radiative balance. However, the molecular composition of ambient HULIS remains poorly constrained. This study employed gas chromatography-orbitrap mass spectrometry to conduct nontargeted molecular characterization of HULIS in ambient PM_2.5 samples. A total of 60–193 organic compounds were identified in HULIS across seasons, and both their quantities (66.7–78.0%) and mass concentrations (75.5–84.6%) were dominated by intermediate-volatility organic compounds (IVOCs). The mass concentrations of IVOCs in both highly oxidized (average carbon oxidation state, $\overline{\mathrm{OS}}$_c > 0) and less oxidized (−1 < $\overline{\mathrm{OS}}$_c ≤ 0) HULIS fractions were approximately four times that in the reduced HULIS fraction ($\overline{\mathrm{OS}}$_c ≤ −1), indicating that the atmospheric oxidation process enhances the dominance of IVOCs in HULIS. Organic acids were the most prevalent substances in IVOCs, accounting for 63.5–78.3% of total IVOC mass concentration in different seasons. Besides, in summer, amines and alcohols also contributed 15.3–17.5% to total IVOC mass concentration, while in winter, N-heterocycles and phenols contributed 16.9–17.5%. This study advances the understanding of the molecular composition of ambient HULIS and highlights the dominance of IVOCs, which enhances the understanding of the atmospheric evolution processes and formation mechanisms of ambient HULIS.