In the past decade, particulate matter with aerodynamic diameter less than 2.5 μm (PM₂.₅) has reached unprecedented levels in China and posed a significant threat to public health. Exploring the long-term trajectory of the PM₂.₅ attributable health burden and corresponding disparities across populations in China yields insights for policymakers regarding the effectiveness of efforts to reduce air pollution exposure. Therefore, we examine how the magnitude and equity of the PM₂.₅-related public health burden has changed nationally, and between provinces, as economic growth and pollution levels varied during 2005–2017. We derive long-term PM₂.₅ exposures in China from satellite-based observations and chemical transport models, and estimate attributable premature mortality using the Global Exposure Mortality Model (GEMM). We characterize national and interprovincial inequality in health outcomes using environmental Lorenz curves and Gini coefficients over the study period. PM₂.₅ exposure is linked to 1.8 (95% CI: 1.6, 2.0) million premature deaths over China in 2017, increasing by 31% from 2005. Approximately 70% of PM₂.₅ attributable deaths were caused by stroke and IHD (ischemic heart disease), though COPD (chronic obstructive pulmonary disease) and LRI (lower respiratory infection) disproportionately affected poorer provinces. While most economic gains and PM₂.₅-related deaths were concentrated in a few provinces, both gains and deaths became more equitably distributed across provinces over time. As a nation, however, trends toward equality were more recent and less clear cut across causes of death. The rise in premature mortality is due primarily to population growth and baseline risks of stroke and IHD. This rising health burden could be alleviated through policies to prevent pollution, exposure, and disease. More targeted programs may be warranted for poorer provinces with a disproportionate share of PM₂.₅-related premature deaths due to COPD and LRI.

Microplastics receive significant societal and scientific attention due to increasing concerns about their impact on the environment and human health. Marine mammals are considered indicators for marine ecosystem health and many species are of conservation concern due to a multitude of anthropogenic stressors. Marine mammals may be vulnerable to microplastic exposure from the environment, via direct ingestion from sea water, and indirect uptake from their prey. Here we present the first systematic review of literature on microplastics and marine mammals, composing of 30 studies in total. The majority of studies examined the gastrointestinal tracts of beached, bycaught or hunted cetaceans and pinnipeds, and found that microplastics were present in all but one study, and the abundance varied between 0 and 88 particles per animal. Additionally, microplastics in pinniped scats (faeces) were detected in eight out of ten studies, with incidences ranging from 0% of animals to 100%. Our review highlights considerable methodological and reporting deficiencies and differences among papers, making comparisons and extrapolation across studies difficult. We suggest best practices to avoid these issues in future studies. In addition to empirical studies that quantified microplastics in animals and scat, ten studies out of 30 (all focussing on cetaceans) tried to estimate the risk of exposure using two main approaches; i) overlaying microplastic in the environment (water or prey) with cetacean habitat or ii) proposing biological or chemical biomarkers of exposure. We discuss advice and best practices on research into the exposure and impact of microplastics in marine mammals. This work on marine ecosystem health indicator species will provide valuable and comparable information in the future.

Increase in plastic pollution causes irreparable harm to the environment lasting for decades. While current data of plastic pollution include marine and terrestrial ecology, the impacts of degraded or intentionally produced microscopic-sized plastics on human health remain unknown. Here, we are proposing the usage of pluripotent stem cells, modern transcriptomics, and bioinformatics as a unique scientific tool to define the link between environmental and intracellular pollution, its outcome on early human development and origin of diseases. This commentary is an urgent appeal to the scientific and policy communities to invest more time and resources to establish reliable standards and methods to define and address the consequences of plastic pollution on human health.

Pyrethroids are a class of the most commonly used insecticides. The urinary metabolites are usually used as biomarkers of pyrethroid exposures in humans. In this study, the temporal variability of urinary pyrethroid biomarkers was investigated among 114 Chinese young-aged adults who provided up to 4–11 urine samples over one year. The detection rates of four urinary pyrethroid biomarkers, 3-phenoxybenzoic acid (3PBA), 4-fluoro-3-phenoxybenzoic acid (4F-3PBA), trans-2,2-(dichloro)-2-dimethylvinylcyclopropane carboxylic acid (trans-DCCA) and cis-2,2-(dichloro)-2-dimethylvinylcyclopropane carboxylic acid (cis-DCCA) were 100%, 8%, 69% and 44%, respectively. The intraclass correlation coefficient (ICC) estimates for 3PBA indicated poor reproducibility (<0.15) in the spot urine samples of young-aged adults over a week, month and year. Log-transformed 3PBA used the least number of random spot urine samples (≥4) per person, which would provide a reliable biomarker estimate (ICC≥0.40) over a year. As the predictors of the top 33% yearly average 3PBA concentrations, the sensitivity and specificity of 3PBA ranged from 0.25 to 0.89, 0.58 to 0.96, respectively. Based on the results of this study, we recommend at least 4 urine samples collected 3 months apart for prospective assessment of pyrethroid exposure in the epidemiological studies to estimate exposure-response relationships between pyrethroids and health outcomes with relative long-term exposure periods.

Coupling of nitrogen removal processes with nitrification (NRₙ) are vital synergistic nitrogen elimination mechanisms in aquatic environments. However, the effects of antibiotics on NRₙ are not well known. In the present work, 20-day continuous-flow experiments combined with ¹⁵N tracing techniques and quantitative PCR were performed to simulate the impact of sulfamethoxazole (SMX, a sulfonamide antibiotic) with near in situ concentration on NRₙ processes in sediments of Yangtze Estuary. Results showed that SMX with near in situ concentration significantly decreased NRₙ, NRw (uncoupling of nitrogen removal processes with nitrification) and actual nitrogen removal rates via inhibiting nitrogen transformation functional genes (AOB, narG, nirS, nosZ) and anammox 16S rRNA gene, while the coupling links between nitrification and nitrogen removal processes were not broken by the exposure. The proportion of NRₙ in total nitrogen removal processes decreased by approximately 10% with SMX addition, due to the different inhibition on AOB, denitrifying genes and anammox 16S rRNA gene. N₂O production and nitrite accumulation remarkably increased with SMX addition under simultaneous nitrification and denitrification, and they strongly correlated with each other. The more severely inhibition on nirS gene (13.6–19.8%) than Nitrospira nxrB gene (0.3–8.2%) revealed that the increased nitrite accumulation with SMX addition mainly occurred in heterotrophic denitrification, suggesting that the increased N₂O production was dominated by the heterotrophic nitrite reduction. Moreover, we estimated that the ratio of external inorganic N eliminated by actual nitrogen removal can upgrade to 6.4–7.4% under circumstances of no inhibition by SMX. This study revealed the effects of SMX with near in situ concentration on NRₙ processes and illustrated the microbial mechanism on functional genes level. Our results highlighted the inhibitory effects of SMX on NRₙ may contribute to reactive N retention and N₂O production in estuarine and coastal ecosystems.

Powder adsorbents show an excellent adsorption capacity for arsenic(As) due to the large specific surface area. However, the performance of powder adsorbents decreases significantly by channeling in the adsorption bed, and the powder is released from the bed. Pelletization of power adsorbent can solve the problems, and bentonite was proposed as a binder to improve the strength. The adsorption capacity and lifetime of pelletized adsorbent were evaluated through a batch and column study. The addition of bentonite decreased adsorption capacity by 16% of pellet without bentonite, but improved compressive strength of adsorbent up to 3.6 times. In the batch test, the maximum adsorption capacity of pelletized adsorbent is 22.2 mg As/g, which is about 40% of powder adsorbent. However, in the column study, pellet adsorbent showed similar adsorption performance and lifetime to commercial and powder adsorbent. As a result, the pellet adsorbent using bentonite is a potential low-cost adsorbent to remove effectively As in the aqueous phase.

Size and magnetic separation of incineration bottom ash (IBA) are common for ferrous metals recovery, however, their influences on the mineral phase and the element redistribution, and subsequently the induced variation of metal leaching potential herein remain limited understanding. The lack of research in this field may misunderstand IBA performances, cause confused results for comparison among various studies, and potentially lead to biased conclusions. We herein quantitatively investigate the effects of size and magnetic separation on the IBA based on element distribution, leaching behavior, morphology, and mineralogy with statistical analysis. For preparation, sieving was performed with the original IBA (to obtain 7 size-fractions termed as OR1-7, respectively), followed by magnetic separation of each, to further yield magnetic fractions (MF1-7) to discriminate nonmagnetic fractions (NF1-7). In this study, we show that size and magnetic separation may pose significant yet different impacts on different fractions, which would affect their leaching potential concerning their respective downstream applications.

Motor vehicles emit a variety of pollutants including metals, petroleum hydrocarbons and polycyclic aromatic hydrocarbons (PAHs). The relationships between metals, petroleum hydrocarbons and PAHs, soil respiration and microbial diversity (fungi and bacteria) were studied using control (n = 3) and roadside soils (n = 27) with different exposure periods to vehicle emissions (2–63 years). Bacterial diversity was found to be higher than control sites (P = 0.002) but was the same across different categories of road age (P = 0.328). Significant (r = −0.49, P = 0.007) contrasting behaviour of fungal and bacterial diversity was reported, with diversity increasing across all road types for bacteria and decreasing across all road types for fungi compared to control soils. Analysis of the bacterial community identified three distinct clusters, separated on age of contamination, suggesting that roadside bacterial communities change over time with pollution from vehicles with the potential development of metal resistant bacteria in roadside soils. In contrast, for fungal communities, a reduction in diversity with time of exposure to roadside vehicle emissions was observed suggesting the potential for reduced ecosystem functionality and soil health in roadside soils. This is the first study in the published literature to include both bacterial and fungal responses from aged roadside soils. The results from this study suggest that normal functionality of soil ecosystem services is being affected in roadside soils, potentially globally.

The development of an eco-friendly and reliable process for the production of nanomaterials is essential to overcome the toxicity and exorbitant cost of conventional methods. As such, a facile and green synthesis method is introduced for the preparation of lignin mediated silver nanoparticles (L-Ag NPs). This is produced by reducing Ag precursors using lignin biopolymers which are formulated by pulsed laser irradiation and an ultrasonication process. Lignin operates as both a reducing and stabilizing agent. The various analytical techniques of ultraviolet–visible spectroscopy, transmission electron microscope and X-ray diffractometer studies were employed to verify the formation of non-aggregated spherical L-Ag NPs with an average size as small as 7–8 nm. The selective sensing capability of the synthesized L-Ag NPs was examined for the detection of hydrogen peroxide and mercury ions in an aqueous environment. Furthermore, the superior catalytic performance of L-Ag NPs was demonstrated by the rapid conversion of toxic 4-nitrophenol and nitrobenzene as targeted pollutants to the corresponding amino compounds. A plausible catalytic reduction mechanism for the removal of toxic nitro-organic pollutants over L-Ag NPs is proposed. This research coincides with existing studies and affirms that L-Ag NPs are an effective sensor that be applied as a catalytic material within environmental remediation and also alternative biomedical applications.

To better understand the real-world emissions of rural vehicles (RVs) in China, 8 China II RVs and 18 China III RVs were tested on a provincial road, rural road and farm road using a portable emissions measurement system. The results are illustrated in contour maps of the speed, acceleration and emission rates and show that CO, HC, NOx and PM emissions differ for the three road types; however, the peak emission points all occur on the provincial road. The average CO, HC, NOx and PM emission factors based on distance for the China II RVs are 9.21, 4.05, 1.68 and 2.58 times higher, respectively, than those of the China III RVs. However, the average NOx emission factors of the China II and III RVs are 2.21 and 1.65 times higher than the corresponding recommended values of national emission inventory guideline, resulting in underestimation of overall RVs’ emissions. Distance-based emission factors of four pollutants ranked from high to low are farm road > rural road > provincial road. In contrast to the average emission factors of the China II RVs on the three road types, those of the China III RVs are significantly less in terms of distance and fuel consumption. The results of other researchers differ from those in this study: the CO emission factor of the China II RVs is 2.12 times higher than that of the China II light-duty diesel vehicles (LDDVs). The PM emission factor of the China III RVs is 2.67 times higher than that of the China III LDDVs. The NOx emission factors of the China II and III RVs are similar to those of the corresponding China II and III LDDVs. Our research increases the understanding of real-world emissions of RVs and can act as great references for policy makers developing RV emission baselines.