Rapid urbanization created unique urban environment with a characteristic of dramatic modification of land cover, consequently causing profound perturbations in the transport and fate of pollutants in urban ecosystem. Taking a hyper-urbanization city (Shanghai) as an example to reveal the influence of urbanization development on pollutant footprint, this study reconstructed and compared historical evolutions of elemental carbon (EC) and polycyclic aromatic hydrocarbons (PAHs) based on two lake sediment cores (DSL: Dianshan Lake; LXL: Luxun Lake) from early- and newly-urbanized areas, respectively. Historical fluxes of EC and total PAH (Σ₁₆PAHs) showed similar and sharply fluctuant increases occurring after the 1950s in the DSL core later than the LXL core after the 1900s. In modern times (after 2000), the mean fluxes of EC and Σ₁₆PAHs in the LXL core were 2.68- and 1.38-fold greater than those in the DSL core, respectively, indicating the stronger influence from more intensive human activities and longer industrial history in early urbanized area. Based on the significant correlations among socioeconomic factors with EC and Σ₁₆PAH fluxes, the extended STIRPAT (stochastic impacts by regression on population, affluence and technology) models were successfully constructed, revealing that significance of these driving factors were in the order of population > the proportion of heavy industry > coal consumption > gross domestic product (GDP) per capita > vehicle amount. In general, the obvious discrepancy in historical stage and intensity of sedimentary EC and PAH accumulations implied that some newly fast-developing cities still have a chance to adjust urban development strategy to avoid more serious pollution.

Hydrotalcite (HT) is a layered double hydroxide (LDH), which is considered as a potential adsorbent to remove anion contaminants. In this study, adsorption of chromate (CrO₄) and phosphate (PO₄) on HT was conducted at various pH and temperatures. Related adsorption mechanisms were determined via the isotherm, kinetic, and competitive adsorption studies as well as the Cr K-edge X-ray absorption fine-structure (XAFS) spectroscopy. The maximum adsorption capacities for CrO₄ and PO₄ on HT were 0.16 and 0.23 mmol g⁻¹. Regarding adsorption kinetics, CrO₄ and PO₄ adsorption on HT could be well described by the second order model, and the rate coefficient of CrO₄ and PO₄ on HT decreased significantly with the increasing pH from 5 to 9. The adsorption kinetics for CrO₄ and PO₄ were divided into fast and slow stages with the boundary at 15 min. This biphasic adsorption behavior might be partially attributed to multiple reactive pathways including anion exchange and surface complexation. Fitting results of Cr K-edge EXAFS analysis showed a direct bonding between CrO₄ and Al on HT surfaces. Such a surface complexation appeared to be the rate-limiting step for CrO₄ adsorption on HT. By contrast, the diffusion through the hydrated interlayer space of HT was the major rate-limiting step for PO₄. This study determined the adsorption behaviors of CrO₄ and PO₄ on HT, including the initial transfer process and the subsequent adsorption mechanisms. Such information could improve the strategy to use HT as the potential adsorbent for the remediation of anionic pollutants.

Fine particulate matter (Particulate matter with diameter ≤ 2.5 μm) is associated with multiple health outcomes, with varying effects across seasons and locations. It remains largely unknown that which components of PM₂.₅ are most harmful to human health.We systematically searched all the relevent studies published before August 1, 2018, on the associations of fine particulate matter constituents with mortality and morbidity, using Web of Science, MEDLINE, PubMed and EMBASE. Studies were included if they explored the associations between short term or long term exposure of fine particulate matter constituents and natural, cardiovascular or respiratory health endpoints. The criteria for the risk of bias was adapted from OHAT and New Castle Ottawa. We applied a random-effects model to derive the risk estimates for each constituent. We performed main analyses restricted to studies which adjusted the PM₂.₅ mass in their models.Significant associations were observed between several PM₂.₅ constituents and different health endpoints. Among them, black carbon and organic carbon were most robustly and consistently associated with all natural, cardiovascular mortality and morbidity. Other potential toxic constituents including nitrate, sulfate, Zinc, silicon, iron, nickel, vanadium, and potassium were associated with adverse cardiovascular health, while nitrate, sulfate and vanadium were relevant for adverse respiratory health outcomes.Our analysis suggests that black carbon and organic carbon are important detrimental components of PM₂.₅, while other constituents are probably hazardous to human health. However, more studies are needed to further confirm our results.

Mangroves act as sinks for terrigenous pollutants to alleviate their influence on offshore marine ecosystem. The nationwide study of PBDEs contamination in mangrove wetlands of China has not been explored, and their risk for human health lack quantitative analysis. In this study, sediment samples were collected in six mangrove wetlands along coastal area of South China to evaluate the levels, congener distributions and ecological risks of eight PBDEs, including BDE-28, -47, −99, −100, −153, −154, −183, and −209. Levels of ∑PBDEs (the sum of seven PBDEs except BDE-209) and BDE-209 were 0.13–2.18 ng g−1 and 1.44–120.28 ng g−1, respectively. In particular, mean level of BDE-209 was highest in Futian, followed by Yunxiao, Fangchenggang, Zhanjiang, Dongzhaigang, and Dongfang. As dominant PBDE congener, BDE-209 accounted for 63.6%–99.1% of the total PBDEs, suggesting the major sources of commercial deca-BDE mixtures. Among seven PBDE congeners except BDE-209, slightly different percentages of PBDE congeners were detected, with BDE-154, -47, and −100 being predominant congeners. Positive relationship was observed for total organic matter (TOM) with BDE-209, with no such relationships found for particle size compositions (clay, silt and sand). As for sediment-dwelling organism, the ecological risks from tri-, tera-, and hexa-BDE congeners could be negligible, and those from penta- and deca-BDE congeners were low or moderate, indicating major ecological risk drivers of penta- and deca-BDE congeners in mangrove wetlands in China. The ecological risk of PBDEs in mangrove sediments for human health was thought to be consumption of fish which would bioaccumulate PBDEs from the contaminated sediment. As for human health, the levels of non-cancer risks of PBDEs were all lower than 1, and the cancer risk was far less than the threshold level (10−6), demonstrating low risk for human health.

The decontamination of U(VI) on graphene oxide/nano-alumina (GO/Al₂O₃) composites were investigated by batch, XRD, FT-IR and XPS techniques. The characterization results showed that GO/Al₂O₃ composites presented a variety of oxygen-containing functional groups, which provided the more surface reactive sites. The batch experiments indicated that sorption equilibrium of U(VI) on GO/Al₂O₃ composites was achieved within 30 min, and the maximum sorption capacity derived from Langmuir model was 142.8 mg/g at pH 6.5. In addition, the slight decrease of sorption capacity was observed even after fifth recycling times. These results indicated that GO/Al₂O₃ composites displayed the fast sorption rate, high sorption capacity and good regeneration performance. No effect of ionic strength revealed the inner-sphere surface complexation of U(VI) on GO/Al₂O₃ composites. FT-IR and XPS analysis demonstrated that the high adsorption of U(VI) on GO/Al₂O₃ was attributed to the various oxygen-bearing functional groups. In addition, the nano Al₂O₃ was transferred to amorphous AlO(OH) mineral phase by XRD pattern, which provided the additional reactive sorption sites. These observations indicated that GO-based composites can be regarded as a promising adsorbent for immobilization and pre-concentration of U(VI) from aqueous solutions in the environmental remediation.

Heavy metals and emerging engineered nanoparticles (ENPs) are two current environmental concerns that have attracted considerable attention. Cerium oxide nanoparticles (CeO₂NPs) are now used in a plethora of industrial products, while cadmium (Cd) is a great environmental concern because of its toxicity to animals and humans. Up to now, the interactions between heavy metals, nanoparticles and plants have not been extensively studied. The main objectives of this study were (i) to determine the synergistic effects of Cd and CeO₂NPs on the physiological parameters of Brassica and their accumulation in plant tissues and (ii) to explore the underlying physiological/phenotypical effects that drive these specific changes in plant accumulation using Artificial Neural Network (ANN) as an alternative methodology to modeling and simulating plant uptake of Ce and Cd. The combinations of three cadmium levels (0 [control] and 0.25 and 1 mg/kg of dry soil) and two CeO₂NPs concentrations (0 [control] and 500 mg/kg of dry soil) were investigated. The results showed high interactions of co-existing CeO₂NPs and Cd on plant uptake of these metal elements and their interactive effects on plant physiology. ANN also identified key physiological factors affecting plant uptake of co-occurring Cd and CeO₂NPs. Specifically, the results showed that root fresh weight and the net photosynthesis rate are parameters governing Ce uptake in plant leaves and roots while root fresh weight and Fᵥ/Fₘ ratio are parameters affecting Cd uptake in leaves and roots. Overall, ANN is a capable approach to model plant uptake of co-occurring CeO₂NPs and Cd.

Secondary inorganic aerosols, including sulfate, nitrate, and ammonium contribute to a large extent to the severe haze pollution events in China. Understanding their formation mechanisms is critical for designing effective mitigation strategies to control haze pollution, especially as the role of nitrate seemed to become more important recently, especially in some megacities. In the present study, simultaneous observations were conducted in two megacities (Chengdu and Chongqing) in Sichuan Basin of southwest China, one of the regions suffering from severe aerosol pollution. One typical long-lasting pollution event in Chengdu and Chongqing was captured during wintertime from December 25, 2016 to January 5, 2017. The campaign-average of hourly concentrations of PM2.5, sulfate, and nitrate, measured by an Aerosol Analyzer (ZSF) were 101 ± 73.8 μg/m3, 15.9 ± 11.8 μg/m3, and 24.9 ± 20.6 μg/m3, respectively, in Chengdu, and were 87.7 ± 53.8 μg/m3, 19.7 ± 13.5 μg/m3, and 15.1 ± 10.1 μg/m3, respectively, in Chongqing. Nitrate contributed substantially to PM2.5 pollution when PM2.5 was lower than 150 μg/m3, largely due to the strong secondary transformation of NOX to nitrate during the occurrence of the pollution episode. Heterogeneous hydrolysis of N2O5 dominated nitrate formation during nighttime, while photochemical reactions and high-RH enhanced gas- to aqueous-phase dissolution of NH3 and HNO3 or cloud processes likely played important roles for nitrate formation during daytime. RH-dependent heterogeneous reactions contributed greatly to the formation of sulfate. NOX is confirmed to play an important role as an oxidant in accelerating the secondary transformation of SO2 to sulfate at high RH and low O3 levels under neutralization condition during heavy PM2.5 pollution episode. Results from this study identified the formation mechanism of nitrate, especially during the daytime, and addressed the importance of heterogeneous inorganic reactions in the formation of heavy aerosol pollution events.

Due to increased use of agrochemicals and growing concerns about ecotoxicology, the development of new insecticides, moving away from those with neurotoxic and broad spectrum effects towards insecticides that are safer for the environment and nontarget beneficial species, has been a research priority. Novaluron stands out among these newer insecticides, is an insect growth regulator that is used for the control of insect pests in crops grown close to mulberry plantations. Mulberry serves as food for the silkworm Bombyx mori, which is a nontarget insect of great economic importance to silk production. We investigated the lethal and sublethal effects of Novaluron on the development of B. mori. Larvae were segregated into experimental groups: the control groups (CGs) and the treatment groups (TGs), which were treated with the Novaluron concentration of 0.15 mL/L. Following exposure, we analyzed: larval mortality, changes in the insect life cicle and cytotoxic effects on the midgut cells. This is the first report about the Novaluron’s effects on B.mori. We detected rupture in the integument, complete cessation of feeding, late development, incomplete ecdysis and production of defective cocoons. After 240 h of exposure, there was 100% mortality in TG larvae exposed in the 3rd instar and 20% mortality from larvae exposed in the 5th instar. Cytotoxic effects was observed, such as dilation of cells, emission of cytoplasmic protrusions, extreme rarefaction of the cytoplasm and nuclei, dilation of the endoplasmic reticulum in addition to changes in mitochondria, the presence of large digestive vacuoles and intercellular spaces and the presence of active caspase. Novaluron exposure impairs the midgut and may affect the physiological functions of this organ. Novaluron additionally compromises several phases of insect development, indicating the importance of toxicology studies that utilize different life stages of nontarget species to evaluate the safe use of insecticides.

There is a growing interest in the occurrence and sources of pharmaceutical substances in the environment. This paper reports the first detailed transect of pharmaceutical occurrence along the River Thames, UK, from source to sea, undertaken during a period of high flow in 2016. In 37 samples a total of 41 pharmaceuticals and 2 lifestyle compounds (cocaine and sucralose) were detected. Total concentration of pharmaceuticals ranged from 0.0012 μg/l to 10.24 μg/l with a median of 2.6 μg/l. Sucralose concentrations varied from <0.01 to 5.9 μg/l with a median concentration of 1.93 μg/l and was detected in every sample except the groundwater-dominated sources of the Thames. Antimicrobials, including those on the surface water watch list (erythromycin, clarithromycin and azithromycin) were detected in every site downstream of the Thames source. Diclofenac, recently on the surface water watch list, was detected in 97% of Thames samples and above the proposed EQS of 0.1 μg/l in 12 samples. Distinct increases in concentration and number of pharmaceuticals were found downstream of the Oxford, Mogdon and Hogsmill wastewater treatment works (WWTW) but were more subdued downstream of the Crossness and Beckton WWTW due to the tidal nature of the Thames and combined sewer outflows. Sucralose was found to be an excellent tracer of wastewaters (treated and untreated) and can be used as a proxy for many pharmaceuticals. Paracetamol and ibuprofen were tracers of untreated wastewater inputs to the Thames due to their high biodegradation within WWTWs.

Breast milk, especially colostrum, is not just a source of nutrients and immune factors for the newborn, but also accumulates environmental persistent pollutants and its diverse microbes affect the early colonization of the newborn's gut. Little is known about associations between environmental pollutants and the microbial composition of human colostrum. We assessed the influence of hexachlorocyclohexane (HCH), a persistent organic pollutant (POP), in colostrums on the microbial composition of human colostrum samples. HCH concentrations in 89 colostrum samples collected from a population living on the easternmost island of China were measured via gas chromatography equipped with mass spectrometer (GC-MS), HCH exposure risks for infants via dietary intake of breast milk were assessed, and for 29 colostrum samples the microbiota were profiled using 16S rRNA gene pyrosequencing to assess the association with HCH exposure levels. Our study confirmed high colostrum exposure levels of total HCHs (12.19 ± 13.68 μg L⁻¹) in this Chinese population. We predominantly identified Proteobacteria (67.6%) and Firmicutes (25.1%) in colostrum and microbial diversity at the genus level differed between samples with different HCH levels; e.g., Pseudomonas which contains several HCH degrading strains was found in significantly higher abundance in γ-HCH rich samples. Also, microbes that were statistically significantly associated with HCH levels were also highly correlated with each other (false discovery rate (FDR)＜0.01) and clustered in network analysis. Microbial diversity is associated with HCH levels in human colostrum and these associations might be attributable to their HCH degrading ability. These finding provide first insights into the role that environmental persistent pollutants may play in the microbial composition of human colostrum and the colonization of the infant gut.