This study systematically reviewed all the cohort studies investigating the relationship between long-term exposure to PM₂.₅ and any health outcome until February 2018. We searched ISI Web of Knowledge, Pubmed, and Scopus databases for peer-reviewed journal research articles published in English. We only extracted the results of the single-pollutant main analysis of each study, excluding the effect modifications and sensitivity analyses. Out of the initial 9523 articles, 203 articles were ultimately included for analysis. Based on the different characteristics of studies such as study design, outcome, exposure assessment method, and statistical model, we calculated the number and relative frequency of analyses with statistically significant and insignificant results. Most of the studies were prospective (84.8%), assessed both genders (66.5%), and focused on a specific age range (86.8%). Most of the articles (78.1%) had used modeling techniques for exposure assessment of cohorts’ participants. Among the total of 317 health outcomes, the most investigated outcomes include mortality due to cardiovascular disease (6.19%), all causes (5.48%), lung cancer (4.00%), ischemic heart disease (3.50%), and non-accidental causes (3.50%). The percentage of analyses with statistically significant results were higher among studies that used prospective design, mortality as the outcome, fixed stations as exposure assessment method, hazard ratio as risk measure, and no covariate adjustment. We can somehow conclude that the choice of right characteristics for cohort studies can make a difference in their results.

Synthesis of silicon materials from fly ash is an ecologically justified process aimed at the transformation of energy sector waste-fly ash into mesoporous silicon material of broad possible application field. In this study, the MCM-41-NH₂ was successfully synthesized from industrial solid waste fly ash via a facile and fast process of alkali fusion method under the assistant of microwave. Due to the employ of microwave, the aging time was controlled within 30 min, which was significantly shorter than that of traditional hydrothermal method (48–72 h). And, the obtained MCM-41-NH₂ was shown an excellent performance to remove Cr(VI) from solution under the investigation of fixed-bed column. The maximum adsorption capacity for Cr(VI) was 53.77 mg/g. Additionally, the effect of initial concentration, flow rate, bed height, and pH on Cr(VI) removal were investigated, and the models of Thomas and Adams–Bohart were applied to predict the experiment data; the correlation coefficients (R²) of Thomas model under the investigated conditions were all close to 1. Furthermore, the adsorbent was characterized by N₂ adsorption–desorption isotherm, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), zeta potential, ultraviolet-visible spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), and NH₃-Temperature Programmed Desorption (NH₃-TPD). The results showed that amino groups play an important role in the adsorption process. Cr(VI) was firstly adsorbed on the surface of the MCM-41-NH₂, and then some of the adsorbed Cr(VI) were reduced to Cr(III) by the release of the protons of the ammonium. The information showed that MCM-41-NH₂ could be an effective and low-cost sorbent for removing Cr(VI) from wastewater. Furthermore, recycling experiments showed that the spent adsorbent had high catalytic performance for methyl mercaptan (CH₃SH). Graphical abstract .

The quaternization of chitosan molecules creates materials with high adsorptive capacity towards textile dyes, which renders them capable of rapidly removing such dyes from a solution. In this study, a novel material was synthesized in bead form to adsorb the Acid Blue 25 textile dye. The adsorption isotherms, kinetics, and thermodynamics of this new material were investigated. The beads were further characterized by FT-IR and SEM studies, as well as their rheological behavior. Bioassays with Daphnia similis analyzed the toxicity of the dye before and after treatments. The Freundlich isotherm model fitted to all the adsorption data in a pH range from 2.50 to 8.50. Kinetic studies showed that adsorption was ruled by an intraparticle diffusion process and reached equilibrium in 270 min, as 39.527 μg mg⁻¹ of dye was sorbed to the beads. Thermodynamic studies showed that adsorption was a spontaneous and endothermic process. Thermodynamics also confirmed that the adsorption was proportionally influenced by higher temperatures. The FT-IR spectroscopy identified the adsorbate/adsorbent binding sites, thus confirming the occurrence of chemisorption. Post-treatment bioassays found a significant decrease in toxicity, obtaining just 10% of D. similis mortality after adsorption treatments. Therefore, the synthesized beads from this research can potentially be applied to the treatment of textile effluents.

To comprehend city-level driving mechanisms of carbon emissions, this paper utilizes spectral cluster and two-layer LMDI (logarithmic mean divisia index) method to systematically assess the contribution values of correlative factors from each cluster to Henan’s carbon emissions increments, and accordingly comes up with more strategies about how to reduce carbon emissions for each cluster on the basis of driving forces of carbon emissions. The results of clustering and the decomposition are as follows: (1) the 18 prefecture-level cities in Henan were divided into five categories by spectral clustering, and there are similar development patterns within each category, so they can learn from each other to improve their own defects of development; (2) this paper utilizes the two-layer LMDI method to divide the factors affecting each cluster of carbon emissions into four types, which includes energy structure, energy intensity, per capita GDP, and population, and calculates the contribution value of each factor. It was concluded that the contribution value of per capita GDP dominantly drove up carbon emissions, while energy intensity played a significant role in offsetting them. Therefore, it is important for Henan’s low-carbon development to control the expansion of economic activity and improve energy efficiency in the future.

Consumer products such as perfluorooctanesulfonic acid (PFOS) and pharmaceuticals (PCPPs) enter aquatic ecosystems through inefficient removal during wastewater treatment. Often, the sterilization process of wastewater includes the addition of sodium hypochlorite that can react with PCPPs and other organic matter (i.e., dissolve organic matter) to generate disinfection by-products and can cause the final effluent to be more harmful to aquatic organisms. Here, we exposed Daphnia magna to two stages of wastewater, the pre-chlorinated wastewater (PreCl) and the final effluent. In addition, we exposed D. magna, to the final effluent with a concentration gradient of added PFOS, to investigate if this persistent contaminant altered the toxicity of the final effluent. After 48 h of contaminant exposure, we measured the daphnids metabolic responses to the different stages of wastewater treatment, and with the addition of PFOS, utilizing proton nuclear magnetic resonance spectroscopy and liquid chromatography tandem mass spectrometry. We found few significant changes to the metabolic profile of animals exposed to the PreCl wastewater; however, animals exposed to the final effluent displayed increases in many amino acids and decreases in some sugar metabolites. With the addition of PFOS to the final effluent, the metabolic profile shifted from increased amino acids and decreased sugar metabolites and energy molecules especially at the low and high concentrations of PFOS. Overall, our results demonstrate the metabolome is sensitive to changes in the final effluent that are caused by sterilization, and with the addition of a persistent contaminant, the metabolic profile is further altered.

A lightweight aggregate (LWA) was manufactured from municipal sewage sludge, gangue, and coal ash. The product performance and environmental safety of the sintered material were evaluated by changing the sludge blending ratio and sintering temperature. The distribution and migratory transformation characteristics of heavy metals in LWA were examined by BCR sequential extraction in combination with inductively coupled plasma optical emission spectrometry (ICP-OES). The environmental safety performance of LWA was comprehensively evaluated by the OPTI index for the first time. The leaching concentration of the heavy metals Pb, Ni, Cu, and Zn in raw materials without sintering reached 1.17, 1.6, 7.84, and 7.56 mg/L, respectively, far exceeding the regulatory threshold value. At 1250 °C, sintering with 60% sludge content resulted in Cu and Zn leaching concentrations of only 0.41 mg/L and 0.37 mg/L, respectively. Furthermore, a big portion of heavy metals were in the residual fraction of sintered LWA. The proportion of comprehensive pollutant toxicity index is only 199.17. Additionally, the mechanical properties of sintered LWA exceed the standards stipulated in the GB/T1743.1-2010 standard. Using sewage sludge to manufacture lightweight aggregate is not only environmentally safe but also produces LWA with good engineering characteristics.

Excess cadmium (Cd) in agricultural soils can be taken up by rice plants and concentrated in the grain, presenting a human health risk. In this study, we field tested the effects of three foliar treatments (zinc (Zn) alone, or combined with manganese (ZnMn) or phosphorus (ZnP)) on the Cd concentration and grain yield of six rice cultivars (C Liangyou 7, Fengyuanyou 272, Xiangwanxian 12, Tianyouhuazhan, Xiangwanxian 13, and Jinyou 284) at the grain filling stage. Our results showed that rice yield and Cd, Zn, Mn, P, and K concentrations were significantly different among the cultivars (p < 0.05); for example, Jinyou 284 recorded lower Cd levels than any other cultivar. Application of Zn, ZnMn, and ZnP had no significant effect on rice yield and Mn, P, and K concentrations for all cultivars. Compared with the control, Cd concentrations after treatment with Zn, ZnMn, and ZnP decreased by 19.03–32.55%, 36.63–55.78% (p < 0.05), and 25.72–49.10%, respectively, while Zn concentrations increased by 11.02–29.38%, 10.63–32.67%, and 11.97–36.82%, respectively. There was a significant negative correlation between Cd and Zn concentrations (p < 0.01). All three treatments increased Zn and reduced Cd concentration in rice grains, though ZnMn was most effective. Therefore, cultivar selection and Zn fertilizer application are effective strategies to minimize Cd concentration in rice grains. However, the lowest result still exceeded the Chinese Cd safety limit (0.2 mg Cd kg⁻¹) by a factor of 2.6, demonstrating that additional effective measures should be simultaneously used to further reduce the accumulation of Cd in rice grains.

A sediment source fingerprinting method, including a Monte Carlo simulation framework, was used to quantify the contributions of terrestrial sources of fine- (< 63 μm) and coarse-grained (63–500 μm) sediments sampled from three categories of coastal sediment deposits in the Jagin catchment, south-east of Jask, Hormozgan province, southern Iran: coastal dunes (CD), terrestrial sand dunes or onshore sediments (TSD), and marine or offshore sediments (MD). Forty-nine geochemical properties were measured in the two size fractions and a three-stage statistical process consisting of a conservation test, the Kruskal–Wallis H test, and stepwise discriminant function analysis (DFA) was applied to select final composite fingerprints for terrestrial source discrimination. Based on the statistical tests, four final fingerprints comprising Be, Ni, K and Cu and seven final fingerprints consisting Cu, Th, Be, Al, La, Mg and Fe were selected for discriminating terrestrial sources of the coastal fine- and coarse-grained sediments, respectively. Two geological spatial sources, including Quaternary (clay flat, high and low level fans and valley terraces) and Palaeocene age deposits, were identified as the main terrestrial sources of the fine-grained sediment sampled from the coastal deposits. A geological spatial source consisting of sandstone with siltstone, mudstone and minor conglomerate (Palaeocene age deposits) was identified as the main terrestrial source for coarse-grained sediment sampled from the coastal deposits.

With increasing environment pollution and bacterial transmitted viral diseases globally, the development of new, effective, and low-cost materials/strategies is the current major challenge. To combat with this alarming problem, three new multi-functional and thermally stable SnO₂NPs@ZIF-8 composites (NC1, NC2, and NC3) were synthesized by a facile and sustainable approach involving in situ encapsulation of SnO₂NPs (150, 300, and 500 μL suspension in methanol) within zeolitic imidazole framework at room temperature. The morphology and crystallinity of ZIF-8 remained unchanged upon the proper encapsulation of SnO₂NPs in its matrix. Herein, for the first time, the antiviral potential of ZIF-8 and SnO₂NPs@ZIF-8 against chikungunya virus is reported by investigating their cytotoxicity against Vero cell line (employing MTT ((3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide)) assay). The maximum non-toxic doses were 0.04 mg mL⁻¹ for ZIF-8 and SnO₂NPs@ZIF-8 and 0.1 mg mL⁻¹ for SnO₂NPs. Further, NC1 exhibited (based on plaque assay) reduction in viral load/titers up to > 80% during post-treatment and > 50% during pre-treatment, greater than that of ZIF-8 and SnO₂NPs due to synergistic effect. Further, NC1 (10 mg) exhibited enhanced photocatalytic efficiency (≥ 96%) for degradation of methylene blue (0.5 × 10⁻⁵ M) at pH ˃ 7.0. The probable mechanism for their antiviral activity and photocatalytic activity has been discussed. The multi-functional composites can effectively be used to reduce water pollution and as remedy for mosquito/bacterial transmitted viral diseases.

Real-time monitoring of source zone of light non-aqueous liquids (LNAPLs) is important for preventing accidental pollution and taking effective underground pollution remediation measures. As a high-precision monitoring technology, cross-hole electrical resistivity tomography (CHERT) has been widely used to obtain static information regarding underground stratigraphic structures and dynamic information regarding fluid motion. The time-lapse data processing method can be used to obtain pollution zone dynamic change information. Since the leakage rate directly affects the diffusion range of pollution, this study simulated the initial evolution process of LNAPL pollution source regions under two different leakage rates. The time-lapse monitoring of the above process was performed using CHERT. The test results show that CHERT can be used to observe the migration of LNAPLs and the initial evolution of the contaminated area. Differences in leakage rate will result in variation in soil wettability and fluid distribution, which will cause changes in soil resistivity in the corresponding region. The low-saturation LNAPL-contaminated area may exhibit low-resistivity characteristics and is easily overlooked in field investigations. In addition, the degree of contamination in the saturated zone can be quantitatively evaluated by CHERT; however, the pollution range and oil saturation value determined by CHERT are underestimated. The results showed the electrical variation characteristics of the initial evolution process of the fresh pollution source area and provide data that will enable early warnings of LNAPL leakage. This shows that CHERT is a promising tool for monitoring LNAPL pollution source leakage even if further research is needed to fully understand the effect of hydrological processes on electronic signals.