We quantified the transport and transformation of Cd in historically contaminated soil (OS) and artificially contaminated soil (NS), treated with 3% (w/w) rice straw biochar prepared at 400 °C (BC400) and 700 °C (BC700) under combined dry-wet and freeze-thaw cycles for 72 days simulating the natural aging process of 8 years. An improved three-layer mesh experiment was developed to simulate the natural situation in field. The result showed that the total Cd concentration increased in the biochar but decreased in the soil, suggesting that Cd was transported from the soil into the biochar during the aging process. The total Cd concentration in BC400 treated with both soils was higher than that in BC700 treated with both soils, however, BC700 displayed stronger ability on immobilizing Cd than BC400 because the Tessier exchangeable Cd fraction in BC700 treated both soils was lower than that in BC400 treated with both soils. The average Tessier exchangeable Cd fraction in the soil and biochar decreased in all treatments during the aging process, indicating that Cd tended to be more stable in the soil for a long term. The result also showed that biochar could immobilizate Cd by decreasing the Tessier exchangeable Cd fraction of soil and biochar, and the quantitative contributions of biochar and soil to Cd immobilization were different in OS and NS treated with BC400 and BC700. The biochar contribution to the reduction in Tessier exchangeable Cd fraction accounted for 40–85% in NS treated with BC400 and 54–82% in NS treated with BC700. However, in OS treated with biochar, the biochar contribution accounted for nearly 100%, and soil had almost no contribution. In summary, OS did not contribute to Cd immobilization, while NS contributed nearly 50% to Cd immobilization, and BC700 was more effective in immobilizing Cd than BC400.

An increasing number of epidemiological studies have examined air pollution as a possible contributor to adverse sleep health, but results are mixed. The aims of this systematic review are to investigate and summarize the associations between exposures to air pollutants and various sleep measures across the lifespan. PubMed, CINAHL, Cochrane, Scopus, Web of Science, and PsycInfo were searched through October 2019 to identify original data-based research examining direct epidemiological associations between ambient and indoor air pollution exposures and various sleep health measures, including sleep quality, sleep duration, sleep disturbances, and daytime sleepiness. Twenty-two articles from 2010 to 2019 were selected for inclusion in this review, including a wide range of study populations (from early childhood to elderly) and locations (10 Asian, 4 North American, 3 European, 5 other). Due to variation in both exposure and outcome assessments, conducting a meta-analysis was not plausible. Twenty-one studies reported a generally positive association between exposure and poor sleep quality. While most studies focused on ambient air pollutants, five assessed the specific effect of indoor exposure. In children and adolescents, increased exposure to both ambient and indoor pollutants is associated with increased respiratory sleep problems and a variety of additional adverse sleep outcomes. In adults, air pollution exposure was most notably related to sleep disordered breathing. Existing literature generally shows a negative relationship between exposures to air pollution and sleep health in populations across different age groups, countries, and measures. While many associations between air pollution and sleep outcomes have been investigated, the mixed study methods and use of subjective air pollution and sleep measures result in a wide range of specific associations. Plausible toxicological mechanisms remain inconclusive. Future studies utilizing objective sleep measures and controlling for all air pollution exposures and individual encounters may help ameliorate variability in the results reported by current published literature.

Wastewater treatment plants (WWTPs) provide optimal conditions for the maintenance and spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). In this work we describe the occurrence of antibiotic resistant faecal coliforms and their mechanisms of antibiotic resistance in the effluent of two urban WWTPs in Ireland. This information is critical to identifying the role of WWTPs in the dissemination of ARB and ARGs into the environment. Effluent samples were collected from two WWTPs in Spring and Autumn of 2015 and 2016. The bacterial susceptibility patterns to 13 antibiotics were determined. The phenotypic tests were carried out to identify AmpC or extended-spectrum β-lactamase (ESBL) producers. The presence of ESBL genes were detected by PCR. Plasmids carrying ESBL genes were transformed into Escherichia coli DH5α recipient and underwent plasmid replicon typing to identify incompatibility groups. More than 90% of isolated faecal coliforms were resistant to amoxicillin and ampicillin, followed by tetracycline (up to 39.82%), ciprofloxacin (up to 31.42%) and trimethoprim (up to 37.61%). Faecal coliforms resistant to colistin (up to 31.62%) and imipenem (up to 15.93%) were detected in all effluent samples. Up to 53.98% of isolated faecal coliforms expressed a multi-drug resistance (MRD) phenotype. AmpC production was confirmed in 5.22% of isolates. The ESBL genes were confirmed for 11.84% of isolates (9.2% of isolates carried blaTEM, 1.4% blaSHV₋₁₂, 0.2% blaCTX₋M₋₁ and 1% blaCTX₋M₋₁₅). Plasmids extracted from 52 ESBL isolates were successfully transformed into recipient E. coli. The detected plasmid incompatibility groups included the IncF group, IncI1, IncHI1/2 and IncA/C. These results provide evidence that treated wastewater is polluted with ARB and MDR faecal coliforms and are sources of ESBL-producing, carbapenem and colistin resistant Enterobacteriaceae.

In this study, the detoxification mechanisms of water-soluble fluorine in the bottom ash and the distribution of fluorine during the spent potlining (SPL) incineration were characterized in response to four calcium compounds using an experimental tube furnace. CaSiO₃, CaO, Ca(OH)₂, and CaCO₃-assisted SPL incineration converted NaF to low toxicity compounds in the bottom ash yielding a conversion range of 54.24–99.45% relative to the individual SPL incineration. The two main mechanisms of the fluorine transformation were the formations of CaF₂ and Ca₄Si₂O₇F₂. The fluorine transformation efficiency was greater with CaSiO₃ than CaO, Ca(OH)₂, and CaCO₃. Our simulations demonstrated that SiO₂ enhanced the conversion of NaF. The fluorine leaching content of the bottom ash was estimated at 13.71 mg⋅L⁻¹ after the SPL co-incineration with CaSiO₃ (Ca:F = 1.2:1). The acid-alkali solutions had no significant effect on the fluorine leaching content of the bottom ash when 3 ≤ pH ≤ 12. Fluorine during the SPL co-incineration with CaSiO₃ (Ca:F = 1.2:1) at 850 °C for 60 min was partitioned into 83.37, 13.90, and 2.72% in the bottom ash, fly ash, and flue gas, respectively. The transformation and detoxification mechanisms of water-soluble fluorine provide new insights into controls on fluorine emission from the SPL incineration.

Microplastic pollution has become an urgent issue because it adversely affects ecosystems. However, efficient methods to detect and characterize microplastic particles are still in development. By conducting a series of laboratory assessments based on near-infrared hyperspectral imaging in the wavelength range of 900–1700 nm, we report the fundamental spectral features of (i) 11 authentic plastics and (ii) 11 filter substrate materials. We found that different plastic polymers showed distinct spectral features at 1150–1250 nm, 1350–1450 nm and 1600–1700 nm, enabling their automatic recognition and identification with spectral separation algorithms. Using an improved hyperspectral imaging system, we demonstrated the detection of three types of microplastic particles, polyethylene, polypropylene and polystyrene, down to 100 μm in diameter. As a filter substrate, a gold-coated polycarbonate filter (GPC0847-BA) showed constant reflectance over 900–1700 nm and a large radiative contrast against loaded plastic particles. Glass fiber filters (GF10 and GF/F) would also be suitable substrates due to their low cost and easy commercial availability. This study provides key parameters for applying hyperspectral imaging techniques for the detection of microplastics.

Pharmaceutically active compounds (PhACs) are widely found in the environment due to vast human consumption. Lots of work has been devoted to investigating the occurrence and seasonal variations globally. To fully understand characteristics and cross-year variation of PhACs in Beijing, 35 PhACs were analyzed in 46 sites across Beijing from both urban and suburban areas. Concentrations of target PhACs were ranged from levels of ng L⁻¹ to μg L⁻¹. Metoprolol (524 ng L⁻¹), caffeine (390 ng L⁻¹) and acetaminophen (156 ng L⁻¹) were the three most abundant non-antibiotics with the highest median concentration, and nalidixic acid (135 ng L⁻¹), erythromycin (64 ng L⁻¹) and sulfamethoxazole (77 ng L⁻¹) were the most abundant antibiotics. Urban and suburban areas are distinguished by PhAC composition in cluster analysis due to different wastewater collection rate. The ratio of easily removable compound group and hardly removable group was then proposed to reflect the wastewater collection rate. The compositional comparison of PhACs in WWTPs’ effluents and their receiving rivers further illustrates the impact of WWTPs in urban area. Higher proportion of antibiotics (>30%) in suburban area reflected the impact of presence of livestock farms, which should be concerned. Further statistical analyses show an improving trend of wastewater collection rate, and excluding metoprolol, an anti-hypertension medicine, the total concentration of 13 target PhACs was reduced by 72% during 2013–2017.

Microplastics (MPs) are polluting the Arctic, but our understanding of their abundance, distribution, and sources is limited. This study quantified MPs down to 10 μm in marine waters of the most populated region in Greenland. A new plastic-free pump-filter system was used to collect MPs from surface waters in the fjord Nuup Kangerlua close to Nuuk. Additionally, we took samples by horizontal tows with a bongo net (300 μm mesh-size). The median concentrations were 142 MPs m⁻³ and 0.12 MPs m⁻³ in the pump and bongo samples, respectively. The most abundant polymer was polyester across stations and sampling types. Fibers were the dominant shape in the bongo samples, while non-fibrous particles dominated in the pump samples. MP abundance was lower in the fjord and increased close to Nuuk and towards the open ocean, indicating that Nuuk is an important point source for MPs. In both samples, concentrations of MPs increased with decreasing size, illustrating the importance of quantifying the smallest fraction of MPs. Thus, the use of methods allowing for a quantification of the smallest MPs is vital to reduce the underestimation of MP concentrations in the environment. The smallest size fraction is also most available to plankton-feeding marine invertebrates and an important entry point for MPs into marine food webs. At the found concentrations, immediate adverse effects on the pelagic food webs are unlikely. However, growing anthropogenic activities could increase the risk of MPs to affect the sensitive Arctic ecosystem.

The contamination of arsenic (As) and cadmium (Cd) in paddy soils is widely reported and these two metals are difficult to be co-remediated due to the contrasting chemical behaviors. This poses a challenge to simultaneously decrease their availability in soil and accumulation in rice via immobilization by amendments, especially in in-situ fields. This study compared the effects of carbide slag, lodestone and biochar on the bioavailability of As and Cd in soil and their accumulation in rice tissues and root Fe–Mn plaque at tillering and mature stages in a paddy field. The addition of three amendments significantly limited the mobilization of As and Cd in soil and decreased their accumulations in brown rice by 30–52% and 9–21%, respectively. Carbide slag was most whereas lodestone least effective in As and Cd immobilization in the tested contaminated soils. Community Bureau of Reference (BCR) sequential extraction analysis showed that the amendments changed the forms of As and Cd to less-available. Activated functional groups of the amendments (e.g. –OH, C–O, OC–O, OH⁻ and CO₃²⁻) sequestered metals by precipitation, adsorption, ion exchange or electrostatic attributes contributed greatly to the As and Cd immobilization in soil. Furthermore, the amendments promoted the formation of Fe–Mn plaque in rice roots, which further limited the mobility of As and Cd in soil and prevented their transport from soil to rice roots. The application of carbide slag and biochar but not lodestone increased rice yield compared to the unamended control, indicating their applicability in situ remediation. Our study gives a strong reference to select immobilizing amendments for food safe production in co-contaminated paddy soils.

Polychlorinated biphenyls (PCBs) are notorious environmental pollutants. For their hydrophobic and lipophilic capability, they are wildly spread to environment to threat human health thus attracts more attention. In this study, we observed increasing numbers of CD163 positive (CD163⁺) macrophages in aortic valve of ApoE⁻/⁻ mice after 2,3,5-trichloro-6-phenyl-[1,4]-benzoquinone (PCB29-pQ) treatment, the metabolite of polychlorinated biphenyl. In addition, in vitro studies identified that PCB29-pQ exposure significantly provoked the shifting of RAW264.7 macrophages and bone marrow derived monocytes (BMDMs) to CD163⁺ macrophages. Upon PCB29-pQ administration, CD163 and CD206 levels were enhanced in RAW264.7 cells as well as in BMDMs. However, the concentration of iron and total cholesterol (TC) were reduced due to the boosting of ferroportin (Fpn) and ATP binding cassette transporter, subfamily A, member 1 (ABCA1) which are efflux transporters of iron and cholesterol individually. Further investigation on mechanism indicated that PCB29-pQ exposure induced reactive oxygen species (ROS), which may result in activation of nuclear factor erythroid 2-related factor 2 (Nrf2), a protein responsible for macrophage polarization. After that, we blocked Nrf2 through Nrf2 shRNA and ROS scavenger NAC, which significantly reversed the shifting of macrophage to CD163⁺ sub-population. These results confirmed the importance of Nrf2 in inducing macrophage polarization. In short, our study uncovered that PCB29-pQ could promote macrophage/monocyte polarization to CD163⁺ macrophage which would be a potential incentive to accelerate atherosclerosis through Nrf2 signaling pathway.

Groundwater pollution early warning has been regarded as an effective tool for regional groundwater pollution prevention, especially in China. In this study, the systemic model was established to assess the groundwater pollution early warning by integrating the present situation of groundwater quality (Q), groundwater quality trend (T) and groundwater pollution risk (R). The model integrated spatial and temporal variation of groundwater quality, and combined the state and process of the groundwater pollution. Q, T and R were assessed by the methods of fuzzy comprehensive assessment, Spearman or nonparametric Mann-Kendall trend test, and overlay index, respectively. Taking the Luoyang City as an example, the groundwater pollution early warning mapping was generated, and verified by corresponding the groundwater quality classes and the early warning degrees. The results showed that the groundwater was dominated by the levels of no warning and light warning, which accounted for 77% of the study area. The serious and tremendous warning areas were affected by the worse trend and relatively bad/bad present situations of groundwater quality with the typical contaminants of total hardness, nitrate, Hg and COD. In summary, the present situation of groundwater quality was the most important factor of groundwater pollution early warning mapping in the study area. The worse trend of groundwater quality played equally a key role in the local regions, as well as the high pollution risk, which was mainly affected by the pollution source loading. Targeted measures for groundwater pollution prevention were proposed in the corresponding degrees of groundwater pollution early warning. The QTR model was proved to be effective for assessing the regional groundwater pollution early warning. The accuracy of the model could be improved if there is further data acquisition of groundwater quality in longer time series and in larger number, and further investigation of pollution sources.The QTR model is proposed and proved to be effective for assessing regional groundwater pollution early warning.