Hexavalent chromium (Cr(VI)) has significantly threatened the environmental health because of its distinct toxicity. A novel magnetic core-shell structured NZVI@ZD composite was designed for simultaneous adsorption and reduction of Cr(VI). NZVI@ZD was synthesized by carbonization of the as-prepared core-shell structure NZVI@zeolitic imidazole framework-67 (ZIF-67). After carbonization, the original ZIF-67 shell shape was preserved well with marginal parts developing to graphitized carbon. Both cobalt (Co) and NZVI nanoparticles were finely dispersed in the porous ZIF-67 derivative (ZD). NZVI@ZD exhibited excellent removal performance for Cr(VI), owing to its high specific surface area and large pore size favorable for Cr(VI) adsorption and diffusion. The maximum adsorption capacity of NZVI@ZD for Cr(VI) was surprisingly as high as 226.5 mg g⁻¹, surpassing the pristine ZIF-67 (29.35 mg g⁻¹) and NZVI@ZIF-67 (36.53 mg g⁻¹). Zeta potential and X-ray photoelectron spectroscopy (XPS) spectra revealed that electrostatic attraction, reduction and precipitation might be involved in the Cr(VI) removal process by NZVI@ZD, resulting in the conversion of the adsorbed Cr(VI) to Cr(III) of lower toxicity and an eventual immobilization on the NZVI@ZD. The magnetic core-shell structured NZVI@ZD possessed superior adsorptive reactivity for Cr(VI) to most other traditional or newly reported materials, thus should be deemed highly efficient for Cr(VI)-contaminated wastewater treatment.

Metal pollution in estuaries represents a serious environmental challenge, especially in areas affected by industrial and mining activities. This study investigates the metal partitioning and availability of rare earth elements (REE), Y and other trace metals (Ag, Tl, U and Cs) in the Ria of Huelva estuary (SW Spain), strongly affected by mining and industrial activities. A 30 h monitoring campaign was performed collecting periodic water samples and deploying diffusive gradient in thin films (DGTs) devices to determine the main factors controlling metal availability. The dissolved concentrations of U (3118–3952 ng/L) and Cs (284–392 ng/L) were in the same order of magnitude than those reported in other estuaries and coastal waters worldwide, however, REE (26–380 ng/L), Y (15–109 ng/L), Ag (14–307 ng/L) and Tl (29–631 ng/L) concentrations exceeded these values for the same salinities. Unlike most metals (i.e. Ag, Tl, U, Cs), which were mainly found in the dissolved form (87–100% of total), REE and Y were found in the particulate phase (22–36% of total). Metal lability was mainly related to the concentration in the water column following this order: U>REE>Y>Ag>Tl. A similar binding mechanism was observed for Tl and Cd, due to its chemical affinity. This relationship between chemical properties and absorption by DGT-resin was also observed for REE (and Y), Rb and Sr, which may cause bioaccumulation upon persistent exposure, considering the ability of these metals to cross the biological membranes. The lability of metals predicted by geochemical codes did not coincide with absorption of labile metals by DGTs due probably to the instability of complexes in contact with the DGT membranes, the inability of metals to form thermodynamically stable complexes or the absorption of colloids. From this work it can be concluded that DGT passive sampling should complement traditional sampling to monitor metal availability in aquatic environments.

On-road remote sensing technology measures the concentration ratios of pollutants over CO₂ in the exhaust plume in half a second when a vehicle passes by a measurement site, providing a rapid, non-intrusive and economic tool for vehicle emissions monitoring and control. A key assumption in such measurement is that the emission ratios are constant for a given plume. However, there is a lack of study on this assumption, whose validity could be affected by a number of factors, especially the engine operating conditions and turbulence. To guide the development of the next-generation remote sensing system, this study is conducted to investigate the effects of various factors on the emissions dispersion process in the vehicle near-wake region and their effects on remote sensing measurement. The emissions dispersion process is modelled using Large Eddy Simulation (LES). The studied factors include the height of the remote sensing beam, vehicle speed, acceleration and side wind. The results show that the measurable CO₂ and NO exhaust plumes are relatively short at 30 km/h cruising speed, indicating that a large percentage of remote sensing readings within the measurement duration (0.5 s) are below the sensor detection limit which would distort the derived emission ratio. In addition, the valid measurement region of NO/CO₂ emission ratio is even shorter than the measurable plume and is at the tailpipe height. The effect of vehicle speed (30–90 km/h) on the measurable plume length is insignificant. Under deceleration condition, the length of the valid NO/CO₂ measurement region is shorter than under cruising and acceleration conditions. Side winds from the far-tailpipe direction have a significant effect on remote sensing measurements. The implications of these findings are discussed and possible solutions to improve the accuracy of remote sensing measurement are proposed.

Indo-Pacific humpback (Sousa chinensis) dolphins are primarily exposed to chlorinated organic contaminants through the consumption of contaminated fish. We assessed the potential risk of chlorinated organic contaminants to Indo-Pacific humpback dolphins by determining the concentration of 21 organochlorine pesticides (OCPs) and 28 polychlorinated biphenyls (PCBs) in 14 fish species collected from the South China Sea coastal waters. The results of the study showed that bioaccumulation of OCPs and PCBs was influenced by sampling location, fish species, and fish niche. The average ∑DDT (Dichlorodiphenyltrichloroethane) concentration was 3 times higher in benthopelagic fish (488 ng/g) compared to pelagic-neritic fish (155 ng/g) from Jiangmen, whereas an opposite pattern of the lower DDTs concentration in benthopelagic and demersal fish compared to pelagic fish from Zhuhai (p < 0.05). Furthermore, the molecular diagnostic ratios using DDT and its metabolites (DDT/(DDD + DDE) were less than one, suggesting the DDT contamination at Zhuhai and Jiangmen may due to the historical agricultural usage of the lands. The reference dose-based (RfD) risk quotient (RQ) suggested that DDTs are potential risk in Qinzhou, which is in accordance with the high DDTs concentration found in fishes captured in Qinzhou. The RfD risk quotient of PCBs is at potential risk for all sites (RQ > 100), except Xiamen and Qinzhou. A highest average ∑DDT concentration was observed Qinzhou. This study showed that fish consumption might pose a health risk to Indo-Pacific humpback dolphins. However, further studies are required to determine the contribution of fish niche to the overall risk.

In recent years, there has been a sharp increase in interest in the development of environmentally friendly technology for burning methane gas hydrate. In addition to solving energy problems, gas hydrates will help to make significant progress in solving environmental problems. The use of gas hydrate combustion technology is shown to reduce harmful emissions. In this work, experimental studies on the combustion of double hydrate powder of propane-methane have been performed at five different ways of combustion organization. Powder heating was realized using: 1) induction heating; 2) radiation and convective heating; 3) using a hot metal body; 4) combustion without forced gas flow and 5) combustion in the presence of forced and free air convection. Currently there has been neither a comprehensive study of the combustion of double gas hydrates, nor a comparison of the combustion efficiency for different methods; besides, no data on emissions have been obtained. The maximum dissociation rate is implemented with the use of induction heating. Using a gas analyzer the concentration of gases during the gas hydrate combustion has been measured. Comparison of different ways of combustion allows optimizing the combustion efficiency of gas hydrates.

Melatonin is a hormone which is generated from pineal gland, and it is responsible for the regulation of wake-sleep cycle. Melatonin is a well-known antioxidant and free radical scavenger to protect against multiple type of tissue damage. While ochratoxin A (OTA) is a mycotoxin found widely in contaminated food and foodstuffs, which causes nephrotoxicity, hepatotoxicity, immunotoxicity, and reproductive damage in humans and animals. In present study we report the toxicity of OTA on porcine oocyte quality and the protective effects of melatonin on OTA-exposed oocytes. Using transcriptome analysis our results show that OTA exposure alters the expression of multiple genes in oocytes, indicating its effect on oocyte maturation. The cellular changes following OTA treatment are examined, and the results show that OTA adversely affects oocyte polar body extrusion, which is confirmed by the delay of Cdc2-mediated cell cycle progression. OTA exposure also disrupts meiotic spindle formation, which is confirmed by altered phosphorylated MAPK expression. RNA-seq screening and further fluorescence staining results show that OTA induces aberrant mitochondria distribution and oxidative phosphorylation defects, which then causes oxidative stress, followed by early apoptosis and autophagy. Treatment with melatonin significantly ameliorates oxidative stress and apoptosis, which further protects cell cycle and spindle formation in OTA-exposed oocytes. Collectively, these results show the protective effects of melatonin against defects induced by OTA during porcine meiotic oocyte maturation.

Destructive development of suburban areas in some metropolises has exposed suburban soils to high risk of potentially toxic trace elements (PTEs) enrichment, which also threatens human and ecosystem health. This study investigated the pollution status, sources and spatial patterns of four PTEs (Pb, Cd, Cr and As) in 1805 soil samples collected from the suburbs of Shanghai in 2015. Nineteen potential sources, including: 6 soil property factors, 10 proximity factors and 3 topography factors, were selected to help explain the PTEs aggregation using logistic regression models from global and local perspectives. The statistical results of PTEs concentration revealed that Cd showed the highest pollution risk in local soils, which was followed by As. Soil property was the primary factor affecting the PTEs (except Cr) enrichment, both identified by global models and local models. The local model particularly emphasized the significant correlation between soil property and PTEs in most parts of the outer suburbs and southeastern inner suburbs. Some proximity factors such as distance to district center and water were negatively correlated with Cd pollution and some topography factors such as elevation and slope were closely related to As pollution. It is worth noting that in the coastal areas, especially Chongming Island, there were obvious PTEs depositions in the soil near the estuary. This study helps to identify the sources of anthropogenic contamination and geogenic enrichment of the four PTEs and their spatial patterns, playing an essential role in formulating regional environmental policies for coastal cities.

Effective and economically viable method to remove elevated metal(loid)s from farm and industrial lands remains a major challenge. In this study, magnetic biochar-based adsorbents with Fe₃O₄ particles embedded in a porous biochar matrix was synthesized via iron (Fe) treated biochar or thermal pyrolysis of Fe treated cedar sawdust. Application and separation of the adsorbent to a multi-contaminated soil slurry simultaneously removed 20–30% of arsenic, cadmium and lead within 24 h. Fast removal of multi-metal(loid)s result from the decrease in all operationally defined fractions of metal(loid)s, not limited to the exchangeable fraction. The direct removal of arsenic-enriched soil particles was observed via micro X-ray fluorescence maps. Furthermore, through comparison of biochars with different production methods, it has been found that magnetization after pyrolysis treatment leads to stronger metals/metalloids adsorption with a higher qₑ (bound sorbate) than other treatments but pyrolysis after magnetization stabilized Fe oxides on the biochar surface, indicating a higher biochar recovery rate (∼65%), and thus a higher metal(loid)s removal efficiency. The stability of Fe oxides on the surface of biochar is the determining factor for the removal efficiency of metal(loid)s from soil.

Exposure to chemicals produced by petrochemical industrial complexes (PICs), such as benzene, ionizing radiation, and particulate matters, may contribute to the development of leukemia. However, epidemiological studies showed controversial results. This systematic review and meta-analysis aimed to summarize the association between residential exposure to PICs and the risk of leukemia incidence, focusing on exposure-response effects. We searched PubMed, Embase, Web of Science, and Cochrane Library databases for studies published before September 1st, 2019. Observational studies investigating residential exposure to PICs and the risk of leukemia were included. The outcome of interest was the incidence of leukemia comparing to reference groups. Relative risk (RR) was used as the summary effect measure, synthesized by characteristics of populations, distance to PICs, and calendar time in meta-regression. We identified 7 observational studies, including 2322 leukemia cases and substantial reference groups, in this meta-analysis. Residential exposure to PICs within a maximal 8-km distance had a 36% increased risk of leukemia (pooled RR = 1.36, 95% CI = 1.14–1.62) compared to controls, regardless of sex and age. In terms of leukemia subtypes, residential exposure to PICs was associated with the risks of acute myeloid leukemia (AML, pooled RR = 1.61, 95% CI = 1.12–2.31) and chronic lymphocytic leukemia (CLL, pooled RR = 1.85, 95% CI = 1.11–6.42). In meta-regression, the positive association occurred after 10 years of follow-up with a pooled RRs of 1.21 (95% CI = 1.02–1.44) and then slightly increased to 1.77 (95% CI = 1.35–2.33) at 30 years after follow-up. No effect modification was found by sex, age, and geographic locations.

Benzene kresoxim-methyl (BKM) is an important methoxyacrylate-based strobilurin fungicide widely used against various phytopathogenic fungi in crops. Uptake, translocation and accumulation of BKM in vegetables remain unknown. This study was designed to investigate uptake, translocation, and accumulation of ¹⁴C-BKM and/or its potential metabolites in Chinese flowering cabbage and water spinach. ¹⁴C-BKM can be gradually taken up to reach a maximum of 44.4% of the applied amount by Chinese flowering cabbage and 34.6% by water spinach at 32 d after application. The ¹⁴CO₂ fractions released from the hydroponic plant system reached 37.8% for cabbage and 45.8% for water spinach, respectively. Concentrations of ¹⁴C in leaves, stems and roots all gradually increased as vegetables growing, with relative 44.9% (cabbage) and 26.8% (water spinach) of translocated from roots to edible leaves. In addition, ¹⁴C in leaves was mainly accumulated in the bottom leaves, which was visualized by quantitative radioautographic imaging. The bioconcentration factor of ¹⁴C ranged from 7.1 to 38.2 mL g⁻¹ for the cabbage and from 8.6 to 24.6 mL g⁻¹ for the water spinach. The translocation factor of BKM ranged from 0.10 to 2.04 for the cabbage and 0.10–0.46 for the water spinach throughout the whole cultivation period, indicating that the cabbage is easier to translocate BKM from roots to leaves and stems than water spinach. In addition, the daily human exposure values of BKM in both vegetables were much lower than the limited dose of 0.15 mg day⁻¹. The results help assess potential accumulation of BMK in vegetables and potential risk.