Canadian goldenrod (Solidago canadensis L.) is a plant that grows in a variety of environmental conditions. It shows high capability to spread in various habitats, including fallow lands and brownfield land. The research aimed at analyzing the content of Pb and Zn in the underground (roots, rhizomes) and aboveground parts (stems, leaves, inflorences) of Solidago canadensis (SC) originating from two locations that are clearly different in terms of metal content in soil. Statistically significant differences were determined in the content of Pb and Zn in soil and particular morphological parts of the plant, depending on the sampling location. It has been shown that in the conditions of increased (compared with natural) Pb and Zn content in the soil, SC may serve as a bioaccumulator of these metals. It was determined that SC can be used as a phytostabilizer of Pb and Zn in soils heavily contaminated with these elements. The content of Zn in the aboveground parts of SC indicates that this plant can also be used for phytoextraction of soils contaminated with this metal.

Performance of raw and two Fe-loaded biochars, produced either by evaporation (E-product, 26.9% Fe) or precipitation (P-product, 12.6% Fe), was evaluated in batch and column testing for As(V) and Sb(III) removal from contaminated neutral drainage (CND). Batch testing results showed that sorption capacity of the E-product tripled for As(V) and quintupled for Sb(III), whereas for the P-product, it doubled for both contaminants, relative to the raw biochar. Moreover, As(V) removal by the E-product reached 90% in less than 8 h, for initial concentrations up to 50 mg/L. In column testing, the E-product efficiently treated the influent [pH 6; 1 mg/L As(V)] for more than 286 days. The pH of the final effluent was within the legally allowed limits (6–9.5) while less than 0.3 mg/L Fe leached out. Based on these findings, Fe-loaded biochar by evaporation (E-product) seems promising for As(V) treatment in CND.

As an important environmental regulation tool, does the environmental information disclosure have the pollution haven effect and adversely affect Chinese export? Research on such topics can provide implications for Chinese policymakers to formulate realistic environmental policies and employ information disclosure environmental regulation tools to coordinate the economic-environmental development. Using the 2003–2013 Annual Survey of Industrial Firms Database and difference-in-difference identification, we examine the effect of environmental information disclosure policy on firm exports and its impacting mechanisms. The empirical results show that the Chinese environmental information disclosure policy has reduced the scale of industrial firms’ exports in the regulated regions, indicating the existence of the pollution heaven effect in China. And also, we find that this policy mainly inhibits export activities of enterprises in coastal areas. Considering enterprise heterogeneity, the policy plays an inhibitory role in the exports of the non-state-owned firms, large firms, and low-productivity firms. Furthermore, the impact mechanism test shows that corporate financing constraint and production costs are important channels for environmental information disclosure policy affecting corporate export activities. It implies that, in developing countries such as China, policymakers and enterprises need to adopt forward-looking strategies to reduce the negative influence of environmental constraints on corporate exports and coordinate environmental governance and sound development of enterprises.

During coal mining activities, a lot of coal gangue is produced, which usually contains high mercury (Hg) concentrations as well as the acid mine drainage (AMD) generator of pyrite. In the present study, the total mercury (THg) and methylmercury (MeHg) in gangue, water, sediment, paddy soil, and rice samples, collected from abandoned coal mining areas, were analyzed. Results showed that the THg concentrations ranged from 0.37 to 35 mg/kg (11 ± 8.4 mg/kg) and 0.15 to 19 mg/kg (2.0 ± 3.9 mg/kg) in gangue and sediments, respectively. For paddy soils, the THg concentrations and MeHg varied from 0.16 to 0.91 mg/kg and 0.71 to 11 ng/g, respectively. Rice samples exhibited wide concentration ranges of THg (3.0–22 ng/g) and MeHg (0.71–8.9 ng/g). Sequential extraction of Hg revealed that the nitric acid-extractable state Hg (F4) was the dominant Hg species in gangue and sediment, while humic acids state Hg (F3) was the dominant form in paddy soil. Compared with gangue, higher percentages of F3 and the residual state Hg (F5) in both sediment and soil samples implied the transformation of F4 to F3 and F5 during transportation. Soil n-HAs (the difference between the total organic carbon and humic acids) were positively correlated with both THg and MeHg in soil and rice, indicating that n-HAs enhance Hg bioavailability under acidic conditions. Further studies should be conducted to reveal the factors influencing the transformation of different Hg fractions, providing ideas on decreasing the bioavailability of Hg in coal mining areas.

Mercury is among the most toxic heavy metals and a widespread environmental pollutant. Mercury chloride (HgCl₂) is an inorganic compound of mercury which is easily absorbed in the gastrointestinal tract and then enters the blood where it can interact with erythrocytes. In this study, the effect of HgCl₂ on human erythrocytes was studied under in vitro conditions. Erythrocytes were treated with different concentrations of HgCl₂ (1–100 μM) for 1 h at 37 °C. Cell lysates were prepared and assayed for several biochemical parameters. HgCl₂ treatment resulted in oxidation of ferrous iron of hemoglobin to ferric form giving methemoglobin which is inactive as an oxygen transporter. However, the activity of methemoglobin reductase was increased. Hemoglobin oxidation was accompanied by heme degradation and the release of free iron. Protein oxidation was greatly increased with a simultaneous decrease in free amino and sulfhydryl groups and glutathione content. The antioxidant power of HgCl₂-treated erythrocytes was impaired resulting in lowered metal reducing and free radical quenching ability of these cells. This suggests that HgCl₂ induces oxidative stress in human erythrocytes. This was confirmed when superoxide anion, hydrogen peroxide, peroxynitrite, and nitric oxide generation were found to be dose-dependently increased in HgCl₂-treated erythrocytes. Glycolysis and pentose phosphate pathway, the two major pathways of glucose metabolism in erythrocytes, were also inhibited. HgCl₂ treatment also inhibited the plasma membrane redox system while the activities of AMP deaminase and glyoxalase-I were increased. These results show that HgCl₂ induces oxidative and nitrosative stress, oxidizes hemoglobin, impairs the antioxidant defense mechanism, and alters metabolic pathways in human erythrocytes.

In this study, MgAl-LDHs and MgFe-LDHs were synthesized via co-precipitation method and in situ coated on pre-washed zeolites through dipping process in beaker. The obtained modified zeolites and original zeolites were utilized as substrates of constructed rapid infiltration systems (CRIS) to remove hexavalent chromium (Cr(VI)) in wastewater. Micro-morphology features and chemical composition of zeolites before and after modification were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence spectrometer (XRF). The SEM, XRD, and XRF results demonstrated the feasibility of LDHs coated on the surface of the original zeolites. Purification experiments in simulated CRIS showed that the Cr(VI) removal rates of zeolites/MgAl-LDHs increased by 110.03% on average every concentration (0.5–16 mg L⁻¹) compared with the original zeolites under 24-h HRT. The adsorption capacity of zeolites/MgAl-LDHs reached 66.98 mg kg⁻¹ at 32 mg L⁻¹ initial Cr(VI) concentration, which is nearly twice that of the original zeolites (33.24 mg kg⁻¹) and 1.5 times higher than that of zeolites/MgFe-LDHs (42.01 mg kg⁻¹). Isothermal adsorption tests showed that the Freundlich isotherm equations gave better fitting to the adsorption process. And zeolites/MgAl-LDHs showed a best fit with pseudo-second-order model which meant that the adsorption of Cr(VI) by zeolites/MgAl-LDHs was dominated by chemisorption. Thermodynamic parameters showed that the process of adsorption for the three substrates was spontaneous and endothermic intrinsically. Zeolites/MgAl-LDHs also displayed nearly 60% desorption rate with low concentration eluent (0.01 mol L⁻¹ NaCl). Therefore, zeolites/MgAl-LDHs were chosen out as an optimal substrate for removing Cr(VI) from wastewater in CRIS. Graphical Abstract

Fixation reactions reduce the concentration of soluble phosphorus (P) and affect crop growth in alkaline calcareous soils. In lab and greenhouse studies, phosphoric acid (PA) or diammonium phosphate (DAP) were evaluated at various P rates (0, 18, 36 and 54 mg kg⁻¹ soil), either as non-mix (designated as NM-PA and NM-DAP, respectively) or after premixing with farmyard manure (FYM) at 400 mg kg⁻¹ soil (designated as PM-PA and PM-DAP, respectively). The amended soil was incubated at 25 °C and 70% water holding capacity for 7 weeks; thereafter, ³²P dynamics were measured using the Freundlich kinetic model. A greenhouse study was also conducted using the same thirteen treatments (as used in incubation experiment) and wheat cultivar (Galaxy 2013) was grown following standard agronomic practices. The results showed that application of PM-PA at the highest rate, which caused maximum change in Pr (ΔPr = 59%) in laboratory condition, also produced maximum P uptake by grain (190.3 mg pot⁻¹) and grain yield (44.1 g pot⁻¹) of wheat in greenhouse experiment. Similarly, regression analysis showed that an increase in Pr values caused a corresponding increase in crop parameters. The results suggested that pre-mixing P fertilizer with FYM could be a viable technique to increase P supply and enhance productivity of wheat in alkaline calcareous soils.

This work examines the strategies adopted by an arbuscular mycorrhizal symbiotic system to ameliorate environmental Pb stress by examining the concentrations of P, Fe, and Pb in the fungal microstructures and the host’s root. In vitro cultures of Ri-T DNA-transformed carrot (Daucus carota L.) roots were inoculated with Glomus intraradices and treated with Pb(NO₃)₂ solution and the extraradical spores and mycelia (S/M) and the root with the vesicles, mycelia, and root cells were subsequently analyzed by polarized energy dispersive x-ray fluorescence (PEDXRF) spectrometry. Upon Pb treatment, within the root, the percentages of mycorrhizal colonization, the vesicles, and mycelia increased as well as the areas of the vesicles and the (extraradical) spores, although the number of spores and arbuscules decreased. The S/M and the mycorrhizal root showed enhanced concentrations of Pb, Fe, and P. These were particularly marked for Fe in the Pb-treated cultures. This indicates a synergistic relationship between the arbuscular mycorrhizal fungus and the host that confers a higher Pb tolerance to the latter by the induction of higher Fe absorption in the host. The intraradical vesicle, mycelia, and arbuscule numbers are interpreted as a “tactic to divert” the intraradical Pb traffic away from the root cells to the higher affinity cell walls of the arbuscular mycorrhizal fungi (AMF) microstructures in the apoplast. The results of this work show that the symbiosis between the AMF G. intraradices and the host plant D. carota distinctly improves the latter’s Pb tolerance, and imply that the appropriate metal tolerant host-AMF combinations could be employed in process designs for the phytoremediation of Pb.

The Huai River basin (located in eastern China) has a population of 180 million and has the highest risk of esophageal cancer (EC) mortality in China. Some studies found that contaminants in drinking water are a major risk factor for cancers of the digestive system. However, the effect of water pollution in the historical period on the current EC mortality remains unclear. Data were collected on the EC mortality rate in 2004 in the Huai River basin in 11 counties, and data on the surface water quality in the region from 1987 to 2004 were used. The Pearson correlation and the GeoDetector q-statistic were employed to explore the association between water pollution and the EC mortality rate in different lag periods, from linear and nonlinear perspectives, respectively. The study showed apparently spatial heterogeneity of the EC mortality rate in the region. The EC mortality rate downstream is significantly higher than that in other regions; in the midstream, the region north of the mainstream has a lower average mortality rate than that south of the area. Upstream, the region north of the mainstream has a higher mortality rate than that in the southern area. The spatial pattern was formed under the influence of water pollution in the historical period. 1996, 1997, and 1998 have the strongest linear or nonlinear effect on the EC mortality rate in 2004, in which the Pearson correlation coefficient and the q-statistic were the highest, 0.79 and 0.89, respectively. Rapid industrialization in the past 20 years has caused environmental problems and poses related health risks. The study indicated that the current EC mortality rate was mainly caused by water pollution from the previous 8 years. The findings provide knowledge about the lag time for pollution effects on the EC mortality rate, and can contribute to the controlling and preventing esophageal cancer.

The chemical and cytotoxicity properties of fine particulate matter (PM₂.₅) at indoor and outdoor environment were characterized in Xi’an, China. The mass concentrations of PM₂.₅ in urban areas (93.29~96.13 μg m⁻³ for indoor and 124.37~154.52 μg m⁻³ for outdoor) were higher than suburban (68.40 μg m⁻³ for indoor and 96.18 μg m⁻³ for outdoor). The PM₂.₅ concentrations from outdoor environment due to fossil fuel combustion were higher than indoor environment. An indoor environment without central heating demonstrated higher organic carbon-to-elemental carbon (OC / EC) ratios and n-alkanes values that potentially attributed to residential coal combustion activities. The cell viability of human epithelial lung cells showed dose-dependent decrease, while nitric oxide (NO) and oxidative potential showed dose-dependent increase under exposure to PM₂.₅. The variations of bioreactivities could be possibly related to different chemical components from different sources. Moderate (0.4 < R < 0.6) to strong (R > 0.6) correlations were observed between bioreactivities and elemental carbon (EC)/secondary aerosols (NO₃⁻, SO₄²⁻, and NH₄⁺)/heavy metals (Ni, Cu, and Pb). The findings suggest PM₂.₅ is associated with particle induced oxidative potential, which are further responsible for respiratory diseases under chronic exposure.