The aim of this study was to investigate the impact of incorporating Walnut leaves (WL) and their biochars produced at three temperatures (200, 400, and 600 °C) on fractionation, availability and maize indices in a naturally calcareous highly contaminated soil of Central Iran. A pot experiment was conducted considering soils treated with 0, 0.5, 1, and 2% (w/w) of WL and their derived biochars. After maize (Zea mays L.) planting, shoot and root dry matter and Pb and Zn concentration in shoots and roots and DTPA-extractable and fractions of Zn and Pb in soils were determined. Results showed showed that biochar amendments substantially modified the partitioning of Zn and Pb from easily available forms to less available forms. The results showed that DTPA-extractable of Zn and Pb and their bioaccumulation were reduced upon the addition of biochars produced at different temperatures and application rates in a calcareous soil. Treating soil with 2% biochar produced at 600 °C increased significantly shoot and root dry matter by 131.4% and 116.7%, respectively and reduced the bioavailability of Zn and Pb (DTPA-TEA extraction) by 49.1%, and 34.9%, respectively (P < 0.05) in comparison to the control. Therefore, biochars were able to reduce metals contamination in treatments and increase maize dry matter. Biochar decreased Zn and Pb concentration in plant tissues and promoted gradual maize growth responses through changing metals fractions. Therefore, biochar as a sorbent for contaminants can assist in maize to mitigate and phytostabilize Zn and Pb in highly contaminated soils.

Chemical treatment could improve the adsorption performance of biochars (BC). In order to deal with Pb(II) pollution, four types of biochars including unmodified, acid-treated, alkali-treated, and magnetic-treated pig manure-derived biochars (PBCs) were prepared. The effect of chemical treatment on the physical property, chemical composition, and the adsorption behavior of biochars was compared. Magnetic and alkali treatment improved pore volume and specific surface areas, and the adsorption capacity and rates were enhanced. In contrast, the adsorption capacity of acid-treated BC decreased due to the significant decrease of ash content. The magnetic samples displayed the satisfactory absorption performance, which could achieve 99.8% removal efficiency within 15 min at a Pb(II) concentration of 50 mg/L. Considering its properties of excellent adsorption performance, fast reaction rate, and convenient recovery by an external magnetic field, magnetic biochar based on pig manure may provide an effective way to remove heavy metals and decrease the pig manure solid waste.

The aim of this work was to study the adsorption kinetic, isotherm, and thermodynamic of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide in raw and boiling-treated sterile bracts of Araucaria angustifolia as novel alternative natural adsorbents. The sterile bracts were characterized by scanning electron microscopy and Fourier-transform infrared spectroscopy. The adsorption and removal of 2,4-D from aqueous solutions were conducted at different contact times, bract granulometries, solution pH, bract masses, initial 2,4-D concentrations, and temperatures. The adsorption kinetic, mechanism, and thermodynamic were evaluated using pseudo-first- and pseudo-second-order kinetic models, non-linear Langmuir, Freundlich, Redlich-Peterson and Sips isotherm models, and Gibbs free energy, enthalpy, and entropy. The maximum removal efficiency of 2,4-D was found with 720 min of contact, 5.0 g of bract containing 31 micron particle sizes, pH = 2.0, and room temperature. The best kinetic and isotherm fits were found with the non-linear pseudo-second-order kinetic model and non-linear Freundlich isotherm model, respectively. Therefore, the adsorption mechanism in the bract structure takes place with multi-layer formation and multi-site interactions due to chemisorption reactions. The adsorption process is thermodynamically favorable, spontaneous, and exothermic. Overall, sterile bract of Araucaria angustifolia could be useful as alternative natural adsorbent for the treatment of water and wastewater contaminated with 2,4-D, mitigating the environmental pollution caused by agricultural crops. Graphical Abstract

Bisphenol A (BPA) and bisphenol S (BPS) are frequently detected in soils and groundwater, which may pose threats to public health and the environment. However, the fate and transport of BPA/BPS in the subsurface media are still not clear. In this study, the retention and transport of BPA/BPS in three different natural soils were investigated with column experiments and mathematical modeling. The results showed that both BPA and BPS had high mobility in saturated soil A (Xinjiang soil), medium mobility in soil B (Changshu soil) media, and no mobility in the soil C (Jilin soil). There was a negative correlation between the mobility of BPA/BPS and soil organic matter (SOM) content because of the strong sorption of BPA/BPS on SOM. BPS showed higher mobility than BPA in the three soils. In addition, with the reduction of SOM of the soil B and C (after H₂O₂-treatment), the mobility of BPA/BPS enhanced dramatically. All these suggest that SOM played a significant role in controlling the retention and transport of BPA/BPS in the soil. Furthermore, the two-site kinetic model simulated the BPA/BPS transport experiment results very well.

Cadmium (Cd) is a heavy metal that poses a huge potential threat to human and animal health. Therefore, it is necessary to study its damage mechanism. In the present study, we have examined the protective effects of Ganoderma lucidum triterpenoids on oxidative stress and apoptosis in the spleen of chickens induced by Cd. One hundred and twenty healthy Hailan white chickens (7-day-old) were randomly divided into the following four groups: control group, Cd group, triterpenoid group, and Cd–triterpenoid group. The chickens were euthanized on the 20th, 40th, and 60th days, and the spleens were removed. Cd and malondialdehyde (MDA) content, antioxidant enzyme (superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px)) activities, and inflammatory factor (tumor necrosis factor alpha (TNF-α) and interleukin (IL-1β and IL-6)) and apoptotic factor (caspase-3, BAX, and Bcl-2) expressions were detected. The results showed that Ganoderma lucidum triterpenoids could reduce the content of Cd and MDA; increase the antioxidant enzyme activities (SOD and GSH-Px); decrease the expression of inflammatory factors (TNF-α) and interleukin (IL-1β and IL-6); increase the expression of apoptotic factor (Bcl-2); and decrease the expression of apoptotic factors (caspase-3 and Bax). It showed that the triterpenoids of Ganoderma lucidum had significant protective effects on oxidative stress and apoptosis of chicken spleen, which provided a theoretical basis for further prevention and treatment of cadmium poisoning.

A growing number of electrochemical oxidation system was employed for the degradation of refractory contaminants. In this study, a boron-doped diamond (BDD) anode/Ti cathode equipped in the differential column batch reactor (DCBR) was utilized for electrochemical oxidation of ciprofloxacin (CIP). The feed solution within the DCBR system was confirmed as a uniform flow state through a computational fluid dynamics (CFD) simulation analysis. The results showed that the BDD anode/Ti cathode electrochemical system was with a high efficiency oxidation performance when treating the CIP contaminant. The CIP was completely degraded within 20 min, and over 50% DOC removed after 120 min. Therefore, two-stage electrochemical oxidation mechanism was proposed. Four major factors, the initial concentration, current density, pH, and electrolyte concentration, on the CIP degradation efficiency were systematically investigated. The CIP degradation curve followed pseudo first-order degradation kinetics. The electric efficiency per order (EE/O) of the electrochemical oxidation system was calculated to determine an optimal operation condition. Moreover, the oxidation intermediates were identified with a mass spectrometry (LC/MS/MS) and the degradation pathways were proposed in this study. The destruction of quinolone moiety and piperazine ring and fluorine substitution were the three possible degradation pathways during BDD anode oxidation process.

Phytoplankton assemblages were investigated in 2015 along the seasonal changes of the Genhe River in the Greater Hinggan Mountains. The survey was performed in June (spring), August (summer), and October (autumn) at nine sampling stations to study the community composition, abundance, and biodiversity. The results showed that 61 species belonging to 16 genera were identified, including Bacillariophyta of 31 species, Dinophyta 2 species, Cyanophyta 2 species, Chlorophyta 20 species, Chrysophyta 2 species, and Cryptophyta 1 species; Besides, Bacillariophyta are dominant species. Shannon-Wiener (H′) and Pielou (J′) indices indicated that phytoplankton community was stable. And these two indices were significantly lower in summer than in spring and autumn. Phytoplankton abundance and biomass show significant differences in each season. The total phytoplankton abundance (1122.3 × 104 ind/L) and biomass (6.5709 mg/L) in summer are much higher than that in spring and autumn. There were few species and low abundance and biomass in the upper reaches of Genhe River; this fact can be explained by the cold climate in the Greater Higgnan Mountains region. Canonical correspondence analysis (CCA) was used to analyze the data. It revealed that Fe³⁺, Cu²⁺, pH, and water temperature (WT) were responsible for most of the variation in space in the phytoplankton community. These environmental parameters play an essential role in the community structure variation of phytoplankton in the upper reaches of Genhe River, the strong association between phytoplankton community structure and ecological factors is varied in each season.

The degradation of organic contaminants in actual textile wastewater was carried out by iron carbon (Fe-C) micro-electrolysis. Different Fe-C micro-electrolysis systems (SIPA and SISA) were established by using scrap iron particle (SIP) and scrap iron shaving (SIS) as anode materials. The optimal condition of both systems was obtained at the initial pH of 3.0, dosage of 30 g/L and Fe/C mass ratio of 1:1. Commercial spherical Fe-C micro-electrolysis material (SFC) was used for comparison under the same condition. The results indicated that total organic carbon (TOC) and chroma removal efficiencies of SIPA and SISA were superior to that of SFC. Total iron concentration in solution and XRD analysis of electrode materials revealed that the former showed relatively high iron corrosion intensity and the physicochemical properties of scrap iron indeed affected the treatment capability. The UV-vis and 3DEEM analysis suggested that the pollutants degradation was mainly attributed to the combination of reduction and oxidation. Furthermore, the potential degradation pathways of actual textile wastewater were illustrated through the GC-MS analysis. Massive dyes, aliphatic acids, and textile auxiliaries were effectively degraded, and the SIPA and SISA exhibited higher performance on the degradation of benzene ring and dechlorination than that by SFC. In addition, SIPA and SISA exhibited high stability and excellent reusability at low cost. Graphical abstract

Air emissions from animal feeding operations (AFOs) can affect public health, environment, and quality of life. Although regulations or lawsuits may force AFOs to reduce air emissions, treatment options are limited and expensive. Trapping particulate matter (PM) emitted from AFOs is important for reducing emissions since many odorous and environmentally important gases are also transported on PM. Since PM emitted by AFOs have relatively high particle density and diameter, its partial filtration might be feasible and effective in reducing air emission. A porous windbreak wall made of lumber and mosquito screen, coupled with a vegetative strip of switchgrass (Panicum virgatum) covering three fans, was evaluated in a tunnel-ventilated swine finishing barn. The system imposed acceptable pressure on the fan (< 13 Pa) and was readily cleaned by rain. The system reduced total suspended particulate (TSP) emission moderately (average reduction of 28%), while reduction in ammonia emissions was low. Odor 10 m downstream of the fans was reduced greatly by 71%. Soil inside the system and vegetation accumulated appreciable amounts of nitrogen and sulfur; the vegetation also trapped appreciable amounts of PM. Overall, this low-cost, retrofittable, and modular system could be used by swine farmers to reduce their emissions, alone or in combination with other mitigation methods to obtain greater reduction in emissions.

We used the community of benthic macroinvertebrates, alongside physical and chemical characteristics of the water, to verify the influence of an urbanized tributary on a Neotropical river. Specifically, our hypothesis is that urbanized tributaries are potentially able to simplify the biological diversity of the rivers where they flow. The collections were sampled in six sites every 2 weeks from April 2013 to March 2014, using artificial substrates. In conjunction with the benthic macroinvertebrate collections, the temperature, pH, and dissolved oxygen were measured using portable devices, as well as ammonia, total nitrogen, total phosphorus, and biochemical oxygen demand (BOD) in the laboratory. Rainfall values were also obtained. We observed a marked fall in the number of taxa and the values of richness, diversity equitability at the point located below the tributary mouth, with predominance of Chironomidae and Annelida. The high capture rates of a few groups considered tolerant and the high concentrations of total nitrogen, total phosphorus, and BOD confirm the alteration of the quality of the water at the sampling point located below the tributary mouth, leading to a local process of ecological simplification.