Modern farming practice features extensive overuse of additives in animal feed. Subsequent use of manure as a fertilizer has resulted in significant heavy metal accumulation in agricultural soil, which is particularly apparent in areas of intensive farming. Here, samples of dairy feed, manure, water, and soil were collected from four intensive dairy farms in China and analyzed to assess selected heavy metal concentrations (Cu, Zn, Cr, Ni, Pb, and Cd). Results revealed that all feed samples contained the selected heavy metals, attesting to the wide use of additives during intensive dairy farming. The average Cr and Pb concentrations were 6.1 to 17.1 times greater than their recommended guidelines. Overall, average heavy metal concentrations in manure decreased in the following order: Zn > Cu > Cr > Ni > Pb > Cd. Using data obtained from the sequential extraction procedure, proposed by the Community Bureau of Reference (BCR), metal bioavailability also decreased according to the following order: Pb (69.4%) > Cr (63.7%) > Ni (60.8%) > Cu (53.4%) > Zn (50.0%) > Cd (34.5%). Heavy metal levels in sampled wastewater were also relatively high; however, surface and well water levels were relatively low. Although use of manure in dairy farming has not resulted in serious pollution until now, Zn, Cu, and Cd are all known to pose significant risk to soil quality. Finally, principal component analysis (PCA) results indicated that heavy metal levels in soil originated predominantly from parent soil materials and were then enhanced by anthropogenic sources.

In this work, diethyl ether (DEE) and compressed natural gas (CNG) port fuel injection (PFI) was investigated in direct injection (DI) compression ignition engine to determine the performance, combustion, and emission behaviors. In dual fuel mode, DEE and neat diesel were used as fuel energy, whereas in homogeneous charge compression ignition (HCCI) mode, DEE, and CNG were used as fuel energy. The engine behavior was analyzed for different inlet charge temperatures. Exergy analysis has been carried out for analyzing the various availability shares in the engine. The maximum brake thermal efficiency of the engine increased at peak load from 27.31% in neat diesel to 29.12% for dual fuel mode (D + CNG). Hydrocarbon and carbon monoxide emissions were reduced and oxides of nitrogen increased with the inlet charge heating mode. Maximum exergy efficiency was observed as 57.1% in dual fuel operation. The result of this work proves that CNG in dual and HCCI are effective for engine operation.

On the basis of previous studies on the relations among foreign direct investment (FDI), environmental regulation, and environmental pollution, this work uses provincial panel data from 2000 to 2014 to study the effects of FDI and environmental regulation on environmental pollution by applying the panel-corrected standard error (PCSE) method. This paper then utilizes environmental regulation as the threshold variable to estimate the threshold effects of environmental regulation on FDI’s influence on environmental pollution in a threshold regression model for the eastern, central, and western regions of China. The results show that stricter environmental regulation can substantially reduce the pollution in each region. FDI can decrease environmental pollution in the eastern and central regions, but it can increase pollution in the western region. There are double-threshold effects of environmental regulation on the effects of FDI on environmental pollution in each region. When the environmental regulation level is between the first threshold and the second threshold, FDI can decrease environmental pollution much more in the eastern and central regions and increase environmental pollution much less in the western region.

Facilitating the separation of photogenerated electron/hole pairs and widening the light-responsive region are crucial to enhance the overall photocatalytic performance of photocatalysts. To achieve this aim, here we have prepared Ag₂S/Bi₄Ti₃O₁₂ heterojunction composite photocatalysts by assembling Ag₂S quantum dots onto the surface of Bi₄Ti₃O₁₂ nanosheets. Transmission electron microscopy observation demonstrates that two types of Ag₂S quantum dots separately with size of 40–70 and 7–17 nm are uniformly assembled onto the surface of large-sized Bi₄Ti₃O₁₂ thin nanosheets. The as-prepared Ag₂S/Bi₄Ti₃O₁₂ heterojunction composites exhibit much enhanced light absorption (particularly in the visible and near-infrared region) and highly efficient separation of electrons and holes photogenerated in Bi₄Ti₃O₁₂. Rhodamine B (RhB) aqueous solution was chosen as the target organic pollutant to evaluate the photocatalytic performance of the samples under simulated sunlight irradiation. It is found that the Ag₂S/Bi₄Ti₃O₁₂ heterojunction composites manifest significantly enhanced photocatalytic activity toward the RhB degradaton. In particular, the 15wt% Ag₂S/Bi₄Ti₃O₁₂ composite exhibits the highest photocatalytic activity, which is ca. 2.8 and 4.0 times higher than bare Bi₄Ti₃O₁₂ and Ag₂S, respectively. The enhanced photocatalytic activity of the composites can be explained as a result of the Z-scheme electron transfer from the conduction band of Bi₄Ti₃O₁₂ to the valence band of Ag₂S, and thus more photogenerated holes in the valence band of Bi₄Ti₃O₁₂ and electrons in the conduction band of Ag₂S are able to participate in the photocatalytic reactions. Active species trapping experiments were carried out, from which it is concluded that photogenerated holes and •O₂⁻ radicals play the dominant and secondary role in the photocatalysis, respectively.

The surface group characteristics of mango cultivar peels and seeds were evaluated by infrared spectra, PZC, and functional group composition. The adsorption/reduction of chromium (VI) in aqueous solutions was investigated by varying pH, contact time, initial Cr(VI) concentration, and adsorbent amount. The results show that both peel and seed powders of the mango cultivars showed significant adsorption/reduction capacity for Cr(VI) and that the desorption process obeys pseudo-second-order kinetics. Optimal adsorption occurred at pH 1.0, using a Cr(VI) concentration of 100 mg/L. On average, at pH 1.0, and a concentration of 3 g/L, the maximum adsorption/reduction capacity of Cr(VI) was 83% (peels 76%, seeds 90%). Of the mango powders tested, the most efficient were Tommy seed (100%) and Coite peel (98%) followed by Coite seed (96%) and Tommy peel powders (95%). The adsorption/reduction of Cr(VI) was complete (100%) by the mango seed, in comparison to the peel powders (97%) after 180 min. The data indicates that mango waste products, such as seed and peel powders, are both excellent candidates for the remediation of Cr(VI) from aqueous systems and due to the higher concentration of gallates and galloyl glucosides, the mango seed powders should be the powders of choice for future remediation projects.

Fungal spores are an important cause of allergic respiratory diseases worldwide. However, little is known about the intradiurnal pattern of spore concentrations of different fungal spore types in the air of the urban area. In this study, we evaluated bihourly variation in spore concentration of eight predominant fungal spore types in the atmosphere of Bratislava city (Agrocybe, Alternaria, Cladosporium, Coprinus, Exosporium, Epicoccum, Ganoderma, Leptosphaeria) with the aim to understand the relationships between the spore concentrations against associated environmental variables. Spore samples were collected using a Hirst-type volumetric aerospore trap from January to December 2016. Alternaria, Cladosporium, Epicoccum and Exosporium peaked during the daytime period between 10:00 and 16:00, while for Agrocybe, Ganoderma, Coprinus and Leptosphaeria, the nighttime peaks (20:00 and 04:00) were observed. Effect of a complex of environmental variables on bihourly concentrations of selected airborne fungal spore taxa was evaluated through multiple regression analysis. Air temperature, wind speed, sunshine duration and precipitation were positively associated with daytime spore types, while the association with nighttime spores was negative. In contrast, relative air humidity influenced negatively Exosporium daytime spore type but positively the Leptosphaeria nighttime spore type. Moreover, a circadian cycle of light and darkness was considered as an important predictor of nighttime spore levels. Among the atmospheric pollutants, PM₁₀ was positively associated with all analysed daytime spores, while except for Leptosphaeria, O₃ was negatively associated with nighttime spore types. NO₂ and PM₁₀ had mixed effects on nighttime spore levels. In general, air temperature, PM₁₀ and wind speed were environmental parameters with great influence on airborne fungal spore concentration, being present in eight, seven and four regression models, respectively. Constructed regression models which the best explained variation in fungal spore concentrations were those for Ganoderma (R² = 0.38) and Alternaria (R² = 0.31).

The pollution of metal(loid)s from indoor and outdoor dust is of great concern because of its impact on human health. The concentrations of nine metal(loid)s (Mn, Cu, Zn, Cd, Cr, Ni, Pb, Hg, and As) were investigated in indoor and outdoor dust samples of university dormitories in winter and summer seasons in Lanzhou City, China. This study revealed the variations of metal(loid) concentrations in dust samples with the seasonal scale and floor heights. The results showed that the concentrations of some metal(loid)s (Cu, Cd, Ni, Pb, and As) in dust samples collected in winter were higher than those of the dust samples collected in summer. The Hg in indoor dust was mainly derived from building materials and indoor human activities. Additionally, the concentrations of some metal(loid)s (Hg, Mn, As, Cu, Cd) in dust samples varied with the height of the floors from ground level. The concentrations of Hg in dust samples collected on upper floors (9–16th floors) were higher than those collected on down floors (1–8th floors), while Mn and As were the opposite of that. Cu and Cd concentrations increased as the floor height increased. Our results demonstrated that the adults and the children (particularly the children) endured potential health risks due to exposure to metal(loid)s from both indoor and outdoor dust in the studied area.

An important aspect of the regulatory process is the performance comparison of regulated firms. This exists in regulated industries where tariffs are determined through a benchmarking process such as the English and Welsh water industry. A double-bootstrap data envelopment analysis (DEA) approach was applied to overcome the uncertainty in efficiency scores and to reveal the influence of environmental variables on 18 water companies in England and Wales during the 2001–2016 period. The results showed that bias and bias-corrected efficiency scores lead to changes in the water companies’ rankings. This reveals the importance of using reliable methodologies to support the decision-making process. Higher levels of average pumping head, leakage, and abstraction of water from reservoirs lead to lower efficiency. In contrast, increased population density leads to larger efficiency. We also link the results from the efficiency of water companies with the regulatory cycle. Our findings can be useful to policy makers for them to better understand water utilities’ performance and to aid them in reshaping their current policies and practices to improve efficiency and provide better service to customers.

An important factor affecting acquisition of pollution elements could be the lichen growth form. The Brunauer–Emmett–Teller theory approach has been used to determinate the specific area surface (BET-area) of solids by gas multilayer adsorption. Taking this standard method as a new tool, we measure the specific thallus area in foliose and fruticose lichens to evaluated area/volume relation for bioaccumulation prospects. Some preliminary results of elemental contents such as REEs (La, Sc, Sr) and pollutants (Cd, Co, Pb) were also measured to support the importance to use for the analysis of these thallus attributes.

Spherical-like MgO nanostructures have been synthesized efficiently via spray-drying combined with calcination using magnesium acetate as magnesium source. The products were characterized by means of X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and the specific surface areas were calculated using the Brunauer–Emmett–Teller (BET) method. The obtained spherical-like MgO nanostructures exhibit uniform pore sizes (7.7 nm) and high specific surface areas (180 m² g⁻¹). The adsorption kinetics and isotherm data agree well with pseudo-second-order model and Langmuir model, indicating the monolayer chemisorption of heavy metal ions. The spherical-like MgO nanostructures exhibited high adsorption performance for Pb(II) and Cd(II) ions, and the maximum adsorption capacities were up to 5214 mg g⁻¹ and 4187 mg g⁻¹, respectively. These values are much higher than those reported MgO-based adsorbents. Moreover, in less than 10 min, Pb(II) and Cd(II) ions in solution can be almost removed, which means that the spherical-like MgO possesses a high adsorption rate. XRD and FTIR analysis revealed the adsorption mechanism of Pb(II) and Cd(II) ions on MgO, which was mainly due to hydroxyl functional groups and ion exchange between Mg and heavy metal ions on the surface of MgO. These favorable performances recommend that the synthesized spherical-like MgO nanostructures would be a potential adsorbent for rapid removal of heavy metal ions from wastewater.