Theoretically, agriculture can be the victim and the cause of climate change. Using annual data for the period of 1970–2014, this study examines the interaction between agriculture technology factors and the environment in terms of carbon emissions in Jordan. The results provide evidence for unidirectional causality running from machinery, subsidies, and other transfers, rural access to an improved water source and fertilizers to carbon emissions. The results also reveal the existence of bidirectional causality between the real income and carbon emissions. The variance error decompositions highlight the importance of subsidies and machinery in explaining carbon emissions. They also show that fertilizers, the crop and livestock production, the land under cereal production, the water access, the agricultural value added, and the real income have an increasing effect on carbon emissions over the forecast period. These results are important so that policy-makers can build up strategies and take in considerations the indicators in order to reduce carbon emissions in Jordan.

Contamination by heavy metals has become a serious environmental pollution issue today due to its potential threat to plant, wildlife, and human health. Photosynthesis, a process in which light energy is used to produce sugar and other organic compounds, is sensitive to heavy metals. In the present study, the response of photosynthetic process and carbon assimilation of Schima superba was investigated under cadmium (Cd) stress. Three Cd concentrations (0, 300, and 600 mg kg⁻¹) were used designated as control (CK), low Cd (L₁), and high Cd treatment (L₂) of plants. Results showed that photosystem II (PSII) acceptor and donor side electron transport were more easily blocked in treatment compared to control, and L₂ have more significant changes than L₁. A substantial decrease of 820 nm reflection curve absorption was observed both in L₁ and L₂ treatments. Special energy fluxes showed significant difference between the control group and the treated group, which indicated that low concentration Cd stress can cause decrease in quantum yield of PSII in plants studied. Non-stomatal factors resulted in a decrease in net photosynthetic rate and a decrease in photosystem activity. Our results suggested that Cd can damage structure and function of the photosynthesis of S. superba young plants.

Waste disposal site is one of the important sinks of chemicals. A significant amount of perfluoroalkyl and polyfluoroalkyl substances (PFASs) such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorohexanoic acid (PFHxA) have been brought into it. Because of their aqueous solubility, PFASs are released to landfill effluent waters, from which PFASs are efficiently collected by adsorption technique using granular activated carbon (GAC). The exhausted GAC is reactivated by heating processes. The mineralization of PFASs during the reactivation process was studied. Being thermally treated in N₂ atmosphere, the recovery rate of mineralized fluorine and PFC homologues including short-chained perfluorocarboxylic acids was determined. If the reagent form of PFOA, PFHxA, and PFOS were treated at 700 °C, the recovery of mineralized fluorine was less than 30, 46, and 72 %, respectively. The rate increased to 51, 74, and 70 %, if PFASs were adsorbed onto GAC in advance; moreover, addition of excess sodium hydroxide (NaOH) improved the recovery to 74, 91, and 90 %. Residual PFAS homologue was less than 1 % of the original amount. Steamed condition did not affect destruction. The significant role of GAC was to suppress volatile release of PFASs from thermal ambient, whereas NaOH enhanced destruction and retained mineralized fluorine on the GAC surface. Comparing the recovery of mineralized fluorine, the degradability of PFOS was considered to be higher than PFOA and PFHxA. Whole mass balance missing 9~26 % of initial amount suggested formation of some volatile organofluoro compounds beyond analytical coverage.

This work presents and discusses experimental results on the characterisation and metal leaching potential of a biogenic, metal-rich sulphidic sludge, generated in a sulphate-reducing bioreactor, operated to treat acidic synthetic solutions bearing Fe, Zn, Ni and Cu. The sustainability of the metal removal bioprocess strongly depends on the fate of the sludge. To propose appropriate management practices, a detailed characterisation of the sludge is necessary. The granulometry, chemical composition and mineralogy of the sludge were initially determined. The mobility of the metals was assessed via a modified Tessier experimental procedure. The leachability of the sludge metal content was determined via a standard compliance method (EN 12457-2) and experiments designed to evaluate the effect of pH and time on metal leaching from the sludge. The sludge metal content sums up to 69.5% dw, namely iron (14.8%), zinc (18.7%), nickel (17.7%) and copper (18.2%) and, based on the criteria set by European Union, the sludge is characterised as hazardous and inappropriate for landfilling without any pretreatment. The sludge consists mainly of very fine poorly crystalline aggregates of Fe, Zn, Cu and Ni sulphides. The fine grain size, the poorly crystalline structure and the oxidation of sulphide upon exposure to water/air render the high metal content of the sludge recoverable.

A laboratory-scale biodegradation and electron transfer based on the sulfur metabolism in the integrated (BESI®) process was used to treat a saline petrochemical nanofiltration concentrate (NFC). The integrated process consisted of activated sludge sulfate reduction (SR), and sulfide oxidation (SO) reactors, and a biofilm nitrification reactor. During the process, the total removal efficiencies of chemical oxygen demand (COD), ammonia nitrogen, and total nitrogen (TN) were 76.2, 83.8, and 73.1%, respectively. In the SR reactor, most of the organic degradation occurred and approximately 70% COD were removed by the sulfate-reducing bacteria (SRB). In the SO reactor, both the autotrophic and heterotrophic denitrifications were observed to take place. In parallel, batch experiments were conducted to detect the effects of different C/S and S/N ratios on COD removal and denitrification efficiency. The batch experiments were also conducted to detect the effects of salinity on COD and sulfate reduction. The composition of pollutants in the wastewater was complex, and some existing organics were not degraded by the SRB. The non-SRB groups also played important roles in the reactor. Under salinity-induced stress, the metabolisms of the SRBs and non-SRB groups were both inhibited. However, 6 g/L NaCl did not have much effect on the final COD removal efficiency. In the batch experiments, the added sulfide served as the electron donor for autotrophic denitrification. The added organics provided substance for heterotrophic denitrification.

Impacts of secondary generated minerals on mineralogical and physical immobilization of toxic elements were investigated for chelate-treated air pollution control (APC) fly ash of a municipal solid waste incinerator. Scanning electron microscope (SEM) observation showed that ettringite was generated after the moistening treatment with/without chelate. Although ettringite can incorporate toxic elements into its structure, elemental analysis by energy dispersive X-ray could not find concentrated points of toxic elements in ettringite structure. This implies that mineralogical immobilization of toxic element by the encapsulation to ettringite structure seems to be limited. Physical immobilization was also investigated by SEM observation of the same APC fly ash particles before and after the moistening treatment. The transfer of soluble elements was inhibited only when insoluble minerals such as gypsum were generated and covered the surface of fly ash particles. Neoformed insoluble minerals prevented soluble elements from leaching and transfer. However, such physical immobilization seems to be limited because insoluble mineral formation with surface coverage was monitored only one time of more than 20 observations. Although uncertainty owing to limited samples with limited observations should be considered, this study concludes that mineralogical and physical immobilization of toxic elements by secondary minerals is limited although secondary minerals are always generated on the surface of APC fly ash particles during chelate treatment.

Electro-Fenton (EF), an advanced oxidation process, can be combined with a biological process for efficient treatment of wastewater containing refractory pollutants such as pharmaceuticals. In this study, a biological process was implemented in a sequencing batch reactor (SBR), which was either preceded or followed by EF treatment. The main goal was to evaluate the potential of two sequences of a combined electrochemical-biological process: EF/SBR and SBR/EF for the treatment of real wastewater spiked with 0.1 mM of caffeine and 5-fluorouracil. The biological removal of COD and pharmaceuticals was improved by extending the acclimation time and increasing concentration of biomass in the SBR. Hardly biodegradable caffeine and COD were completely removed during the EF post-treatment (SBR/EF). During the EF/SBR sequence, complete removal of pharmaceuticals was achieved by EF within 30 min at applied current 800 mA. With a current of 500 and 800 mA, the initially very low BOD₅/COD ratio increased up to 0.38 and 0.58, respectively, after 30 min. The efficiency of the biological post-treatment was influenced by the biodegradability enhancement after EF pre-treatment. The choice of an adequate sequence of such a combined process is significantly related to the wastewater characteristics as well as the treatment objectives.

This is the first attempt to explore linkages among industrialization, urbanization, energy consumption, CO2 emissions, and economic growth based on estimations in simultaneous equations framework. An economic growth model is extended to incorporate industrialization as shift factor and pollutant emissions as determinant of total factor productivity. A country panel of 30 Chinese provinces/cities and three regional panels, for periods 2000–2016, are estimated employing Augmented Mean Group (AMG) estimator as well as Common Correlated Effects Mean Group (CCEMG) estimator that are robust to both cross-sectional dependence and cointegration. The empirical findings are as follows: (i) the impact of urbanization on economic growth varied from negative to neutral to positive for western-, intermediate-, and eastern-economic zone, respectively, and is known as “urbanization ladder effect,” (ii) moving from western to eastern economic zone, as regions develop, industry expansion has more powerful impact on economic growth, and thus, we define it as “industry expansion effect,” (iii) industrialization promotes rapid urbanization in less developed and less employment saturated regions; hence, we name it as “employment saturation effect,” (iv) economic growth in more developed regions pulled the CO2 emissions downward, while pushed it upward in case of less developed regions; therefore, we call it “growth pull/push effect,” and (v) in bidirectional causality between energy consumption and economic growth, the “feedback effect” of economic growth remained dominant for all four panels. Based on empirical findings, policies are suggested for Chinese economy. Further, these policies have potential to extract implications for the rest of the world.

The original publication of this paper contains a mistake. Data on Table 1 under TR and TL column have been interchanged: that is compounds 1-12 and their amounts refer to TL; compounds 1-8 and related amounts refer to TR (see Fig. 1).

Fine particle matters (PM₂.₅) is a well-known risk factor for cardiovascular diseases. However, the underlying molecular mechanisms are largely unknown. Vascular hyper-reactivity plays an important roles in the pathogenesis of cardiovascular diseases. The present study was designed to investigate a hypothesis that PM₂.₅ up-regulated endothelin receptors in mesenteric artery and the potential underlying mechanisms. Rat mesenteric arteries were cultured with PM₂.₅. The artery contractile responses were recorded by a sensitive myograph. ETB and ETA receptor expressions of mRNA and protein were assessed by quantitative real-time PCR, Western blotting, and immunohistochemistry, respectively. Results showed that ETB receptor agonist, sarafotoxin 6c induced a negligible contraction in fresh artery segments, while ETA receptor agonist, ET-1 induced an obvious contraction. After organ culture, the contraction curve mediated by ETB and ETA receptors were shifted toward the left. PM₂.₅ 1.0 μg/ml cultured for 16 h further enhanced ETB and ETA receptor-mediated contractile responses with a markedly increased maximal contraction. The organ culture enhanced ETB and ETA receptor mRNA and protein levels from fresh arteries, which were further increased by PM₂.₅. The U0126 (MEK/ERK1/2 inhibitor) and SB203580 (p38 inhibitor) significantly attenuated both organ cultured-induced and PM₂.₅-induced up-regulation of ETB receptor. U0126 also suppressed organ culture-increased and PM₂.₅-increased expressions of ETA receptor. SB203580 only suppressed PM₂.₅-induced enhanced expressions of ETA receptor In conclusion, airborne PM₂.₅ up-regulates ETB and ETA receptors of mesenteric artery via p38 MAPK and MEK/ERK1/2 MAPK pathways.